infutil.c

来自「This is a resource based on j2me embedde」· C语言 代码 · 共 116 行

/*
 * @(#)infutil.c	1.18 06/10/10
 *
 * Portions Copyright  2000-2008 Sun Microsystems, Inc. All Rights
 * Reserved.  Use is subject to license terms.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation.
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License version 2 for more details (a copy is
 * included at /legal/license.txt).
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions.
 */

/* inflate_util.c -- data and routines common to blocks and codes
 * Copyright (C) 1995-1996 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 */

const 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;
}