SecurityServer/MacYarrow/zlib/infutil.c

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 /* inflate_util.c -- data and routines common to blocks and codes
  20  * Copyright (C) 1995-1998 Mark Adler
  21  * For conditions of distribution and use, see copyright notice in zlib.h
  22  */
  23
  24 #include "zutil.h"
  25 #include "infblock.h"
  26 #include "inftrees.h"
  27 #include "infcodes.h"
  28 #include "infutil.h"
  29
  30 struct inflate_codes_state {int dummy;}; /* for buggy compilers */
  31
  32 /* And'ing with mask[n] masks the lower n bits */
  33 uInt inflate_mask[17] = {
  34     0x0000,
  35     0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
  36     0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
  37 };
  38
  39
  40 /* copy as much as possible from the sliding window to the output area */
  41 int inflate_flush(s, z, r)
  42 inflate_blocks_statef *s;
  43 z_streamp z;
  44 int r;
  45 {
  46   uInt n;
  47   Bytef *p;
  48   Bytef *q;
  49
  50   /* local copies of source and destination pointers */
  51   p = z->next_out;
  52   q = s->read;
  53
  54   /* compute number of bytes to copy as far as end of window */
  55   n = (uInt)((q <= s->write ? s->write : s->end) - q);
  56   if (n > z->avail_out) n = z->avail_out;
  57   if (n && r == Z_BUF_ERROR) r = Z_OK;
  58
  59   /* update counters */
  60   z->avail_out -= n;
  61   z->total_out += n;
  62
  63   /* update check information */
  64   if (s->checkfn != Z_NULL)
  65     z->adler = s->check = (*s->checkfn)(s->check, q, n);
  66
  67   /* copy as far as end of window */
  68   zmemcpy(p, q, n);
  69   p += n;
  70   q += n;
  71
  72   /* see if more to copy at beginning of window */
  73   if (q == s->end)
  74   {
  75     /* wrap pointers */
  76     q = s->window;
  77     if (s->write == s->end)
  78       s->write = s->window;
  79
  80     /* compute bytes to copy */
  81     n = (uInt)(s->write - q);
  82     if (n > z->avail_out) n = z->avail_out;
  83     if (n && r == Z_BUF_ERROR) r = Z_OK;
  84
  85     /* update counters */
  86     z->avail_out -= n;
  87     z->total_out += n;
  88
  89     /* update check information */
  90     if (s->checkfn != Z_NULL)
  91       z->adler = s->check = (*s->checkfn)(s->check, q, n);
  92
  93     /* copy */
  94     zmemcpy(p, q, n);
  95     p += n;
  96     q += n;
  97   }
  98
  99   /* update pointers */
 100   z->next_out = p;
 101   s->read = q;
 102
 103   /* done */
 104   return r;
 105 }