include/sys/zmod.h

   1 #ifndef _SPL_ZMOD_H
   2 #define _SPL_ZMOD_H
   3
   4 #include <linux/zlib.h>
   5
   6 /* NOTE: z_compress_level/z_uncompress are nearly identical copies of
   7  * the compress2/uncompress functions provided by the official zlib
   8  * package available at http://zlib.net/.  The only changes made we to
   9  * slightly adapt the functioned called to match the linux kernel
  10  * implementation of zlib.
  11  */
  12
  13 /* ===========================================================================
  14  * Compresses the source buffer into the destination buffer. The level
  15  * parameter has the same meaning as in deflateInit.  sourceLen is the byte
  16  * length of the source buffer. Upon entry, destLen is the total size of the
  17  * destination buffer, which must be at least 0.1% larger than sourceLen plus
  18  * 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
  19  *
  20  * compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  21  * memory, Z_BUF_ERROR if there was not enough room in the output buffer,
  22  * Z_STREAM_ERROR if the level parameter is invalid.
  23  */
  24 static __inline__ int
  25 z_compress_level(Byte *dest, uLong *destLen, const Byte *source,
  26                  uLong sourceLen, int level)
  27 {
  28         z_stream stream;
  29         int err;
  30
  31         stream.next_in = (Byte *)source;
  32         stream.avail_in = (uInt)sourceLen;
  33 #ifdef MAXSEG_64K
  34         /* Check for source > 64K on 16-bit machine: */
  35         if ((uLong)stream.avail_in != sourceLen)
  36                 return Z_BUF_ERROR;
  37 #endif
  38         stream.next_out = dest;
  39         stream.avail_out = (uInt)*destLen;
  40
  41         if ((uLong)stream.avail_out != *destLen)
  42                 return Z_BUF_ERROR;
  43
  44         err = zlib_deflateInit(&stream, level);
  45         if (err != Z_OK)
  46                 return err;
  47
  48         err = zlib_deflate(&stream, Z_FINISH);
  49         if (err != Z_STREAM_END) {
  50                 zlib_deflateEnd(&stream);
  51                 return err == Z_OK ? Z_BUF_ERROR : err;
  52         }
  53         *destLen = stream.total_out;
  54
  55         err = zlib_deflateEnd(&stream);
  56         return err;
  57 } /* z_compress_level() */
  58
  59 /* ===========================================================================
  60  * Decompresses the source buffer into the destination buffer.  sourceLen is
  61  * the byte length of the source buffer. Upon entry, destLen is the total
  62  * size of the destination buffer, which must be large enough to hold the
  63  * entire uncompressed data. (The size of the uncompressed data must have
  64  * been saved previously by the compressor and transmitted to the decompressor
  65  * by some mechanism outside the scope of this compression library.)
  66  * Upon exit, destLen is the actual size of the compressed buffer.
  67  * This function can be used to decompress a whole file at once if the
  68  * input file is mmap'ed.
  69  *
  70  * uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
  71  * enough memory, Z_BUF_ERROR if there was not enough room in the output
  72  * buffer, or Z_DATA_ERROR if the input data was corrupted.
  73  */
  74 static __inline__ int
  75 z_uncompress(Byte *dest, uLong *destLen, const Byte *source, uLong sourceLen)
  76 {
  77         z_stream stream;
  78         int err;
  79
  80         stream.next_in = (Byte *)source;
  81         stream.avail_in = (uInt)sourceLen;
  82         /* Check for source > 64K on 16-bit machine: */
  83         if ((uLong)stream.avail_in != sourceLen)
  84                 return Z_BUF_ERROR;
  85
  86         stream.next_out = dest;
  87         stream.avail_out = (uInt)*destLen;
  88
  89         if ((uLong)stream.avail_out != *destLen)
  90                 return Z_BUF_ERROR;
  91
  92         err = zlib_inflateInit(&stream);
  93         if (err != Z_OK)
  94                 return err;
  95
  96         err = zlib_inflate(&stream, Z_FINISH);
  97         if (err != Z_STREAM_END) {
  98                 zlib_inflateEnd(&stream);
  99
 100                 if (err == Z_NEED_DICT ||
 101                    (err == Z_BUF_ERROR && stream.avail_in == 0))
 102                         return Z_DATA_ERROR;
 103
 104                 return err;
 105         }
 106         *destLen = stream.total_out;
 107
 108         err = zlib_inflateEnd(&stream);
 109         return err;
 110 } /* z_uncompress() */
 111
 112 #endif /* SPL_ZMOD_H */