compressutils.c

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/* SPDX-FileCopyrightText: 2013-2023 Greenbone AG
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */
 
#if !defined(ZLIB_CONST)
#define ZLIB_CONST
#endif
 
#include "compressutils.h"
 
#include <glib.h> /* for g_free, g_malloc0 */
#include <zlib.h> /* for z_stream, Z_NULL, Z_OK, Z_BUF_ERROR, Z_STREAM_END */
 
#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "libgvm util"
 
void *
gvm_compress (const void *src, unsigned long srclen, unsigned long *dstlen)
{
  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;
        }
    }
}
 
void *
gvm_uncompress (const void *src, unsigned long srclen, unsigned long *dstlen)
{
  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;
        }
    }
}
 
void *
gvm_compress_gzipheader (const void *src, unsigned long srclen,
                         unsigned long *dstlen)
{
  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;
        }
    }
}