/*
* Common bit i/o utils
- * Copyright (c) 2000, 2001 Fabrice Bellard.
+ * Copyright (c) 2000, 2001 Fabrice Bellard
* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
+ * Copyright (c) 2010 Loren Merritt
*
* alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
- * @file bitstream.c
+ * @file
* bitstream api.
*/
#include "avcodec.h"
-#include "bitstream.h"
-
-/**
- * Same as av_mallocz_static(), but does a realloc.
- *
- * @param[in] ptr The block of memory to reallocate.
- * @param[in] size The requested size.
- * @return Block of memory of requested size.
- * @deprecated. Code which uses ff_realloc_static is broken/misdesigned.
- * and should correctly use static arrays
- */
-attribute_deprecated void *ff_realloc_static(void *ptr, unsigned int size);
-
-void align_put_bits(PutBitContext *s)
+#include "internal.h"
+#include "mathops.h"
+#include "get_bits.h"
+#include "put_bits.h"
+
+const uint8_t ff_log2_run[41]={
+ 0, 0, 0, 0, 1, 1, 1, 1,
+ 2, 2, 2, 2, 3, 3, 3, 3,
+ 4, 4, 5, 5, 6, 6, 7, 7,
+ 8, 9,10,11,12,13,14,15,
+16,17,18,19,20,21,22,23,
+24,
+};
+
+void avpriv_align_put_bits(PutBitContext *s)
{
-#ifdef ALT_BITSTREAM_WRITER
- put_bits(s,( - s->index) & 7,0);
-#else
- put_bits(s,s->bit_left & 7,0);
-#endif
+ put_bits(s, s->bit_left & 7, 0);
}
-void ff_put_string(PutBitContext * pbc, char *s, int put_zero)
+void avpriv_put_string(PutBitContext *pb, const char *string,
+ int terminate_string)
{
- while(*s){
- put_bits(pbc, 8, *s);
- s++;
+ while (*string) {
+ put_bits(pb, 8, *string);
+ string++;
}
- if(put_zero)
- put_bits(pbc, 8, 0);
+ if (terminate_string)
+ put_bits(pb, 8, 0);
}
-void ff_copy_bits(PutBitContext *pb, uint8_t *src, int length)
+void avpriv_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
{
- const uint16_t *srcw= (uint16_t*)src;
- int words= length>>4;
- int bits= length&15;
+ int words = length >> 4;
+ int bits = length & 15;
int i;
- if(length==0) return;
+ if (length == 0)
+ return;
- if(ENABLE_SMALL || words < 16 || put_bits_count(pb)&7){
- for(i=0; i<words; i++) put_bits(pb, 16, be2me_16(srcw[i]));
- }else{
- for(i=0; put_bits_count(pb)&31; i++)
+ if (CONFIG_SMALL || words < 16 || put_bits_count(pb) & 7) {
+ for (i = 0; i < words; i++)
+ put_bits(pb, 16, AV_RB16(src + 2 * i));
+ } else {
+ for (i = 0; put_bits_count(pb) & 31; i++)
put_bits(pb, 8, src[i]);
flush_put_bits(pb);
- memcpy(pbBufPtr(pb), src+i, 2*words-i);
- skip_put_bytes(pb, 2*words-i);
+ memcpy(put_bits_ptr(pb), src + i, 2 * words - i);
+ skip_put_bytes(pb, 2 * words - i);
}
- put_bits(pb, bits, be2me_16(srcw[words])>>(16-bits));
+ put_bits(pb, bits, AV_RB16(src + 2 * words) >> (16 - bits));
}
/* VLC decoding */
-//#define DEBUG_VLC
-
-#define GET_DATA(v, table, i, wrap, size) \
-{\
- const uint8_t *ptr = (const uint8_t *)table + i * wrap;\
- switch(size) {\
- case 1:\
- v = *(const uint8_t *)ptr;\
- break;\
- case 2:\
- v = *(const uint16_t *)ptr;\
- break;\
- default:\
- v = *(const uint32_t *)ptr;\
- break;\
- }\
+#define GET_DATA(v, table, i, wrap, size) \
+{ \
+ const uint8_t *ptr = (const uint8_t *)table + i * wrap; \
+ switch(size) { \
+ case 1: \
+ v = *(const uint8_t *)ptr; \
+ break; \
+ case 2: \
+ v = *(const uint16_t *)ptr; \
+ break; \
+ default: \
+ v = *(const uint32_t *)ptr; \
+ break; \
+ } \
}
static int alloc_table(VLC *vlc, int size, int use_static)
{
- int index;
- index = vlc->table_size;
