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