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.

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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769
/* cairo-output-stream.c: Output stream abstraction
 *
 * Copyright © 2005 Red Hat, Inc
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is Red Hat, Inc.
 *
 * Author(s):
 *	Kristian Høgsberg <krh@redhat.com>
 */

#define _BSD_SOURCE /* for snprintf() */
#include "cairoint.h"

#include "cairo-output-stream-private.h"
#include "cairo-error-private.h"
#include "cairo-compiler-private.h"

#include <stdio.h>
#include <locale.h>
#include <errno.h>

/* Numbers printed with %f are printed with this number of significant
 * digits after the decimal.
 */
#define SIGNIFICANT_DIGITS_AFTER_DECIMAL 6

/* Numbers printed with %g are assumed to only have %CAIRO_FIXED_FRAC_BITS
 * bits of precision available after the decimal point.
 *
 * FIXED_POINT_DECIMAL_DIGITS specifies the minimum number of decimal
 * digits after the decimal point required to preserve the available
 * precision.
 *
 * The conversion is:
 *
 * <programlisting>
 * FIXED_POINT_DECIMAL_DIGITS = ceil( CAIRO_FIXED_FRAC_BITS * ln(2)/ln(10) )
 * </programlisting>
 *
 * We can replace ceil(x) with (int)(x+1) since x will never be an
 * integer for any likely value of %CAIRO_FIXED_FRAC_BITS.
 */
#define FIXED_POINT_DECIMAL_DIGITS ((int)(CAIRO_FIXED_FRAC_BITS*0.301029996 + 1))

void
_cairo_output_stream_init (cairo_output_stream_t            *stream,
			   cairo_output_stream_write_func_t  write_func,
			   cairo_output_stream_flush_func_t  flush_func,
			   cairo_output_stream_close_func_t  close_func)
{
    stream->write_func = write_func;
    stream->flush_func = flush_func;
    stream->close_func = close_func;
    stream->position = 0;
    stream->status = CAIRO_STATUS_SUCCESS;
    stream->closed = FALSE;
}

cairo_status_t
_cairo_output_stream_fini (cairo_output_stream_t *stream)
{
    return _cairo_output_stream_close (stream);
}

const cairo_output_stream_t _cairo_output_stream_nil = {
    NULL, /* write_func */
    NULL, /* flush_func */
    NULL, /* close_func */
    0,    /* position */
    CAIRO_STATUS_NO_MEMORY,
    FALSE /* closed */
};

static const cairo_output_stream_t _cairo_output_stream_nil_write_error = {
    NULL, /* write_func */
    NULL, /* flush_func */
    NULL, /* close_func */
    0,    /* position */
    CAIRO_STATUS_WRITE_ERROR,
    FALSE /* closed */
};

typedef struct _cairo_output_stream_with_closure {
    cairo_output_stream_t	 base;
    cairo_write_func_t		 write_func;
    cairo_close_func_t		 close_func;
    void			*closure;
} cairo_output_stream_with_closure_t;


static cairo_status_t
closure_write (cairo_output_stream_t *stream,
	       const unsigned char *data, unsigned int length)
{
    cairo_output_stream_with_closure_t *stream_with_closure =
	(cairo_output_stream_with_closure_t *) stream;

    if (stream_with_closure->write_func == NULL)
	return CAIRO_STATUS_SUCCESS;

    return stream_with_closure->write_func (stream_with_closure->closure,
					    data, length);
}

static cairo_status_t
closure_close (cairo_output_stream_t *stream)
{
    cairo_output_stream_with_closure_t *stream_with_closure =
	(cairo_output_stream_with_closure_t *) stream;

    if (stream_with_closure->close_func != NULL)
	return stream_with_closure->close_func (stream_with_closure->closure);
    else
	return CAIRO_STATUS_SUCCESS;
}

cairo_output_stream_t *
_cairo_output_stream_create (cairo_write_func_t		write_func,
			     cairo_close_func_t		close_func,
			     void			*closure)
{
    cairo_output_stream_with_closure_t *stream;

    stream = malloc (sizeof (cairo_output_stream_with_closure_t));
    if (unlikely (stream == NULL)) {
	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
    }

