DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (31ec81b5d7bb)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298 4299 4300
//
//  file:  regexcmp.cpp
//
//  Copyright (C) 2002-2012 International Business Machines Corporation and others.
//  All Rights Reserved.
//
//  This file contains the ICU regular expression compiler, which is responsible
//  for processing a regular expression pattern into the compiled form that
//  is used by the match finding engine.
//

#include "unicode/utypes.h"

#if !UCONFIG_NO_REGULAR_EXPRESSIONS

#include "unicode/ustring.h"
#include "unicode/unistr.h"
#include "unicode/uniset.h"
#include "unicode/uchar.h"
#include "unicode/uchriter.h"
#include "unicode/parsepos.h"
#include "unicode/parseerr.h"
#include "unicode/regex.h"
#include "unicode/utf.h"
#include "unicode/utf16.h"
#include "patternprops.h"
#include "putilimp.h"
#include "cmemory.h"
#include "cstring.h"
#include "uvectr32.h"
#include "uvectr64.h"
#include "uassert.h"
#include "ucln_in.h"
#include "uinvchar.h"

#include "regeximp.h"
#include "regexcst.h"   // Contains state table for the regex pattern parser.
                        //   generated by a Perl script.
#include "regexcmp.h"
#include "regexst.h"
#include "regextxt.h"



U_NAMESPACE_BEGIN


//------------------------------------------------------------------------------
//
//  Constructor.
//
//------------------------------------------------------------------------------
RegexCompile::RegexCompile(RegexPattern *rxp, UErrorCode &status) :
   fParenStack(status), fSetStack(status), fSetOpStack(status)
{
    // Lazy init of all shared global sets (needed for init()'s empty text)
    RegexStaticSets::initGlobals(&status);

    fStatus           = &status;

    fRXPat            = rxp;
    fScanIndex        = 0;
    fLastChar         = -1;
    fPeekChar         = -1;
    fLineNum          = 1;
    fCharNum          = 0;
    fQuoteMode        = FALSE;
    fInBackslashQuote = FALSE;
    fModeFlags        = fRXPat->fFlags | 0x80000000;
    fEOLComments      = TRUE;

    fMatchOpenParen   = -1;
    fMatchCloseParen  = -1;

    if (U_SUCCESS(status) && U_FAILURE(rxp->fDeferredStatus)) {
        status = rxp->fDeferredStatus;
    }
}

static const UChar      chAmp       = 0x26;      // '&'
static const UChar      chDash      = 0x2d;      // '-'


//------------------------------------------------------------------------------
//
//  Destructor
//
//------------------------------------------------------------------------------
RegexCompile::~RegexCompile() {
}

static inline void addCategory(UnicodeSet *set, int32_t value, UErrorCode& ec) {
    set->addAll(UnicodeSet().applyIntPropertyValue(UCHAR_GENERAL_CATEGORY_MASK, value, ec));
}

//------------------------------------------------------------------------------
//
//  Compile regex pattern.   The state machine for rexexp pattern parsing is here.
//                           The state tables are hand-written in the file regexcst.txt,
//                           and converted to the form used here by a perl
//                           script regexcst.pl
//
//------------------------------------------------------------------------------
void    RegexCompile::compile(
                         const UnicodeString &pat,   // Source pat to be compiled.
                         UParseError &pp,            // Error position info
                         UErrorCode &e)              // Error Code
{
    fRXPat->fPatternString = new UnicodeString(pat);
    UText patternText = UTEXT_INITIALIZER;
    utext_openConstUnicodeString(&patternText, fRXPat->fPatternString, &e);
    
    if (U_SUCCESS(e)) {
        compile(&patternText, pp, e);
        utext_close(&patternText);
    }
}

//
//   compile, UText mode
//     All the work is actually done here.
//
void    RegexCompile::compile(
                         UText *pat,                 // Source pat to be compiled.
                         UParseError &pp,            // Error position info
                         UErrorCode &e)              // Error Code
{
    fStatus             = &e;
    fParseErr           = &pp;
    fStackPtr           = 0;
    fStack[fStackPtr]   = 0;

    if (U_FAILURE(*fStatus)) {
        return;
    }

    // There should be no pattern stuff in the RegexPattern object.  They can not be reused.
    U_ASSERT(fRXPat->fPattern == NULL || utext_nativeLength(fRXPat->fPattern) == 0);

    // Prepare the RegexPattern object to receive the compiled pattern.
    fRXPat->fPattern        = utext_clone(fRXPat->fPattern, pat, FALSE, TRUE, fStatus);
    fRXPat->fStaticSets     = RegexStaticSets::gStaticSets->fPropSets;
    fRXPat->fStaticSets8    = RegexStaticSets::gStaticSets->fPropSets8;


    // Initialize the pattern scanning state machine
    fPatternLength = utext_nativeLength(pat);
    uint16_t                state = 1;
    const RegexTableEl      *tableEl;

    // UREGEX_LITERAL force entire pattern to be treated as a literal string.
    if (fModeFlags & UREGEX_LITERAL) {
        fQuoteMode = TRUE;
    }

    nextChar(fC);                        // Fetch the first char from the pattern string.

    //
    // Main loop for the regex pattern parsing state machine.
    //   Runs once per state transition.
    //   Each time through optionally performs, depending on the state table,
    //      - an advance to the the next pattern char
    //      - an action to be performed.
    //      - pushing or popping a state to/from the local state return stack.
    //   file regexcst.txt is the source for the state table.  The logic behind
    //     recongizing the pattern syntax is there, not here.
    //
    for (;;) {
        //  Bail out if anything has gone wrong.
        //  Regex pattern parsing stops on the first error encountered.
        if (U_FAILURE(*fStatus)) {
            break;
        }

        U_ASSERT(state != 0);

        // Find the state table element that matches the input char from the pattern, or the
        //    class of the input character.  Start with the first table row for this
        //    state, then linearly scan forward until we find a row that matches the
        //    character.  The last row for each state always matches all characters, so
        //    the search will stop there, if not before.
        //
        tableEl = &gRuleParseStateTable[state];
        REGEX_SCAN_DEBUG_PRINTF(("char, line, col = (\'%c\', %d, %d)    state=%s ",
            fC.fChar, fLineNum, fCharNum, RegexStateNames[state]));

        for (;;) {    // loop through table rows belonging to this state, looking for one
                      //   that matches the current input char.
            REGEX_SCAN_DEBUG_PRINTF(("."));
            if (tableEl->fCharClass < 127 && fC.fQuoted == FALSE &&   tableEl->fCharClass == fC.fChar) {
                // Table row specified an individual character, not a set, and
                //   the input character is not quoted, and
                //   the input character matched it.
                break;
            }
            if (tableEl->fCharClass == 255) {
                // Table row specified default, match anything character class.
                break;
            }
            if (tableEl->fCharClass == 254 && fC.fQuoted)  {
                // Table row specified "quoted" and the char was quoted.
                break;
            }
            if (tableEl->fCharClass == 253 && fC.fChar == (UChar32)-1)  {
                // Table row specified eof and we hit eof on the input.
                break;
            }

            if (tableEl->fCharClass >= 128 && tableEl->fCharClass < 240 &&   // Table specs a char class &&
                fC.fQuoted == FALSE &&                                       //   char is not escaped &&
                fC.fChar != (UChar32)-1) {                                   //   char is not EOF
                U_ASSERT(tableEl->fCharClass <= 137);
                if (RegexStaticSets::gStaticSets->fRuleSets[tableEl->fCharClass-128].contains(fC.fChar)) {
                    // Table row specified a character class, or set of characters,
                    //   and the current char matches it.
                    break;
                }
            }

            // No match on this row, advance to the next  row for this state,
            tableEl++;
        }
        REGEX_SCAN_DEBUG_PRINTF(("\n"));

        //
        // We've found the row of the state table that matches the current input
        //   character from the rules string.
        // Perform any action specified  by this row in the state table.
        if (doParseActions(tableEl->fAction) == FALSE) {
            // Break out of the state machine loop if the
            //   the action signalled some kind of error, or
            //   the action was to exit, occurs on normal end-of-rules-input.
            break;
        }

        if (tableEl->fPushState != 0) {
            fStackPtr++;
            if (fStackPtr >= kStackSize) {
                error(U_REGEX_INTERNAL_ERROR);
                REGEX_SCAN_DEBUG_PRINTF(("RegexCompile::parse() - state stack overflow.\n"));
                fStackPtr--;
            }
            fStack[fStackPtr] = tableEl->fPushState;
        }

        //
        //  NextChar.  This is where characters are actually fetched from the pattern.
        //             Happens under control of the 'n' tag in the state table.
        //
        if (tableEl->fNextChar) {
            nextChar(fC);
        }

        // Get the next state from the table entry, or from the
        //   state stack if the next state was specified as "pop".
        if (tableEl->fNextState != 255) {
            state = tableEl->fNextState;
        } else {
            state = fStack[fStackPtr];
            fStackPtr--;
            if (fStackPtr < 0) {
                // state stack underflow
                // This will occur if the user pattern has mis-matched parentheses,
                //   with extra close parens.
                //
                fStackPtr++;
                error(U_REGEX_MISMATCHED_PAREN);
            }
        }

    }

    if (U_FAILURE(*fStatus)) {
        // Bail out if the pattern had errors.
        //   Set stack cleanup:  a successful compile would have left it empty,
        //   but errors can leave temporary sets hanging around.
        while (!fSetStack.empty()) {
            delete (UnicodeSet *)fSetStack.pop();
        }
        return;
    }

    //
    // The pattern has now been read and processed, and the compiled code generated.
    //

    //
    // Compute the number of digits requried for the largest capture group number.
    //
    fRXPat->fMaxCaptureDigits = 1;
    int32_t  n = 10;
    int32_t  groupCount = fRXPat->fGroupMap->size();
    while (n <= groupCount) {
        fRXPat->fMaxCaptureDigits++;
        n *= 10;
    }

    //
    // The pattern's fFrameSize so far has accumulated the requirements for
    //   storage for capture parentheses, counters, etc. that are encountered
    //   in the pattern.  Add space for the two variables that are always
    //   present in the saved state:  the input string position (int64_t) and
    //   the position in the compiled pattern.
    //
    fRXPat->fFrameSize+=RESTACKFRAME_HDRCOUNT;

    //
    // Optimization pass 1: NOPs, back-references, and case-folding
    //
    stripNOPs();

    //
    // Get bounds for the minimum and maximum length of a string that this
    //   pattern can match.  Used to avoid looking for matches in strings that
    //   are too short.
    //
    fRXPat->fMinMatchLen = minMatchLength(3, fRXPat->fCompiledPat->size()-1);

    //
    // Optimization pass 2: match start type
    //
    matchStartType();

    //
    // Set up fast latin-1 range sets
    //
    int32_t numSets = fRXPat->fSets->size();
    fRXPat->fSets8 = new Regex8BitSet[numSets];
    // Null pointer check.
    if (fRXPat->fSets8 == NULL) {
        e = *fStatus = U_MEMORY_ALLOCATION_ERROR;
        return;
    }
    int32_t i;
    for (i=0; i<numSets; i++) {
        UnicodeSet *s = (UnicodeSet *)fRXPat->fSets->elementAt(i);
        fRXPat->fSets8[i].init(s);
    }

}





//------------------------------------------------------------------------------
//
//  doParseAction        Do some action during regex pattern parsing.
//                       Called by the parse state machine.
//
//                       Generation of the match engine PCode happens here, or
//                       in functions called from the parse actions defined here.
//
//
//------------------------------------------------------------------------------
UBool RegexCompile::doParseActions(int32_t action)
{
    UBool   returnVal = TRUE;

    switch ((Regex_PatternParseAction)action) {

    case doPatStart:
        // Start of pattern compiles to:
        //0   SAVE   2        Fall back to position of FAIL
        //1   jmp    3
        //2   FAIL            Stop if we ever reach here.
        //3   NOP             Dummy, so start of pattern looks the same as
        //                    the start of an ( grouping.
        //4   NOP             Resreved, will be replaced by a save if there are
        //                    OR | operators at the top level
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_STATE_SAVE, 2), *fStatus);
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_JMP,  3), *fStatus);
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_FAIL, 0), *fStatus);

        // Standard open nonCapture paren action emits the two NOPs and
        //   sets up the paren stack frame.
        doParseActions(doOpenNonCaptureParen);
        break;

    case doPatFinish:
        // We've scanned to the end of the pattern
        //  The end of pattern compiles to:
        //        URX_END
        //    which will stop the runtime match engine.
        //  Encountering end of pattern also behaves like a close paren,
        //   and forces fixups of the State Save at the beginning of the compiled pattern
        //   and of any OR operations at the top level.
        //
        handleCloseParen();
        if (fParenStack.size() > 0) {
            // Missing close paren in pattern.
            error(U_REGEX_MISMATCHED_PAREN);
        }

