Commit f53a2931 authored by Reimar Döffinger's avatar Reimar Döffinger

faster copy functions for lzo decoder that also need padding

Originally committed as revision 4882 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent ac44871c
......@@ -232,7 +232,7 @@ static int decode_init(AVCodecContext *avctx) {
c->linelen = avctx->width * avctx->bits_per_sample / 8;
c->height = avctx->height;
c->decomp_size = c->height * c->linelen;
c->decomp_buf = av_malloc(c->decomp_size);
c->decomp_buf = av_malloc(c->decomp_size + LZO_OUTPUT_PADDING);
if (!c->decomp_buf) {
av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
return 1;
......
......@@ -17,12 +17,18 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "common.h"
//! avoid e.g. MPlayers fast_memcpy, it slows things down here
#undef memcpy
#include <string.h>
#include "lzo.h"
//! define if we may write up to 12 bytes beyond the output buffer
#define OUTBUF_PADDED 1
//! define if we may read up to 4 bytes beyond the input buffer
#define INBUF_PADDED 1
typedef struct LZOContext {
uint8_t *in, *in_end;
uint8_t *out, *out_end;
int out_size;
uint8_t *out_start, *out, *out_end;
int error;
} LZOContext;
......@@ -57,17 +63,29 @@ static inline int get_len(LZOContext *c, int x, int mask) {
* \param cnt number of bytes to copy, must be > 0
*/
static inline void copy(LZOContext *c, int cnt) {
if (c->in + cnt > c->in_end) {
cnt = c->in_end - c->in;
register uint8_t *src = c->in;
register uint8_t *dst = c->out;
if (src + cnt > c->in_end) {
cnt = c->in_end - src;
c->error |= LZO_INPUT_DEPLETED;
}
if (c->out + cnt > c->out_end) {
cnt = c->out_end - c->out;
if (dst + cnt > c->out_end) {
cnt = c->out_end - dst;
c->error |= LZO_OUTPUT_FULL;
}
do {
*c->out++ = *c->in++;
} while (--cnt);
#if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
src += 4;
dst += 4;
cnt -= 4;
if (cnt > 0)
#endif
memcpy(dst, src, cnt);
c->in = src + cnt;
c->out = dst + cnt;
}
/**
......@@ -75,20 +93,59 @@ static inline void copy(LZOContext *c, int cnt) {
* \param back how many bytes back we start
* \param cnt number of bytes to copy, must be > 0
*
* cnt > back is valid, this will copy the bytes we just copied.
* cnt > back is valid, this will copy the bytes we just copied,
* thus creating a repeating pattern with a period length of back.
*/
static inline void copy_backptr(LZOContext *c, int back, int cnt) {
if (c->out - back < c->out_end - c->out_size) {
register uint8_t *src = &c->out[-back];
register uint8_t *dst = c->out;
if (src < c->out_start) {
c->error |= LZO_INVALID_BACKPTR;
return;
}
if (c->out + cnt > c->out_end) {
cnt = c->out_end - c->out;
if (dst + cnt > c->out_end) {
cnt = c->out_end - dst;
c->error |= LZO_OUTPUT_FULL;
}
do {
*c->out++ = c->out[-back];
} while (--cnt);
if (back == 1) {
memset(dst, *src, cnt);
dst += cnt;
} else {
#ifdef OUTBUF_PADDED
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
src += 4;
dst += 4;
cnt -= 4;
if (cnt > 0) {
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
dst[4] = src[4];
dst[5] = src[5];
dst[6] = src[6];
dst[7] = src[7];
src += 8;
dst += 8;
cnt -= 8;
}
#endif
if (cnt > 0) {
int blocklen = back;
while (cnt > blocklen) {
memcpy(dst, src, blocklen);
dst += blocklen;
cnt -= blocklen;
blocklen <<= 1;
}
memcpy(dst, src, cnt);
}
dst += cnt;
}
c->out = dst;
}
/**
......@@ -98,6 +155,9 @@ static inline void copy_backptr(LZOContext *c, int back, int cnt) {
* \param in input buffer
* \param inlen size of input buffer, number of bytes left are returned here
* \return 0 on success, otherwise error flags, see lzo.h
*
* make sure all buffers are appropriately padded, in must provide
* LZO_INPUT_PADDING, out must provide LZO_OUTPUT_PADDING additional bytes
*/
int lzo1x_decode(void *out, int *outlen, void *in, int *inlen) {
enum {COPY, BACKPTR} state = COPY;
......@@ -105,9 +165,8 @@ int lzo1x_decode(void *out, int *outlen, void *in, int *inlen) {
LZOContext c;
c.in = in;
c.in_end = in + *inlen;
c.out = out;
c.out = c.out_start = out;
c.out_end = out + * outlen;
c.out_size = *outlen;
c.error = 0;
x = get_byte(&c);
if (x > 17) {
......
......@@ -6,6 +6,9 @@
#define LZO_INVALID_BACKPTR 4
#define LZO_ERROR 8
#define LZO_INPUT_PADDING 4
#define LZO_OUTPUT_PADDING 12
int lzo1x_decode(void *out, int *outlen, void *in, int *inlen);
#endif
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