| /* |
| * API for creating VLC trees |
| * Copyright (c) 2000, 2001 Fabrice Bellard |
| * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> |
| * Copyright (c) 2010 Loren Merritt |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg 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, |
| * 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 |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include <inttypes.h> |
| #include <stdint.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include "libavutil/attributes.h" |
| #include "libavutil/avassert.h" |
| #include "libavutil/error.h" |
| #include "libavutil/internal.h" |
| #include "libavutil/intreadwrite.h" |
| #include "libavutil/log.h" |
| #include "libavutil/macros.h" |
| #include "libavutil/mem.h" |
| #include "libavutil/qsort.h" |
| #include "libavutil/reverse.h" |
| #include "vlc.h" |
| |
| #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; \ |
| case 4: \ |
| default: \ |
| av_assert1(size == 4); \ |
| v = *(const uint32_t *)ptr; \ |
| break; \ |
| } \ |
| } |
| |
| |
| static int alloc_table(VLC *vlc, int size, int use_static) |
| { |
| int index = vlc->table_size; |
| |
| vlc->table_size += size; |
| if (vlc->table_size > vlc->table_allocated) { |
| if (use_static) |
| abort(); // cannot do anything, vlc_init() is used with too little memory |
| vlc->table_allocated += (1 << vlc->bits); |
| vlc->table = av_realloc_f(vlc->table, vlc->table_allocated, sizeof(*vlc->table)); |
| if (!vlc->table) { |
| vlc->table_allocated = 0; |
| vlc->table_size = 0; |
| return AVERROR(ENOMEM); |
| } |
| memset(vlc->table + vlc->table_allocated - (1 << vlc->bits), 0, sizeof(*vlc->table) << vlc->bits); |
| } |
| return index; |
| } |
| |
| #define LOCALBUF_ELEMS 1500 // the maximum currently needed is 1296 by rv34 |
| |
| 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; |
| VLCBaseType 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 vlc_common_init(VLC *vlc, int nb_bits, int nb_codes, |
| VLCcode **buf, int flags) |
| { |
| vlc->bits = nb_bits; |
| vlc->table_size = 0; |
| if (flags & VLC_INIT_USE_STATIC) { |
| av_assert0(nb_codes <= LOCALBUF_ELEMS); |
| } else { |
| vlc->table = NULL; |
| vlc->table_allocated = 0; |
| } |
| if (nb_codes > LOCALBUF_ELEMS) { |
| *buf = av_malloc_array(nb_codes, sizeof(VLCcode)); |
| if (!*buf) |
| return AVERROR(ENOMEM); |
| } |
| |
| return 0; |
| } |
| |
| 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 initialized |
| * |
| * @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 table_size, table_index; |
| VLCElem *table; |
| |
| if (table_nb_bits > 30) |
| return AVERROR(EINVAL); |
| table_size = 1 << table_nb_bits; |
| table_index = alloc_table(vlc, table_size, flags & VLC_INIT_USE_STATIC); |
| ff_dlog(NULL, "new table index=%d size=%d\n", table_index, table_size); |
| if (table_index < 0) |
| return table_index; |
| table = &vlc->table[table_index]; |
| |
| /* first pass: map codes and compute auxiliary table sizes */ |
| for (int i = 0; i < nb_codes; i++) { |
| int n = codes[i].bits; |
| uint32_t code = codes[i].code; |
| int symbol = codes[i].symbol; |
| ff_dlog(NULL, "i=%d n=%d code=0x%"PRIx32"\n", i, n, code); |
| if (n <= table_nb_bits) { |
| /* no need to add another table */ |
| int j = code >> (32 - table_nb_bits); |
| int nb = 1 << (table_nb_bits - n); |
| int inc = 1; |
| |
| if (flags & VLC_INIT_OUTPUT_LE) { |
| j = bitswap_32(code); |
| inc = 1 << n; |
| } |
| for (int k = 0; k < nb; k++) { |
| int bits = table[j].len; |
| int oldsym = table[j].sym; |
| ff_dlog(NULL, "%4x: code=%d n=%d\n", j, i, n); |
| if ((bits || oldsym) && (bits != n || oldsym != symbol)) { |