        // add the END operation to the compiled pattern.
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_END, 0), *fStatus);

        // Terminate the pattern compilation state machine.
        returnVal = FALSE;
        break;



    case doOrOperator:
        // Scanning a '|', as in (A|B)
        {
            // Generate code for any pending literals preceding the '|'
            fixLiterals(FALSE);

            // Insert a SAVE operation at the start of the pattern section preceding
            //   this OR at this level.  This SAVE will branch the match forward
            //   to the right hand side of the OR in the event that the left hand
            //   side fails to match and backtracks.  Locate the position for the
            //   save from the location on the top of the parentheses stack.
            int32_t savePosition = fParenStack.popi();
            int32_t op = (int32_t)fRXPat->fCompiledPat->elementAti(savePosition);
            U_ASSERT(URX_TYPE(op) == URX_NOP);  // original contents of reserved location
            op = URX_BUILD(URX_STATE_SAVE, fRXPat->fCompiledPat->size()+1);
            fRXPat->fCompiledPat->setElementAt(op, savePosition);

            // Append an JMP operation into the compiled pattern.  The operand for
            //  the JMP will eventually be the location following the ')' for the
            //  group.  This will be patched in later, when the ')' is encountered.
            op = URX_BUILD(URX_JMP, 0);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // Push the position of the newly added JMP op onto the parentheses stack.
            // This registers if for fixup when this block's close paren is encountered.
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);

            // Append a NOP to the compiled pattern.  This is the slot reserved
            //   for a SAVE in the event that there is yet another '|' following
            //   this one.
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);
        }
        break;


    case doOpenCaptureParen:
        // Open Paren.
        //   Compile to a
        //      - NOP, which later may be replaced by a save-state if the
        //         parenthesized group gets a * quantifier, followed by
        //      - START_CAPTURE  n    where n is stack frame offset to the capture group variables.
        //      - NOP, which may later be replaced by a save-state if there
        //             is an '|' alternation within the parens.
        //
        //    Each capture group gets three slots in the save stack frame:
        //         0: Capture Group start position (in input string being matched.)
        //         1: Capture Group end position.
        //         2: Start of Match-in-progress.
        //    The first two locations are for a completed capture group, and are
        //     referred to by back references and the like.
        //    The third location stores the capture start position when an START_CAPTURE is
        //      encountered.  This will be promoted to a completed capture when (and if) the corresponding
        //      END_CAPTURE is encountered.
        {
            fixLiterals();
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
            int32_t  varsLoc    = fRXPat->fFrameSize;    // Reserve three slots in match stack frame.
            fRXPat->fFrameSize += 3;
            int32_t  cop        = URX_BUILD(URX_START_CAPTURE, varsLoc);
            fRXPat->fCompiledPat->addElement(cop, *fStatus);
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);

            // On the Parentheses stack, start a new frame and add the postions
            //   of the two NOPs.  Depending on what follows in the pattern, the
            //   NOPs may be changed to SAVE_STATE or JMP ops, with a target
            //   address of the end of the parenthesized group.
            fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
            fParenStack.push(capturing, *fStatus);                        // Frame type.
            fParenStack.push(fRXPat->fCompiledPat->size()-3, *fStatus);   // The first  NOP location
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP loc

            // Save the mapping from group number to stack frame variable position.
            fRXPat->fGroupMap->addElement(varsLoc, *fStatus);
        }
         break;

    case doOpenNonCaptureParen:
        // Open non-caputuring (grouping only) Paren.
        //   Compile to a
        //      - NOP, which later may be replaced by a save-state if the
        //         parenthesized group gets a * quantifier, followed by
        //      - NOP, which may later be replaced by a save-state if there
        //             is an '|' alternation within the parens.
        {
            fixLiterals();
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);

            // On the Parentheses stack, start a new frame and add the postions
            //   of the two NOPs.
            fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
            fParenStack.push(plain,      *fStatus);                       // Begin a new frame.
            fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first  NOP location
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP loc
        }
         break;


    case doOpenAtomicParen:
        // Open Atomic Paren.  (?>
        //   Compile to a
        //      - NOP, which later may be replaced if the parenthesized group
        //         has a quantifier, followed by
        //      - STO_SP  save state stack position, so it can be restored at the ")"
        //      - NOP, which may later be replaced by a save-state if there
        //             is an '|' alternation within the parens.
        {
            fixLiterals();
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
            int32_t  varLoc    = fRXPat->fDataSize;    // Reserve a data location for saving the
            fRXPat->fDataSize += 1;                    //  state stack ptr.
            int32_t  stoOp     = URX_BUILD(URX_STO_SP, varLoc);
            fRXPat->fCompiledPat->addElement(stoOp, *fStatus);
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);

            // On the Parentheses stack, start a new frame and add the postions
            //   of the two NOPs.  Depending on what follows in the pattern, the
            //   NOPs may be changed to SAVE_STATE or JMP ops, with a target
            //   address of the end of the parenthesized group.
            fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
            fParenStack.push(atomic, *fStatus);                           // Frame type.
            fParenStack.push(fRXPat->fCompiledPat->size()-3, *fStatus);   // The first NOP
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP
        }
        break;


    case doOpenLookAhead:
        // Positive Look-ahead   (?=  stuff  )
        //
        //   Note:   Addition of transparent input regions, with the need to
        //           restore the original regions when failing out of a lookahead
        //           block, complicated this sequence.  Some conbined opcodes
        //           might make sense - or might not, lookahead aren't that common.
        //
        //      Caution:  min match length optimization knows about this
        //               sequence; don't change without making updates there too.
        //
        // Compiles to
        //    1    START_LA     dataLoc     Saves SP, Input Pos
        //    2.   STATE_SAVE   4            on failure of lookahead, goto 4
        //    3    JMP          6           continue ...
        //
        //    4.   LA_END                   Look Ahead failed.  Restore regions.
        //    5.   BACKTRACK                and back track again.
        //
        //    6.   NOP              reserved for use by quantifiers on the block.
        //                          Look-ahead can't have quantifiers, but paren stack
        //                             compile time conventions require the slot anyhow.
        //    7.   NOP              may be replaced if there is are '|' ops in the block.
        //    8.     code for parenthesized stuff.
        //    9.   LA_END
        //
        //  Two data slots are reserved, for saving the stack ptr and the input position.
        {
            fixLiterals();
            int32_t dataLoc = fRXPat->fDataSize;
            fRXPat->fDataSize += 2;
            int32_t op = URX_BUILD(URX_LA_START, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            op = URX_BUILD(URX_STATE_SAVE, fRXPat->fCompiledPat->size()+ 2);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            op = URX_BUILD(URX_JMP, fRXPat->fCompiledPat->size()+ 3);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
            
            op = URX_BUILD(URX_LA_END, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            op = URX_BUILD(URX_BACKTRACK, 0);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
            
            op = URX_BUILD(URX_NOP, 0);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // On the Parentheses stack, start a new frame and add the postions
            //   of the NOPs.
            fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
            fParenStack.push(lookAhead, *fStatus);                        // Frame type.
            fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first  NOP location
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP location
        }
        break;

    case doOpenLookAheadNeg:
        // Negated Lookahead.   (?! stuff )
        // Compiles to
        //    1.    START_LA    dataloc
        //    2.    SAVE_STATE  7         // Fail within look-ahead block restores to this state,
        //                                //   which continues with the match.
        //    3.    NOP                   // Std. Open Paren sequence, for possible '|'
        //    4.       code for parenthesized stuff.
        //    5.    END_LA                // Cut back stack, remove saved state from step 2.
        //    6.    BACKTRACK             // code in block succeeded, so neg. lookahead fails.
        //    7.    END_LA                // Restore match region, in case look-ahead was using
        //                                        an alternate (transparent) region.
        {
            fixLiterals();
            int32_t dataLoc = fRXPat->fDataSize;
            fRXPat->fDataSize += 2;
            int32_t op = URX_BUILD(URX_LA_START, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            op = URX_BUILD(URX_STATE_SAVE, 0);    // dest address will be patched later.
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            op = URX_BUILD(URX_NOP, 0);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // On the Parentheses stack, start a new frame and add the postions
            //   of the StateSave and NOP.
            fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
            fParenStack.push(negLookAhead, *fStatus);                    // Frame type
            fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The STATE_SAVE location
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP location

            // Instructions #5 - #7 will be added when the ')' is encountered.
        }
        break;

    case doOpenLookBehind:
        {
            //   Compile a (?<= look-behind open paren.
            //
            //          Compiles to
            //              0       URX_LB_START     dataLoc
            //              1       URX_LB_CONT      dataLoc
            //              2                        MinMatchLen
            //              3                        MaxMatchLen
            //              4       URX_NOP          Standard '(' boilerplate.
            //              5       URX_NOP          Reserved slot for use with '|' ops within (block).
            //              6         <code for LookBehind expression>
            //              7       URX_LB_END       dataLoc    # Check match len, restore input  len
            //              8       URX_LA_END       dataLoc    # Restore stack, input pos
            //
            //          Allocate a block of matcher data, to contain (when running a match)
            //              0:    Stack ptr on entry
            //              1:    Input Index on entry
            //              2:    Start index of match current match attempt.
            //              3:    Original Input String len.

            // Generate match code for any pending literals.
            fixLiterals();

            // Allocate data space
            int32_t dataLoc = fRXPat->fDataSize;
            fRXPat->fDataSize += 4;

            // Emit URX_LB_START
            int32_t op = URX_BUILD(URX_LB_START, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // Emit URX_LB_CONT
            op = URX_BUILD(URX_LB_CONT, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
            fRXPat->fCompiledPat->addElement(0,  *fStatus);    // MinMatchLength.  To be filled later.
            fRXPat->fCompiledPat->addElement(0,  *fStatus);    // MaxMatchLength.  To be filled later.

            // Emit the NOP
            op = URX_BUILD(URX_NOP, 0);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // On the Parentheses stack, start a new frame and add the postions
            //   of the URX_LB_CONT and the NOP.
            fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
            fParenStack.push(lookBehind, *fStatus);                       // Frame type
            fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first NOP location
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The 2nd   NOP location

            // The final two instructions will be added when the ')' is encountered.
        }

        break;

    case doOpenLookBehindNeg:
        {
            //   Compile a (?<! negated look-behind open paren.
            //
            //          Compiles to
            //              0       URX_LB_START     dataLoc    # Save entry stack, input len
            //              1       URX_LBN_CONT     dataLoc    # Iterate possible match positions
            //              2                        MinMatchLen
            //              3                        MaxMatchLen
            //              4                        continueLoc (9)
            //              5       URX_NOP          Standard '(' boilerplate.
            //              6       URX_NOP          Reserved slot for use with '|' ops within (block).
            //              7         <code for LookBehind expression>
            //              8       URX_LBN_END      dataLoc    # Check match len, cause a FAIL
            //              9       ...
            //
            //          Allocate a block of matcher data, to contain (when running a match)
            //              0:    Stack ptr on entry
            //              1:    Input Index on entry
            //              2:    Start index of match current match attempt.
            //              3:    Original Input String len.

            // Generate match code for any pending literals.
            fixLiterals();

            // Allocate data space
            int32_t dataLoc = fRXPat->fDataSize;
            fRXPat->fDataSize += 4;

            // Emit URX_LB_START
            int32_t op = URX_BUILD(URX_LB_START, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // Emit URX_LBN_CONT
            op = URX_BUILD(URX_LBN_CONT, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
            fRXPat->fCompiledPat->addElement(0,  *fStatus);    // MinMatchLength.  To be filled later.
            fRXPat->fCompiledPat->addElement(0,  *fStatus);    // MaxMatchLength.  To be filled later.
            fRXPat->fCompiledPat->addElement(0,  *fStatus);    // Continue Loc.    To be filled later.

            // Emit the NOP
            op = URX_BUILD(URX_NOP, 0);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // On the Parentheses stack, start a new frame and add the postions
            //   of the URX_LB_CONT and the NOP.
            fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
            fParenStack.push(lookBehindN, *fStatus);                      // Frame type
            fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first NOP location
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The 2nd   NOP location

            // The final two instructions will be added when the ')' is encountered.
        }
        break;

    case doConditionalExpr:
        // Conditionals such as (?(1)a:b)
    case doPerlInline:
        // Perl inline-condtionals.  (?{perl code}a|b) We're not perl, no way to do them.
        error(U_REGEX_UNIMPLEMENTED);
        break;


    case doCloseParen:
        handleCloseParen();
        if (fParenStack.size() <= 0) {
            //  Extra close paren, or missing open paren.
            error(U_REGEX_MISMATCHED_PAREN);
        }
        break;

    case doNOP:
        break;


    case doBadOpenParenType:
    case doRuleError:
        error(U_REGEX_RULE_SYNTAX);
        break;


    case doMismatchedParenErr:
        error(U_REGEX_MISMATCHED_PAREN);
        break;

    case doPlus:
        //  Normal '+'  compiles to
        //     1.   stuff to be repeated  (already built)
        //     2.   jmp-sav 1
        //     3.   ...
        //
        //  Or, if the item to be repeated can match a zero length string,
        //     1.   STO_INP_LOC  data-loc
        //     2.      body of stuff to be repeated
        //     3.   JMP_SAV_X    2
        //     4.   ...

