lib/zlib_inflate/infutil.c

   1 /* inflate_util.c -- data and routines common to blocks and codes
   2  * Copyright (C) 1995-1998 Mark Adler
   3  * For conditions of distribution and use, see copyright notice in zlib.h
   4  */
   5
   6 #include <linux/zutil.h>
   7 #include "infblock.h"
   8 #include "inftrees.h"
   9 #include "infcodes.h"
  10 #include "infutil.h"
  11
  12 struct inflate_codes_state;
  13
  14 /* And'ing with mask[n] masks the lower n bits */
  15 uInt zlib_inflate_mask[17] = {
  16     0x0000,
  17     0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
  18     0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
  19 };
  20
  21
  22 /* copy as much as possible from the sliding window to the output area */
  23 int zlib_inflate_flush(
  24         inflate_blocks_statef *s,
  25         z_streamp z,
  26         int r
  27 )
  28 {
  29   uInt n;
  30   Byte *p;
  31   Byte *q;
  32
  33   /* local copies of source and destination pointers */
  34   p = z->next_out;
  35   q = s->read;
  36
  37   /* compute number of bytes to copy as far as end of window */
  38   n = (uInt)((q <= s->write ? s->write : s->end) - q);
  39   if (n > z->avail_out) n = z->avail_out;
  40   if (n && r == Z_BUF_ERROR) r = Z_OK;
  41
  42   /* update counters */
  43   z->avail_out -= n;
  44   z->total_out += n;
  45
  46   /* update check information */
  47   if (s->checkfn != NULL)
  48     z->adler = s->check = (*s->checkfn)(s->check, q, n);
  49
  50   /* copy as far as end of window */
  51   memcpy(p, q, n);
  52   p += n;
  53   q += n;
  54
  55   /* see if more to copy at beginning of window */
  56   if (q == s->end)
  57   {
  58     /* wrap pointers */
  59     q = s->window;
  60     if (s->write == s->end)
  61       s->write = s->window;
  62
  63     /* compute bytes to copy */
  64     n = (uInt)(s->write - q);
  65     if (n > z->avail_out) n = z->avail_out;
  66     if (n && r == Z_BUF_ERROR) r = Z_OK;
  67
  68     /* update counters */
  69     z->avail_out -= n;
  70     z->total_out += n;
  71
  72     /* update check information */
  73     if (s->checkfn != NULL)
  74       z->adler = s->check = (*s->checkfn)(s->check, q, n);
  75
  76     /* copy */
  77     memcpy(p, q, n);
  78     p += n;
  79     q += n;
  80   }
  81
  82   /* update pointers */
  83   z->next_out = p;
  84   s->read = q;
  85
  86   /* done */
  87   return r;
  88 }