/* 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 */
}
/* 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 */
}