1/*
2 * This file is part of Libav.
3 *
4 * Libav is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * Libav is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with Libav; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19/**
20 * @file
21 * Common code for Vorbis I encoder and decoder
22 * @author Denes Balatoni  ( dbalatoni programozo hu )
23 */
24
25#define BITSTREAM_READER_LE
26#include "avcodec.h"
27#include "get_bits.h"
28
29#include "vorbis.h"
30
31
32/* Helper functions */
33
34// x^(1/n)
35unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
36{
37    unsigned int ret = 0, i, j;
38
39    do {
40        ++ret;
41        for (i = 0, j = ret; i < n - 1; i++)
42            j *= ret;
43    } while (j <= x);
44
45    return ret - 1;
46}
47
48// Generate vlc codes from vorbis huffman code lengths
49
50// the two bits[p] > 32 checks should be redundant, all calling code should
51// already ensure that, but since it allows overwriting the stack it seems
52// reasonable to check redundantly.
53int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)
54{
55    uint32_t exit_at_level[33] = { 404 };
56
57    unsigned i, j, p, code;
58
59#ifdef DEBUG
60    GetBitContext gb;
61#endif
62
63    for (p = 0; (bits[p] == 0) && (p < num); ++p)
64        ;
65    if (p == num) {
66//        av_log(vc->avccontext, AV_LOG_INFO, "An empty codebook. Heh?! \n");
67        return 0;
68    }
69
70    codes[p] = 0;
71    if (bits[p] > 32)
72        return 1;
73    for (i = 0; i < bits[p]; ++i)
74        exit_at_level[i+1] = 1 << i;
75
76#ifdef DEBUG
77    av_log(NULL, AV_LOG_INFO, " %u. of %u code len %d code %d - ", p, num, bits[p], codes[p]);
78    init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);
79    for (i = 0; i < bits[p]; ++i)
80        av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
81    av_log(NULL, AV_LOG_INFO, "\n");
82#endif
83
84    ++p;
85
86    for (; p < num; ++p) {
87        if (bits[p] > 32)
88             return 1;
89        if (bits[p] == 0)
90             continue;
91        // find corresponding exit(node which the tree can grow further from)
92        for (i = bits[p]; i > 0; --i)
93            if (exit_at_level[i])
94                break;
95        if (!i) // overspecified tree
96             return 1;
97        code = exit_at_level[i];
98        exit_at_level[i] = 0;
99        // construct code (append 0s to end) and introduce new exits
100        for (j = i + 1 ;j <= bits[p]; ++j)
101            exit_at_level[j] = code + (1 << (j - 1));
102        codes[p] = code;
103
104#ifdef DEBUG
105        av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);
106        init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);
107        for (i = 0; i < bits[p]; ++i)
108            av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
109        av_log(NULL, AV_LOG_INFO, "\n");
110#endif
111
112    }
113
114    //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
115    for (p = 1; p < 33; p++)
116        if (exit_at_level[p])
117            return 1;
118
119    return 0;
120}
121
122int ff_vorbis_ready_floor1_list(AVCodecContext *avccontext,
123                                vorbis_floor1_entry *list, int values)
124{
125    int i;
126    list[0].sort = 0;
127    list[1].sort = 1;
128    for (i = 2; i < values; i++) {
129        int j;
130        list[i].low  = 0;
131        list[i].high = 1;
132        list[i].sort = i;
133        for (j = 2; j < i; j++) {
134            int tmp = list[j].x;
135            if (tmp < list[i].x) {
136                if (tmp > list[list[i].low].x)
137                    list[i].low  =  j;
138            } else {
139                if (tmp < list[list[i].high].x)
140                    list[i].high = j;
141            }
142        }
143    }
144    for (i = 0; i < values - 1; i++) {
145        int j;
146        for (j = i + 1; j < values; j++) {
147            if (list[i].x == list[j].x) {
148                av_log(avccontext, AV_LOG_ERROR,
149                       "Duplicate value found in floor 1 X coordinates\n");
150                return AVERROR_INVALIDDATA;
151            }
152            if (list[list[i].sort].x > list[list[j].sort].x) {
153                int tmp = list[i].sort;
154                list[i].sort = list[j].sort;
155                list[j].sort = tmp;
156            }
157        }
158    }
159    return 0;
160}
161
162static inline void render_line_unrolled(intptr_t x, int y, int x1,
163                                        intptr_t sy, int ady, int adx,
164                                        float *buf)
165{
166    int err = -adx;
167    x -= x1 - 1;
168    buf += x1 - 1;
169    while (++x < 0) {
170        err += ady;
171        if (err >= 0) {
172            err += ady - adx;
173            y   += sy;
174            buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
175        }
176        buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
177    }
178    if (x <= 0) {
179        if (err + ady >= 0)
180            y += sy;
181        buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
182    }
183}
184
185static void render_line(int x0, int y0, int x1, int y1, float *buf)
186{
187    int dy  = y1 - y0;
188    int adx = x1 - x0;
189    int ady = FFABS(dy);
190    int sy  = dy < 0 ? -1 : 1;
191    buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];
192    if (ady*2 <= adx) { // optimized common case
193        render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
194    } else {
195        int base  = dy / adx;
196        int x     = x0;
197        int y     = y0;
198        int err   = -adx;
199        ady -= FFABS(base) * adx;
200        while (++x < x1) {
201            y += base;
202            err += ady;
203            if (err >= 0) {
204                err -= adx;
205                y   += sy;
206            }
207            buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
208        }
209    }
210}
211
212void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,
213                                  uint16_t *y_list, int *flag,
214                                  int multiplier, float *out, int samples)
215{
216    int lx, ly, i;
217    lx = 0;
218    ly = y_list[0] * multiplier;
219    for (i = 1; i < values; i++) {
220        int pos = list[i].sort;
221        if (flag[pos]) {
222            int x1 = list[pos].x;
223            int y1 = y_list[pos] * multiplier;
224            if (lx < samples)
225                render_line(lx, ly, FFMIN(x1,samples), y1, out);
226            lx = x1;
227            ly = y1;
228        }
229        if (lx >= samples)
230            break;
231    }
232    if (lx < samples)
233        render_line(lx, ly, samples, ly, out);
234}
235