*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ * 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;
if (c->in < c->in_end)
return *c->in++;
c->error |= LZO_INPUT_DEPLETED;
- return -1;
+ return 1;
}
/**
* \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;
}
/**
* \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;
}
/**
* \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;
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) {
while (!c.error) {
int cnt, back;
if (x >> 4) {
- state = BACKPTR;
if (x >> 6) {
cnt = (x >> 5) - 1;
back = (get_byte(&c) << 3) + ((x >> 2) & 7) + 1;
}
copy_backptr(&c, back, cnt + 2);
cnt = x & 3;
+ state = cnt ? BACKPTR : COPY;
if (cnt)
copy(&c, cnt);
- else
- state = (state == COPY) ? BACKPTR : COPY;
x = get_byte(&c);
}
*inlen = c.in_end - c.in;