        //
        //  Or, if the item to be repeated is simple
        //     1.   Item to be repeated.
        //     2.   LOOP_SR_I    set number  (assuming repeated item is a set ref)
        //     3.   LOOP_C       stack location
        {
            int32_t  topLoc = blockTopLoc(FALSE);        // location of item #1
            int32_t  frameLoc;

            // Check for simple constructs, which may get special optimized code.
            if (topLoc == fRXPat->fCompiledPat->size() - 1) {
                int32_t repeatedOp = (int32_t)fRXPat->fCompiledPat->elementAti(topLoc);

                if (URX_TYPE(repeatedOp) == URX_SETREF) {
                    // Emit optimized code for [char set]+
                    int32_t loopOpI = URX_BUILD(URX_LOOP_SR_I, URX_VAL(repeatedOp));
                    fRXPat->fCompiledPat->addElement(loopOpI, *fStatus);
                    frameLoc = fRXPat->fFrameSize;
                    fRXPat->fFrameSize++;
                    int32_t loopOpC = URX_BUILD(URX_LOOP_C, frameLoc);
                    fRXPat->fCompiledPat->addElement(loopOpC, *fStatus);
                    break;
                }

                if (URX_TYPE(repeatedOp) == URX_DOTANY ||
                    URX_TYPE(repeatedOp) == URX_DOTANY_ALL ||
                    URX_TYPE(repeatedOp) == URX_DOTANY_UNIX) {
                    // Emit Optimized code for .+ operations.
                    int32_t loopOpI = URX_BUILD(URX_LOOP_DOT_I, 0);
                    if (URX_TYPE(repeatedOp) == URX_DOTANY_ALL) {
                        // URX_LOOP_DOT_I operand is a flag indicating ". matches any" mode.
                        loopOpI |= 1;
                    }
                    if (fModeFlags & UREGEX_UNIX_LINES) {
                        loopOpI |= 2;
                    }
                    fRXPat->fCompiledPat->addElement(loopOpI, *fStatus);
                    frameLoc = fRXPat->fFrameSize;
                    fRXPat->fFrameSize++;
                    int32_t loopOpC = URX_BUILD(URX_LOOP_C, frameLoc);
                    fRXPat->fCompiledPat->addElement(loopOpC, *fStatus);
                    break;
                }

            }

            // General case.

            // Check for minimum match length of zero, which requires
            //    extra loop-breaking code.
            if (minMatchLength(topLoc, fRXPat->fCompiledPat->size()-1) == 0) {
                // Zero length match is possible.
                // Emit the code sequence that can handle it.
                insertOp(topLoc);
                frameLoc =  fRXPat->fFrameSize;
                fRXPat->fFrameSize++;

                int32_t op = URX_BUILD(URX_STO_INP_LOC, frameLoc);
                fRXPat->fCompiledPat->setElementAt(op, topLoc);

                op = URX_BUILD(URX_JMP_SAV_X, topLoc+1);
                fRXPat->fCompiledPat->addElement(op, *fStatus);
            } else {
                // Simpler code when the repeated body must match something non-empty
                int32_t  jmpOp  = URX_BUILD(URX_JMP_SAV, topLoc);
                fRXPat->fCompiledPat->addElement(jmpOp, *fStatus);
            }
        }
        break;

    case doNGPlus:
        //  Non-greedy '+?'  compiles to
        //     1.   stuff to be repeated  (already built)
        //     2.   state-save  1
        //     3.   ...
        {
            int32_t topLoc      = blockTopLoc(FALSE);
            int32_t saveStateOp = URX_BUILD(URX_STATE_SAVE, topLoc);
            fRXPat->fCompiledPat->addElement(saveStateOp, *fStatus);
        }
        break;


    case doOpt:
        // Normal (greedy) ? quantifier.
        //  Compiles to
        //     1. state save 3
        //     2.    body of optional block
        //     3. ...
        // Insert the state save into the compiled pattern, and we're done.
        {
            int32_t   saveStateLoc = blockTopLoc(TRUE);
            int32_t   saveStateOp  = URX_BUILD(URX_STATE_SAVE, fRXPat->fCompiledPat->size());
            fRXPat->fCompiledPat->setElementAt(saveStateOp, saveStateLoc);
        }
        break;

    case doNGOpt:
        // Non-greedy ?? quantifier
        //   compiles to
        //    1.  jmp   4
        //    2.     body of optional block
        //    3   jmp   5
        //    4.  state save 2
        //    5    ...
        //  This code is less than ideal, with two jmps instead of one, because we can only
        //  insert one instruction at the top of the block being iterated.
        {
            int32_t  jmp1_loc = blockTopLoc(TRUE);
            int32_t  jmp2_loc = fRXPat->fCompiledPat->size();

            int32_t  jmp1_op  = URX_BUILD(URX_JMP, jmp2_loc+1);
            fRXPat->fCompiledPat->setElementAt(jmp1_op, jmp1_loc);

            int32_t  jmp2_op  = URX_BUILD(URX_JMP, jmp2_loc+2);
            fRXPat->fCompiledPat->addElement(jmp2_op, *fStatus);

            int32_t  save_op  = URX_BUILD(URX_STATE_SAVE, jmp1_loc+1);
            fRXPat->fCompiledPat->addElement(save_op, *fStatus);
        }
        break;


    case doStar:
        // Normal (greedy) * quantifier.
        // Compiles to
        //       1.   STATE_SAVE   4
        //       2.      body of stuff being iterated over
        //       3.   JMP_SAV      2
        //       4.   ...
        //
        // Or, if the body is a simple [Set],
        //       1.   LOOP_SR_I    set number
        //       2.   LOOP_C       stack location
        //       ...
        //
        // Or if this is a .*
        //       1.   LOOP_DOT_I    (. matches all mode flag)
        //       2.   LOOP_C        stack location
        //
        // Or, if the body can match a zero-length string, to inhibit infinite loops,
        //       1.   STATE_SAVE   5
        //       2.   STO_INP_LOC  data-loc
        //       3.      body of stuff
        //       4.   JMP_SAV_X    2
        //       5.   ...
        {
            // location of item #1, the STATE_SAVE
            int32_t   topLoc = blockTopLoc(FALSE);
            int32_t   dataLoc = -1;

            // Check for simple *, where the construct being repeated
            //   compiled to single opcode, and might be optimizable.
            if (topLoc == fRXPat->fCompiledPat->size() - 1) {
                int32_t repeatedOp = (int32_t)fRXPat->fCompiledPat->elementAti(topLoc);

                if (URX_TYPE(repeatedOp) == URX_SETREF) {
                    // Emit optimized code for a [char set]*
                    int32_t loopOpI = URX_BUILD(URX_LOOP_SR_I, URX_VAL(repeatedOp));
                    fRXPat->fCompiledPat->setElementAt(loopOpI, topLoc);
                    dataLoc = fRXPat->fFrameSize;
                    fRXPat->fFrameSize++;
                    int32_t loopOpC = URX_BUILD(URX_LOOP_C, dataLoc);
                    fRXPat->fCompiledPat->addElement(loopOpC, *fStatus);
                    break;
                }

                if (URX_TYPE(repeatedOp) == URX_DOTANY ||
                    URX_TYPE(repeatedOp) == URX_DOTANY_ALL ||
                    URX_TYPE(repeatedOp) == URX_DOTANY_UNIX) {
                    // Emit Optimized code for .* operations.
                    int32_t loopOpI = URX_BUILD(URX_LOOP_DOT_I, 0);
                    if (URX_TYPE(repeatedOp) == URX_DOTANY_ALL) {
                        // URX_LOOP_DOT_I operand is a flag indicating . matches any mode.
                        loopOpI |= 1;
                    }
                    if ((fModeFlags & UREGEX_UNIX_LINES) != 0) {
                        loopOpI |= 2;
                    }
                    fRXPat->fCompiledPat->setElementAt(loopOpI, topLoc);
                    dataLoc = fRXPat->fFrameSize;
                    fRXPat->fFrameSize++;
                    int32_t loopOpC = URX_BUILD(URX_LOOP_C, dataLoc);
                    fRXPat->fCompiledPat->addElement(loopOpC, *fStatus);
                    break;
                }
            }

            // Emit general case code for this *
            // The optimizations did not apply.

            int32_t   saveStateLoc = blockTopLoc(TRUE);
            int32_t   jmpOp        = URX_BUILD(URX_JMP_SAV, saveStateLoc+1);

            // Check for minimum match length of zero, which requires
            //    extra loop-breaking code.
            if (minMatchLength(saveStateLoc, fRXPat->fCompiledPat->size()-1) == 0) {
                insertOp(saveStateLoc);
                dataLoc =  fRXPat->fFrameSize;
                fRXPat->fFrameSize++;

                int32_t op = URX_BUILD(URX_STO_INP_LOC, dataLoc);
                fRXPat->fCompiledPat->setElementAt(op, saveStateLoc+1);
                jmpOp      = URX_BUILD(URX_JMP_SAV_X, saveStateLoc+2);
            }

            // Locate the position in the compiled pattern where the match will continue
            //   after completing the *.   (4 or 5 in the comment above)
            int32_t continueLoc = fRXPat->fCompiledPat->size()+1;

            // Put together the save state op store it into the compiled code.
            int32_t saveStateOp = URX_BUILD(URX_STATE_SAVE, continueLoc);
            fRXPat->fCompiledPat->setElementAt(saveStateOp, saveStateLoc);

            // Append the URX_JMP_SAV or URX_JMPX operation to the compiled pattern.
            fRXPat->fCompiledPat->addElement(jmpOp, *fStatus);
        }
        break;

    case doNGStar:
        // Non-greedy *? quantifier
        // compiles to
        //     1.   JMP    3
        //     2.      body of stuff being iterated over
        //     3.   STATE_SAVE  2
        //     4    ...
        {
            int32_t     jmpLoc  = blockTopLoc(TRUE);                   // loc  1.
            int32_t     saveLoc = fRXPat->fCompiledPat->size();        // loc  3.
            int32_t     jmpOp   = URX_BUILD(URX_JMP, saveLoc);
            int32_t     stateSaveOp = URX_BUILD(URX_STATE_SAVE, jmpLoc+1);
            fRXPat->fCompiledPat->setElementAt(jmpOp, jmpLoc);
            fRXPat->fCompiledPat->addElement(stateSaveOp, *fStatus);
        }
        break;


    case doIntervalInit:
        // The '{' opening an interval quantifier was just scanned.
        // Init the counter varaiables that will accumulate the values as the digits
        //    are scanned.
        fIntervalLow = 0;
        fIntervalUpper = -1;
        break;

    case doIntevalLowerDigit:
        // Scanned a digit from the lower value of an {lower,upper} interval
        {
            int32_t digitValue = u_charDigitValue(fC.fChar);
            U_ASSERT(digitValue >= 0);
            fIntervalLow = fIntervalLow*10 + digitValue;
            if (fIntervalLow < 0) {
                error(U_REGEX_NUMBER_TOO_BIG);
            }
        }
        break;

    case doIntervalUpperDigit:
        // Scanned a digit from the upper value of an {lower,upper} interval
        {
            if (fIntervalUpper < 0) {
                fIntervalUpper = 0;
            }
            int32_t digitValue = u_charDigitValue(fC.fChar);
            U_ASSERT(digitValue >= 0);
            fIntervalUpper = fIntervalUpper*10 + digitValue;
            if (fIntervalUpper < 0) {
                error(U_REGEX_NUMBER_TOO_BIG);
            }
        }
        break;

    case doIntervalSame:
        // Scanned a single value interval like {27}.  Upper = Lower.
        fIntervalUpper = fIntervalLow;
        break;

    case doInterval:
        // Finished scanning a normal {lower,upper} interval.  Generate the code for it.
        if (compileInlineInterval() == FALSE) {
            compileInterval(URX_CTR_INIT, URX_CTR_LOOP);
        }
        break;

    case doPossessiveInterval:
        // Finished scanning a Possessive {lower,upper}+ interval.  Generate the code for it.
        {
            // Remember the loc for the top of the block being looped over.
            //   (Can not reserve a slot in the compiled pattern at this time, because
            //    compileInterval needs to reserve also, and blockTopLoc can only reserve
            //    once per block.)
            int32_t topLoc = blockTopLoc(FALSE);

            // Produce normal looping code.
            compileInterval(URX_CTR_INIT, URX_CTR_LOOP);

            // Surround the just-emitted normal looping code with a STO_SP ... LD_SP
            //  just as if the loop was inclosed in atomic parentheses.

