GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/huffman.c Lines: 91 97 93.8 %
Date: 2019-11-22 03:34:36 Branches: 92 102 90.2 %

Line Branch Exec Source
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/*
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 * Copyright (c) 2006 Konstantin Shishkov
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 * Copyright (c) 2007 Loren Merritt
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * huffman tree builder and VLC generator
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 */
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#include <stdint.h>
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#include "libavutil/qsort.h"
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#include "libavutil/common.h"
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#include "avcodec.h"
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#include "huffman.h"
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#include "vlc.h"
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/* symbol for Huffman tree node */
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#define HNODE -1
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typedef struct HeapElem {
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    uint64_t val;
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    int name;
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} HeapElem;
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1973140
static void heap_sift(HeapElem *h, int root, int size)
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{
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14116069
    while (root * 2 + 1 < size) {
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13354908
        int child = root * 2 + 1;
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13354908
        if (child < size - 1 && h[child].val > h[child+1].val)
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6177070
            child++;
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13354908
        if (h[root].val > h[child].val) {
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12142929
            FFSWAP(HeapElem, h[root], h[child]);
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12142929
            root = child;
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        } else
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1211979
            break;
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    }
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1973140
}
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2446
int ff_huff_gen_len_table(uint8_t *dst, const uint64_t *stats, int stats_size, int skip0)
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{
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2446
    HeapElem *h  = av_malloc_array(sizeof(*h), stats_size);
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2446
    int *up      = av_malloc_array(sizeof(*up) * 2, stats_size);
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2446
    uint8_t *len = av_malloc_array(sizeof(*len) * 2, stats_size);
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2446
    uint16_t *map= av_malloc_array(sizeof(*map), stats_size);
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    int offset, i, next;
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2446
    int size = 0;
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2446
    int ret = 0;
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2446
    if (!h || !up || !len || !map) {
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        ret = AVERROR(ENOMEM);
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        goto end;
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    }
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877454
    for (i = 0; i<stats_size; i++) {
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875008
        dst[i] = 255;
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875008
        if (stats[i] || !skip0)
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791317
            map[size++] = i;
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    }
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2446
    for (offset = 1; ; offset <<= 1) {
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793763
        for (i=0; i < size; i++) {
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791317
            h[i].name = i;
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791317
            h[i].val = (stats[map[i]] << 14) + offset;
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        }
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397844
        for (i = size / 2 - 1; i >= 0; i--)
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395398
            heap_sift(h, i, size);
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791317
        for (next = size; next < size * 2 - 1; next++) {
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            // merge the two smallest entries, and put it back in the heap
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788871
            uint64_t min1v = h[0].val;
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788871
            up[h[0].name] = next;
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788871
            h[0].val = INT64_MAX;
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788871
            heap_sift(h, 0, size);
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788871
            up[h[0].name] = next;
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788871
            h[0].name = next;
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788871
            h[0].val += min1v;
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788871
            heap_sift(h, 0, size);
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        }
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2446
        len[2 * size - 2] = 0;
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788871
        for (i = 2 * size - 3; i >= size; i--)
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786425
            len[i] = len[up[i]] + 1;
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793763
        for (i = 0; i < size; i++) {
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791317
            dst[map[i]] = len[up[i]] + 1;
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791317
            if (dst[map[i]] >= 32) break;
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        }
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2446
        if (i==size) break;
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    }
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2446
end:
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2446
    av_free(h);
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2446
    av_free(up);
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2446
    av_free(len);
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2446
    av_free(map);
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2446
    return ret;
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}
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319323
static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat,
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                           Node *nodes, int node,
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                           uint32_t pfx, int pl, int *pos, int no_zero_count)
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{
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    int s;
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319323
    s = nodes[node].sym;
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319323
    if (s != HNODE || (no_zero_count && !nodes[node].count)) {
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162210
        bits[*pos] = pfx;
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162210
        lens[*pos] = pl;
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162210
        xlat[*pos] = s;
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162210
        (*pos)++;
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    } else {
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157113
        pfx <<= 1;
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157113
        pl++;
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157113
        get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0, pfx, pl,
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                       pos, no_zero_count);
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157113
        pfx |= 1;
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157113
        get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0 + 1, pfx, pl,
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                       pos, no_zero_count);
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    }
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319323
}
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139
5097
static int build_huff_tree(VLC *vlc, Node *nodes, int head, int flags, int nb_bits)
140
{
141
5097
    int no_zero_count = !(flags & FF_HUFFMAN_FLAG_ZERO_COUNT);
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    uint32_t bits[256];
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    int16_t lens[256];
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    uint8_t xlat[256];
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5097
    int pos = 0;
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147
5097
    get_tree_codes(bits, lens, xlat, nodes, head, 0, 0,
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                   &pos, no_zero_count);
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5097
    return ff_init_vlc_sparse(vlc, nb_bits, pos, lens, 2, 2, bits, 4, 4, xlat, 1, 1, 0);
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}
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152
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/**
154
 * nodes size must be 2*nb_codes
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 * first nb_codes nodes.count must be set
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 */
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5097
int ff_huff_build_tree(AVCodecContext *avctx, VLC *vlc, int nb_codes, int nb_bits,
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                       Node *nodes, HuffCmp cmp, int flags)
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{
160
    int i, j;
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    int cur_node;
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5097
    int64_t sum = 0;
163
164
167307
    for (i = 0; i < nb_codes; i++) {
165
162210
        nodes[i].sym = i;
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162210
        nodes[i].n0 = -2;
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162210
        sum += nodes[i].count;
168
    }
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170
5097
    if (sum >> 31) {
171
        av_log(avctx, AV_LOG_ERROR,
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               "Too high symbol frequencies. "
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               "Tree construction is not possible\n");
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        return -1;
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    }
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851113
    AV_QSORT(nodes, nb_codes, Node, cmp);
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5097
    cur_node = nb_codes;
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5097
    nodes[nb_codes*2-1].count = 0;
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167307
    for (i = 0; i < nb_codes * 2 - 1; i += 2) {
180
162210
        uint32_t cur_count = nodes[i].count + nodes[i+1].count;
181
        // find correct place to insert new node, and
182
        // make space for the new node while at it
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5708460
        for(j = cur_node; j > i + 2; j--){
184
5685299
            if(cur_count > nodes[j-1].count ||
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5617648
               (cur_count == nodes[j-1].count &&
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101452
                !(flags & FF_HUFFMAN_FLAG_HNODE_FIRST)))
187
                break;
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5546250
            nodes[j] = nodes[j - 1];
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        }
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162210
        nodes[j].sym = HNODE;
191
162210
        nodes[j].count = cur_count;
192
162210
        nodes[j].n0 = i;
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162210
        cur_node++;
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    }
195
5097
    if (build_huff_tree(vlc, nodes, nb_codes * 2 - 2, flags, nb_bits) < 0) {
196
        av_log(avctx, AV_LOG_ERROR, "Error building tree\n");
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        return -1;
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    }
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5097
    return 0;
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}