yading@11: /*
yading@11:  * LZO 1x decompression
yading@11:  * Copyright (c) 2006 Reimar Doeffinger
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include <string.h>
yading@11: 
yading@11: #include "avutil.h"
yading@11: #include "common.h"
yading@11: #include "intreadwrite.h"
yading@11: #include "lzo.h"
yading@11: 
yading@11: /// Define if we may write up to 12 bytes beyond the output buffer.
yading@11: #define OUTBUF_PADDED 1
yading@11: /// Define if we may read up to 8 bytes beyond the input buffer.
yading@11: #define INBUF_PADDED 1
yading@11: 
yading@11: typedef struct LZOContext {
yading@11:     const uint8_t *in, *in_end;
yading@11:     uint8_t *out_start, *out, *out_end;
yading@11:     int error;
yading@11: } LZOContext;
yading@11: 
yading@11: /**
yading@11:  * @brief Reads one byte from the input buffer, avoiding an overrun.
yading@11:  * @return byte read
yading@11:  */
yading@11: static inline int get_byte(LZOContext *c)
yading@11: {
yading@11:     if (c->in < c->in_end)
yading@11:         return *c->in++;
yading@11:     c->error |= AV_LZO_INPUT_DEPLETED;
yading@11:     return 1;
yading@11: }
yading@11: 
yading@11: #ifdef INBUF_PADDED
yading@11: #define GETB(c) (*(c).in++)
yading@11: #else
yading@11: #define GETB(c) get_byte(&(c))
yading@11: #endif
yading@11: 
yading@11: /**
yading@11:  * @brief Decodes a length value in the coding used by lzo.
yading@11:  * @param x previous byte value
yading@11:  * @param mask bits used from x
yading@11:  * @return decoded length value
yading@11:  */
yading@11: static inline int get_len(LZOContext *c, int x, int mask)
yading@11: {
yading@11:     int cnt = x & mask;
yading@11:     if (!cnt) {
yading@11:         while (!(x = get_byte(c)))
yading@11:             cnt += 255;
yading@11:         cnt += mask + x;
yading@11:     }
yading@11:     return cnt;
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * @brief Copies bytes from input to output buffer with checking.
yading@11:  * @param cnt number of bytes to copy, must be >= 0
yading@11:  */
yading@11: static inline void copy(LZOContext *c, int cnt)
yading@11: {
yading@11:     register const uint8_t *src = c->in;
yading@11:     register uint8_t *dst       = c->out;
yading@11:     if (cnt > c->in_end - src) {
yading@11:         cnt       = FFMAX(c->in_end - src, 0);
yading@11:         c->error |= AV_LZO_INPUT_DEPLETED;
yading@11:     }
yading@11:     if (cnt > c->out_end - dst) {
yading@11:         cnt       = FFMAX(c->out_end - dst, 0);
yading@11:         c->error |= AV_LZO_OUTPUT_FULL;
yading@11:     }
yading@11: #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
yading@11:     AV_COPY32U(dst, src);
yading@11:     src += 4;
yading@11:     dst += 4;
yading@11:     cnt -= 4;
yading@11:     if (cnt > 0)
yading@11: #endif
yading@11:     memcpy(dst, src, cnt);
yading@11:     c->in  = src + cnt;
yading@11:     c->out = dst + cnt;
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * @brief Copies previously decoded bytes to current position.
yading@11:  * @param back how many bytes back we start, must be > 0
yading@11:  * @param cnt number of bytes to copy, must be >= 0
yading@11:  *
yading@11:  * cnt > back is valid, this will copy the bytes we just copied,
yading@11:  * thus creating a repeating pattern with a period length of back.
