compressutils.h File Reference

API related to data compression (gzip format.) More...

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Functions
void *	gvm_compress (const void *, unsigned long, unsigned long *)
	Compresses data in src buffer. More...
void *	gvm_compress_gzipheader (const void *, unsigned long, unsigned long *)
	Compresses data in src buffer, gzip format compatible. More...
void *	gvm_uncompress (const void *, unsigned long, unsigned long *)
	Uncompresses data in src buffer. More...

Detailed Description

API related to data compression (gzip format.)

Definition in file compressutils.h.

Function Documentation

gvm_compress()

void* gvm_compress	(	const void *	src,
		unsigned long	srclen,
		unsigned long *	dstlen
	)

Compresses data in src buffer.

Parameters

[in]	src	Buffer of data to compress.
[in]	srclen	Length of data to compress.
[out]	dstlen	Length of compressed data.

Returns

Pointer to compressed data if success, NULL otherwise.

Definition at line 47 of file compressutils.c.

{
  unsigned long buflen = srclen * 2;

  if (src == NULL || dstlen == NULL)
    return NULL;

  if (buflen < 30)
    buflen = 30;

  while (1)
    {
      int err;
      void *buffer;
      z_stream strm;

      /* Initialize deflate state */
      strm.zalloc = Z_NULL;
      strm.zfree = Z_NULL;
      strm.opaque = Z_NULL;
      strm.avail_in = srclen;
#ifdef z_const
      strm.next_in = src;
#else
      /* Workaround for older zlib. */
      strm.next_in = (void *) src;
#endif
      if (deflateInit (&strm, Z_DEFAULT_COMPRESSION) != Z_OK)
        return NULL;

      buffer = g_malloc0 (buflen);
      strm.avail_out = buflen;
      strm.next_out = buffer;

      err = deflate (&strm, Z_SYNC_FLUSH);
      deflateEnd (&strm);
      switch (err)
        {
        case Z_OK:
        case Z_STREAM_END:
          if (strm.avail_out != 0)
            {
              *dstlen = strm.total_out;
              return buffer;
            }
          /* Fallthrough. */
        case Z_BUF_ERROR:
          g_free (buffer);
          buflen *= 2;
          break;

        default:
          g_free (buffer);
          return NULL;
        }
    }
}

gvm_compress_gzipheader()

void* gvm_compress_gzipheader	(	const void *	src,
		unsigned long	srclen,
		unsigned long *	dstlen
	)

Compresses data in src buffer, gzip format compatible.

Parameters

[in]	src	Buffer of data to compress.
[in]	srclen	Length of data to compress.
[out]	dstlen	Length of compressed data.

Returns

Pointer to compressed data if success, NULL otherwise.

Definition at line 185 of file compressutils.c.

{
  unsigned long buflen = srclen * 2;
  int windowsBits = 15;
  int GZIP_ENCODING = 16;

  if (src == NULL || dstlen == NULL)
    return NULL;

  if (buflen < 30)
    buflen = 30;

  while (1)
    {
      int err;
      void *buffer;
      z_stream strm;

      /* Initialize deflate state */
      strm.zalloc = Z_NULL;
      strm.zfree = Z_NULL;
      strm.opaque = Z_NULL;
      strm.avail_in = srclen;
#ifdef z_const
      strm.next_in = src;
#else
      /* Workaround for older zlib. */
      strm.next_in = (void *) src;
#endif

      if (deflateInit2 (&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
                        windowsBits | GZIP_ENCODING, 8, Z_DEFAULT_STRATEGY)
          != Z_OK)
        return NULL;

      buffer = g_malloc0 (buflen);
      strm.avail_out = buflen;
      strm.next_out = buffer;

      err = deflate (&strm, Z_FINISH);
      deflateEnd (&strm);
      switch (err)
        {
        case Z_OK:
        case Z_STREAM_END:
          if (strm.avail_out != 0)
            {
              *dstlen = strm.total_out;
              return buffer;
            }
          /* Fallthrough. */
        case Z_BUF_ERROR:
          g_free (buffer);
          buflen *= 2;
          break;

        default:
          g_free (buffer);
          return NULL;
        }
    }
}

gvm_uncompress()

void* gvm_uncompress	(	const void *	src,
		unsigned long	srclen,
		unsigned long *	dstlen
	)

Uncompresses data in src buffer.

Parameters

[in]	src	Buffer of data to uncompress.
[in]	srclen	Length of data to uncompress.
[out]	dstlen	Length of uncompressed data.

Returns

Pointer to uncompressed data if success, NULL otherwise.

Definition at line 115 of file compressutils.c.

{
  unsigned long buflen = srclen * 2;

  if (src == NULL || dstlen == NULL)
    return NULL;

  while (1)
    {
      int err;
      void *buffer;
      z_stream strm;

      /* Initialize inflate state */
      strm.zalloc = Z_NULL;
      strm.zfree = Z_NULL;
      strm.opaque = Z_NULL;
      strm.avail_in = srclen;
#ifdef z_const
      strm.next_in = src;
#else
      /* Workaround for older zlib. */
      strm.next_in = (void *) src;
#endif
      /*
       * From: http://www.zlib.net/manual.html
       * Add 32 to windowBits to enable zlib and gzip decoding with automatic
       * header detection.
       */
      if (inflateInit2 (&strm, 15 + 32) != Z_OK)
        return NULL;

      buffer = g_malloc0 (buflen);
      strm.avail_out = buflen;
      strm.next_out = buffer;

      err = inflate (&strm, Z_SYNC_FLUSH);
      inflateEnd (&strm);
      switch (err)
        {
        case Z_OK:
        case Z_STREAM_END:
          if (strm.avail_out != 0)
            {
              *dstlen = strm.total_out;
              return buffer;
            }
          /* Fallthrough. */
        case Z_BUF_ERROR:
          g_free (buffer);
          buflen *= 2;
          break;

        default:
          g_free (buffer);
          return NULL;
        }
    }
}