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/* @(#) $Id: uncompr.c,v 1.3 2001/12/27 21:00:18 jbj Exp $ */
/*
 * Copyright (C) 1995-1998 Jean-loup Gailly.
 * For conditions of distribution and use, see copyright notice in zlib.h 
 */

/**
 * \file uncompr.c
 * Decompress a memory buffer.
 */

#include "zlib.h"
#include "zutil.h"	/* XXX for zmemzero() */

/*@access z_streamp@*/

/* ========================================================================= */
/**
 * Decompresses the source buffer into the destination buffer.  sourceLen is
 * the byte length of the source buffer. Upon entry, destLen is the total
 * size of the destination buffer, which must be large enough to hold the
 * entire uncompressed data. (The size of the uncompressed data must have
 * been saved previously by the compressor and transmitted to the decompressor
 * by some mechanism outside the scope of this compression library.)
 * Upon exit, destLen is the actual size of the compressed buffer.
 * This function can be used to decompress a whole file at once if the
 * input file is mmap'ed.
 *
 * uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
 * enough memory, Z_BUF_ERROR if there was not enough room in the output
 * buffer, or Z_DATA_ERROR if the input data was corrupted.
 */
int ZEXPORT uncompress (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen)
{
    z_stream stream;
    int err;

    zmemzero(&stream, sizeof(stream));
    stream.next_in = (Bytef*)source;
    stream.avail_in = (uInt)sourceLen;
    /* Check for source > 64K on 16-bit machine: */
    if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;

    stream.next_out = dest;
    stream.avail_out = (uInt)*destLen;
    if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;

    stream.zalloc = (alloc_func)NULL;
    stream.zfree = (free_func)NULL;

    err = inflateInit(&stream);
    if (err != Z_OK) return err;

    err = inflate(&stream, Z_FINISH);
    if (err != Z_STREAM_END) {
        inflateEnd(&stream);
        return err == Z_OK ? Z_BUF_ERROR : err;
    }
    *destLen = stream.total_out;

    err = inflateEnd(&stream);
    return err;
}