yading@11:  */
yading@11: static inline void copy_backptr(LZOContext *c, int back, int cnt)
yading@11: {
yading@11:     register uint8_t *dst       = c->out;
yading@11:     if (dst - c->out_start < back) {
yading@11:         c->error |= AV_LZO_INVALID_BACKPTR;
yading@11:         return;
yading@11:     }
yading@11:     if (cnt > c->out_end - dst) {
yading@11:         cnt       = FFMAX(c->out_end - dst, 0);
yading@11:         c->error |= AV_LZO_OUTPUT_FULL;
yading@11:     }
yading@11:     av_memcpy_backptr(dst, back, cnt);
yading@11:     c->out = dst + cnt;
yading@11: }
yading@11: 
yading@11: int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen)
yading@11: {
yading@11:     int state = 0;
yading@11:     int x;
yading@11:     LZOContext c;
yading@11:     if (*outlen <= 0 || *inlen <= 0) {
yading@11:         int res = 0;
yading@11:         if (*outlen <= 0)
yading@11:             res |= AV_LZO_OUTPUT_FULL;
yading@11:         if (*inlen <= 0)
yading@11:             res |= AV_LZO_INPUT_DEPLETED;
yading@11:         return res;
yading@11:     }
yading@11:     c.in      = in;
yading@11:     c.in_end  = (const uint8_t *)in + *inlen;
yading@11:     c.out     = c.out_start = out;
yading@11:     c.out_end = (uint8_t *)out + *outlen;
yading@11:     c.error   = 0;
yading@11:     x         = GETB(c);
yading@11:     if (x > 17) {
yading@11:         copy(&c, x - 17);
yading@11:         x = GETB(c);
yading@11:         if (x < 16)
yading@11:             c.error |= AV_LZO_ERROR;
yading@11:     }
yading@11:     if (c.in > c.in_end)
yading@11:         c.error |= AV_LZO_INPUT_DEPLETED;
yading@11:     while (!c.error) {
yading@11:         int cnt, back;
yading@11:         if (x > 15) {
yading@11:             if (x > 63) {
yading@11:                 cnt  = (x >> 5) - 1;
yading@11:                 back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
yading@11:             } else if (x > 31) {
yading@11:                 cnt  = get_len(&c, x, 31);
yading@11:                 x    = GETB(c);
yading@11:                 back = (GETB(c) << 6) + (x >> 2) + 1;
yading@11:             } else {
yading@11:                 cnt   = get_len(&c, x, 7);
yading@11:                 back  = (1 << 14) + ((x & 8) << 11);
yading@11:                 x     = GETB(c);
yading@11:                 back += (GETB(c) << 6) + (x >> 2);
yading@11:                 if (back == (1 << 14)) {
yading@11:                     if (cnt != 1)
yading@11:                         c.error |= AV_LZO_ERROR;
yading@11:                     break;
yading@11:                 }
yading@11:             }
yading@11:         } else if (!state) {
yading@11:             cnt = get_len(&c, x, 15);
yading@11:             copy(&c, cnt + 3);
yading@11:             x = GETB(c);
yading@11:             if (x > 15)
yading@11:                 continue;
yading@11:             cnt  = 1;
yading@11:             back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
yading@11:         } else {
yading@11:             cnt  = 0;
yading@11:             back = (GETB(c) << 2) + (x >> 2) + 1;
yading@11:         }
yading@11:         copy_backptr(&c, back, cnt + 2);
yading@11:         state =
yading@11:         cnt   = x & 3;
yading@11:         copy(&c, cnt);
yading@11:         x = GETB(c);
yading@11:     }
yading@11:     *inlen = c.in_end - c.in;
yading@11:     if (c.in > c.in_end)
yading@11:         *inlen = 0;
yading@11:     *outlen = c.out_end - c.out;
yading@11:     return c.error;
yading@11: }
yading@11: 
yading@11: #ifdef TEST
yading@11: #include <stdio.h>
yading@11: #include <lzo/lzo1x.h>
yading@11: #include "log.h"
yading@11: #define MAXSZ (10*1024*1024)
yading@11: 
yading@11: /* Define one of these to 1 if you wish to benchmark liblzo
yading@11:  * instead of our native implementation. */
yading@11: #define BENCHMARK_LIBLZO_SAFE   0
yading@11: #define BENCHMARK_LIBLZO_UNSAFE 0
yading@11: 
yading@11: int main(int argc, char *argv[]) {
yading@11:     FILE *in = fopen(argv[1], "rb");
yading@11:     uint8_t *orig = av_malloc(MAXSZ + 16);
yading@11:     uint8_t *comp = av_malloc(2*MAXSZ + 16);
yading@11:     uint8_t *decomp = av_malloc(MAXSZ + 16);
yading@11:     size_t s = fread(orig, 1, MAXSZ, in);
yading@11:     lzo_uint clen = 0;
yading@11:     long tmp[LZO1X_MEM_COMPRESS];
yading@11:     int inlen, outlen;
yading@11:     int i;
yading@11:     av_log_set_level(AV_LOG_DEBUG);
yading@11:     lzo1x_999_compress(orig, s, comp, &clen, tmp);
yading@11:     for (i = 0; i < 300; i++) {
yading@11: START_TIMER
yading@11:         inlen = clen; outlen = MAXSZ;
yading@11: #if BENCHMARK_LIBLZO_SAFE
yading@11:         if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
yading@11: #elif BENCHMARK_LIBLZO_UNSAFE
yading@11:         if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
yading@11: #else
yading@11:         if (av_lzo1x_decode(decomp, &outlen, comp, &inlen))
yading@11: #endif
yading@11:             av_log(NULL, AV_LOG_ERROR, "decompression error\n");
yading@11: STOP_TIMER("lzod")
yading@11:     }
yading@11:     if (memcmp(orig, decomp, s))
yading@11:         av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
yading@11:     else
yading@11:         av_log(NULL, AV_LOG_ERROR, "decompression OK\n");
yading@11:     return 0;
yading@11: }
yading@11: #endif