thirdparty/freetype-2.3.12/src/gzip/infutil.c

   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 */
  14 local 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 */
  22 local int inflate_flush( /* s, z, r) */
  23 inflate_blocks_statef *s,
  24 z_streamp z,
  25 int 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 }