            // First the STO_SP before the start of the loop
            insertOp(topLoc);
            int32_t  varLoc    = fRXPat->fDataSize;    // Reserve a data location for saving the
            fRXPat->fDataSize += 1;                    //  state stack ptr.
            int32_t  op        = URX_BUILD(URX_STO_SP, varLoc);
            fRXPat->fCompiledPat->setElementAt(op, topLoc);

            int32_t loopOp = (int32_t)fRXPat->fCompiledPat->popi();
            U_ASSERT(URX_TYPE(loopOp) == URX_CTR_LOOP && URX_VAL(loopOp) == topLoc);
            loopOp++;     // point LoopOp after the just-inserted STO_SP
            fRXPat->fCompiledPat->push(loopOp, *fStatus);

            // Then the LD_SP after the end of the loop
            op = URX_BUILD(URX_LD_SP, varLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
        }

        break;

    case doNGInterval:
        // Finished scanning a non-greedy {lower,upper}? interval.  Generate the code for it.
        compileInterval(URX_CTR_INIT_NG, URX_CTR_LOOP_NG);
        break;

    case doIntervalError:
        error(U_REGEX_BAD_INTERVAL);
        break;

    case doLiteralChar:
        // We've just scanned a "normal" character from the pattern,
        literalChar(fC.fChar);
        break;


    case doEscapedLiteralChar:
        // We've just scanned an backslashed escaped character with  no
        //   special meaning.  It represents itself.
        if ((fModeFlags & UREGEX_ERROR_ON_UNKNOWN_ESCAPES) != 0 &&
            ((fC.fChar >= 0x41 && fC.fChar<= 0x5A) ||     // in [A-Z]
            (fC.fChar >= 0x61 && fC.fChar <= 0x7a))) {   // in [a-z]
               error(U_REGEX_BAD_ESCAPE_SEQUENCE);
             }
        literalChar(fC.fChar);
        break;


    case doDotAny:
        // scanned a ".",  match any single character.
        {
            fixLiterals(FALSE);
            int32_t   op;
            if (fModeFlags & UREGEX_DOTALL) {
                op = URX_BUILD(URX_DOTANY_ALL, 0);
            } else if (fModeFlags & UREGEX_UNIX_LINES) {
                op = URX_BUILD(URX_DOTANY_UNIX, 0);
            } else {
                op = URX_BUILD(URX_DOTANY, 0);
            }
            fRXPat->fCompiledPat->addElement(op, *fStatus);
        }
        break;

    case doCaret:
        {
            fixLiterals(FALSE);
            int32_t op = 0;
            if (       (fModeFlags & UREGEX_MULTILINE) == 0 && (fModeFlags & UREGEX_UNIX_LINES) == 0) {
                op = URX_CARET;
            } else if ((fModeFlags & UREGEX_MULTILINE) != 0 && (fModeFlags & UREGEX_UNIX_LINES) == 0) {
                op = URX_CARET_M;
            } else if ((fModeFlags & UREGEX_MULTILINE) == 0 && (fModeFlags & UREGEX_UNIX_LINES) != 0) {
                op = URX_CARET;   // Only testing true start of input. 
            } else if ((fModeFlags & UREGEX_MULTILINE) != 0 && (fModeFlags & UREGEX_UNIX_LINES) != 0) {
                op = URX_CARET_M_UNIX;
            }
            fRXPat->fCompiledPat->addElement(URX_BUILD(op, 0), *fStatus);
        }
        break;

    case doDollar:
        {
            fixLiterals(FALSE);
            int32_t op = 0;
            if (       (fModeFlags & UREGEX_MULTILINE) == 0 && (fModeFlags & UREGEX_UNIX_LINES) == 0) {
                op = URX_DOLLAR;
            } else if ((fModeFlags & UREGEX_MULTILINE) != 0 && (fModeFlags & UREGEX_UNIX_LINES) == 0) {
                op = URX_DOLLAR_M;
            } else if ((fModeFlags & UREGEX_MULTILINE) == 0 && (fModeFlags & UREGEX_UNIX_LINES) != 0) {
                op = URX_DOLLAR_D;
            } else if ((fModeFlags & UREGEX_MULTILINE) != 0 && (fModeFlags & UREGEX_UNIX_LINES) != 0) {
                op = URX_DOLLAR_MD;
            }
            fRXPat->fCompiledPat->addElement(URX_BUILD(op, 0), *fStatus);
        }
        break;

    case doBackslashA:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_CARET, 0), *fStatus);
        break;

    case doBackslashB:
        {
            #if  UCONFIG_NO_BREAK_ITERATION==1
            if (fModeFlags & UREGEX_UWORD) {
                error(U_UNSUPPORTED_ERROR);
            }
            #endif
            fixLiterals(FALSE);
            int32_t op = (fModeFlags & UREGEX_UWORD)? URX_BACKSLASH_BU : URX_BACKSLASH_B;
            fRXPat->fCompiledPat->addElement(URX_BUILD(op, 1), *fStatus);
        }
        break;

    case doBackslashb:
        {
            #if  UCONFIG_NO_BREAK_ITERATION==1
            if (fModeFlags & UREGEX_UWORD) {
                error(U_UNSUPPORTED_ERROR);
            }
            #endif
            fixLiterals(FALSE);
            int32_t op = (fModeFlags & UREGEX_UWORD)? URX_BACKSLASH_BU : URX_BACKSLASH_B;
            fRXPat->fCompiledPat->addElement(URX_BUILD(op, 0), *fStatus);
        }
        break;

    case doBackslashD:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_D, 1), *fStatus);
        break;

    case doBackslashd:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_D, 0), *fStatus);
        break;

    case doBackslashG:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_G, 0), *fStatus);
        break;

    case doBackslashS:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(
            URX_BUILD(URX_STAT_SETREF_N, URX_ISSPACE_SET), *fStatus);
        break;

    case doBackslashs:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(
            URX_BUILD(URX_STATIC_SETREF, URX_ISSPACE_SET), *fStatus);
        break;

    case doBackslashW:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(
            URX_BUILD(URX_STAT_SETREF_N, URX_ISWORD_SET), *fStatus);
        break;

    case doBackslashw:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(
            URX_BUILD(URX_STATIC_SETREF, URX_ISWORD_SET), *fStatus);
        break;

    case doBackslashX:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_X, 0), *fStatus);
        break;


    case doBackslashZ:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_DOLLAR, 0), *fStatus);
        break;

    case doBackslashz:
        fixLiterals(FALSE);
        fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_Z, 0), *fStatus);
        break;

    case doEscapeError:
        error(U_REGEX_BAD_ESCAPE_SEQUENCE);
        break;

    case doExit:
        fixLiterals(FALSE);
        returnVal = FALSE;
        break;

    case doProperty:
        {
            fixLiterals(FALSE);
            UnicodeSet *theSet = scanProp();
            compileSet(theSet);
        }
        break;

    case doNamedChar:
        {
            UChar32 c = scanNamedChar();
            literalChar(c);
        }
        break;
        

    case doBackRef:
        // BackReference.  Somewhat unusual in that the front-end can not completely parse
        //                 the regular expression, because the number of digits to be consumed
        //                 depends on the number of capture groups that have been defined.  So
        //                 we have to do it here instead.
        {
            int32_t  numCaptureGroups = fRXPat->fGroupMap->size();
            int32_t  groupNum = 0;
            UChar32  c        = fC.fChar;

            for (;;) {
                // Loop once per digit, for max allowed number of digits in a back reference.
                int32_t digit = u_charDigitValue(c);
                groupNum = groupNum * 10 + digit;
                if (groupNum >= numCaptureGroups) {
                    break;
                }
                c = peekCharLL();
                if (RegexStaticSets::gStaticSets->fRuleDigitsAlias->contains(c) == FALSE) {
                    break;
                }
                nextCharLL();
            }

            // Scan of the back reference in the source regexp is complete.  Now generate
            //  the compiled code for it.
            // Because capture groups can be forward-referenced by back-references,
            //  we fill the operand with the capture group number.  At the end
            //  of compilation, it will be changed to the variable's location.
            U_ASSERT(groupNum > 0);  // Shouldn't happen.  '\0' begins an octal escape sequence,
                                     //    and shouldn't enter this code path at all.
            fixLiterals(FALSE);
            int32_t  op;
            if (fModeFlags & UREGEX_CASE_INSENSITIVE) {
                op = URX_BUILD(URX_BACKREF_I, groupNum);
            } else {
                op = URX_BUILD(URX_BACKREF, groupNum);
            }
            fRXPat->fCompiledPat->addElement(op, *fStatus);
        }
        break;


    case doPossessivePlus:
        // Possessive ++ quantifier.
        // Compiles to
        //       1.   STO_SP
        //       2.      body of stuff being iterated over
        //       3.   STATE_SAVE 5
        //       4.   JMP        2
        //       5.   LD_SP
        //       6.   ...
        //
        //  Note:  TODO:  This is pretty inefficient.  A mass of saved state is built up
        //                then unconditionally discarded.  Perhaps introduce a new opcode.  Ticket 6056
        //
        {
            // Emit the STO_SP
            int32_t   topLoc = blockTopLoc(TRUE);
            int32_t   stoLoc = fRXPat->fDataSize;
            fRXPat->fDataSize++;       // Reserve the data location for storing save stack ptr.
            int32_t   op     = URX_BUILD(URX_STO_SP, stoLoc);
            fRXPat->fCompiledPat->setElementAt(op, topLoc);

            // Emit the STATE_SAVE
            op = URX_BUILD(URX_STATE_SAVE, fRXPat->fCompiledPat->size()+2);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // Emit the JMP
            op = URX_BUILD(URX_JMP, topLoc+1);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // Emit the LD_SP
            op = URX_BUILD(URX_LD_SP, stoLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
        }
        break;

    case doPossessiveStar:
        // Possessive *+ quantifier.
        // Compiles to
        //       1.   STO_SP       loc
        //       2.   STATE_SAVE   5
        //       3.      body of stuff being iterated over
        //       4.   JMP          2
        //       5.   LD_SP        loc
        //       6    ...
        // TODO:  do something to cut back the state stack each time through the loop.
        {
            // Reserve two slots at the top of the block.
            int32_t   topLoc = blockTopLoc(TRUE);
            insertOp(topLoc);

            // emit   STO_SP     loc
            int32_t   stoLoc = fRXPat->fDataSize;
            fRXPat->fDataSize++;       // Reserve the data location for storing save stack ptr.
            int32_t   op     = URX_BUILD(URX_STO_SP, stoLoc);
            fRXPat->fCompiledPat->setElementAt(op, topLoc);

            // Emit the SAVE_STATE   5
            int32_t L7 = fRXPat->fCompiledPat->size()+1;
            op = URX_BUILD(URX_STATE_SAVE, L7);
            fRXPat->fCompiledPat->setElementAt(op, topLoc+1);

            // Append the JMP operation.
            op = URX_BUILD(URX_JMP, topLoc+1);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // Emit the LD_SP       loc
            op = URX_BUILD(URX_LD_SP, stoLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
        }
        break;

    case doPossessiveOpt:
        // Possessive  ?+ quantifier.
        //  Compiles to
        //     1. STO_SP      loc
        //     2. SAVE_STATE  5
        //     3.    body of optional block
        //     4. LD_SP       loc
        //     5. ...
        //
        {
            // Reserve two slots at the top of the block.
            int32_t   topLoc = blockTopLoc(TRUE);
            insertOp(topLoc);

            // Emit the STO_SP
            int32_t   stoLoc = fRXPat->fDataSize;
            fRXPat->fDataSize++;       // Reserve the data location for storing save stack ptr.
            int32_t   op     = URX_BUILD(URX_STO_SP, stoLoc);
            fRXPat->fCompiledPat->setElementAt(op, topLoc);

            // Emit the SAVE_STATE
            int32_t   continueLoc = fRXPat->fCompiledPat->size()+1;
            op = URX_BUILD(URX_STATE_SAVE, continueLoc);
            fRXPat->fCompiledPat->setElementAt(op, topLoc+1);