    _cairo_output_stream_init (&stream->base,
			       closure_write, NULL, closure_close);
    stream->write_func = write_func;
    stream->close_func = close_func;
    stream->closure = closure;

    return &stream->base;
}

cairo_output_stream_t *
_cairo_output_stream_create_in_error (cairo_status_t status)
{
    cairo_output_stream_t *stream;

    /* check for the common ones */
    if (status == CAIRO_STATUS_NO_MEMORY)
	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
    if (status == CAIRO_STATUS_WRITE_ERROR)
	return (cairo_output_stream_t *) &_cairo_output_stream_nil_write_error;

    stream = malloc (sizeof (cairo_output_stream_t));
    if (unlikely (stream == NULL)) {
	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
    }

    _cairo_output_stream_init (stream, NULL, NULL, NULL);
    stream->status = status;

    return stream;
}

cairo_status_t
_cairo_output_stream_flush (cairo_output_stream_t *stream)
{
    cairo_status_t status;

    if (stream->closed)
	return stream->status;

    if (stream == &_cairo_output_stream_nil ||
	stream == &_cairo_output_stream_nil_write_error)
    {
	return stream->status;
    }

    if (stream->flush_func) {
	status = stream->flush_func (stream);
	/* Don't overwrite a pre-existing status failure. */
	if (stream->status == CAIRO_STATUS_SUCCESS)
	    stream->status = status;
    }

    return stream->status;
}

cairo_status_t
_cairo_output_stream_close (cairo_output_stream_t *stream)
{
    cairo_status_t status;

    if (stream->closed)
	return stream->status;

    if (stream == &_cairo_output_stream_nil ||
	stream == &_cairo_output_stream_nil_write_error)
    {
	return stream->status;
    }

    if (stream->close_func) {
	status = stream->close_func (stream);
	/* Don't overwrite a pre-existing status failure. */
	if (stream->status == CAIRO_STATUS_SUCCESS)
	    stream->status = status;
    }

    stream->closed = TRUE;

    return stream->status;
}

cairo_status_t
_cairo_output_stream_destroy (cairo_output_stream_t *stream)
{
    cairo_status_t status;

    assert (stream != NULL);

    if (stream == &_cairo_output_stream_nil ||
	stream == &_cairo_output_stream_nil_write_error)
    {
	return stream->status;
    }

    status = _cairo_output_stream_fini (stream);
    free (stream);

    return status;
}

void
_cairo_output_stream_write (cairo_output_stream_t *stream,
			    const void *data, size_t length)
{
    if (length == 0)
	return;

    if (stream->status)
	return;

    stream->status = stream->write_func (stream, data, length);
    stream->position += length;
}

void
_cairo_output_stream_write_hex_string (cairo_output_stream_t *stream,
				       const unsigned char *data,
				       size_t length)
{
    const char hex_chars[] = "0123456789abcdef";
    char buffer[2];
    unsigned int i, column;

    if (stream->status)
	return;

    for (i = 0, column = 0; i < length; i++, column++) {
	if (column == 38) {
	    _cairo_output_stream_write (stream, "\n", 1);
	    column = 0;
	}
	buffer[0] = hex_chars[(data[i] >> 4) & 0x0f];
	buffer[1] = hex_chars[data[i] & 0x0f];
	_cairo_output_stream_write (stream, buffer, 2);
    }
}

/* Format a double in a locale independent way and trim trailing
 * zeros.  Based on code from Alex Larson <alexl@redhat.com>.
 * http://mail.gnome.org/archives/gtk-devel-list/2001-October/msg00087.html
 *
 * The code in the patch is copyright Red Hat, Inc under the LGPL, but
 * has been relicensed under the LGPL/MPL dual license for inclusion
 * into cairo (see COPYING). -- Kristian Høgsberg <krh@redhat.com>
 */
static void
_cairo_dtostr (char *buffer, size_t size, double d, cairo_bool_t limited_precision)
{
    struct lconv *locale_data;
    const char *decimal_point;
    int decimal_point_len;
    char *p;
    int decimal_len;
    int num_zeros, decimal_digits;

    /* Omit the minus sign from negative zero. */
    if (d == 0.0)
	d = 0.0;

