コード例 #1
0
ファイル: compr.c プロジェクト: BackupTheBerlios/wl530g-svn
/* jffs2_compress:
 * @data: Pointer to uncompressed data
 * @cdata: Pointer to returned pointer to buffer for compressed data
 * @datalen: On entry, holds the amount of data available for compression.
 *	On exit, expected to hold the amount of data actually compressed.
 * @cdatalen: On entry, holds the amount of space available for compressed
 *	data. On exit, expected to hold the actual size of the compressed
 *	data.
 *
 * Returns: Byte to be stored with data indicating compression type used.
 * Zero is used to show that the data could not be compressed - the 
 * compressed version was actually larger than the original.
 *
 * If the cdata buffer isn't large enough to hold all the uncompressed data,
 * jffs2_compress should compress as much as will fit, and should set 
 * *datalen accordingly to show the amount of data which were compressed.
 */
unsigned char jffs2_compress(unsigned char *data_in, unsigned char **cpage_out, 
		    uint32_t *datalen, uint32_t *cdatalen)
{
#ifdef JFFS2_COMPRESSION
	int ret;

	*cpage_out = kmalloc(*cdatalen, GFP_KERNEL);
	if (!*cpage_out) {
		printk(KERN_WARNING "No memory for compressor allocation. Compression failed\n");
		goto out;
	}

#ifdef JFFS2_USE_ZLIB
	ret = jffs2_zlib_compress(data_in, *cpage_out, datalen, cdatalen);
	if (!ret) {
		return JFFS2_COMPR_ZLIB;
	}
#endif
#ifdef JFFS2_USE_DYNRUBIN
	ret = jffs2_dynrubin_compress(data_in, *cpage_out, datalen, cdatalen);
	if (!ret) {
		return JFFS2_COMPR_DYNRUBIN;
	}
#endif
#ifdef JFFS2_USE_RUBINMIPS
	ret = jffs2_rubinmips_compress(data_in, *cpage_out, datalen, cdatalen);
	if (!ret) {
		return JFFS2_COMPR_RUBINMIPS;
	}
#endif
#ifdef JFFS2_USE_RTIME
	/* rtime does manage to recompress already-compressed data */
	ret = jffs2_rtime_compress(data_in, *cpage_out, datalen, cdatalen);
	if (!ret) {
		return JFFS2_COMPR_RTIME;
	}
#endif
	kfree(*cpage_out);
#endif /* Compression */
 out:
	*cpage_out = data_in;
	*datalen = *cdatalen;
	return JFFS2_COMPR_NONE; /* We failed to compress */
}
コード例 #2
0
ファイル: compr.c プロジェクト: iPodLinux/linux-2.6.7-ipod
/* jffs2_compress:
 * @data: Pointer to uncompressed data
 * @cdata: Pointer to buffer for compressed data
 * @datalen: On entry, holds the amount of data available for compression.
 *	On exit, expected to hold the amount of data actually compressed.
 * @cdatalen: On entry, holds the amount of space available for compressed
 *	data. On exit, expected to hold the actual size of the compressed
 *	data.
 *
 * Returns: Byte to be stored with data indicating compression type used.
 * Zero is used to show that the data could not be compressed - the 
 * compressed version was actually larger than the original.
 *
 * If the cdata buffer isn't large enough to hold all the uncompressed data,
 * jffs2_compress should compress as much as will fit, and should set 
 * *datalen accordingly to show the amount of data which were compressed.
 */
unsigned char jffs2_compress(unsigned char *data_in, unsigned char *cpage_out, 
		    uint32_t *datalen, uint32_t *cdatalen)
{
	int ret;

	ret = jffs2_zlib_compress(data_in, cpage_out, datalen, cdatalen);
	if (!ret) {
		return JFFS2_COMPR_ZLIB;
	}
#if 0 /* Disabled 23/9/1. With zlib it hardly ever gets a look in */
	ret = jffs2_dynrubin_compress(data_in, cpage_out, datalen, cdatalen);
	if (!ret) {
		return JFFS2_COMPR_DYNRUBIN;
	}
#endif
#if 0 /* Disabled 26/2/1. Obsoleted by dynrubin */
	ret = jffs2_rubinmips_compress(data_in, cpage_out, datalen, cdatalen);
	if (!ret) {
		return JFFS2_COMPR_RUBINMIPS;
	}
#endif
	/* rtime does manage to recompress already-compressed data */
	ret = jffs2_rtime_compress(data_in, cpage_out, datalen, cdatalen);
	if (!ret) {
		return JFFS2_COMPR_RTIME;
	}
#if 0
	/* We don't need to copy. Let the caller special-case the COMPR_NONE case. */
	/* If we get here, no compression is going to work */
	/* But we might want to use the fragmentation part -- Arjan */
	memcpy(cpage_out,data_in,min(*datalen,*cdatalen));
	if (*datalen > *cdatalen)
		*datalen = *cdatalen;
#endif		
	return JFFS2_COMPR_NONE; /* We failed to compress */

}