| av_log(NULL, AV_LOG_ERROR, "incorrect codes\n"); |
| return AVERROR_INVALIDDATA; |
| } |
| table[j].len = n; |
| table[j].sym = symbol; |
| j += inc; |
| } |
| } else { |
| /* fill auxiliary table recursively */ |
| uint32_t code_prefix; |
| int index, subtable_bits, j, k; |
| |
| 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); |
| } |
| subtable_bits = FFMIN(subtable_bits, table_nb_bits); |
| j = (flags & VLC_INIT_OUTPUT_LE) ? bitswap_32(code_prefix) >> (32 - table_nb_bits) : code_prefix; |
| table[j].len = -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 index; |
| /* note: realloc has been done, so reload tables */ |
| table = &vlc->table[table_index]; |
| table[j].sym = index; |
| if (table[j].sym != index) { |
| avpriv_request_sample(NULL, "strange codes"); |
| return AVERROR_PATCHWELCOME; |
| } |
| i = k-1; |
| } |
| } |
| |
| for (int i = 0; i < table_size; i++) { |
| if (table[i].len == 0) |
| table[i].sym = -1; |
| } |
| |
| return table_index; |
| } |
| |
| static int vlc_common_end(VLC *vlc, int nb_bits, int nb_codes, VLCcode *codes, |
| int flags, VLCcode localbuf[LOCALBUF_ELEMS]) |
| { |
| int ret = build_table(vlc, nb_bits, nb_codes, codes, flags); |
| |
| if (flags & VLC_INIT_USE_STATIC) { |
| if (vlc->table_size != vlc->table_allocated && |
| !(flags & (VLC_INIT_STATIC_OVERLONG & ~VLC_INIT_USE_STATIC))) |
| av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated); |
| av_assert0(ret >= 0); |
| } else { |
| if (codes != localbuf) |
| av_free(codes); |
| if (ret < 0) { |
| av_freep(&vlc->table); |
| return ret; |
| } |
| } |
| return 0; |
| } |
| |
| int ff_vlc_init_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 localbuf[LOCALBUF_ELEMS], *buf = localbuf; |
| int j, ret; |
| |
| ret = vlc_common_init(vlc, nb_bits, nb_codes, &buf, flags); |
| if (ret < 0) |
| return ret; |
| |
| av_assert0(symbols_size <= 2 || !symbols); |
| j = 0; |
| #define COPY(condition)\ |
| for (int i = 0; i < nb_codes; i++) { \ |
| unsigned len; \ |
| GET_DATA(len, bits, i, bits_wrap, bits_size); \ |
| if (!(condition)) \ |
| continue; \ |
| if (len > 3*nb_bits || len > 32) { \ |
| av_log(NULL, AV_LOG_ERROR, "Too long VLC (%u) in vlc_init\n", len);\ |
| if (buf != localbuf) \ |
| av_free(buf); \ |
| return AVERROR(EINVAL); \ |
| } \ |
| buf[j].bits = len; \ |
| GET_DATA(buf[j].code, codes, i, codes_wrap, codes_size); \ |
| if (buf[j].code >= (1LL<<buf[j].bits)) { \ |
| av_log(NULL, AV_LOG_ERROR, "Invalid code %"PRIx32" for %d in " \ |
| "vlc_init\n", buf[j].code, i); \ |
| if (buf != localbuf) \ |
| av_free(buf); \ |
| return AVERROR(EINVAL); \ |
| } \ |
| if (flags & VLC_INIT_INPUT_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(len > nb_bits); |
| // qsort is the slowest part of vlc_init, and could probably be improved or avoided |
| AV_QSORT(buf, j, struct VLCcode, compare_vlcspec); |
| COPY(len && len <= nb_bits); |
| nb_codes = j; |
| |
| return vlc_common_end(vlc, nb_bits, nb_codes, buf, |
| flags, localbuf); |
| } |
| |
| int ff_vlc_init_from_lengths(VLC *vlc, int nb_bits, int nb_codes, |
| const int8_t *lens, int lens_wrap, |
| const void *symbols, int symbols_wrap, int symbols_size, |
| int offset, int flags, void *logctx) |
| { |
| VLCcode localbuf[LOCALBUF_ELEMS], *buf = localbuf; |
| uint64_t code; |
| int ret, j, len_max = FFMIN(32, 3 * nb_bits); |
| |
| ret = vlc_common_init(vlc, nb_bits, nb_codes, &buf, flags); |
| if (ret < 0) |
| return ret; |
| |
| j = code = 0; |
| for (int i = 0; i < nb_codes; i++, lens += lens_wrap) { |
| int len = *lens; |
| if (len > 0) { |
| unsigned sym; |
| |
| buf[j].bits = len; |
| if (symbols) |
| GET_DATA(sym, symbols, i, symbols_wrap, symbols_size) |
| else |
| sym = i; |
