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/**
* @file
* Common code for Vorbis I encoder and decoder
* @author Denes Balatoni ( dbalatoni programozo hu )
*
* This file is part of FFmpeg.
*
* 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.
*
* 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Common code for Vorbis I encoder and decoder
* @author Denes Balatoni ( dbalatoni programozo hu )
*/
#include "libavutil/common.h"
#include "avcodec.h"
#include "vorbis.h"
/* Helper functions */
// x^(1/n)
unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
{
unsigned int ret = 0, i, j;
do {
++ret;
for (i = 0, j = ret; i < n - 1; i++)
j *= ret;
} while (j <= x);
return ret - 1;
}
// Generate vlc codes from vorbis huffman code lengths
// the two bits[p] > 32 checks should be redundant, all calling code should
// already ensure that, but since it allows overwriting the stack it seems
// reasonable to check redundantly.
int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)
{
uint32_t exit_at_level[33] = { 404 };
unsigned i, j, p, code;
for (p = 0; (p < num) && (bits[p] == 0); ++p)
;
if (p == num)
return 0;
codes[p] = 0;
if (bits[p] > 32)
return AVERROR_INVALIDDATA;
for (i = 0; i < bits[p]; ++i)
exit_at_level[i+1] = 1 << i;
++p;
for (i = p; (i < num) && (bits[i] == 0); ++i)
;
if (i == num)
return 0;
for (; p < num; ++p) {
if (bits[p] > 32)
return AVERROR_INVALIDDATA;
if (bits[p] == 0)
continue;
// find corresponding exit(node which the tree can grow further from)
for (i = bits[p]; i > 0; --i)
if (exit_at_level[i])
break;
if (!i) // overspecified tree
return AVERROR_INVALIDDATA;
code = exit_at_level[i];
exit_at_level[i] = 0;
// construct code (append 0s to end) and introduce new exits
for (j = i + 1 ;j <= bits[p]; ++j)
exit_at_level[j] = code + (1 << (j - 1));
codes[p] = code;
}
//no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
for (p = 1; p < 33; p++)
if (exit_at_level[p])
return AVERROR_INVALIDDATA;
return 0;
}
int ff_vorbis_ready_floor1_list(AVCodecContext *avctx,
vorbis_floor1_entry *list, int values)
{
int i;
list[0].sort = 0;
list[1].sort = 1;
for (i = 2; i < values; i++) {
int j;
list[i].low = 0;
list[i].high = 1;
list[i].sort = i;
for (j = 2; j < i; j++) {
int tmp = list[j].x;
if (tmp < list[i].x) {
if (tmp > list[list[i].low].x)
list[i].low = j;
} else {
if (tmp < list[list[i].high].x)
list[i].high = j;
}
}
}
for (i = 0; i < values - 1; i++) {
int j;
for (j = i + 1; j < values; j++) {
if (list[i].x == list[j].x) {
av_log(avctx, AV_LOG_ERROR,
"Duplicate value found in floor 1 X coordinates\n");
return AVERROR_INVALIDDATA;
}
if (list[list[i].sort].x > list[list[j].sort].x) {
int tmp = list[i].sort;
list[i].sort = list[j].sort;
list[j].sort = tmp;
}
}
}
return 0;
}
static inline void render_line_unrolled(intptr_t x, int y, int x1,
intptr_t sy, int ady, int adx,
float *buf)
{
int err = -adx;
x -= x1 - 1;
buf += x1 - 1;
while (++x < 0) {
err += ady;
if (err >= 0) {
err += ady - adx;
y += sy;
buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
}
buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
}
if (x <= 0) {
if (err + ady >= 0)
y += sy;
buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
}
}
static void render_line(int x0, int y0, int x1, int y1, float *buf)
{
int dy = y1 - y0;
int adx = x1 - x0;
int ady = FFABS(dy);
int sy = dy < 0 ? -1 : 1;
buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];
if (ady*2 <= adx) { // optimized common case
render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
} else {
int base = dy / adx;
int x = x0;
int y = y0;
int err = -adx;
ady -= FFABS(base) * adx;
while (++x < x1) {
y += base;
err += ady;
if (err >= 0) {
err -= adx;
y += sy;
}
buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
}
}
}
void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,
uint16_t *y_list, int *flag,
int multiplier, float *out, int samples)
{
int lx, ly, i;
lx = 0;
ly = y_list[0] * multiplier;
for (i = 1; i < values; i++) {
int pos = list[i].sort;
if (flag[pos]) {
int x1 = list[pos].x;
int y1 = y_list[pos] * multiplier;
if (lx < samples)
render_line(lx, ly, FFMIN(x1,samples), y1, out);
lx = x1;
ly = y1;
}
if (lx >= samples)
break;
}
if (lx < samples)
render_line(lx, ly, samples, ly, out);
}
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