+ int index = vlc->table_size;
+
vlc->table_size += size;
if (vlc->table_size > vlc->table_allocated) {
+ int err;
+ if (use_static)
+ return AVERROR_BUG;
vlc->table_allocated += (1 << vlc->bits);
- if(use_static)
- vlc->table = ff_realloc_static(vlc->table,
- sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
- else
- vlc->table = av_realloc(vlc->table,
- sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
- if (!vlc->table)
- return -1;
+ if ((err = av_reallocp(&vlc->table,
+ sizeof(VLC_TYPE) * 2 *
+ vlc->table_allocated)) < 0) {
+ vlc->table_allocated = 0;
+ vlc->table_size = 0;
+ return err;
+ }
}
return index;
}
-static int build_table(VLC *vlc, int table_nb_bits,
- int nb_codes,
- const void *bits, int bits_wrap, int bits_size,
- const void *codes, int codes_wrap, int codes_size,
- const void *symbols, int symbols_wrap, int symbols_size,
- uint32_t code_prefix, int n_prefix, int flags)
+static av_always_inline uint32_t bitswap_32(uint32_t x)
+{
+ return (uint32_t)ff_reverse[ x & 0xFF] << 24 |
+ (uint32_t)ff_reverse[(x >> 8) & 0xFF] << 16 |
+ (uint32_t)ff_reverse[(x >> 16) & 0xFF] << 8 |
+ (uint32_t)ff_reverse[ x >> 24];
+}
+
+typedef struct VLCcode {
+ uint8_t bits;
+ uint16_t symbol;
+ /** codeword, with the first bit-to-be-read in the msb
+ * (even if intended for a little-endian bitstream reader) */
+ uint32_t code;
+} VLCcode;
+
+static int compare_vlcspec(const void *a, const void *b)
+{
+ const VLCcode *sa = a, *sb = b;
+ return (sa->code >> 1) - (sb->code >> 1);
+}
+/**
+ * Build VLC decoding tables suitable for use with get_vlc().
+ *
+ * @param vlc the context to be initted
+ *
+ * @param table_nb_bits max length of vlc codes to store directly in this table
+ * (Longer codes are delegated to subtables.)
+ *
+ * @param nb_codes number of elements in codes[]
+ *
+ * @param codes descriptions of the vlc codes
+ * These must be ordered such that codes going into the same subtable are contiguous.
+ * Sorting by VLCcode.code is sufficient, though not necessary.
+ */
+static int build_table(VLC *vlc, int table_nb_bits, int nb_codes,
+ VLCcode *codes, int flags)
{
- int i, j, k, n, table_size, table_index, nb, n1, index, code_prefix2, symbol;
+ int table_size, table_index, index, code_prefix, symbol, subtable_bits;
+ int i, j, k, n, nb, inc;
uint32_t code;
VLC_TYPE (*table)[2];
table_size = 1 << table_nb_bits;
- table_index = alloc_table(vlc, table_size, flags & INIT_VLC_USE_STATIC);
-#ifdef DEBUG_VLC
- av_log(NULL,AV_LOG_DEBUG,"new table index=%d size=%d code_prefix=%x n=%d\n",
- table_index, table_size, code_prefix, n_prefix);
-#endif
+ table_index = alloc_table(vlc, table_size, flags & INIT_VLC_USE_NEW_STATIC);
+ ff_dlog(NULL, "new table index=%d size=%d\n", table_index, table_size);
if (table_index < 0)
- return -1;
+ return table_index;
table = &vlc->table[table_index];
- for(i=0;i<table_size;i++) {
+ for (i = 0; i < table_size; i++) {
table[i][1] = 0; //bits
table[i][0] = -1; //codes
}
- /* first pass: map codes and compute auxillary table sizes */
- for(i=0;i<nb_codes;i++) {
- GET_DATA(n, bits, i, bits_wrap, bits_size);
- GET_DATA(code, codes, i, codes_wrap, codes_size);
- /* we accept tables with holes */
- if (n <= 0)
- continue;
- if (!symbols)
- symbol = i;
- else
- GET_DATA(symbol, symbols, i, symbols_wrap, symbols_size);
-#if defined(DEBUG_VLC) && 0
- av_log(NULL,AV_LOG_DEBUG,"i=%d n=%d code=0x%x\n", i, n, code);
