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#undef V_DEBUG
24//#define V_DEBUG
25
26#define ALT_BITSTREAM_READER_LE
27#include "avcodec.h"
28#include "get_bits.h"
29
30#include "vorbis.h"
31
32
33/* Helper functions */
34
35// x^(1/n)
36unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
37{
38    unsigned int ret = 0, i, j;
39
40    do {
41        ++ret;
42        for (i = 0, j = ret; i < n - 1; i++)
43            j *= ret;
44    } while (j <= x);
45
46    return ret - 1;
47}
48
49// Generate vlc codes from vorbis huffman code lengths
50
51// the two bits[p] > 32 checks should be redundant, all calling code should
52// already ensure that, but since it allows overwriting the stack it seems
53// reasonable to check redundantly.
54int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, uint_fast32_t num)
55{
56    uint_fast32_t exit_at_level[33] = {
57        404, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
58          0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
59
60    uint_fast8_t i, j;
61    uint_fast32_t code, p;
62
63#ifdef V_DEBUG
64    GetBitContext gb;
65#endif
66
67    for (p = 0; (bits[p] == 0) && (p < num); ++p)
68        ;
69    if (p == num) {
70//        av_log(vc->avccontext, AV_LOG_INFO, "An empty codebook. Heh?! \n");
71        return 0;
72    }
73
74    codes[p] = 0;
75    if (bits[p] > 32)
76        return 1;
77    for (i = 0; i < bits[p]; ++i)
78        exit_at_level[i+1] = 1 << i;
79
80#ifdef V_DEBUG
81    av_log(NULL, AV_LOG_INFO, " %d. of %d code len %d code %d - ", p, num, bits[p], codes[p]);
82    init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);
83    for (i = 0; i < bits[p]; ++i)
84        av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
85    av_log(NULL, AV_LOG_INFO, "\n");
86#endif
87
88    ++p;
89
90    for (; p < num; ++p) {
91        if (bits[p] > 32)
92             return 1;
93        if (bits[p] == 0)
94             continue;
95        // find corresponding exit(node which the tree can grow further from)
96        for (i = bits[p]; i > 0; --i)
97            if (exit_at_level[i])
98                break;
99        if (!i) // overspecified tree
100             return 1;
101        code = exit_at_level[i];
102        exit_at_level[i] = 0;
103        // construct code (append 0s to end) and introduce new exits
104        for (j = i + 1 ;j <= bits[p]; ++j)
105            exit_at_level[j] = code + (1 << (j - 1));
106        codes[p] = code;
107
108#ifdef V_DEBUG
109        av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);
110        init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);
111        for (i = 0; i < bits[p]; ++i)
112            av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
113        av_log(NULL, AV_LOG_INFO, "\n");
114#endif
115
116    }
117
118    //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
119    for (p = 1; p < 33; p++)
120        if (exit_at_level[p])
121            return 1;
122
123    return 0;
124}
125
126void ff_vorbis_ready_floor1_list(vorbis_floor1_entry * list, int values)
127{
128    int i;
129    list[0].sort = 0;
130    list[1].sort = 1;
131    for (i = 2; i < values; i++) {
132        int j;
133        list[i].low  = 0;
134        list[i].high = 1;
135        list[i].sort = i;
136        for (j = 2; j < i; j++) {
137            int tmp = list[j].x;
138            if (tmp < list[i].x) {
139                if (tmp > list[list[i].low].x)
140                    list[i].low  =  j;
141            } else {
142                if (tmp < list[list[i].high].x)
143                    list[i].high = j;
144            }
145        }
146    }
147    for (i = 0; i < values - 1; i++) {
148        int j;
149        for (j = i + 1; j < values; j++) {
150            if (list[list[i].sort].x > list[list[j].sort].x) {
151                int tmp = list[i].sort;
152                list[i].sort = list[j].sort;
153                list[j].sort = tmp;
154            }
155        }
156    }
157}
158
159static inline void render_line_unrolled(intptr_t x, intptr_t y, int x1,
160                                        intptr_t sy, int ady, int adx,
161                                        float *buf)
162{
163    int err = -adx;
164    x -= x1 - 1;
165    buf += x1 - 1;
166    while (++x < 0) {
167        err += ady;
168        if (err >= 0) {
169            err += ady - adx;
170            y   += sy;
171            buf[x++] = ff_vorbis_floor1_inverse_db_table[y];
172        }
173        buf[x] = ff_vorbis_floor1_inverse_db_table[y];
174    }
175    if (x <= 0) {
176        if (err + ady >= 0)
177            y += sy;
178        buf[x] = ff_vorbis_floor1_inverse_db_table[y];
179    }
180}
181
182static void render_line(int x0, int y0, int x1, int y1, float *buf)
183{
184    int dy  = y1 - y0;
185    int adx = x1 - x0;
186    int ady = FFABS(dy);
187    int sy  = dy < 0 ? -1 : 1;
188    buf[x0] = ff_vorbis_floor1_inverse_db_table[y0];
189    if (ady*2 <= adx) { // optimized common case
190        render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
191    } else {
192        int base = dy / adx;
193        int x    = x0;
194        int y    = y0;
195        int err  = -adx;
196        ady -= FFABS(base) * adx;
197        while (++x < x1) {
198            y += base;
199            err += ady;
200            if (err >= 0) {
201                err -= adx;
202                y   += sy;
203            }
204            buf[x] = ff_vorbis_floor1_inverse_db_table[y];
205        }
206    }
207}
208
209void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,
210                                  uint_fast16_t *y_list, int *flag,
211                                  int multiplier, float *out, int samples)
212{
213    int lx, ly, i;
214    lx = 0;
215    ly = y_list[0] * multiplier;
216    for (i = 1; i < values; i++) {
217        int pos = list[i].sort;
218        if (flag[pos]) {
219            int x1 = list[pos].x;
220            int y1 = y_list[pos] * multiplier;
221            if (lx < samples)
222                render_line(lx, ly, FFMIN(x1,samples), y1, out);
223            lx = x1;
224            ly = y1;
225        }
226        if (lx >= samples)
227            break;
228    }
229    if (lx < samples)
230        render_line(lx, ly, samples, ly, out);
231}
232