www.pudn.com > ZLib-check.rar > infutil.c

/* inflate_util.c -- data and routines common to blocks and codes 
 * Copyright (C) 1995-2002 Mark Adler 
 * For conditions of distribution and use, see copyright notice in zlib.h  
 */ 
 
#include "zutil.h" 
#include "infblock.h" 
#include "inftrees.h" 
#include "infcodes.h" 
#include "infutil.h" 
 
struct inflate_codes_state {int dummy;}; /* for buggy compilers */ 
 
/* And'ing with mask[n] masks the lower n bits */ 
uInt inflate_mask[17] = { 
    0x0000, 
    0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, 
    0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff 
}; 
 
 
/* copy as much as possible from the sliding window to the output area */ 
int inflate_flush(s, z, r) 
inflate_blocks_statef *s; 
z_streamp z; 
int r; 
{ 
  uInt n; 
  Bytef *p; 
  Bytef *q; 
 
  /* local copies of source and destination pointers */ 
  p = z->next_out; 
  q = s->read; 
 
  /* compute number of bytes to copy as far as end of window */ 
  n = (uInt)((q <= s->write ? s->write : s->end) - q); 
  if (n > z->avail_out) n = z->avail_out; 
  if (n && r == Z_BUF_ERROR) r = Z_OK; 
 
  /* update counters */ 
  z->avail_out -= n; 
  z->total_out += n; 
 
  /* update check information */ 
  if (s->checkfn != Z_NULL) 
    z->adler = s->check = (*s->checkfn)(s->check, q, n); 
 
  /* copy as far as end of window */ 
  zmemcpy(p, q, n); 
  p += n; 
  q += n; 
 
  /* see if more to copy at beginning of window */ 
  if (q == s->end) 
  { 
    /* wrap pointers */ 
    q = s->window; 
    if (s->write == s->end) 
      s->write = s->window; 
 
    /* compute bytes to copy */ 
    n = (uInt)(s->write - q); 
    if (n > z->avail_out) n = z->avail_out; 
    if (n && r == Z_BUF_ERROR) r = Z_OK; 
 
    /* update counters */ 
    z->avail_out -= n; 
    z->total_out += n; 
 
    /* update check information */ 
    if (s->checkfn != Z_NULL) 
      z->adler = s->check = (*s->checkfn)(s->check, q, n); 
 
    /* copy */ 
    zmemcpy(p, q, n); 
    p += n; 
    q += n; 
  } 
 
  /* update pointers */ 
  z->next_out = p; 
  s->read = q; 
 
  /* done */ 
  return r; 
}