#ifdef HAVE_LOCALECONV
    locale_data = localeconv ();
    decimal_point = locale_data->decimal_point;
    decimal_point_len = strlen (decimal_point);
#else
    decimal_point = ".";
    decimal_point_len = 1;
#endif

    assert (decimal_point_len != 0);

    if (limited_precision) {
	snprintf (buffer, size, "%.*f", FIXED_POINT_DECIMAL_DIGITS, d);
    } else {
	/* Using "%f" to print numbers less than 0.1 will result in
	 * reduced precision due to the default 6 digits after the
	 * decimal point.
	 *
	 * For numbers is < 0.1, we print with maximum precision and count
	 * the number of zeros between the decimal point and the first
	 * significant digit. We then print the number again with the
	 * number of decimal places that gives us the required number of
	 * significant digits. This ensures the number is correctly
	 * rounded.
	 */
	if (fabs (d) >= 0.1) {
	    snprintf (buffer, size, "%f", d);
	} else {
	    snprintf (buffer, size, "%.18f", d);
	    p = buffer;

	    if (*p == '+' || *p == '-')
		p++;

	    while (_cairo_isdigit (*p))
		p++;

	    if (strncmp (p, decimal_point, decimal_point_len) == 0)
		p += decimal_point_len;

	    num_zeros = 0;
	    while (*p++ == '0')
		num_zeros++;

	    decimal_digits = num_zeros + SIGNIFICANT_DIGITS_AFTER_DECIMAL;

	    if (decimal_digits < 18)
		snprintf (buffer, size, "%.*f", decimal_digits, d);
	}
    }
    p = buffer;

    if (*p == '+' || *p == '-')
	p++;

    while (_cairo_isdigit (*p))
	p++;

    if (strncmp (p, decimal_point, decimal_point_len) == 0) {
	*p = '.';
	decimal_len = strlen (p + decimal_point_len);
	memmove (p + 1, p + decimal_point_len, decimal_len);
	p[1 + decimal_len] = 0;

	/* Remove trailing zeros and decimal point if possible. */
	for (p = p + decimal_len; *p == '0'; p--)
	    *p = 0;

	if (*p == '.') {
	    *p = 0;
	    p--;
	}
    }
}

enum {
    LENGTH_MODIFIER_LONG = 0x100
};

/* Here's a limited reimplementation of printf.  The reason for doing
 * this is primarily to special case handling of doubles.  We want
 * locale independent formatting of doubles and we want to trim
 * trailing zeros.  This is handled by dtostr() above, and the code
 * below handles everything else by calling snprintf() to do the
 * formatting.  This functionality is only for internal use and we
 * only implement the formats we actually use.
 */
void
_cairo_output_stream_vprintf (cairo_output_stream_t *stream,
			      const char *fmt, va_list ap)
{
#define SINGLE_FMT_BUFFER_SIZE 32
    char buffer[512], single_fmt[SINGLE_FMT_BUFFER_SIZE];
    int single_fmt_length;
    char *p;
    const char *f, *start;
    int length_modifier, width;
    cairo_bool_t var_width;

    if (stream->status)
	return;

    f = fmt;
    p = buffer;
    while (*f != '\0') {
	if (p == buffer + sizeof (buffer)) {
	    _cairo_output_stream_write (stream, buffer, sizeof (buffer));
	    p = buffer;
	}

	if (*f != '%') {
	    *p++ = *f++;
	    continue;
	}

	start = f;
	f++;

	if (*f == '0')
	    f++;

        var_width = FALSE;
        if (*f == '*') {
            var_width = TRUE;
	    f++;
        }

	while (_cairo_isdigit (*f))
	    f++;

	length_modifier = 0;
	if (*f == 'l') {
	    length_modifier = LENGTH_MODIFIER_LONG;
	    f++;
	}

	/* The only format strings exist in the cairo implementation
	 * itself. So there's an internal consistency problem if any
	 * of them is larger than our format buffer size. */
	single_fmt_length = f - start + 1;
	assert (single_fmt_length + 1 <= SINGLE_FMT_BUFFER_SIZE);

	/* Reuse the format string for this conversion. */
	memcpy (single_fmt, start, single_fmt_length);
	single_fmt[single_fmt_length] = '\0';