            // Emit the LD_SP
            op = URX_BUILD(URX_LD_SP, stoLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
        }
        break;


    case doBeginMatchMode:
        fNewModeFlags = fModeFlags;
        fSetModeFlag  = TRUE;
        break;

    case doMatchMode:   //  (?i)    and similar
        {
            int32_t  bit = 0;
            switch (fC.fChar) {
            case 0x69: /* 'i' */   bit = UREGEX_CASE_INSENSITIVE; break;
            case 0x64: /* 'd' */   bit = UREGEX_UNIX_LINES;       break;
            case 0x6d: /* 'm' */   bit = UREGEX_MULTILINE;        break;
            case 0x73: /* 's' */   bit = UREGEX_DOTALL;           break;
            case 0x75: /* 'u' */   bit = 0; /* Unicode casing */  break;
            case 0x77: /* 'w' */   bit = UREGEX_UWORD;            break;
            case 0x78: /* 'x' */   bit = UREGEX_COMMENTS;         break;
            case 0x2d: /* '-' */   fSetModeFlag = FALSE;          break;
            default:
                U_ASSERT(FALSE);   // Should never happen.  Other chars are filtered out
                                   // by the scanner.
            }
            if (fSetModeFlag) {
                fNewModeFlags |= bit;
            } else {
                fNewModeFlags &= ~bit;
            }
        }
        break;

    case doSetMatchMode:
        // Emit code to match any pending literals, using the not-yet changed match mode.
        fixLiterals();

        // We've got a (?i) or similar.  The match mode is being changed, but
        //   the change is not scoped to a parenthesized block.
        U_ASSERT(fNewModeFlags < 0);
        fModeFlags = fNewModeFlags;

        break;


    case doMatchModeParen:
        // We've got a (?i: or similar.  Begin a parenthesized block, save old
        //   mode flags so they can be restored at the close of the block.
        //
        //   Compile to a
        //      - NOP, which later may be replaced by a save-state if the
        //         parenthesized group gets a * quantifier, followed by
        //      - NOP, which may later be replaced by a save-state if there
        //             is an '|' alternation within the parens.
        {
            fixLiterals(FALSE);
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);

            // On the Parentheses stack, start a new frame and add the postions
            //   of the two NOPs (a normal non-capturing () frame, except for the
            //   saving of the orignal mode flags.)
            fParenStack.push(fModeFlags, *fStatus);
            fParenStack.push(flags, *fStatus);                            // Frame Marker
            fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first NOP
            fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP

            // Set the current mode flags to the new values.
            U_ASSERT(fNewModeFlags < 0);
            fModeFlags = fNewModeFlags;
        }
        break;

    case doBadModeFlag:
        error(U_REGEX_INVALID_FLAG);
        break;

    case doSuppressComments:
        // We have just scanned a '(?'.  We now need to prevent the character scanner from
        // treating a '#' as a to-the-end-of-line comment.
        //   (This Perl compatibility just gets uglier and uglier to do...)
        fEOLComments = FALSE;
        break;


    case doSetAddAmp:
        {
          UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
          set->add(chAmp);
        }
        break;

    case doSetAddDash:
        {
          UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
          set->add(chDash);
        }
        break;

     case doSetBackslash_s:
        {
         UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
         set->addAll(*RegexStaticSets::gStaticSets->fPropSets[URX_ISSPACE_SET]);
         break;
        }

     case doSetBackslash_S:
        {
            UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
            UnicodeSet SSet(*RegexStaticSets::gStaticSets->fPropSets[URX_ISSPACE_SET]);
            SSet.complement();
            set->addAll(SSet);
            break;
        }

    case doSetBackslash_d:
        {
            UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
            // TODO - make a static set, ticket 6058.
            addCategory(set, U_GC_ND_MASK, *fStatus);
            break;
        }

    case doSetBackslash_D:
        {
            UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
            UnicodeSet digits;
            // TODO - make a static set, ticket 6058.
            digits.applyIntPropertyValue(UCHAR_GENERAL_CATEGORY_MASK, U_GC_ND_MASK, *fStatus);
            digits.complement();
            set->addAll(digits);
            break;
        }

    case doSetBackslash_w:
        {
            UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
            set->addAll(*RegexStaticSets::gStaticSets->fPropSets[URX_ISWORD_SET]);
            break;
        }

    case doSetBackslash_W:
        {
            UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
            UnicodeSet SSet(*RegexStaticSets::gStaticSets->fPropSets[URX_ISWORD_SET]);
            SSet.complement();
            set->addAll(SSet);
            break;
        }

    case doSetBegin:
        fixLiterals(FALSE);
        fSetStack.push(new UnicodeSet(), *fStatus);
        fSetOpStack.push(setStart, *fStatus);
        if ((fModeFlags & UREGEX_CASE_INSENSITIVE) != 0) {
            fSetOpStack.push(setCaseClose, *fStatus);
        }
        break;

    case doSetBeginDifference1:
        //  We have scanned something like [[abc]-[
        //  Set up a new UnicodeSet for the set beginning with the just-scanned '['
        //  Push a Difference operator, which will cause the new set to be subtracted from what
        //    went before once it is created.
        setPushOp(setDifference1);
        fSetOpStack.push(setStart, *fStatus);
        if ((fModeFlags & UREGEX_CASE_INSENSITIVE) != 0) {
            fSetOpStack.push(setCaseClose, *fStatus);
        }
        break;

    case doSetBeginIntersection1:
        //  We have scanned something like  [[abc]&[
        //   Need both the '&' operator and the open '[' operator.
        setPushOp(setIntersection1);
        fSetOpStack.push(setStart, *fStatus);
        if ((fModeFlags & UREGEX_CASE_INSENSITIVE) != 0) {
            fSetOpStack.push(setCaseClose, *fStatus);
        }
        break;

    case doSetBeginUnion:
        //  We have scanned something like  [[abc][
        //     Need to handle the union operation explicitly [[abc] | [
        setPushOp(setUnion);
        fSetOpStack.push(setStart, *fStatus);
        if ((fModeFlags & UREGEX_CASE_INSENSITIVE) != 0) {
            fSetOpStack.push(setCaseClose, *fStatus);
        }
        break;

    case doSetDifference2:
        // We have scanned something like [abc--
        //   Consider this to unambiguously be a set difference operator.
        setPushOp(setDifference2);
        break;

    case doSetEnd:
        // Have encountered the ']' that closes a set.
        //    Force the evaluation of any pending operations within this set,
        //    leave the completed set on the top of the set stack.
        setEval(setEnd);
        U_ASSERT(fSetOpStack.peeki()==setStart);
        fSetOpStack.popi();
        break;

    case doSetFinish:
        {
        // Finished a complete set expression, including all nested sets.
        //   The close bracket has already triggered clearing out pending set operators,
        //    the operator stack should be empty and the operand stack should have just
        //    one entry, the result set.
        U_ASSERT(fSetOpStack.empty());
        UnicodeSet *theSet = (UnicodeSet *)fSetStack.pop();
        U_ASSERT(fSetStack.empty());
        compileSet(theSet);
        break;
        }
        
    case doSetIntersection2:
        // Have scanned something like [abc&&
        setPushOp(setIntersection2);
        break;

    case doSetLiteral:
        // Union the just-scanned literal character into the set being built.
        //    This operation is the highest precedence set operation, so we can always do
        //    it immediately, without waiting to see what follows.  It is necessary to perform
        //    any pending '-' or '&' operation first, because these have the same precedence
        //    as union-ing in a literal' 
        {
            setEval(setUnion);
            UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
            s->add(fC.fChar);
            fLastSetLiteral = fC.fChar;
            break;
        }

    case doSetLiteralEscaped:
        // A back-slash escaped literal character was encountered.
        // Processing is the same as with setLiteral, above, with the addition of
        //  the optional check for errors on escaped ASCII letters.
        {
            if ((fModeFlags & UREGEX_ERROR_ON_UNKNOWN_ESCAPES) != 0 &&
                ((fC.fChar >= 0x41 && fC.fChar<= 0x5A) ||     // in [A-Z]
                 (fC.fChar >= 0x61 && fC.fChar <= 0x7a))) {   // in [a-z]
                error(U_REGEX_BAD_ESCAPE_SEQUENCE);
            }
            setEval(setUnion);
            UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
            s->add(fC.fChar);
            fLastSetLiteral = fC.fChar;
            break;
        }

        case doSetNamedChar:
        // Scanning a \N{UNICODE CHARACTER NAME}
        //  Aside from the source of the character, the processing is identical to doSetLiteral,
        //    above.
        {
            UChar32  c = scanNamedChar();
            setEval(setUnion);
            UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
            s->add(c);
            fLastSetLiteral = c;
            break;
        }

    case doSetNamedRange:
        // We have scanned literal-\N{CHAR NAME}.  Add the range to the set.
        // The left character is already in the set, and is saved in fLastSetLiteral.
        // The right side needs to be picked up, the scan is at the 'N'.
        // Lower Limit > Upper limit being an error matches both Java
        //        and ICU UnicodeSet behavior.
        {
            UChar32  c = scanNamedChar();
            if (U_SUCCESS(*fStatus) && fLastSetLiteral > c) {
                error(U_REGEX_INVALID_RANGE);
            }
            UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
            s->add(fLastSetLiteral, c);
            fLastSetLiteral = c;
            break;
        }


    case  doSetNegate:
        // Scanned a '^' at the start of a set.
        // Push the negation operator onto the set op stack.
        // A twist for case-insensitive matching:
        //   the case closure operation must happen _before_ negation.
        //   But the case closure operation will already be on the stack if it's required.
        //   This requires checking for case closure, and swapping the stack order
        //    if it is present.
        {
            int32_t  tosOp = fSetOpStack.peeki();
            if (tosOp == setCaseClose) {
                fSetOpStack.popi();
                fSetOpStack.push(setNegation, *fStatus);
                fSetOpStack.push(setCaseClose, *fStatus);
            } else {
                fSetOpStack.push(setNegation, *fStatus);
            }
        }
        break;

    case doSetNoCloseError:
        error(U_REGEX_MISSING_CLOSE_BRACKET);
        break;

    case doSetOpError:
        error(U_REGEX_RULE_SYNTAX);   //  -- or && at the end of a set.  Illegal.
        break;

    case doSetPosixProp:
        {
            UnicodeSet *s = scanPosixProp();
            if (s != NULL) {
                UnicodeSet *tos = (UnicodeSet *)fSetStack.peek();
                tos->addAll(*s);
                delete s;
            }  // else error.  scanProp() reported the error status already.
        }
        break;
        
    case doSetProp:
        //  Scanned a \p \P within [brackets].
        {
            UnicodeSet *s = scanProp();
            if (s != NULL) {
                UnicodeSet *tos = (UnicodeSet *)fSetStack.peek();
                tos->addAll(*s);
                delete s;
            }  // else error.  scanProp() reported the error status already.
        }
        break;


    case doSetRange:
        // We have scanned literal-literal.  Add the range to the set.
        // The left character is already in the set, and is saved in fLastSetLiteral.
        // The right side is the current character.
        // Lower Limit > Upper limit being an error matches both Java
        //        and ICU UnicodeSet behavior.
        {
        if (fLastSetLiteral > fC.fChar) {
            error(U_REGEX_INVALID_RANGE);  
        }
        UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
        s->add(fLastSetLiteral, fC.fChar);
        break;
        }

    default:
        U_ASSERT(FALSE);
        error(U_REGEX_INTERNAL_ERROR);
        break;
    }

    if (U_FAILURE(*fStatus)) {
        returnVal = FALSE;
    }

    return returnVal;
}



//------------------------------------------------------------------------------
//
//   literalChar           We've encountered a literal character from the pattern,
//                             or an escape sequence that reduces to a character.
//                         Add it to the string containing all literal chars/strings from
//                             the pattern.
//
//------------------------------------------------------------------------------
void RegexCompile::literalChar(UChar32 c)  {
    fLiteralChars.append(c);
}


//------------------------------------------------------------------------------
//
//    fixLiterals           When compiling something that can follow a literal
//                          string in a pattern, emit the code to match the
//                          accumulated literal string.
//
//                          Optionally, split the last char of the string off into
//                          a single "ONE_CHAR" operation, so that quantifiers can
//                          apply to that char alone.  Example:   abc*
//                          The * must apply to the 'c' only.
//
//------------------------------------------------------------------------------
void    RegexCompile::fixLiterals(UBool split) {
    int32_t  op = 0;                       // An op from/for the compiled pattern.

