diff options
Diffstat (limited to 'libavcodec/huffman.c')
-rw-r--r-- | libavcodec/huffman.c | 69 |
1 files changed, 45 insertions, 24 deletions
diff --git a/libavcodec/huffman.c b/libavcodec/huffman.c index 3b15aa2..df1141b 100644 --- a/libavcodec/huffman.c +++ b/libavcodec/huffman.c @@ -2,20 +2,20 @@ * Copyright (c) 2006 Konstantin Shishkov * Copyright (c) 2007 Loren Merritt * - * This file is part of Libav. + * This file is part of FFmpeg. * - * Libav is free software; you can redistribute it and/or + * 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. * - * Libav is distributed in the hope that it will be useful, + * 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 Libav; if not, write to the Free Software + * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ @@ -26,7 +26,8 @@ #include <stdint.h> -#include"libavutil/common.h" +#include "libavutil/qsort.h" +#include "libavutil/common.h" #include "avcodec.h" #include "huffman.h" @@ -54,18 +55,31 @@ static void heap_sift(HeapElem *h, int root, int size) } } -void ff_huff_gen_len_table(uint8_t *dst, const uint64_t *stats) +int ff_huff_gen_len_table(uint8_t *dst, const uint64_t *stats, int stats_size, int skip0) { - HeapElem h[256]; - int up[2*256]; - int len[2*256]; + HeapElem *h = av_malloc_array(sizeof(*h), stats_size); + int *up = av_malloc_array(sizeof(*up) * 2, stats_size); + uint8_t *len = av_malloc_array(sizeof(*len) * 2, stats_size); + uint16_t *map= av_malloc_array(sizeof(*map), stats_size); int offset, i, next; - int size = 256; + int size = 0; + int ret = 0; + + if (!h || !up || !len || !map) { + ret = AVERROR(ENOMEM); + goto end; + } + + for (i = 0; i<stats_size; i++) { + dst[i] = 255; + if (stats[i] || !skip0) + map[size++] = i; + } for (offset = 1; ; offset <<= 1) { for (i=0; i < size; i++) { h[i].name = i; - h[i].val = (stats[i] << 8) + offset; + h[i].val = (stats[map[i]] << 14) + offset; } for (i = size / 2 - 1; i >= 0; i--) heap_sift(h, i, size); @@ -86,11 +100,17 @@ void ff_huff_gen_len_table(uint8_t *dst, const uint64_t *stats) for (i = 2 * size - 3; i >= size; i--) len[i] = len[up[i]] + 1; for (i = 0; i < size; i++) { - dst[i] = len[up[i]] + 1; - if (dst[i] >= 32) break; + dst[map[i]] = len[up[i]] + 1; + if (dst[map[i]] >= 32) break; } if (i==size) break; } +end: + av_free(h); + av_free(up); + av_free(len); + av_free(map); + return ret; } static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat, @@ -153,22 +173,23 @@ int ff_huff_build_tree(AVCodecContext *avctx, VLC *vlc, int nb_codes, int nb_bit "Tree construction is not possible\n"); return -1; } - qsort(nodes, nb_codes, sizeof(Node), cmp); + AV_QSORT(nodes, nb_codes, Node, cmp); cur_node = nb_codes; nodes[nb_codes*2-1].count = 0; for (i = 0; i < nb_codes * 2 - 1; i += 2) { - nodes[cur_node].sym = HNODE; - nodes[cur_node].count = nodes[i].count + nodes[i + 1].count; - nodes[cur_node].n0 = i; - for (j = cur_node; j > 0; j--) { - if (nodes[j].count > nodes[j - 1].count || - (nodes[j].count == nodes[j - 1].count && - (!(flags & FF_HUFFMAN_FLAG_HNODE_FIRST) || - nodes[j].n0 == j - 1 || nodes[j].n0 == j - 2 || - (nodes[j].sym!=HNODE && nodes[j-1].sym!=HNODE)))) + uint32_t cur_count = nodes[i].count + nodes[i+1].count; + // find correct place to insert new node, and + // make space for the new node while at it + for(j = cur_node; j > i + 2; j--){ + if(cur_count > nodes[j-1].count || + (cur_count == nodes[j-1].count && + !(flags & FF_HUFFMAN_FLAG_HNODE_FIRST))) break; - FFSWAP(Node, nodes[j], nodes[j - 1]); + nodes[j] = nodes[j - 1]; } + nodes[j].sym = HNODE; + nodes[j].count = cur_count; + nodes[j].n0 = i; cur_node++; } if (build_huff_tree(vlc, nodes, nb_codes * 2 - 2, flags, nb_bits) < 0) { |