greg/pcompress
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Add matrix transpose to Delta2 encoding.

Browse source 
Change confusing structure member name.
This commit is contained in:
Moinak Ghosh 2012-12-13 21:18:16 +05:30
parent 375ebefa0d
commit b0f41c2888
11 changed files with 75 additions and 30 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
adaptive_compress.c
View file

@ -98,7 +98,7 @@ adapt_stats(int show)
void
adapt_props(algo_props_t *data, int level, int64_t chunksize)
{
data->delta2_stride = 200;
data->delta2_span = 200;
}
int

2
bzip2_compress.c
View file

@ -50,7 +50,7 @@ bzip2_stats(int show)
void
bzip2_props(algo_props_t *data, int level, int64_t chunksize) {
data->delta2_stride = 200;
data->delta2_span = 200;
}
int

65
delta2/delta2.c
View file

@ -30,18 +30,23 @@
* Bytes are packed into integers in big-endian format.
*
* After an optimal stride length has been identified the encoder
* performs a delta run length encoding on the spans. Two types of
* performs a delta run length encoding on the spans. Three types of
* objects are output by the encoder:
* 1) A literal run of unmodified bytes. Header: 1 zero byte followed
* by a 64bit length in bytes.
* 2) An encoded run length of a series in arithmetic progression.
* Header: 1 byte stride length
* 2) A literal run of transposed bytes containing at least 87% below
* threshold sequences.
* Header: 1 byte stride length with high bit set.
* 64bit length of span in bytes.
* 3) An encoded run length of a series in arithmetic progression.
* Header: 1 byte stride length (must be less than 128)
* 64bit length of span in bytes
* 64bit starting value of series
* 64bit delta value
*/
#include <stdio.h>
#include <utils.h>
#include <transpose.h>
#include "delta2.h"
// Size of original data. 64 bits.
@ -59,6 +64,9 @@
// 64bit delta value
#define DELTA_HDR (1 + (sizeof (uint64_t)) * 3)
// Minimum span length
#define MIN_THRESH (50)
int
delta2_encode(uchar_t *src, uint64_t srclen, uchar_t *dst, uint64_t *dstlen, int rle_thresh)
{
@ -68,7 +76,10 @@ delta2_encode(uchar_t *src, uint64_t srclen, uchar_t *dst, uint64_t *dstlen, int
uchar_t *pos, *pos1, *pos2, stride, st1;
uchar_t strides[4] = {3, 5, 7, 8};
int st, sz;
DEBUG_STAT_EN(uint32_t num_trans);
if (rle_thresh < MIN_THRESH)
return (-1);
gtot1 = ULL_MAX;
stride = 0;
sz = sizeof (strides) / sizeof (strides[0]);
@ -107,13 +118,11 @@ delta2_encode(uchar_t *src, uint64_t srclen, uchar_t *dst, uint64_t *dstlen, int
vl1 = vl2;
pos += st1;
}
if (snum > 1) {
if (snum > rle_thresh) {
gtot2 += DELTA_HDR;
} else {
gtot2 += snum;
}
}
if (gtot2 < gtot1) {
gtot1 = gtot2;
stride = st1;
@ -139,6 +148,8 @@ delta2_encode(uchar_t *src, uint64_t srclen, uchar_t *dst, uint64_t *dstlen, int
pos1 += MAIN_HDR;
pos2 = pos1;
pos1 += LIT_HDR;
gtot2 = 0;
DEBUG_STAT_EN(num_trans = 0);
vl2 = *((uint64_t *)pos);
vl2 = htonll(vl2);
@ -154,13 +165,27 @@ delta2_encode(uchar_t *src, uint64_t srclen, uchar_t *dst, uint64_t *dstlen, int
if (snum > rle_thresh) {
if (gtot1 > 0) {
/*
* Encode previous literal run, if any.
* Encode previous literal run, if any. If the literal run
* has enough large sequences just below threshold, do a
* matrix transpose on the range in the hope of achieving
* a better compression ratio.
*/
if (gtot2 >= ((gtot1 >> 1) + (gtot1 >> 2) + (gtot1 >> 3))) {
*pos2 = stride | 128;
pos2++;
*((uint64_t *)pos2) = htonll(gtot1);
pos2 += sizeof (uint64_t);
transpose(pos - (gtot1+snum), pos2, gtot1, stride, ROW);
DEBUG_STAT_EN(num_trans++);
} else {
*pos2 = 0;
pos2++;
*((uint64_t *)pos2) = htonll(gtot1);
pos2 += (gtot1 + sizeof (uint64_t));
pos2 += sizeof (uint64_t);
}
pos2 += gtot1;
gtot1 = 0;
gtot2 = 0;
}
/*
* RLE Encode delta series.
@ -176,6 +201,8 @@ delta2_encode(uchar_t *src, uint64_t srclen, uchar_t *dst, uint64_t *dstlen, int
pos1 = pos2 + LIT_HDR;
} else {
gtot1 += snum;
if (snum >= 50)
gtot2 += snum;
}
snum = 0;
sval = vl2;
@ -230,6 +257,7 @@ delta2_encode(uchar_t *src, uint64_t srclen, uchar_t *dst, uint64_t *dstlen, int
}
}
*dstlen = pos2 - dst;
DEBUG_STAT_EN(printf("%u transpositions\n", num_trans));
return (0);
}
@ -262,10 +290,27 @@ delta2_decode(uchar_t *src, uint64_t srclen, uchar_t *dst, uint64_t *dstlen)
if (out + rcnt > *dstlen) {
return (-1);
}
for (cnt = 0; cnt < rcnt; cnt++) {
*pos1 = *pos;
pos++; pos1++; out++;
memcpy(pos1, pos, rcnt);
pos += rcnt;
pos1 += rcnt;
out += rcnt;
} else if (*pos & 128) {
int stride;
/*
* Copy over literal run of transposed bytes and inverse-transpose.
*/
stride = (*pos & 127);
pos++;
rcnt = ntohll(*((uint64_t *)pos));
pos += sizeof (rcnt);
if (out + rcnt > *dstlen) {
return (-1);
}
transpose(pos, pos1, rcnt, stride, COL);
pos += rcnt;
pos1 += rcnt;
out += rcnt;
} else {
stride = *pos;
pos++;