    // If no literal characters have been scanned but not yet had code generated
    //   for them, nothing needs to be done.
    if (fLiteralChars.length() == 0) {
        return;
    }

    int32_t indexOfLastCodePoint = fLiteralChars.moveIndex32(fLiteralChars.length(), -1);
    UChar32 lastCodePoint = fLiteralChars.char32At(indexOfLastCodePoint);

    // Split:  We need to  ensure that the last item in the compiled pattern 
    //     refers only to the last literal scanned in the pattern, so that
    //     quantifiers (*, +, etc.) affect only it, and not a longer string.
    //     Split before case folding for case insensitive matches.

    if (split) {
        fLiteralChars.truncate(indexOfLastCodePoint);
        fixLiterals(FALSE);   // Recursive call, emit code to match the first part of the string.
                              //  Note that the truncated literal string may be empty, in which case
                              //  nothing will be emitted.

        literalChar(lastCodePoint);  // Re-add the last code point as if it were a new literal.
        fixLiterals(FALSE);          // Second recursive call, code for the final code point.
        return;
    }

    // If we are doing case-insensitive matching, case fold the string.  This may expand
    //   the string, e.g. the German sharp-s turns into "ss"
    if (fModeFlags & UREGEX_CASE_INSENSITIVE) {
        fLiteralChars.foldCase();
        indexOfLastCodePoint = fLiteralChars.moveIndex32(fLiteralChars.length(), -1);
        lastCodePoint = fLiteralChars.char32At(indexOfLastCodePoint);
    }

    if (indexOfLastCodePoint == 0) {
        // Single character, emit a URX_ONECHAR op to match it.
        if ((fModeFlags & UREGEX_CASE_INSENSITIVE) && 
                 u_hasBinaryProperty(lastCodePoint, UCHAR_CASE_SENSITIVE)) {
            op = URX_BUILD(URX_ONECHAR_I, lastCodePoint);
        } else {
            op = URX_BUILD(URX_ONECHAR, lastCodePoint);
        }
        fRXPat->fCompiledPat->addElement(op, *fStatus);
    } else {
        // Two or more chars, emit a URX_STRING to match them.
        if (fModeFlags & UREGEX_CASE_INSENSITIVE) {
            op = URX_BUILD(URX_STRING_I, fRXPat->fLiteralText.length());
        } else {
            // TODO here:  add optimization to split case sensitive strings of length two
            //             into two single char ops, for efficiency.
            op = URX_BUILD(URX_STRING, fRXPat->fLiteralText.length());
        }
        fRXPat->fCompiledPat->addElement(op, *fStatus);
        op = URX_BUILD(URX_STRING_LEN, fLiteralChars.length());
        fRXPat->fCompiledPat->addElement(op, *fStatus);
        
        // Add this string into the accumulated strings of the compiled pattern.
        fRXPat->fLiteralText.append(fLiteralChars);
    }

    fLiteralChars.remove();
}






//------------------------------------------------------------------------------
//
//   insertOp()             Insert a slot for a new opcode into the already
//                          compiled pattern code.
//
//                          Fill the slot with a NOP.  Our caller will replace it
//                          with what they really wanted.
//
//------------------------------------------------------------------------------
void   RegexCompile::insertOp(int32_t where) {
    UVector64 *code = fRXPat->fCompiledPat;
    U_ASSERT(where>0 && where < code->size());

    int32_t  nop = URX_BUILD(URX_NOP, 0);
    code->insertElementAt(nop, where, *fStatus);

    // Walk through the pattern, looking for any ops with targets that
    //  were moved down by the insert.  Fix them.
    int32_t loc;
    for (loc=0; loc<code->size(); loc++) {
        int32_t op = (int32_t)code->elementAti(loc);
        int32_t opType = URX_TYPE(op);
        int32_t opValue = URX_VAL(op);
        if ((opType == URX_JMP         ||
            opType == URX_JMPX         ||
            opType == URX_STATE_SAVE   ||
            opType == URX_CTR_LOOP     ||
            opType == URX_CTR_LOOP_NG  ||
            opType == URX_JMP_SAV      ||
            opType == URX_JMP_SAV_X    ||
            opType == URX_RELOC_OPRND)    && opValue > where) {
            // Target location for this opcode is after the insertion point and
            //   needs to be incremented to adjust for the insertion.
            opValue++;
            op = URX_BUILD(opType, opValue);
            code->setElementAt(op, loc);
        }
    }

    // Now fix up the parentheses stack.  All positive values in it are locations in
    //  the compiled pattern.   (Negative values are frame boundaries, and don't need fixing.)
    for (loc=0; loc<fParenStack.size(); loc++) {
        int32_t x = fParenStack.elementAti(loc);
        U_ASSERT(x < code->size());
        if (x>where) {
            x++;
            fParenStack.setElementAt(x, loc);
        }
    }

    if (fMatchCloseParen > where) {
        fMatchCloseParen++;
    }
    if (fMatchOpenParen > where) {
        fMatchOpenParen++;
    }
}



//------------------------------------------------------------------------------
//
//   blockTopLoc()          Find or create a location in the compiled pattern
//                          at the start of the operation or block that has
//                          just been compiled.  Needed when a quantifier (* or
//                          whatever) appears, and we need to add an operation
//                          at the start of the thing being quantified.
//
//                          (Parenthesized Blocks) have a slot with a NOP that
//                          is reserved for this purpose.  .* or similar don't
//                          and a slot needs to be added.
//
//       parameter reserveLoc   :  TRUE -  ensure that there is space to add an opcode
//                                         at the returned location.
//                                 FALSE - just return the address,
//                                         do not reserve a location there.
//
//------------------------------------------------------------------------------
int32_t   RegexCompile::blockTopLoc(UBool reserveLoc) {
    int32_t   theLoc;
    fixLiterals(TRUE);  // Emit code for any pending literals.
                        //   If last item was a string, emit separate op for the its last char.
    if (fRXPat->fCompiledPat->size() == fMatchCloseParen)
    {
        // The item just processed is a parenthesized block.
        theLoc = fMatchOpenParen;   // A slot is already reserved for us.
        U_ASSERT(theLoc > 0);
        U_ASSERT(URX_TYPE(((uint32_t)fRXPat->fCompiledPat->elementAti(theLoc))) == URX_NOP);
    }
    else {
        // Item just compiled is a single thing, a ".", or a single char, a string or a set reference.
        // No slot for STATE_SAVE was pre-reserved in the compiled code.
        // We need to make space now.
        theLoc = fRXPat->fCompiledPat->size()-1;
        int32_t opAtTheLoc = (int32_t)fRXPat->fCompiledPat->elementAti(theLoc);
        if (URX_TYPE(opAtTheLoc) == URX_STRING_LEN) {
            // Strings take two opcode, we want the position of the first one.
            // We can have a string at this point if a single character case-folded to two.
            theLoc--;
        }
        if (reserveLoc) {
            int32_t  nop = URX_BUILD(URX_NOP, 0);
            fRXPat->fCompiledPat->insertElementAt(nop, theLoc, *fStatus);
        }
    }
    return theLoc;
}



//------------------------------------------------------------------------------
//
//    handleCloseParen      When compiling a close paren, we need to go back
//                          and fix up any JMP or SAVE operations within the
//                          parenthesized block that need to target the end
//                          of the block.  The locations of these are kept on
//                          the paretheses stack.
//
//                          This function is called both when encountering a
//                          real ) and at the end of the pattern.
//
//------------------------------------------------------------------------------
void  RegexCompile::handleCloseParen() {
    int32_t   patIdx;
    int32_t   patOp;
    if (fParenStack.size() <= 0) {
        error(U_REGEX_MISMATCHED_PAREN);
        return;
    }

    // Emit code for any pending literals.
    fixLiterals(FALSE);

    // Fixup any operations within the just-closed parenthesized group
    //    that need to reference the end of the (block).
    //    (The first one popped from the stack is an unused slot for
    //     alternation (OR) state save, but applying the fixup to it does no harm.)
    for (;;) {
        patIdx = fParenStack.popi();
        if (patIdx < 0) {
            // value < 0 flags the start of the frame on the paren stack.
            break;
        }
        U_ASSERT(patIdx>0 && patIdx <= fRXPat->fCompiledPat->size());
        patOp = (int32_t)fRXPat->fCompiledPat->elementAti(patIdx);
        U_ASSERT(URX_VAL(patOp) == 0);          // Branch target for JMP should not be set.
        patOp |= fRXPat->fCompiledPat->size();  // Set it now.
        fRXPat->fCompiledPat->setElementAt(patOp, patIdx);
        fMatchOpenParen     = patIdx;
    }

    //  At the close of any parenthesized block, restore the match mode flags  to
    //  the value they had at the open paren.  Saved value is
    //  at the top of the paren stack.
    fModeFlags = fParenStack.popi();
    U_ASSERT(fModeFlags < 0);

    // DO any additional fixups, depending on the specific kind of
    // parentesized grouping this is

    switch (patIdx) {
    case plain:
    case flags:
        // No additional fixups required.
        //   (Grouping-only parentheses)
        break;
    case capturing:
        // Capturing Parentheses.
        //   Insert a End Capture op into the pattern.
        //   The frame offset of the variables for this cg is obtained from the
        //       start capture op and put it into the end-capture op.
        {
            int32_t   captureOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen+1);
            U_ASSERT(URX_TYPE(captureOp) == URX_START_CAPTURE);

            int32_t   frameVarLocation = URX_VAL(captureOp);
            int32_t   endCaptureOp = URX_BUILD(URX_END_CAPTURE, frameVarLocation);
            fRXPat->fCompiledPat->addElement(endCaptureOp, *fStatus);
        }
        break;
    case atomic:
        // Atomic Parenthesis.
        //   Insert a LD_SP operation to restore the state stack to the position
        //   it was when the atomic parens were entered.
        {
            int32_t   stoOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen+1);
            U_ASSERT(URX_TYPE(stoOp) == URX_STO_SP);
            int32_t   stoLoc = URX_VAL(stoOp);
            int32_t   ldOp   = URX_BUILD(URX_LD_SP, stoLoc);
            fRXPat->fCompiledPat->addElement(ldOp, *fStatus);
        }
        break;

    case lookAhead:
        {
            int32_t  startOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen-5);
            U_ASSERT(URX_TYPE(startOp) == URX_LA_START);
            int32_t dataLoc  = URX_VAL(startOp);
            int32_t op       = URX_BUILD(URX_LA_END, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
        }
        break;

    case negLookAhead:
        {
            // See comment at doOpenLookAheadNeg
            int32_t  startOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen-1);
            U_ASSERT(URX_TYPE(startOp) == URX_LA_START);
            int32_t dataLoc  = URX_VAL(startOp);
            int32_t op       = URX_BUILD(URX_LA_END, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
            op               = URX_BUILD(URX_BACKTRACK, 0);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
            op               = URX_BUILD(URX_LA_END, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // Patch the URX_SAVE near the top of the block.
            // The destination of the SAVE is the final LA_END that was just added.
            int32_t saveOp   = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen);
            U_ASSERT(URX_TYPE(saveOp) == URX_STATE_SAVE);
            int32_t dest     = fRXPat->fCompiledPat->size()-1;
            saveOp           = URX_BUILD(URX_STATE_SAVE, dest);
            fRXPat->fCompiledPat->setElementAt(saveOp, fMatchOpenParen);
        }
        break;

    case lookBehind:
        {
            // See comment at doOpenLookBehind.

            // Append the URX_LB_END and URX_LA_END to the compiled pattern.
            int32_t  startOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen-4);
            U_ASSERT(URX_TYPE(startOp) == URX_LB_START);
            int32_t dataLoc  = URX_VAL(startOp);
            int32_t op       = URX_BUILD(URX_LB_END, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);
                    op       = URX_BUILD(URX_LA_END, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // Determine the min and max bounds for the length of the
            //  string that the pattern can match.
            //  An unbounded upper limit is an error.
            int32_t patEnd   = fRXPat->fCompiledPat->size() - 1;
            int32_t minML    = minMatchLength(fMatchOpenParen, patEnd);
            int32_t maxML    = maxMatchLength(fMatchOpenParen, patEnd);
            if (maxML == INT32_MAX) {
                error(U_REGEX_LOOK_BEHIND_LIMIT);
                break;
            }
            U_ASSERT(minML <= maxML);

            // Insert the min and max match len bounds into the URX_LB_CONT op that
            //  appears at the top of the look-behind block, at location fMatchOpenParen+1
            fRXPat->fCompiledPat->setElementAt(minML,  fMatchOpenParen-2);
            fRXPat->fCompiledPat->setElementAt(maxML,  fMatchOpenParen-1);

        }
        break;



    case lookBehindN:
        {
            // See comment at doOpenLookBehindNeg.

