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Annotation of embedaddon/sudo/zlib/compress.c, revision 1.1

1.1     ! misho       1: /* compress.c -- compress a memory buffer
        !             2:  * Copyright (C) 1995-2005 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:      Compresses the source buffer into the destination buffer. The level
        !            13:    parameter has the same meaning as in deflateInit.  sourceLen is the byte
        !            14:    length of the source buffer. Upon entry, destLen is the total size of the
        !            15:    destination buffer, which must be at least 0.1% larger than sourceLen plus
        !            16:    12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
        !            17: 
        !            18:      compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
        !            19:    memory, Z_BUF_ERROR if there was not enough room in the output buffer,
        !            20:    Z_STREAM_ERROR if the level parameter is invalid.
        !            21: */
        !            22: int ZEXPORT compress2 (dest, destLen, source, sourceLen, level)
        !            23:     Bytef *dest;
        !            24:     uLongf *destLen;
        !            25:     const Bytef *source;
        !            26:     uLong sourceLen;
        !            27:     int level;
        !            28: {
        !            29:     z_stream stream;
        !            30:     int err;
        !            31: 
        !            32:     stream.next_in = (Bytef*)source;
        !            33:     stream.avail_in = (uInt)sourceLen;
        !            34: #ifdef MAXSEG_64K
        !            35:     /* Check for source > 64K on 16-bit machine: */
        !            36:     if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
        !            37: #endif
        !            38:     stream.next_out = dest;
        !            39:     stream.avail_out = (uInt)*destLen;
        !            40:     if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;
        !            41: 
        !            42:     stream.zalloc = (alloc_func)0;
        !            43:     stream.zfree = (free_func)0;
        !            44:     stream.opaque = (voidpf)0;
        !            45: 
        !            46:     err = deflateInit(&stream, level);
        !            47:     if (err != Z_OK) return err;
        !            48: 
        !            49:     err = deflate(&stream, Z_FINISH);
        !            50:     if (err != Z_STREAM_END) {
        !            51:         deflateEnd(&stream);
        !            52:         return err == Z_OK ? Z_BUF_ERROR : err;
        !            53:     }
        !            54:     *destLen = stream.total_out;
        !            55: 
        !            56:     err = deflateEnd(&stream);
        !            57:     return err;
        !            58: }
        !            59: 
        !            60: /* ===========================================================================
        !            61:  */
        !            62: int ZEXPORT compress (dest, destLen, source, sourceLen)
        !            63:     Bytef *dest;
        !            64:     uLongf *destLen;
        !            65:     const Bytef *source;
        !            66:     uLong sourceLen;
        !            67: {
        !            68:     return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
        !            69: }
        !            70: 
        !            71: /* ===========================================================================
        !            72:      If the default memLevel or windowBits for deflateInit() is changed, then
        !            73:    this function needs to be updated.
        !            74:  */
        !            75: uLong ZEXPORT compressBound (sourceLen)
        !            76:     uLong sourceLen;
        !            77: {
        !            78:     return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
        !            79:            (sourceLen >> 25) + 13;
        !            80: }