1/**
2 * @file
3 * Common code for Vorbis I encoder and decoder
4 * @author Denes Balatoni  ( dbalatoni programozo hu )
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23/**
24 * @file
25 * Common code for Vorbis I encoder and decoder
26 * @author Denes Balatoni  ( dbalatoni programozo hu )
27 */
28
29#define BITSTREAM_READER_LE
30#include "avcodec.h"
31#include "get_bits.h"
32
33#include "vorbis.h"
34
35
36/* Helper functions */
37
38// x^(1/n)
39unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
40{
41    unsigned int ret = 0, i, j;
42
43    do {
44        ++ret;
45        for (i = 0, j = ret; i < n - 1; i++)
46            j *= ret;
47    } while (j <= x);
48
49    return ret - 1;
50}
51
52// Generate vlc codes from vorbis huffman code lengths
53
54// the two bits[p] > 32 checks should be redundant, all calling code should
55// already ensure that, but since it allows overwriting the stack it seems
56// reasonable to check redundantly.
57int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)
58{
59    uint32_t exit_at_level[33] = { 404 };
60
61    unsigned i, j, p, code;
62
63#ifdef DEBUG
64    GetBitContext gb;
65#endif
66
67    for (p = 0; (bits[p] == 0) && (p < num); ++p)
68        ;
69    if (p == num)
70        return 0;
71
72    codes[p] = 0;
73    if (bits[p] > 32)
74        return AVERROR_INVALIDDATA;
75    for (i = 0; i < bits[p]; ++i)
76        exit_at_level[i+1] = 1 << i;
77
78#ifdef DEBUG
79    av_log(NULL, AV_LOG_INFO, " %u. of %u code len %d code %d - ", p, num, bits[p], codes[p]);
80    init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);
81    for (i = 0; i < bits[p]; ++i)
82        av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
83    av_log(NULL, AV_LOG_INFO, "\n");
84#endif
85
86    ++p;
87
88    for (i = p; (bits[i] == 0) && (i < num); ++i)
89        ;
90    if (i == num)
91        return 0;
92
93    for (; p < num; ++p) {
94        if (bits[p] > 32)
95             return AVERROR_INVALIDDATA;
96        if (bits[p] == 0)
97             continue;
98        // find corresponding exit(node which the tree can grow further from)
99        for (i = bits[p]; i > 0; --i)
100            if (exit_at_level[i])
101                break;
102        if (!i) // overspecified tree
103             return AVERROR_INVALIDDATA;
104        code = exit_at_level[i];
105        exit_at_level[i] = 0;
106        // construct code (append 0s to end) and introduce new exits
107        for (j = i + 1 ;j <= bits[p]; ++j)
108            exit_at_level[j] = code + (1 << (j - 1));
109        codes[p] = code;
110
111#ifdef DEBUG
112        av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);
113        init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);
114        for (i = 0; i < bits[p]; ++i)
115            av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
116        av_log(NULL, AV_LOG_INFO, "\n");
117#endif
118
119    }
120
121    //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
122    for (p = 1; p < 33; p++)
123        if (exit_at_level[p])
124            return AVERROR_INVALIDDATA;
125
126    return 0;
127}
128
129int ff_vorbis_ready_floor1_list(AVCodecContext *avctx,
130                                vorbis_floor1_entry *list, int values)
131{
132    int i;
133    list[0].sort = 0;
134    list[1].sort = 1;
135    for (i = 2; i < values; i++) {
136        int j;
137        list[i].low  = 0;
138        list[i].high = 1;
139        list[i].sort = i;
140        for (j = 2; j < i; j++) {
141            int tmp = list[j].x;
142            if (tmp < list[i].x) {
143                if (tmp > list[list[i].low].x)
144                    list[i].low  =  j;
145            } else {
146                if (tmp < list[list[i].high].x)
147                    list[i].high = j;
148            }
149        }
150    }
151    for (i = 0; i < values - 1; i++) {
152        int j;
153        for (j = i + 1; j < values; j++) {
154            if (list[i].x == list[j].x) {
155                av_log(avctx, AV_LOG_ERROR,
156                       "Duplicate value found in floor 1 X coordinates\n");
157                return AVERROR_INVALIDDATA;
158            }
159            if (list[list[i].sort].x > list[list[j].sort].x) {
160                int tmp = list[i].sort;
161                list[i].sort = list[j].sort;
162                list[j].sort = tmp;
163            }
164        }
165    }
166    return 0;
167}
168
169static inline void render_line_unrolled(intptr_t x, int y, int x1,
170                                        intptr_t sy, int ady, int adx,
171                                        float *buf)
172{
173    int err = -adx;
174    x -= x1 - 1;
175    buf += x1 - 1;
176    while (++x < 0) {
177        err += ady;
178        if (err >= 0) {
179            err += ady - adx;
180            y   += sy;
181            buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
182        }
183        buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
184    }
185    if (x <= 0) {
186        if (err + ady >= 0)
187            y += sy;
188        buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
189    }
190}
191
192static void render_line(int x0, int y0, int x1, int y1, float *buf)
193{
194    int dy  = y1 - y0;
195    int adx = x1 - x0;
196    int ady = FFABS(dy);
197    int sy  = dy < 0 ? -1 : 1;
198    buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];
199    if (ady*2 <= adx) { // optimized common case
200        render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
201    } else {
202        int base  = dy / adx;
203        int x     = x0;
204        int y     = y0;
205        int err   = -adx;
206        ady -= FFABS(base) * adx;
207        while (++x < x1) {
208            y += base;
209            err += ady;
210            if (err >= 0) {
211                err -= adx;
212                y   += sy;
213            }
214            buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
215        }
216    }
217}
218
219void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,
220                                  uint16_t *y_list, int *flag,
221                                  int multiplier, float *out, int samples)
222{
223    int lx, ly, i;
224    lx = 0;
225    ly = y_list[0] * multiplier;
226    for (i = 1; i < values; i++) {
227        int pos = list[i].sort;
228        if (flag[pos]) {
229            int x1 = list[pos].x;
230            int y1 = y_list[pos] * multiplier;
231            if (lx < samples)
232                render_line(lx, ly, FFMIN(x1,samples), y1, out);
233            lx = x1;
234            ly = y1;
235        }
236        if (lx >= samples)
237            break;
238    }
239    if (lx < samples)
240        render_line(lx, ly, samples, ly, out);
241}
242