-#endif
- /* if code matches the prefix, it is in the table */
- n -= n_prefix;
- if(flags & INIT_VLC_LE)
- code_prefix2= code & (n_prefix>=32 ? 0xffffffff : (1 << n_prefix)-1);
- else
- code_prefix2= code >> n;
- if (n > 0 && code_prefix2 == code_prefix) {
- if (n <= table_nb_bits) {
- /* no need to add another table */
- j = (code << (table_nb_bits - n)) & (table_size - 1);
- nb = 1 << (table_nb_bits - n);
- for(k=0;k<nb;k++) {
- if(flags & INIT_VLC_LE)
- j = (code >> n_prefix) + (k<<n);
-#ifdef DEBUG_VLC
- av_log(NULL, AV_LOG_DEBUG, "%4x: code=%d n=%d\n",
- j, i, n);
-#endif
- if (table[j][1] /*bits*/ != 0) {
- av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
- return -1;
- }
- table[j][1] = n; //bits
- table[j][0] = symbol;
- j++;
+ /* first pass: map codes and compute auxiliary table sizes */
+ for (i = 0; i < nb_codes; i++) {
+ n = codes[i].bits;
+ code = codes[i].code;
+ symbol = codes[i].symbol;
+ ff_dlog(NULL, "i=%d n=%d code=0x%x\n", i, n, code);
+ if (n <= table_nb_bits) {
+ /* no need to add another table */
+ j = code >> (32 - table_nb_bits);
+ nb = 1 << (table_nb_bits - n);
+ inc = 1;
+ if (flags & INIT_VLC_LE) {
+ j = bitswap_32(code);
+ inc = 1 << n;
+ }
+ for (k = 0; k < nb; k++) {
+ ff_dlog(NULL, "%4x: code=%d n=%d\n", j, i, n);
+ if (table[j][1] /*bits*/ != 0) {
+ av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
+ return AVERROR_INVALIDDATA;
}
- } else {
- n -= table_nb_bits;
- j = (code >> ((flags & INIT_VLC_LE) ? n_prefix : n)) & ((1 << table_nb_bits) - 1);
-#ifdef DEBUG_VLC
- av_log(NULL,AV_LOG_DEBUG,"%4x: n=%d (subtable)\n",
- j, n);
-#endif
- /* compute table size */
- n1 = -table[j][1]; //bits
- if (n > n1)
- n1 = n;
- table[j][1] = -n1; //bits
+ table[j][1] = n; //bits
+ table[j][0] = symbol;
+ j += inc;
}
- }
- }
-
- /* second pass : fill auxillary tables recursively */
- for(i=0;i<table_size;i++) {
- n = table[i][1]; //bits
- if (n < 0) {
- n = -n;
- if (n > table_nb_bits) {
- n = table_nb_bits;
- table[i][1] = -n; //bits
+ } else {
+ /* fill auxiliary table recursively */
+ n -= table_nb_bits;
+ code_prefix = code >> (32 - table_nb_bits);
+ subtable_bits = n;
+ codes[i].bits = n;
+ codes[i].code = code << table_nb_bits;
+ for (k = i+1; k < nb_codes; k++) {
+ n = codes[k].bits - table_nb_bits;
+ if (n <= 0)
+ break;
+ code = codes[k].code;
+ if (code >> (32 - table_nb_bits) != code_prefix)
+ break;
+ codes[k].bits = n;
+ codes[k].code = code << table_nb_bits;
+ subtable_bits = FFMAX(subtable_bits, n);
}
- index = build_table(vlc, n, nb_codes,
- bits, bits_wrap, bits_size,
- codes, codes_wrap, codes_size,
- symbols, symbols_wrap, symbols_size,
- (flags & INIT_VLC_LE) ? (code_prefix | (i << n_prefix)) : ((code_prefix << table_nb_bits) | i),
- n_prefix + table_nb_bits, flags);
+ subtable_bits = FFMIN(subtable_bits, table_nb_bits);
+ j = (flags & INIT_VLC_LE) ? bitswap_32(code_prefix) >> (32 - table_nb_bits) : code_prefix;
+ table[j][1] = -subtable_bits;
+ ff_dlog(NULL, "%4x: n=%d (subtable)\n",
+ j, codes[i].bits + table_nb_bits);
+ index = build_table(vlc, subtable_bits, k-i, codes+i, flags);
if (index < 0)
- return -1;
+ return index;
/* note: realloc has been done, so reload tables */
table = &vlc->table[table_index];
- table[i][0] = index; //code
+ table[j][0] = index; //code
+ i = k-1;
}
}
return table_index;
(byte/word/long) to store the 'bits', 'codes', and 'symbols' tables.