            // Append the URX_LBN_END to the compiled pattern.
            int32_t  startOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen-5);
            U_ASSERT(URX_TYPE(startOp) == URX_LB_START);
            int32_t dataLoc  = URX_VAL(startOp);
            int32_t op       = URX_BUILD(URX_LBN_END, dataLoc);
            fRXPat->fCompiledPat->addElement(op, *fStatus);

            // Determine the min and max bounds for the length of the
            //  string that the pattern can match.
            //  An unbounded upper limit is an error.
            int32_t patEnd   = fRXPat->fCompiledPat->size() - 1;
            int32_t minML    = minMatchLength(fMatchOpenParen, patEnd);
            int32_t maxML    = maxMatchLength(fMatchOpenParen, patEnd);
            if (maxML == INT32_MAX) {
                error(U_REGEX_LOOK_BEHIND_LIMIT);
                break;
            }
            U_ASSERT(minML <= maxML);

            // Insert the min and max match len bounds into the URX_LB_CONT op that
            //  appears at the top of the look-behind block, at location fMatchOpenParen+1
            fRXPat->fCompiledPat->setElementAt(minML,  fMatchOpenParen-3);
            fRXPat->fCompiledPat->setElementAt(maxML,  fMatchOpenParen-2);

            // Insert the pattern location to continue at after a successful match
            //  as the last operand of the URX_LBN_CONT
            op = URX_BUILD(URX_RELOC_OPRND, fRXPat->fCompiledPat->size());
            fRXPat->fCompiledPat->setElementAt(op,  fMatchOpenParen-1);
        }
        break;



    default:
        U_ASSERT(FALSE);
    }

    // remember the next location in the compiled pattern.
    // The compilation of Quantifiers will look at this to see whether its looping
    //   over a parenthesized block or a single item
    fMatchCloseParen = fRXPat->fCompiledPat->size();
}



//------------------------------------------------------------------------------
//
//   compileSet       Compile the pattern operations for a reference to a
//                    UnicodeSet.
//
//------------------------------------------------------------------------------
void        RegexCompile::compileSet(UnicodeSet *theSet)
{
    if (theSet == NULL) {
        return;
    }
    //  Remove any strings from the set.
    //  There shoudn't be any, but just in case.
    //     (Case Closure can add them; if we had a simple case closure avaialble that
    //      ignored strings, that would be better.)
    theSet->removeAllStrings();
    int32_t  setSize = theSet->size();

    switch (setSize) {
    case 0:
        {
            // Set of no elements.   Always fails to match.
            fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKTRACK, 0), *fStatus);
            delete theSet;
        }
        break;

    case 1:
        {
            // The set contains only a single code point.  Put it into
            //   the compiled pattern as a single char operation rather
            //   than a set, and discard the set itself.
            literalChar(theSet->charAt(0));
            delete theSet;
        }
        break;

    default:
        {
            //  The set contains two or more chars.  (the normal case)
            //  Put it into the compiled pattern as a set.
            int32_t setNumber = fRXPat->fSets->size();
            fRXPat->fSets->addElement(theSet, *fStatus);
            int32_t setOp = URX_BUILD(URX_SETREF, setNumber);
            fRXPat->fCompiledPat->addElement(setOp, *fStatus);
        }
    }
}


//------------------------------------------------------------------------------
//
//   compileInterval    Generate the code for a {min, max} style interval quantifier.
//                      Except for the specific opcodes used, the code is the same
//                      for all three types (greedy, non-greedy, possessive) of
//                      intervals.  The opcodes are supplied as parameters.
//
//                      The code for interval loops has this form:
//                         0  CTR_INIT   counter loc (in stack frame)
//                         1             5  patt address of CTR_LOOP at bottom of block
//                         2             min count
//                         3             max count   (-1 for unbounded)
//                         4  ...        block to be iterated over
//                         5  CTR_LOOP
//
//                       In
//------------------------------------------------------------------------------
void        RegexCompile::compileInterval(int32_t InitOp,  int32_t LoopOp)
{
    // The CTR_INIT op at the top of the block with the {n,m} quantifier takes
    //   four slots in the compiled code.  Reserve them.
    int32_t   topOfBlock = blockTopLoc(TRUE);
    insertOp(topOfBlock);
    insertOp(topOfBlock);
    insertOp(topOfBlock);

    // The operands for the CTR_INIT opcode include the index in the matcher data
    //   of the counter.  Allocate it now.
    int32_t   counterLoc = fRXPat->fFrameSize;
    fRXPat->fFrameSize++;

    int32_t   op = URX_BUILD(InitOp, counterLoc);
    fRXPat->fCompiledPat->setElementAt(op, topOfBlock);

    // The second operand of CTR_INIT is the location following the end of the loop.
    //   Must put in as a URX_RELOC_OPRND so that the value will be adjusted if the
    //   compilation of something later on causes the code to grow and the target
    //   position to move.
    int32_t loopEnd = fRXPat->fCompiledPat->size();
    op = URX_BUILD(URX_RELOC_OPRND, loopEnd);
    fRXPat->fCompiledPat->setElementAt(op, topOfBlock+1);

    // Followed by the min and max counts.
    fRXPat->fCompiledPat->setElementAt(fIntervalLow, topOfBlock+2);
    fRXPat->fCompiledPat->setElementAt(fIntervalUpper, topOfBlock+3);

    // Apend the CTR_LOOP op.  The operand is the location of the CTR_INIT op.
    //   Goes at end of the block being looped over, so just append to the code so far.
    op = URX_BUILD(LoopOp, topOfBlock);
    fRXPat->fCompiledPat->addElement(op, *fStatus);

    if ((fIntervalLow & 0xff000000) != 0 ||
        (fIntervalUpper > 0 && (fIntervalUpper & 0xff000000) != 0)) {
            error(U_REGEX_NUMBER_TOO_BIG);
        }

    if (fIntervalLow > fIntervalUpper && fIntervalUpper != -1) {
        error(U_REGEX_MAX_LT_MIN);
    }
}



UBool RegexCompile::compileInlineInterval() {
    if (fIntervalUpper > 10 || fIntervalUpper < fIntervalLow) {
        // Too big to inline.  Fail, which will cause looping code to be generated.
        //   (Upper < Lower picks up unbounded upper and errors, both.)
        return FALSE;
    }

    int32_t   topOfBlock = blockTopLoc(FALSE);
    if (fIntervalUpper == 0) {
        // Pathological case.  Attempt no matches, as if the block doesn't exist.
        fRXPat->fCompiledPat->setSize(topOfBlock);
        return TRUE;
    }

    if (topOfBlock != fRXPat->fCompiledPat->size()-1 && fIntervalUpper != 1) {
        // The thing being repeated is not a single op, but some
        //   more complex block.  Do it as a loop, not inlines.
        //   Note that things "repeated" a max of once are handled as inline, because
        //     the one copy of the code already generated is just fine.
        return FALSE;
    }

    // Pick up the opcode that is to be repeated
    //
    int32_t op = (int32_t)fRXPat->fCompiledPat->elementAti(topOfBlock);

    // Compute the pattern location where the inline sequence
    //   will end, and set up the state save op that will be needed.
    //
    int32_t endOfSequenceLoc = fRXPat->fCompiledPat->size()-1
                                + fIntervalUpper + (fIntervalUpper-fIntervalLow);
    int32_t saveOp = URX_BUILD(URX_STATE_SAVE, endOfSequenceLoc);
    if (fIntervalLow == 0) {
        insertOp(topOfBlock);
        fRXPat->fCompiledPat->setElementAt(saveOp, topOfBlock);
    }



    //  Loop, emitting the op for the thing being repeated each time.
    //    Loop starts at 1 because one instance of the op already exists in the pattern,
    //    it was put there when it was originally encountered.
    int32_t i;
    for (i=1; i<fIntervalUpper; i++ ) {
        if (i == fIntervalLow) {
            fRXPat->fCompiledPat->addElement(saveOp, *fStatus);
        }
        if (i > fIntervalLow) {
            fRXPat->fCompiledPat->addElement(saveOp, *fStatus);
        }
        fRXPat->fCompiledPat->addElement(op, *fStatus);
    }
    return TRUE;
}



//------------------------------------------------------------------------------
//
//   matchStartType    Determine how a match can start.
//                     Used to optimize find() operations.
//
//                     Operation is very similar to minMatchLength().  Walk the compiled
//                     pattern, keeping an on-going minimum-match-length.  For any
//                     op where the min match coming in is zero, add that ops possible
//                     starting matches to the possible starts for the overall pattern.
//
//------------------------------------------------------------------------------
void   RegexCompile::matchStartType() {
    if (U_FAILURE(*fStatus)) {
        return;
    }


    int32_t    loc;                    // Location in the pattern of the current op being processed.
    int32_t    op;                     // The op being processed
    int32_t    opType;                 // The opcode type of the op
    int32_t    currentLen = 0;         // Minimum length of a match to this point (loc) in the pattern
    int32_t    numInitialStrings = 0;  // Number of strings encountered that could match at start.

    UBool      atStart = TRUE;         // True if no part of the pattern yet encountered
                                       //   could have advanced the position in a match.
                                       //   (Maximum match length so far == 0)

    // forwardedLength is a vector holding minimum-match-length values that
    //   are propagated forward in the pattern by JMP or STATE_SAVE operations.
    //   It must be one longer than the pattern being checked because some  ops
    //   will jmp to a end-of-block+1 location from within a block, and we must
    //   count those when checking the block.
    int32_t end = fRXPat->fCompiledPat->size();
    UVector32  forwardedLength(end+1, *fStatus);
    forwardedLength.setSize(end+1);
    for (loc=3; loc<end; loc++) {
        forwardedLength.setElementAt(INT32_MAX, loc);
    }

    for (loc = 3; loc<end; loc++) {
        op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
        opType = URX_TYPE(op);

        // The loop is advancing linearly through the pattern.
        // If the op we are now at was the destination of a branch in the pattern,
        // and that path has a shorter minimum length than the current accumulated value,
        // replace the current accumulated value.
        if (forwardedLength.elementAti(loc) < currentLen) {
            currentLen = forwardedLength.elementAti(loc);
            U_ASSERT(currentLen>=0 && currentLen < INT32_MAX);
        }

        switch (opType) {
            // Ops that don't change the total length matched
        case URX_RESERVED_OP:
        case URX_END:
        case URX_FAIL:
        case URX_STRING_LEN:
        case URX_NOP:
        case URX_START_CAPTURE:
        case URX_END_CAPTURE:
        case URX_BACKSLASH_B:
        case URX_BACKSLASH_BU:
        case URX_BACKSLASH_G:
        case URX_BACKSLASH_Z:
        case URX_DOLLAR:
        case URX_DOLLAR_M:
        case URX_DOLLAR_D:
        case URX_DOLLAR_MD:
        case URX_RELOC_OPRND:
        case URX_STO_INP_LOC:
        case URX_BACKREF:         // BackRef.  Must assume that it might be a zero length match
        case URX_BACKREF_I:
                
        case URX_STO_SP:          // Setup for atomic or possessive blocks.  Doesn't change what can match.
        case URX_LD_SP:
            break;

        case URX_CARET:
            if (atStart) {
                fRXPat->fStartType = START_START;
            }
            break;

        case URX_CARET_M:
        case URX_CARET_M_UNIX:
            if (atStart) {
                fRXPat->fStartType = START_LINE;
            }
            break;

        case URX_ONECHAR:
            if (currentLen == 0) {
                // This character could appear at the start of a match.
                //   Add it to the set of possible starting characters.
                fRXPat->fInitialChars->add(URX_VAL(op));
                numInitialStrings += 2;
            }
            currentLen++;
            atStart = FALSE;
            break;


        case URX_SETREF:
            if (currentLen == 0) {
                int32_t  sn = URX_VAL(op);
                U_ASSERT(sn > 0 && sn < fRXPat->fSets->size());
                const UnicodeSet *s = (UnicodeSet *)fRXPat->fSets->elementAt(sn);
                fRXPat->fInitialChars->addAll(*s);
                numInitialStrings += 2;
            }
            currentLen++;
            atStart = FALSE;
            break;

        case URX_LOOP_SR_I:
            // [Set]*, like a SETREF, above, in what it can match,
            //  but may not match at all, so currentLen is not incremented.
            if (currentLen == 0) {
                int32_t  sn = URX_VAL(op);
                U_ASSERT(sn > 0 && sn < fRXPat->fSets->size());
                const UnicodeSet *s = (UnicodeSet *)fRXPat->fSets->elementAt(sn);
                fRXPat->fInitialChars->addAll(*s);
                numInitialStrings += 2;
            }
            atStart = FALSE;
            break;

        case URX_LOOP_DOT_I:
            if (currentLen == 0) {
                // .* at the start of a pattern.
                //    Any character can begin the match.
                fRXPat->fInitialChars->clear();
                fRXPat->fInitialChars->complement();
                numInitialStrings += 2;
            }
            atStart = FALSE;
            break;


        case URX_STATIC_SETREF:
            if (currentLen == 0) {
                int32_t  sn = URX_VAL(op);
                U_ASSERT(sn>0 && sn<URX_LAST_SET);
                const UnicodeSet *s = fRXPat->fStaticSets[sn];
                fRXPat->fInitialChars->addAll(*s);
                numInitialStrings += 2;
            }
            currentLen++;
            atStart = FALSE;
            break;



        case URX_STAT_SETREF_N:
            if (currentLen == 0) {
                int32_t  sn = URX_VAL(op);
                const UnicodeSet *s = fRXPat->fStaticSets[sn];
                UnicodeSet sc(*s);
                sc.complement();
                fRXPat->fInitialChars->addAll(sc);
                numInitialStrings += 2;
            }
            currentLen++;
            atStart = FALSE;
            break;



        case URX_BACKSLASH_D:
            // Digit Char
             if (currentLen == 0) {
                 UnicodeSet s;
                 s.applyIntPropertyValue(UCHAR_GENERAL_CATEGORY_MASK, U_GC_ND_MASK, *fStatus);
                 if (URX_VAL(op) != 0) {
                     s.complement();
                 }
                 fRXPat->fInitialChars->addAll(s);
                 numInitialStrings += 2;
            }
            currentLen++;
            atStart = FALSE;
            break;


        case URX_ONECHAR_I:
            // Case Insensitive Single Character.
            if (currentLen == 0) {
                UChar32  c = URX_VAL(op);
                if (u_hasBinaryProperty(c, UCHAR_CASE_SENSITIVE)) {

