1 /* uncompr.c -- decompress a memory buffer

     2  * Copyright (C) 1995-2003 Jean-loup Gailly.

     3  * For conditions of distribution and use, see copyright notice in zlib.h

     4  */

     5 

     6 /* @(#) $Id$ */

     7 

     8 #define ZLIB_INTERNAL

     9 #include "zlib.h"

    10 

    11 /* ===========================================================================

    12      Decompresses the source buffer into the destination buffer.  sourceLen is

    13    the byte length of the source buffer. Upon entry, destLen is the total

    14    size of the destination buffer, which must be large enough to hold the

    15    entire uncompressed data. (The size of the uncompressed data must have

    16    been saved previously by the compressor and transmitted to the decompressor

    17    by some mechanism outside the scope of this compression library.)

    18    Upon exit, destLen is the actual size of the compressed buffer.

    19      This function can be used to decompress a whole file at once if the

    20    input file is mmap'ed.

    21 

    22      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not

    23    enough memory, Z_BUF_ERROR if there was not enough room in the output

    24    buffer, or Z_DATA_ERROR if the input data was corrupted.

    25 */

    26 int ZEXPORT uncompress (dest, destLen, source, sourceLen)

    27     Bytef *dest;

    28     uLongf *destLen;

    29     const Bytef *source;

    30     uLong sourceLen;

    31 {

    32     z_stream stream;

    33     int err;

    34 

    35     stream.next_in = (Bytef*)source;

    36     stream.avail_in = (uInt)sourceLen;

    37     /* Check for source > 64K on 16-bit machine: */

    38     if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;

    39 

    40     stream.next_out = dest;

    41     stream.avail_out = (uInt)*destLen;

    42     if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;

    43 

    44     stream.zalloc = (alloc_func)0;

    45     stream.zfree = (free_func)0;

    46 

    47     err = inflateInit(&stream);

    48     if (err != Z_OK) return err;

    49 

    50     err = inflate(&stream, Z_FINISH);

    51     if (err != Z_STREAM_END) {

    52         inflateEnd(&stream);

    53         if (err == Z_NEED_DICT || (err == Z_BUF_ERROR && stream.avail_in == 0))

    54             return Z_DATA_ERROR;

    55         return err;

    56     }

    57     *destLen = stream.total_out;

    58 

    59     err = inflateEnd(&stream);

    60     return err;

    61 }