summaryrefslogtreecommitdiff
path: root/Build/source/libs/cairo/cairo-1.12.8/src/cairo-output-stream.c
blob: cc7e300c936036699208b92b1a451fd8668cc546 (plain)
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
/* 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-array-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;

    locale_data = localeconv ();
    decimal_point = locale_data->decimal_point;
    decimal_point_len = strlen (decimal_point);

    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;
}