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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 14:29:10 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 14:29:10 +0000 |
commit | 2aa4a82499d4becd2284cdb482213d541b8804dd (patch) | |
tree | b80bf8bf13c3766139fbacc530efd0dd9d54394c /media/ffvpx/libavcodec/bitstream.c | |
parent | Initial commit. (diff) | |
download | firefox-2aa4a82499d4becd2284cdb482213d541b8804dd.tar.xz firefox-2aa4a82499d4becd2284cdb482213d541b8804dd.zip |
Adding upstream version 86.0.1.upstream/86.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'media/ffvpx/libavcodec/bitstream.c')
-rw-r--r-- | media/ffvpx/libavcodec/bitstream.c | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/media/ffvpx/libavcodec/bitstream.c b/media/ffvpx/libavcodec/bitstream.c new file mode 100644 index 0000000000..be8a0f634d --- /dev/null +++ b/media/ffvpx/libavcodec/bitstream.c @@ -0,0 +1,362 @@ +/* + * Common bit i/o utils + * 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. + * + * 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 + */ + +/** + * @file + * bitstream api. + */ + +#include "libavutil/avassert.h" +#include "libavutil/qsort.h" +#include "avcodec.h" +#include "internal.h" +#include "mathops.h" +#include "put_bits.h" +#include "vlc.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) +{ + put_bits(s, s->bit_left & 7, 0); +} + +void avpriv_put_string(PutBitContext *pb, const char *string, + int terminate_string) +{ + while (*string) { + put_bits(pb, 8, *string); + string++; + } + if (terminate_string) + put_bits(pb, 8, 0); +} + +void avpriv_copy_bits(PutBitContext *pb, const uint8_t *src, int length) +{ + int words = length >> 4; + int bits = length & 15; + int i; + + if (length == 0) + return; + + av_assert0(length <= put_bits_left(pb)); + + 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(put_bits_ptr(pb), src + i, 2 * words - i); + skip_put_bytes(pb, 2 * words - i); + } + + put_bits(pb, bits, AV_RB16(src + 2 * words) >> (16 - bits)); +} + +/* VLC decoding */ + +#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: \ + v = *(const uint32_t *)ptr; \ + break; \ + default: \ + av_assert1(0); \ + } \ +} + + +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, init_vlc() is used with too little memory + vlc->table_allocated += (1 << vlc->bits); + vlc->table = av_realloc_f(vlc->table, vlc->table_allocated, sizeof(VLC_TYPE) * 2); + 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_TYPE) * 2 << vlc->bits); + } + return index; +} + +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 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, index, code_prefix, symbol, subtable_bits; + int i, j, k, n, nb, inc; + uint32_t code; + volatile VLC_TYPE (* volatile table)[2]; // the double volatile is needed to prevent an internal compiler error in gcc 4.2 + + table_size = 1 << table_nb_bits; + if (table_nb_bits > 30) + return AVERROR(EINVAL); + 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 table_index; + table = (volatile VLC_TYPE (*)[2])&vlc->table[table_index]; + + /* 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%"PRIx32"\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++) { + int bits = table[j][1]; + int oldsym = table[j][0]; + 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][1] = n; //bits + table[j][0] = symbol; + j += inc; + } + } 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); + } + 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 index; + /* note: realloc has been done, so reload tables */ + table = (volatile VLC_TYPE (*)[2])&vlc->table[table_index]; + table[j][0] = index; //code + if (table[j][0] != index) { + avpriv_request_sample(NULL, "strange codes"); + return AVERROR_PATCHWELCOME; + } + i = k-1; + } + } + + for (i = 0; i < table_size; i++) { + if (table[i][1] == 0) //bits + table[i][0] = -1; //codes + } + + return table_index; +} + + +/* Build VLC decoding tables suitable for use with get_vlc(). + + 'nb_bits' sets the decoding table size (2^nb_bits) entries. The + bigger it is, the faster is the decoding. But it should not be too + big to save memory and L1 cache. '9' is a good compromise. + + 'nb_codes' : number of vlcs codes + + 'bits' : table which gives the size (in bits) of each vlc code. + + 'codes' : table which gives the bit pattern of of each vlc code. + + 'symbols' : table which gives the values to be returned from get_vlc(). + + 'xxx_wrap' : give the number of bytes between each entry of the + 'bits' or 'codes' tables. + + 'xxx_size' : gives the number of bytes of each entry of the 'bits' + or 'codes' tables. Currently 1,2 and 4 are supported. + + 'wrap' and 'size' make it possible to use any memory configuration and types + (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 ff_free_vlc() will be used. +*/ +int ff_init_vlc_sparse(VLC *vlc_arg, 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; + VLCcode localbuf[1500]; // the maximum currently needed is 1296 by rv34 + VLC localvlc, *vlc; + + vlc = vlc_arg; + vlc->bits = nb_bits; + if (flags & INIT_VLC_USE_NEW_STATIC) { + av_assert0(nb_codes + 1 <= FF_ARRAY_ELEMS(localbuf)); + buf = localbuf; + localvlc = *vlc_arg; + vlc = &localvlc; + vlc->table_size = 0; + } else { + vlc->table = NULL; + vlc->table_allocated = 0; + vlc->table_size = 0; + + buf = av_malloc_array((nb_codes + 1), sizeof(VLCcode)); + if (!buf) + return AVERROR(ENOMEM); + } + + + av_assert0(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; \ + if (buf[j].bits > 3*nb_bits || buf[j].bits>32) { \ + av_log(NULL, AV_LOG_ERROR, "Too long VLC (%d) in init_vlc\n", buf[j].bits);\ + if (!(flags & INIT_VLC_USE_NEW_STATIC)) \ + av_free(buf); \ + return AVERROR(EINVAL); \ + } \ + 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 " \ + "init_vlc\n", buf[j].code, i); \ + if (!(flags & INIT_VLC_USE_NEW_STATIC)) \ + av_free(buf); \ + return AVERROR(EINVAL); \ + } \ + 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 + AV_QSORT(buf, j, struct VLCcode, compare_vlcspec); + COPY(buf[j].bits && buf[j].bits <= nb_bits); + nb_codes = j; + + ret = build_table(vlc, nb_bits, nb_codes, buf, flags); + + if (flags & INIT_VLC_USE_NEW_STATIC) { + if(vlc->table_size != vlc->table_allocated) + av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated); + + av_assert0(ret >= 0); + *vlc_arg = *vlc; + } else { + av_free(buf); + if (ret < 0) { + av_freep(&vlc->table); + return ret; + } + } + return 0; +} + + +void ff_free_vlc(VLC *vlc) +{ + av_freep(&vlc->table); +} |