/*
 * Copyright (C) 1995-2002 Jean-loup Gailly.
 * For conditions of distribution and use, see copyright notice in zlib.h 
 */

/**
 * \file compress.c
 * Compress a memory buffer.
 */

#include "zlib.h"

/*@access z_streamp@*/

/* ========================================================================== */
/**
 * Compresses the source buffer into the destination buffer. The level
 * parameter has the same meaning as in deflateInit.  sourceLen is the byte
 * length of the source buffer. Upon entry, destLen is the total size of the
 * destination buffer, which must be at least 0.1% larger than sourceLen plus
 * 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
 *
 * compress2 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,
 * Z_STREAM_ERROR if the level parameter is invalid.
 */
int ZEXPORT compress2 (Bytef * dest, uLongf * destLen, const Bytef * source,
		uLong sourceLen, int level)
{
    z_stream stream;
    int err;

    stream.next_in = (Bytef*)source;
    stream.avail_in = (uInt)sourceLen;
#ifdef MAXSEG_64K
    /* Check for source > 64K on 16-bit machine: */
    if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
#endif
    stream.next_out = dest;
    stream.avail_out = (uInt)*destLen;
    if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;

    stream.zalloc = (alloc_func)0;
    stream.zfree = (free_func)0;
    stream.opaque = (voidpf)0;

    err = deflateInit(&stream, level);
    if (err != Z_OK) return err;

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

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

/* ========================================================================== */
int ZEXPORT compress (Bytef * dest, uLongf * destLen, const Bytef * source,
		uLong sourceLen)
{
    return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
}

/* ===========================================================================
     If the default memLevel or windowBits for deflateInit() is changed, then
   this function needs to be updated.
 */
uLong ZEXPORT compressBound (uLong sourceLen)
{
    return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + 11;
}