| buf[j].symbol = sym + offset; |
| buf[j++].code = code; |
| } else if (len < 0) { |
| len = -len; |
| } else |
| continue; |
| if (len > len_max || code & ((1U << (32 - len)) - 1)) { |
| av_log(logctx, AV_LOG_ERROR, "Invalid VLC (length %u)\n", len); |
| goto fail; |
| } |
| code += 1U << (32 - len); |
| if (code > UINT32_MAX + 1ULL) { |
| av_log(logctx, AV_LOG_ERROR, "Overdetermined VLC tree\n"); |
| goto fail; |
| } |
| } |
| return vlc_common_end(vlc, nb_bits, j, buf, flags, localbuf); |
| fail: |
| if (buf != localbuf) |
| av_free(buf); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| av_cold void ff_vlc_init_table_from_lengths(VLCElem table[], int table_size, |
| int nb_bits, int nb_codes, |
| const int8_t *lens, int lens_wrap, |
| const void *symbols, int symbols_wrap, int symbols_size, |
| int offset, int flags) |
| { |
| VLC vlc = { .table = table, .table_allocated = table_size }; |
| |
| ff_vlc_init_from_lengths(&vlc, nb_bits, nb_codes, lens, lens_wrap, |
| symbols, symbols_wrap, symbols_size, |
| offset, flags | VLC_INIT_USE_STATIC, NULL); |
| } |
| |
| av_cold const VLCElem *ff_vlc_init_tables_from_lengths(VLCInitState *state, |
| int nb_bits, int nb_codes, |
| const int8_t *lens, int lens_wrap, |
| const void *symbols, int symbols_wrap, int symbols_size, |
| int offset, int flags) |
| { |
| VLC vlc = { .table = state->table, .table_allocated = state->size }; |
| |
| ff_vlc_init_from_lengths(&vlc, nb_bits, nb_codes, lens, lens_wrap, |
| symbols, symbols_wrap, symbols_size, |
| offset, flags | VLC_INIT_STATIC_OVERLONG, NULL); |
| |
| state->table += vlc.table_size; |
| state->size -= vlc.table_size; |
| |
| return vlc.table; |
| } |
| |
| av_cold void ff_vlc_init_table_sparse(VLCElem table[], int table_size, |
| 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) |
| { |
| VLC vlc = { .table = table, .table_allocated = table_size }; |
| |
| ff_vlc_init_sparse(&vlc, nb_bits, nb_codes, |
| bits, bits_wrap, bits_size, |
| codes, codes_wrap, codes_size, |
| symbols, symbols_wrap, symbols_size, |
| flags | VLC_INIT_USE_STATIC); |
| } |
| |
| av_cold const VLCElem *ff_vlc_init_tables_sparse(VLCInitState *state, |
| 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) |
| { |
| VLC vlc = { .table = state->table, .table_allocated = state->size }; |
| |
| ff_vlc_init_sparse(&vlc, nb_bits, nb_codes, |
| bits, bits_wrap, bits_size, |
| codes, codes_wrap, codes_size, |
| symbols, symbols_wrap, symbols_size, |
| flags | VLC_INIT_STATIC_OVERLONG); |
| |
| state->table += vlc.table_size; |
| state->size -= vlc.table_size; |
| |
| return vlc.table; |
| } |
| |
| static void add_level(VLC_MULTI_ELEM *table, const int is16bit, |
| const int num, const int numbits, |
| const VLCcode *buf, |
| uint32_t curcode, int curlen, |
| int curlimit, int curlevel, |
| const int minlen, const int max, |
| unsigned* levelcnt, VLC_MULTI_ELEM info) |
| { |
| int max_symbols = VLC_MULTI_MAX_SYMBOLS >> is16bit; |
| for (int i = num-1; i >= max; i--) { |
| for (int j = 0; j < 2; j++) { |
| int newlimit, sym; |
| int t = j ? i-1 : i; |
| int l = buf[t].bits; |
| uint32_t code; |
| |
| sym = buf[t].symbol; |
| if (l >= curlimit) |
| return; |
| code = curcode + (buf[t].code >> curlen); |
| newlimit = curlimit - l; |
| l += curlen; |
| if (is16bit) info.val16[curlevel] = sym; |
| else info.val8[curlevel] = sym&0xFF; |
| |
| if (curlevel) { // let's not add single entries |
| uint32_t val = code >> (32 - numbits); |
| uint32_t nb = val + (1U << (numbits - l)); |
| info.len = l; |
| info.num = curlevel+1; |
| for (; val < nb; val++) |
| AV_COPY64(table+val, &info); |
| levelcnt[curlevel-1]++; |
| } |
| |
| if (curlevel+1 < max_symbols && newlimit >= minlen) { |