	/* Flush contents of buffer before snprintf()'ing into it. */
	_cairo_output_stream_write (stream, buffer, p - buffer);

	/* We group signed and unsigned together in this switch, the
	 * only thing that matters here is the size of the arguments,
	 * since we're just passing the data through to sprintf(). */
	switch (*f | length_modifier) {
	case '%':
	    buffer[0] = *f;
	    buffer[1] = 0;
	    break;
	case 'd':
	case 'u':
	case 'o':
	case 'x':
	case 'X':
            if (var_width) {
                width = va_arg (ap, int);
                snprintf (buffer, sizeof buffer,
                          single_fmt, width, va_arg (ap, int));
            } else {
                snprintf (buffer, sizeof buffer, single_fmt, va_arg (ap, int));
            }
	    break;
	case 'd' | LENGTH_MODIFIER_LONG:
	case 'u' | LENGTH_MODIFIER_LONG:
	case 'o' | LENGTH_MODIFIER_LONG:
	case 'x' | LENGTH_MODIFIER_LONG:
	case 'X' | LENGTH_MODIFIER_LONG:
            if (var_width) {
                width = va_arg (ap, int);
                snprintf (buffer, sizeof buffer,
                          single_fmt, width, va_arg (ap, long int));
            } else {
                snprintf (buffer, sizeof buffer,
                          single_fmt, va_arg (ap, long int));
            }
	    break;
	case 's':
	    snprintf (buffer, sizeof buffer,
		      single_fmt, va_arg (ap, const char *));
	    break;
	case 'f':
	    _cairo_dtostr (buffer, sizeof buffer, va_arg (ap, double), FALSE);
	    break;
	case 'g':
	    _cairo_dtostr (buffer, sizeof buffer, va_arg (ap, double), TRUE);
	    break;
	case 'c':
	    buffer[0] = va_arg (ap, int);
	    buffer[1] = 0;
	    break;
	default:
	    ASSERT_NOT_REACHED;
	}
	p = buffer + strlen (buffer);
	f++;
    }

    _cairo_output_stream_write (stream, buffer, p - buffer);
}

void
_cairo_output_stream_printf (cairo_output_stream_t *stream,
			     const char *fmt, ...)
{
    va_list ap;

    va_start (ap, fmt);

    _cairo_output_stream_vprintf (stream, fmt, ap);

    va_end (ap);
}

long
_cairo_output_stream_get_position (cairo_output_stream_t *stream)
{
    return stream->position;
}

cairo_status_t
_cairo_output_stream_get_status (cairo_output_stream_t *stream)
{
    return stream->status;
}

/* Maybe this should be a configure time option, so embedded targets
 * don't have to pull in stdio. */


typedef struct _stdio_stream {
    cairo_output_stream_t	 base;
    FILE			*file;
} stdio_stream_t;

static cairo_status_t
stdio_write (cairo_output_stream_t *base,
	     const unsigned char *data, unsigned int length)
{
    stdio_stream_t *stream = (stdio_stream_t *) base;

    if (fwrite (data, 1, length, stream->file) != length)
	return _cairo_error (CAIRO_STATUS_WRITE_ERROR);

    return CAIRO_STATUS_SUCCESS;
}

static cairo_status_t
stdio_flush (cairo_output_stream_t *base)
{
    stdio_stream_t *stream = (stdio_stream_t *) base;

    fflush (stream->file);

    if (ferror (stream->file))
	return _cairo_error (CAIRO_STATUS_WRITE_ERROR);
    else
	return CAIRO_STATUS_SUCCESS;
}

static cairo_status_t
stdio_close (cairo_output_stream_t *base)
{
    cairo_status_t status;
    stdio_stream_t *stream = (stdio_stream_t *) base;

    status = stdio_flush (base);

    fclose (stream->file);

    return status;
}

cairo_output_stream_t *
_cairo_output_stream_create_for_file (FILE *file)
{
    stdio_stream_t *stream;

    if (file == NULL) {
	_cairo_error_throw (CAIRO_STATUS_WRITE_ERROR);
	return (cairo_output_stream_t *) &_cairo_output_stream_nil_write_error;
    }

    stream = malloc (sizeof *stream);
    if (unlikely (stream == NULL)) {
	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
    }

