lzf_d.c

/*
 * Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de>
 * 
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 * 
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 * 
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#include <stdio.h>

#include "lzfP.h"

#if AVOID_ERRNO
# define SET_ERRNO(n)
#else
# include <errno.h>
# define SET_ERRNO(n) errno = (n)
#endif

#if (__i386 || __amd64) && __GNUC__ >= 3
# define lzf_movsb(dst, src, len)                \
   asm ("rep movsb"                              \
        : "=D" (dst), "=S" (src), "=c" (len)     \
        :  "0" (dst),  "1" (src),  "2" (len));
#endif

#define CHECK_INPUT 1
unsigned int 
lzf_decompress (const void *const in_data,  unsigned int in_len,
                void             *out_data, unsigned int out_len){
  u8 const *ip = (const u8 *)in_data;
  u8       *op = (u8 *)out_data;
  u8 const *const in_end  = ip + in_len;
  u8       *const out_end = op + out_len;
  do {
    unsigned int ctrl = *ip++;
    if (ctrl < (1 << 5)) { /* literal run */ 
      ctrl++;

      if (op + ctrl > out_end) {
        SET_ERRNO (E2BIG);
        return 0;
      }

#if CHECK_INPUT
      if (ip + ctrl > in_end){
        SET_ERRNO (EINVAL);
        return 0;
      }
#endif

#ifdef lzf_movsb
      lzf_movsb (op, ip, ctrl);
#else
      do
        *op++ = *ip++;
      while (--ctrl);
#endif
    } else { /* back reference */
      unsigned int len = ctrl >> 5;

      u8 *ref = op - ((ctrl & 0x1f) << 8) - 1;

#if CHECK_INPUT
      if (ip >= in_end) {
        SET_ERRNO (EINVAL);
        return 0;
      }
#endif
      if (len == 7) {
        len += *ip++;
#if CHECK_INPUT
        if (ip >= in_end) {
          SET_ERRNO (EINVAL);
          return 0;
        }
#endif
      }

      ref -= *ip++;

      if (op + len + 2 > out_end) {
        SET_ERRNO (E2BIG);
        return 0;
      }

      if (ref < (u8 *)out_data) {
        SET_ERRNO (EINVAL);
        return 0;
      }


#ifdef lzf_movsb
      len += 2;
      lzf_movsb (op, ref, len);
#else
      *op++ = *ref++;
      *op++ = *ref++;

      do
        *op++ = *ref++;
      while (--len);
	   printf ("b len=%u\n", len);
#endif
    }
  } while (ip < in_end);

  return op - (u8 *)out_data;
}