| add_level(table, is16bit, num, numbits, buf, |
| code, l, newlimit, curlevel+1, |
| minlen, max, levelcnt, info); |
| } |
| } |
| } |
| } |
| |
| static int vlc_multi_gen(VLC_MULTI_ELEM *table, const VLC *single, |
| const int is16bit, const int nb_codes, const int numbits, |
| VLCcode *buf, void *logctx) |
| { |
| int minbits, maxbits, max; |
| unsigned count[VLC_MULTI_MAX_SYMBOLS-1] = { 0, }; |
| VLC_MULTI_ELEM info = { 0 }; |
| int count0 = 0; |
| |
| for (int j = 0; j < 1<<numbits; j++) { |
| if (single->table[j].len > 0) { |
| count0 ++; |
| j += (1 << (numbits - single->table[j].len)) - 1; |
| } |
| } |
| |
| minbits = 32; |
| maxbits = 0; |
| |
| for (int n = nb_codes - count0; n < nb_codes; n++) { |
| minbits = FFMIN(minbits, buf[n].bits); |
| maxbits = FFMAX(maxbits, buf[n].bits); |
| } |
| av_assert0(maxbits <= numbits); |
| |
| for (max = nb_codes; max > nb_codes - count0; max--) { |
| // We can only add a code that fits with the shortest other code into the table |
| // We assume the table is sorted by bits and we skip subtables which from our |
| // point of view are basically random corrupted entries |
| // If we have not a single useable vlc we end with max = nb_codes |
| if (buf[max - 1].bits+minbits > numbits) |
| break; |
| } |
| |
| for (int j = 0; j < 1<<numbits; j++) { |
| table[j].len = single->table[j].len; |
| table[j].num = single->table[j].len > 0 ? 1 : 0; |
| if (is16bit) |
| table[j].val16[0] = single->table[j].sym; |
| else |
| table[j].val8[0] = single->table[j].sym; |
| } |
| |
| add_level(table, is16bit, nb_codes, numbits, buf, |
| 0, 0, FFMIN(maxbits, numbits), 0, minbits, max, count, info); |
| |
| av_log(logctx, AV_LOG_DEBUG, "Joint: %d/%d/%d/%d/%d codes min=%ubits max=%u\n", |
| count[0], count[1], count[2], count[3], count[4], minbits, max); |
| |
| return 0; |
| } |
| |
| int ff_vlc_init_multi_from_lengths(VLC *vlc, VLC_MULTI *multi, int nb_bits, int nb_elems, |
| int nb_codes, const int8_t *lens, int lens_wrap, |
| const void *symbols, int symbols_wrap, int symbols_size, |
| int offset, int flags, void *logctx) |
| { |
| VLCcode localbuf[LOCALBUF_ELEMS], *buf = localbuf; |
| uint64_t code; |
| int ret, j, len_max = FFMIN(32, 3 * nb_bits); |
| |
| ret = vlc_common_init(vlc, nb_bits, nb_codes, &buf, flags); |
| if (ret < 0) |
| return ret; |
| |
| multi->table = av_malloc(sizeof(*multi->table) << nb_bits); |
| if (!multi->table) |
| return AVERROR(ENOMEM); |
| |
| j = code = 0; |
| for (int i = 0; i < nb_codes; i++, lens += lens_wrap) { |
| int len = *lens; |
| if (len > 0) { |
| unsigned sym; |
| |
| buf[j].bits = len; |
| if (symbols) |
| GET_DATA(sym, symbols, i, symbols_wrap, symbols_size) |
| else |
| sym = i; |
| buf[j].symbol = sym + offset; |
| buf[j++].code = code; |
| } else if (len < 0) { |
| len = -len; |
| } else |
| continue; |
| if (len > len_max || code & ((1U << (32 - len)) - 1)) { |
| av_log(logctx, AV_LOG_ERROR, "Invalid VLC (length %u)\n", len); |
| goto fail; |
| } |
| code += 1U << (32 - len); |
| if (code > UINT32_MAX + 1ULL) { |
| av_log(logctx, AV_LOG_ERROR, "Overdetermined VLC tree\n"); |
| goto fail; |
| } |
| } |
| ret = vlc_common_end(vlc, nb_bits, j, buf, flags, buf); |
| if (ret < 0) |
| goto fail; |
| ret = vlc_multi_gen(multi->table, vlc, nb_elems > 256, j, nb_bits, buf, logctx); |
| if (buf != localbuf) |
| av_free(buf); |
| return ret; |
| fail: |
| if (buf != localbuf) |
| av_free(buf); |
| ff_vlc_free_multi(multi); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| void ff_vlc_free_multi(VLC_MULTI *vlc) |
| { |
| av_freep(&vlc->table); |
| } |
| |
| void ff_vlc_free(VLC *vlc) |
| { |
| av_freep(&vlc->table); |
| } |