Line data    Source code

       1             : /* compress.c -- compress a memory buffer
       2             :  * Copyright (C) 1995-2005, 2014, 2016 Jean-loup Gailly, Mark Adler
       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          72 : 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          72 :     const uInt max = (uInt)-1;
      32             :     uLong left;
      33             : 
      34          72 :     left = *destLen;
      35          72 :     *destLen = 0;
      36             : 
      37          72 :     stream.zalloc = (alloc_func)0;
      38          72 :     stream.zfree = (free_func)0;
      39          72 :     stream.opaque = (voidpf)0;
      40             : 
      41          72 :     err = deflateInit(&stream, level);
      42          72 :     if (err != Z_OK) return err;
      43             : 
      44          72 :     stream.next_out = dest;
      45          72 :     stream.avail_out = 0;
      46          72 :     stream.next_in = (z_const Bytef *)source;
      47          72 :     stream.avail_in = 0;
      48             : 
      49             :     do {
      50          72 :         if (stream.avail_out == 0) {
      51          72 :             stream.avail_out = left > (uLong)max ? max : (uInt)left;
      52          72 :             left -= stream.avail_out;
      53             :         }
      54          72 :         if (stream.avail_in == 0) {
      55          72 :             stream.avail_in = sourceLen > (uLong)max ? max : (uInt)sourceLen;
      56          72 :             sourceLen -= stream.avail_in;
      57             :         }
      58          72 :         err = deflate(&stream, sourceLen ? Z_NO_FLUSH : Z_FINISH);
      59          72 :     } while (err == Z_OK);
      60             : 
      61          72 :     *destLen = stream.total_out;
      62          72 :     deflateEnd(&stream);
      63          72 :     return err == Z_STREAM_END ? Z_OK : err;
      64             : }
      65             : 
      66             : /* ===========================================================================
      67             :  */
      68          72 : int ZEXPORT compress (dest, destLen, source, sourceLen)
      69             :     Bytef *dest;
      70             :     uLongf *destLen;
      71             :     const Bytef *source;
      72             :     uLong sourceLen;
      73             : {
      74          72 :     return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
      75             : }
      76             : 
      77             : /* ===========================================================================
      78             :      If the default memLevel or windowBits for deflateInit() is changed, then
      79             :    this function needs to be updated.
      80             :  */
      81          72 : uLong ZEXPORT compressBound (sourceLen)
      82             :     uLong sourceLen;
      83             : {
      84         144 :     return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
      85         144 :            (sourceLen >> 25) + 13;
      86             : }