compressutils.c File Reference

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

#include "compressutils.h"
#include <glib.h>
#include <zlib.h>

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Macros
#define	ZLIB_CONST
	For z_const to be defined as const.
#define	_GNU_SOURCE
#define	G_LOG_DOMAIN   "libgvm util"
	GLib logging domain.

Functions
void *	gvm_compress (const void *src, unsigned long srclen, unsigned long *dstlen)
	Compresses data in src buffer.
void *	gvm_uncompress (const void *src, unsigned long srclen, unsigned long *dstlen)
	Uncompresses data in src buffer.
void *	gvm_compress_gzipheader (const void *src, unsigned long srclen, unsigned long *dstlen)
	Compresses data in src buffer, gzip format compatible.
static ssize_t	gz_file_read (void *cookie, char *buffer, size_t buffer_size)
	Read decompressed data from a gzip file.
static int	gz_file_close (void *cookie)
	Close a gzip file.
FILE *	gvm_gzip_open_file_reader (const char *path)
	Opens a gzip file as a FILE* stream for reading and decompression.
FILE *	gvm_gzip_open_file_reader_fd (int fd)
	Opens a gzip file as a FILE* stream for reading and decompression.

Detailed Description

Functions related to data compression (gzip format.).

Definition in file compressutils.c.

Macro Definition Documentation

_GNU_SOURCE

#define _GNU_SOURCE

Definition at line 18 of file compressutils.c.

G_LOG_DOMAIN

#define G_LOG_DOMAIN   "libgvm util"

GLib logging domain.

Definition at line 29 of file compressutils.c.

ZLIB_CONST

#define ZLIB_CONST

For z_const to be defined as const.

Definition at line 15 of file compressutils.c.

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. Caller must g_free.

Definition at line 42 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;
        }
    }
}

Referenced by Ensure().

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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. Caller must g_free.

Definition at line 182 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;
        }
    }
}

Referenced by Ensure(), Ensure(), and Ensure().

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gvm_gzip_open_file_reader()

FILE * gvm_gzip_open_file_reader

(

const char *

path

)

Opens a gzip file as a FILE* stream for reading and decompression.

Parameters

[in]

path

Path to the gzip file to open.

Returns

The FILE* on success, NULL otherwise.

Definition at line 287 of file compressutils.c.

{
  static cookie_io_functions_t io_functions = {
    .read = gz_file_read,
    .write = NULL,
    .seek = NULL,
    .close = gz_file_close,
  };
 
  if (path == NULL)
    {
      return NULL;
    }
 
  gzFile gz_file = gzopen (path, "r");
  if (gz_file == NULL)
    {
      return NULL;
    }
 
  FILE *file = fopencookie (gz_file, "r", io_functions);
  return file;
}

References gz_file_close(), and gz_file_read().

Referenced by Ensure().

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gvm_gzip_open_file_reader_fd()

FILE * gvm_gzip_open_file_reader_fd

(

int

fd

)

Opens a gzip file as a FILE* stream for reading and decompression.

Parameters

[in]

fd

File descriptor of the gzip file to open.

Returns

The FILE* on success, NULL otherwise.

Definition at line 319 of file compressutils.c.

{
  static cookie_io_functions_t io_functions = {
    .read = gz_file_read,
    .write = NULL,
    .seek = NULL,
    .close = gz_file_close,
  };
 
  if (fd < 0)
    {
      return NULL;
    }
 
  gzFile gz_file = gzdopen (fd, "r");
  if (gz_file == NULL)
    {
      return NULL;
    }
 
  FILE *file = fopencookie (gz_file, "r", io_functions);
  return file;
}

References gz_file_close(), and gz_file_read().

Referenced by Ensure().

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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. Caller must g_free.

Definition at line 111 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;
        }
    }
}

Referenced by Ensure(), and Ensure().

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gz_file_close()

int gz_file_close ( void * cookie )

static

Close a gzip file.

Parameters

[in]

cookie

The gzFile to close.

Returns

0 on success, other values on error (see gzclose() from zlib).

Definition at line 271 of file compressutils.c.

{
  gzFile gz_file = cookie;
 
  return gzclose (gz_file);
  ;
}

Referenced by gvm_gzip_open_file_reader(), and gvm_gzip_open_file_reader_fd().

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gz_file_read()

ssize_t gz_file_read ( void * cookie, char * buffer, size_t buffer_size )

static

Read decompressed data from a gzip file.

Parameters

[in]	cookie	The gzFile to read from.
[in]	buffer	The buffer to output decompressed data to.
[in]	buffer_size	The size of the buffer.

Returns

The number of bytes read into the buffer.

Definition at line 256 of file compressutils.c.

{
  gzFile gz_file = cookie;
 
  return gzread (gz_file, buffer, buffer_size);
}

Referenced by gvm_gzip_open_file_reader(), and gvm_gzip_open_file_reader_fd().

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