    _cairo_output_stream_init (&stream->base,
			       stdio_write, stdio_flush, stdio_flush);
    stream->file = file;

    return &stream->base;
}

cairo_output_stream_t *
_cairo_output_stream_create_for_filename (const char *filename)
{
    stdio_stream_t *stream;
    FILE *file;

    if (filename == NULL)
	return _cairo_null_stream_create ();

    file = fopen (filename, "wb");
    if (file == NULL) {
	switch (errno) {
	case ENOMEM:
	    _cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
	    return (cairo_output_stream_t *) &_cairo_output_stream_nil;
	default:
	    _cairo_error_throw (CAIRO_STATUS_WRITE_ERROR);
	    return (cairo_output_stream_t *) &_cairo_output_stream_nil_write_error;
	}
    }

    stream = malloc (sizeof *stream);
    if (unlikely (stream == NULL)) {
	fclose (file);
	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
    }

    _cairo_output_stream_init (&stream->base,
			       stdio_write, stdio_flush, stdio_close);
    stream->file = file;

    return &stream->base;
}


typedef struct _memory_stream {
    cairo_output_stream_t	base;
    cairo_array_t		array;
} memory_stream_t;

static cairo_status_t
memory_write (cairo_output_stream_t *base,
	      const unsigned char *data, unsigned int length)
{
    memory_stream_t *stream = (memory_stream_t *) base;

    return _cairo_array_append_multiple (&stream->array, data, length);
}

static cairo_status_t
memory_close (cairo_output_stream_t *base)
{
    memory_stream_t *stream = (memory_stream_t *) base;

    _cairo_array_fini (&stream->array);

    return CAIRO_STATUS_SUCCESS;
}

cairo_output_stream_t *
_cairo_memory_stream_create (void)
{
    memory_stream_t *stream;

    stream = malloc (sizeof *stream);
    if (unlikely (stream == NULL)) {
	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
    }

    _cairo_output_stream_init (&stream->base, memory_write, NULL, memory_close);
    _cairo_array_init (&stream->array, 1);

    return &stream->base;
}

cairo_status_t
_cairo_memory_stream_destroy (cairo_output_stream_t *abstract_stream,
			      unsigned char **data_out,
			      unsigned long *length_out)
{
    memory_stream_t *stream;
    cairo_status_t status;

    status = abstract_stream->status;
    if (unlikely (status))
	return _cairo_output_stream_destroy (abstract_stream);

    stream = (memory_stream_t *) abstract_stream;

    *length_out = _cairo_array_num_elements (&stream->array);
    *data_out = malloc (*length_out);
    if (unlikely (*data_out == NULL)) {
	status = _cairo_output_stream_destroy (abstract_stream);
	assert (status == CAIRO_STATUS_SUCCESS);
	return _cairo_error (CAIRO_STATUS_NO_MEMORY);
    }
    memcpy (*data_out, _cairo_array_index (&stream->array, 0), *length_out);

    return _cairo_output_stream_destroy (abstract_stream);
}

void
_cairo_memory_stream_copy (cairo_output_stream_t *base,
			   cairo_output_stream_t *dest)
{
    memory_stream_t *stream = (memory_stream_t *) base;

    if (dest->status)
	return;

    if (base->status) {
	dest->status = base->status;
	return;
    }

    _cairo_output_stream_write (dest,
				_cairo_array_index (&stream->array, 0),
				_cairo_array_num_elements (&stream->array));
}

int
_cairo_memory_stream_length (cairo_output_stream_t *base)
{
    memory_stream_t *stream = (memory_stream_t *) base;

    return _cairo_array_num_elements (&stream->array);
}

static cairo_status_t
null_write (cairo_output_stream_t *base,
	    const unsigned char *data, unsigned int length)
{
    return CAIRO_STATUS_SUCCESS;
}

cairo_output_stream_t *
_cairo_null_stream_create (void)
{
    cairo_output_stream_t *stream;

    stream = malloc (sizeof *stream);
    if (unlikely (stream == NULL)) {
	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
    }

    _cairo_output_stream_init (stream, null_write, NULL, NULL);

    return stream;
}