'use_static' should be set to 1 for tables, which should be freed
- with av_free_static(), 0 if free_vlc() will be used.
+ with av_free_static(), 0 if ff_free_vlc() will be used.
*/
-int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
- const void *bits, int bits_wrap, int bits_size,
- const void *codes, int codes_wrap, int codes_size,
- const void *symbols, int symbols_wrap, int symbols_size,
- int flags)
+int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
+ const void *bits, int bits_wrap, int bits_size,
+ const void *codes, int codes_wrap, int codes_size,
+ const void *symbols, int symbols_wrap, int symbols_size,
+ int flags)
{
+ VLCcode *buf;
+ int i, j, ret;
+
vlc->bits = nb_bits;
- if(!(flags & INIT_VLC_USE_STATIC)) {
- vlc->table = NULL;
- vlc->table_allocated = 0;
- vlc->table_size = 0;
- } else {
- /* Static tables are initially always NULL, return
- if vlc->table != NULL to avoid double allocation */
- if(vlc->table)
+ if (flags & INIT_VLC_USE_NEW_STATIC) {
+ if (vlc->table_size && vlc->table_size == vlc->table_allocated) {
return 0;
+ } else if (vlc->table_size) {
+ return AVERROR_BUG;
+ }
+ } else {
+ vlc->table = NULL;
+ vlc->table_allocated = 0;
+ vlc->table_size = 0;
}
-#ifdef DEBUG_VLC
- av_log(NULL,AV_LOG_DEBUG,"build table nb_codes=%d\n", nb_codes);
-#endif
+ ff_dlog(NULL, "build table nb_codes=%d\n", nb_codes);
+
+ buf = av_malloc((nb_codes + 1) * sizeof(VLCcode));
+ if (!buf)
+ return AVERROR(ENOMEM);
+
+ assert(symbols_size <= 2 || !symbols);
+ j = 0;
+#define COPY(condition) \
+ for (i = 0; i < nb_codes; i++) { \
+ GET_DATA(buf[j].bits, bits, i, bits_wrap, bits_size); \
+ if (!(condition)) \
+ continue; \
+ GET_DATA(buf[j].code, codes, i, codes_wrap, codes_size); \
+ if (flags & INIT_VLC_LE) \
+ buf[j].code = bitswap_32(buf[j].code); \
+ else \
+ buf[j].code <<= 32 - buf[j].bits; \
+ if (symbols) \
+ GET_DATA(buf[j].symbol, symbols, i, symbols_wrap, symbols_size) \
+ else \
+ buf[j].symbol = i; \
+ j++; \
+ }
+ COPY(buf[j].bits > nb_bits);
+ // qsort is the slowest part of init_vlc, and could probably be improved or avoided
+ qsort(buf, j, sizeof(VLCcode), compare_vlcspec);
+ COPY(buf[j].bits && buf[j].bits <= nb_bits);
+ nb_codes = j;
- if (build_table(vlc, nb_bits, nb_codes,
- bits, bits_wrap, bits_size,
- codes, codes_wrap, codes_size,
- symbols, symbols_wrap, symbols_size,
- 0, 0, flags) < 0) {
+ ret = build_table(vlc, nb_bits, nb_codes, buf, flags);
+
+ av_free(buf);
+ if (ret < 0) {
av_freep(&vlc->table);
- return -1;
+ return ret;
}
+ if ((flags & INIT_VLC_USE_NEW_STATIC) &&
+ vlc->table_size != vlc->table_allocated)
+ av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n",
+ vlc->table_size, vlc->table_allocated);
return 0;
}
-void free_vlc(VLC *vlc)
+void ff_free_vlc(VLC *vlc)
{
av_freep(&vlc->table);
}
-
projects / ffmpeg / blobdiff