source: trunk/poppler/freetype-2.1.10/src/gzip/infutil.c @ 2

Last change on this file since 2 was 2, checked in by Eugene Romanenko, 15 years ago

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File size: 1.9 KB
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1/* inflate_util.c -- data and routines common to blocks and codes
2 * Copyright (C) 1995-2002 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
4 */
5
6#include "zutil.h"
7#include "infblock.h"
8#include "inftrees.h"
9#include "infcodes.h"
10#include "infutil.h"
11
12
13/* And'ing with mask[n] masks the lower n bits */
14local const uInt inflate_mask[17] = {
15    0x0000,
16    0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
17    0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
18};
19
20
21/* copy as much as possible from the sliding window to the output area */
22local int inflate_flush( /* s, z, r) */
23inflate_blocks_statef *s,
24z_streamp z,
25int r )
26{
27  uInt n;
28  Bytef *p;
29  Bytef *q;
30
31  /* local copies of source and destination pointers */
32  p = z->next_out;
33  q = s->read;
34
35  /* compute number of bytes to copy as far as end of window */
36  n = (uInt)((q <= s->write ? s->write : s->end) - q);
37  if (n > z->avail_out) n = z->avail_out;
38  if (n && r == Z_BUF_ERROR) r = Z_OK;
39
40  /* update counters */
41  z->avail_out -= n;
42  z->total_out += n;
43
44  /* update check information */
45  if (s->checkfn != Z_NULL)
46    z->adler = s->check = (*s->checkfn)(s->check, q, n);
47
48  /* copy as far as end of window */
49  zmemcpy(p, q, n);
50  p += n;
51  q += n;
52
53  /* see if more to copy at beginning of window */
54  if (q == s->end)
55  {
56    /* wrap pointers */
57    q = s->window;
58    if (s->write == s->end)
59      s->write = s->window;
60
61    /* compute bytes to copy */
62    n = (uInt)(s->write - q);
63    if (n > z->avail_out) n = z->avail_out;
64    if (n && r == Z_BUF_ERROR) r = Z_OK;
65
66    /* update counters */
67    z->avail_out -= n;
68    z->total_out += n;
69
70    /* update check information */
71    if (s->checkfn != Z_NULL)
72      z->adler = s->check = (*s->checkfn)(s->check, q, n);
73
74    /* copy */
75    zmemcpy(p, q, n);
76    p += n;
77    q += n;
78  }
79
80  /* update pointers */
81  z->next_out = p;
82  s->read = q;
83
84  /* done */
85  return r;
86}
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