                    // Disable optimizations on first char of match.
                    // TODO: Compute the set of chars that case fold to this char, or to
                    //       a string that begins with this char.
                    //       For simple case folding, this code worked:
                    //   UnicodeSet s(c, c);
                    //   s.closeOver(USET_CASE_INSENSITIVE);
                    //   fRXPat->fInitialChars->addAll(s);

                    fRXPat->fInitialChars->clear();
                    fRXPat->fInitialChars->complement();
                } else {
                    // Char has no case variants.  Just add it as-is to the
                    //   set of possible starting chars.
                    fRXPat->fInitialChars->add(c);
                }
                numInitialStrings += 2;
            }
            currentLen++;
            atStart = FALSE;
            break;


        case URX_BACKSLASH_X:   // Grahpeme Cluster.  Minimum is 1, max unbounded.
        case URX_DOTANY_ALL:    // . matches one or two.
        case URX_DOTANY:
        case URX_DOTANY_UNIX:
            if (currentLen == 0) {
                // These constructs are all bad news when they appear at the start
                //   of a match.  Any character can begin the match.
                fRXPat->fInitialChars->clear();
                fRXPat->fInitialChars->complement();
                numInitialStrings += 2;
            }
            currentLen++;
            atStart = FALSE;
            break;


        case URX_JMPX:
            loc++;             // Except for extra operand on URX_JMPX, same as URX_JMP.
        case URX_JMP:
            {
                int32_t  jmpDest = URX_VAL(op);
                if (jmpDest < loc) {
                    // Loop of some kind.  Can safely ignore, the worst that will happen
                    //  is that we understate the true minimum length
                    currentLen = forwardedLength.elementAti(loc+1);

                } else {
                    // Forward jump.  Propagate the current min length to the target loc of the jump.
                    U_ASSERT(jmpDest <= end+1);
                    if (forwardedLength.elementAti(jmpDest) > currentLen) {
                        forwardedLength.setElementAt(currentLen, jmpDest);
                    }
                }
            }
            atStart = FALSE;
            break;

        case URX_JMP_SAV:
        case URX_JMP_SAV_X:
            // Combo of state save to the next loc, + jmp backwards.
            //   Net effect on min. length computation is nothing.
            atStart = FALSE;
            break;

        case URX_BACKTRACK:
            // Fails are kind of like a branch, except that the min length was
            //   propagated already, by the state save.
            currentLen = forwardedLength.elementAti(loc+1);
            atStart = FALSE;
            break;


        case URX_STATE_SAVE:
            {
                // State Save, for forward jumps, propagate the current minimum.
                //             of the state save.
                int32_t  jmpDest = URX_VAL(op);
                if (jmpDest > loc) {
                    if (currentLen < forwardedLength.elementAti(jmpDest)) {
                        forwardedLength.setElementAt(currentLen, jmpDest);
                    }
                }
            }
            atStart = FALSE;
            break;




        case URX_STRING:
            {
                loc++;
                int32_t stringLenOp = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                int32_t stringLen   = URX_VAL(stringLenOp);
                U_ASSERT(URX_TYPE(stringLenOp) == URX_STRING_LEN);
                U_ASSERT(stringLenOp >= 2);
                if (currentLen == 0) {
                    // Add the starting character of this string to the set of possible starting
                    //   characters for this pattern.
                    int32_t stringStartIdx = URX_VAL(op);
                    UChar32  c = fRXPat->fLiteralText.char32At(stringStartIdx);
                    fRXPat->fInitialChars->add(c);

                    // Remember this string.  After the entire pattern has been checked,
                    //  if nothing else is identified that can start a match, we'll use it.
                    numInitialStrings++;
                    fRXPat->fInitialStringIdx = stringStartIdx;
                    fRXPat->fInitialStringLen = stringLen;
                }

                currentLen += stringLen;
                atStart = FALSE;
            }
            break;

        case URX_STRING_I:
            {
                // Case-insensitive string.  Unlike exact-match strings, we won't
                //   attempt a string search for possible match positions.  But we
                //   do update the set of possible starting characters.
                loc++;
                int32_t stringLenOp = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                int32_t stringLen   = URX_VAL(stringLenOp);
                U_ASSERT(URX_TYPE(stringLenOp) == URX_STRING_LEN);
                U_ASSERT(stringLenOp >= 2);
                if (currentLen == 0) {
                    // Add the starting character of this string to the set of possible starting
                    //   characters for this pattern.
                    int32_t stringStartIdx = URX_VAL(op);
                    UChar32  c = fRXPat->fLiteralText.char32At(stringStartIdx);
                    UnicodeSet s(c, c);

                    // TODO:  compute correct set of starting chars for full case folding.
                    //        For the moment, say any char can start.
                    // s.closeOver(USET_CASE_INSENSITIVE);
                    s.clear();
                    s.complement();

                    fRXPat->fInitialChars->addAll(s);
                    numInitialStrings += 2;  // Matching on an initial string not possible.
                }
                currentLen += stringLen;
                atStart = FALSE;
            }
            break;

        case URX_CTR_INIT:
        case URX_CTR_INIT_NG:
            {
                // Loop Init Ops.  These don't change the min length, but they are 4 word ops
                //   so location must be updated accordingly.
                // Loop Init Ops.
                //   If the min loop count == 0
                //      move loc forwards to the end of the loop, skipping over the body.
                //   If the min count is > 0,
                //      continue normal processing of the body of the loop.
                int32_t loopEndLoc   = (int32_t)fRXPat->fCompiledPat->elementAti(loc+1);
                        loopEndLoc   = URX_VAL(loopEndLoc);
                int32_t minLoopCount = (int32_t)fRXPat->fCompiledPat->elementAti(loc+2);
                if (minLoopCount == 0) {
                    // Min Loop Count of 0, treat like a forward branch and
                    //   move the current minimum length up to the target
                    //   (end of loop) location.
                    U_ASSERT(loopEndLoc <= end+1);
                    if (forwardedLength.elementAti(loopEndLoc) > currentLen) {
                        forwardedLength.setElementAt(currentLen, loopEndLoc);
                    }
                }
                loc+=3;  // Skips over operands of CTR_INIT
            }
            atStart = FALSE;
            break;


        case URX_CTR_LOOP:
        case URX_CTR_LOOP_NG:
            // Loop ops.
            //  The jump is conditional, backwards only.
            atStart = FALSE;
            break;

        case URX_LOOP_C:
            // More loop ops.  These state-save to themselves.
            //   don't change the minimum match
            atStart = FALSE;
            break;


        case URX_LA_START:
        case URX_LB_START:
            {
                // Look-around.  Scan forward until the matching look-ahead end,
                //   without processing the look-around block.  This is overly pessimistic.
                
                // Keep track of the nesting depth of look-around blocks.  Boilerplate code for
                //   lookahead contains two LA_END instructions, so count goes up by two
                //   for each LA_START.
                int32_t  depth = (opType == URX_LA_START? 2: 1);
                for (;;) {
                    loc++;
                    op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                    if (URX_TYPE(op) == URX_LA_START) {
                        depth+=2;
                    }
                    if (URX_TYPE(op) == URX_LB_START) {
                        depth++;
                    }
                    if (URX_TYPE(op) == URX_LA_END || URX_TYPE(op)==URX_LBN_END) {
                        depth--;
                        if (depth == 0) {
                            break;
                        }
                    }
                    if (URX_TYPE(op) == URX_STATE_SAVE) {
                        // Need this because neg lookahead blocks will FAIL to outside
                        //   of the block.
                        int32_t  jmpDest = URX_VAL(op);
                        if (jmpDest > loc) {
                            if (currentLen < forwardedLength.elementAti(jmpDest)) {
                                forwardedLength.setElementAt(currentLen, jmpDest);
                            }
                        }
                    }
                    U_ASSERT(loc <= end);
                }
            }
            break;

        case URX_LA_END:
        case URX_LB_CONT:
        case URX_LB_END:
        case URX_LBN_CONT:
        case URX_LBN_END:
            U_ASSERT(FALSE);     // Shouldn't get here.  These ops should be
                                 //  consumed by the scan in URX_LA_START and LB_START

            break;

        default:
            U_ASSERT(FALSE);
            }

        }


    // We have finished walking through the ops.  Check whether some forward jump
    //   propagated a shorter length to location end+1.
    if (forwardedLength.elementAti(end+1) < currentLen) {
        currentLen = forwardedLength.elementAti(end+1);
    }


    fRXPat->fInitialChars8->init(fRXPat->fInitialChars);


    // Sort out what we should check for when looking for candidate match start positions.
    // In order of preference,
    //     1.   Start of input text buffer.
    //     2.   A literal string.
    //     3.   Start of line in multi-line mode.
    //     4.   A single literal character.
    //     5.   A character from a set of characters.
    //
    if (fRXPat->fStartType == START_START) {
        // Match only at the start of an input text string.
        //    start type is already set.  We're done.
    } else if (numInitialStrings == 1 && fRXPat->fMinMatchLen > 0) {
        // Match beginning only with a literal string.
        UChar32  c = fRXPat->fLiteralText.char32At(fRXPat->fInitialStringIdx);
        U_ASSERT(fRXPat->fInitialChars->contains(c));
        fRXPat->fStartType   = START_STRING;
        fRXPat->fInitialChar = c;
    } else if (fRXPat->fStartType == START_LINE) {
        // Match at start of line in Multi-Line mode.
        // Nothing to do here; everything is already set.
    } else if (fRXPat->fMinMatchLen == 0) {
        // Zero length match possible.  We could start anywhere.
        fRXPat->fStartType = START_NO_INFO;
    } else if (fRXPat->fInitialChars->size() == 1) {
        // All matches begin with the same char.
        fRXPat->fStartType   = START_CHAR;
        fRXPat->fInitialChar = fRXPat->fInitialChars->charAt(0);
        U_ASSERT(fRXPat->fInitialChar != (UChar32)-1);
    } else if (fRXPat->fInitialChars->contains((UChar32)0, (UChar32)0x10ffff) == FALSE &&
        fRXPat->fMinMatchLen > 0) {
        // Matches start with a set of character smaller than the set of all chars.
        fRXPat->fStartType = START_SET;
    } else {
        // Matches can start with anything
        fRXPat->fStartType = START_NO_INFO;
    }

    return;
}



//------------------------------------------------------------------------------
//
//   minMatchLength    Calculate the length of the shortest string that could
//                     match the specified pattern.
//                     Length is in 16 bit code units, not code points.
//
//                     The calculated length may not be exact.  The returned
//                     value may be shorter than the actual minimum; it must
//                     never be longer.
//
//                     start and end are the range of p-code operations to be
//                     examined.  The endpoints are included in the range.
//
//------------------------------------------------------------------------------
int32_t   RegexCompile::minMatchLength(int32_t start, int32_t end) {
    if (U_FAILURE(*fStatus)) {
        return 0;
    }

    U_ASSERT(start <= end);
    U_ASSERT(end < fRXPat->fCompiledPat->size());


    int32_t    loc;
    int32_t    op;
    int32_t    opType;
    int32_t    currentLen = 0;


    // forwardedLength is a vector holding minimum-match-length values that
    //   are propagated forward in the pattern by JMP or STATE_SAVE operations.
    //   It must be one longer than the pattern being checked because some  ops
    //   will jmp to a end-of-block+1 location from within a block, and we must
    //   count those when checking the block.
    UVector32  forwardedLength(end+2, *fStatus);
    forwardedLength.setSize(end+2);
    for (loc=start; loc<=end+1; loc++) {
        forwardedLength.setElementAt(INT32_MAX, loc);
    }

    for (loc = start; loc<=end; loc++) {
        op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
        opType = URX_TYPE(op);

        // The loop is advancing linearly through the pattern.
        // If the op we are now at was the destination of a branch in the pattern,
        // and that path has a shorter minimum length than the current accumulated value,
        // replace the current accumulated value.
        // U_ASSERT(currentLen>=0 && currentLen < INT32_MAX);  // MinLength == INT32_MAX for some
                                                               //   no-match-possible cases.
        if (forwardedLength.elementAti(loc) < currentLen) {
            currentLen = forwardedLength.elementAti(loc);
            U_ASSERT(currentLen>=0 && currentLen < INT32_MAX);
        }

        switch (opType) {
            // Ops that don't change the total length matched
        case URX_RESERVED_OP:
        case URX_END:
        case