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.

Implementation

Mercurial (27a812186ff4)

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
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 *
 * Copyright (C) 2012 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#ifndef yarr_YarrCanonicalizeUCS2_h
#define yarr_YarrCanonicalizeUCS2_h

#include <stdint.h>

#include "yarr/wtfbridge.h"

namespace JSC { namespace Yarr {

// This set of data (autogenerated using YarrCanonicalizeUCS2.js into YarrCanonicalizeUCS2.cpp)
// provides information for each UCS2 code point as to the set of code points that it should
// match under the ES5.1 case insensitive RegExp matching rules, specified in 15.10.2.8.
enum UCS2CanonicalizationType {
    CanonicalizeUnique,               // No canonically equal values, e.g. 0x0.
    CanonicalizeSet,                  // Value indicates a set in characterSetInfo.
    CanonicalizeRangeLo,              // Value is positive delta to pair, E.g. 0x41 has value 0x20, -> 0x61.
    CanonicalizeRangeHi,              // Value is positive delta to pair, E.g. 0x61 has value 0x20, -> 0x41.
    CanonicalizeAlternatingAligned,   // Aligned consequtive pair, e.g. 0x1f4,0x1f5.
    CanonicalizeAlternatingUnaligned  // Unaligned consequtive pair, e.g. 0x241,0x242.
};
struct UCS2CanonicalizationRange { uint16_t begin, end, value, type; };
extern const size_t UCS2_CANONICALIZATION_RANGES;
extern const uint16_t* const characterSetInfo[];
extern const UCS2CanonicalizationRange rangeInfo[];

// This table is similar to the full rangeInfo table, however this maps from UCS2 codepoints to
// the set of Latin1 codepoints that could match.
enum LatinCanonicalizationType {
    CanonicalizeLatinSelf,     // This character is in the Latin1 range, but has no canonical equivalent in the range.
    CanonicalizeLatinMask0x20, // One of a pair of characters, under the mask 0x20.
    CanonicalizeLatinOther,    // This character is not in the Latin1 range, but canonicalizes to another that is.
    CanonicalizeLatinInvalid   // Cannot match against Latin1 input.
};
struct LatinCanonicalizationRange { uint16_t begin, end, value, type; };
extern const size_t LATIN_CANONICALIZATION_RANGES;
extern const LatinCanonicalizationRange latinRangeInfo[];

// This searches in log2 time over ~364 entries, so should typically result in 8 compares.
inline const UCS2CanonicalizationRange* rangeInfoFor(UChar ch)
{
    const UCS2CanonicalizationRange* info = rangeInfo;
    size_t entries = UCS2_CANONICALIZATION_RANGES;

    while (true) {
        size_t candidate = entries >> 1;
        const UCS2CanonicalizationRange* candidateInfo = info + candidate;
        if (ch < candidateInfo->begin)
            entries = candidate;
        else if (ch <= candidateInfo->end)
            return candidateInfo;
        else {
            info = candidateInfo + 1;
            entries -= (candidate + 1);
        }
    }
}

// Should only be called for characters that have one canonically matching value.
inline UChar getCanonicalPair(const UCS2CanonicalizationRange* info, UChar ch)
{
    ASSERT(ch >= info->begin && ch <= info->end);
    switch (info->type) {
    case CanonicalizeRangeLo:
        return ch + info->value;
    case CanonicalizeRangeHi:
        return ch - info->value;
    case CanonicalizeAlternatingAligned:
        return ch ^ 1;
    case CanonicalizeAlternatingUnaligned:
        return ((ch - 1) ^ 1) + 1;
    default:
        ASSERT_NOT_REACHED();
    }
    ASSERT_NOT_REACHED();
    return 0;
}

// Returns true if no other UCS2 codepoint can match this value.
inline bool isCanonicallyUnique(UChar ch)
{
    return rangeInfoFor(ch)->type == CanonicalizeUnique;
}

// Returns true if values are equal, under the canonicalization rules.
inline bool areCanonicallyEquivalent(UChar a, UChar b)
{
    const UCS2CanonicalizationRange* info = rangeInfoFor(a);
    switch (info->type) {
    case CanonicalizeUnique:
        return a == b;
    case CanonicalizeSet: {
        for (const uint16_t* set = characterSetInfo[info->value]; (a = *set); ++set) {
            if (a == b)
                return true;
        }
        return false;
    }
    case CanonicalizeRangeLo:
        return (a == b) || (a + info->value == b);
    case CanonicalizeRangeHi:
        return (a == b) || (a - info->value == b);
    case CanonicalizeAlternatingAligned:
        return (a | 1) == (b | 1);
    case CanonicalizeAlternatingUnaligned:
        return ((a - 1) | 1) == ((b - 1) | 1);
    }

    ASSERT_NOT_REACHED();
    return false;
}

} } // JSC::Yarr

#endif /* yarr_YarrCanonicalizeUCS2_h */