2
libbsc_compress.c
View file

@ -79,7 +79,7 @@ libbsc_props(algo_props_t *data, int level, int64_t chunksize) {
data->buf_extra = 0;
data->c_max_threads = 8;
data->d_max_threads = 8;
data->delta2_stride = 150;
data->delta2_span = 150;
}
int

2
lz4_compress.c
View file

@ -56,7 +56,7 @@ lz4_props(algo_props_t *data, int level, int64_t chunksize) {
data->compress_mt_capable = 0;
data->decompress_mt_capable = 0;
data->buf_extra = lz4_buf_extra(chunksize);
data->delta2_stride = 50;
data->delta2_span = 50;
}
int

2
lzfx_compress.c
View file

@ -41,7 +41,7 @@ lz_fx_stats(int show)
void
lz_fx_props(algo_props_t *data, int level, int64_t chunksize) {
data->delta2_stride = 50;
data->delta2_span = 50;
}
int

4
lzma_compress.c
View file

@ -52,7 +52,7 @@ lzma_mt_props(algo_props_t *data, int level, int64_t chunksize) {
data->decompress_mt_capable = 0;
data->buf_extra = 0;
data->c_max_threads = 2;
data->delta2_stride = 150;
data->delta2_span = 150;
}
void
@ -60,7 +60,7 @@ lzma_props(algo_props_t *data, int level, int64_t chunksize) {
data->compress_mt_capable = 0;
data->decompress_mt_capable = 0;
data->buf_extra = 0;
data->delta2_stride = 150;
data->delta2_span = 150;
}
/*

4
main.c
View file

@ -215,9 +215,9 @@ preproc_compress(compress_func_ptr cmp_func, void *src, uint64_t srclen, void *d
return (-1);
}
if (enable_delta2_encode && props->delta2_stride > 0) {
if (enable_delta2_encode && props->delta2_span > 0) {
_dstlen = srclen;
result = delta2_encode(src, srclen, dst, &_dstlen, props->delta2_stride);
result = delta2_encode(src, srclen, dst, &_dstlen, props->delta2_span);
if (result != -1) {
memcpy(src, dst, _dstlen);
srclen = _dstlen;

2
ppmd_compress.c
View file

@ -63,7 +63,7 @@ ppmd_stats(int show)
void
ppmd_props(algo_props_t *data, int level, int64_t chunksize) {
data->delta2_stride = 100;
data->delta2_span = 100;
}
int

4
utils/utils.h
View file

@ -111,7 +111,7 @@ typedef struct {
int nthreads;
int c_max_threads;
int d_max_threads;
int delta2_stride;
int delta2_span;
} algo_props_t;
typedef enum {
@ -206,7 +206,7 @@ init_algo_props(algo_props_t *props)
props->nthreads = 1;
props->c_max_threads = 1;
props->d_max_threads = 1;
props->delta2_stride = 0;
props->delta2_span = 0;
}
#ifdef __cplusplus

2
zlib_compress.c
View file

@ -91,7 +91,7 @@ zlib_stats(int show)
void
zlib_props(algo_props_t *data, int level, int64_t chunksize) {
data->delta2_stride = 50;
data->delta2_span = 50;
}
int