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/*
* Common code for AAC cube-root table
*
* Copyright (c) 2010 Reimar Döffinger <[email protected]>
*
* 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
*/
#include <math.h>
#include "cbrt_data.h"
#include "libavutil/attributes.h"
#ifdef HAVE_AV_CONFIG_H // Only include libm.h when building for the target, not the host
#include "libavutil/libm.h"
#endif
av_cold void ff_cbrt_dbl_tableinit(double tmp_lut[TMP_LUT_SIZE])
{
for (int idx = 0; idx < TMP_LUT_SIZE; ++idx)
tmp_lut[idx] = 1;
/* have to take care of non-squarefree numbers; notice that sqrt(LUT_SIZE) = 90;
* idx == 44 corresponds to 89. */
for (int idx = 1; idx < 45; ++idx) {
if (tmp_lut[idx] == 1) {
int i = 2 * idx + 1;
double cbrt_val = i * cbrt(i);
for (int k = i; k < LUT_SIZE; k *= i) {
// We only have to handle k, 3 * k, 5 * k,...,
// because only these are odd. The corresponding indices are
// k >> 1, (k >> 1) + k, (k >> 1) + 2 * k,...
for (int idx2 = k >> 1; idx2 < TMP_LUT_SIZE; idx2 += k)
tmp_lut[idx2] *= cbrt_val;
}
}
}
for (int idx = 45; idx < TMP_LUT_SIZE; ++idx) {
if (tmp_lut[idx] == 1) {
int i = 2 * idx + 1;
double cbrt_val = i * cbrt(i);
for (int idx2 = idx; idx2 < TMP_LUT_SIZE; idx2 += i)
tmp_lut[idx2] *= cbrt_val;
}
}
}
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