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Diffstat (limited to 'deps/flac-1.3.2/src/libFLAC/fixed.c')
| -rw-r--r-- | deps/flac-1.3.2/src/libFLAC/fixed.c | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/deps/flac-1.3.2/src/libFLAC/fixed.c b/deps/flac-1.3.2/src/libFLAC/fixed.c new file mode 100644 index 0000000..1e2d5b2 --- /dev/null +++ b/deps/flac-1.3.2/src/libFLAC/fixed.c @@ -0,0 +1,395 @@ +/* libFLAC - Free Lossless Audio Codec library + * Copyright (C) 2000-2009 Josh Coalson + * Copyright (C) 2011-2016 Xiph.Org Foundation + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * - Neither the name of the Xiph.org Foundation nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <math.h> +#include <string.h> +#include "share/compat.h" +#include "private/bitmath.h" +#include "private/fixed.h" +#include "private/macros.h" +#include "FLAC/assert.h" + +#ifdef local_abs +#undef local_abs +#endif +#define local_abs(x) ((unsigned)((x)<0? -(x) : (x))) + +#ifdef FLAC__INTEGER_ONLY_LIBRARY +/* rbps stands for residual bits per sample + * + * (ln(2) * err) + * rbps = log (-----------) + * 2 ( n ) + */ +static FLAC__fixedpoint local__compute_rbps_integerized(FLAC__uint32 err, FLAC__uint32 n) +{ + FLAC__uint32 rbps; + unsigned bits; /* the number of bits required to represent a number */ + int fracbits; /* the number of bits of rbps that comprise the fractional part */ + + FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint)); + FLAC__ASSERT(err > 0); + FLAC__ASSERT(n > 0); + + FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE); + if(err <= n) + return 0; + /* + * The above two things tell us 1) n fits in 16 bits; 2) err/n > 1. + * These allow us later to know we won't lose too much precision in the + * fixed-point division (err<<fracbits)/n. + */ + + fracbits = (8*sizeof(err)) - (FLAC__bitmath_ilog2(err)+1); + + err <<= fracbits; + err /= n; + /* err now holds err/n with fracbits fractional bits */ + + /* + * Whittle err down to 16 bits max. 16 significant bits is enough for + * our purposes. + */ + FLAC__ASSERT(err > 0); + bits = FLAC__bitmath_ilog2(err)+1; + if(bits > 16) { + err >>= (bits-16); + fracbits -= (bits-16); + } + rbps = (FLAC__uint32)err; + + /* Multiply by fixed-point version of ln(2), with 16 fractional bits */ + rbps *= FLAC__FP_LN2; + fracbits += 16; + FLAC__ASSERT(fracbits >= 0); + + /* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */ + { + const int f = fracbits & 3; + if(f) { + rbps >>= f; + fracbits -= f; + } + } + + rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1)); + + if(rbps == 0) + return 0; + + /* + * The return value must have 16 fractional bits. Since the whole part + * of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits + * must be >= -3, these assertion allows us to be able to shift rbps + * left if necessary to get 16 fracbits without losing any bits of the + * whole part of rbps. + * + * There is a slight chance due to accumulated error that the whole part + * will require 6 bits, so we use 6 in the assertion. Really though as + * long as it fits in 13 bits (32 - (16 - (-3))) we are fine. + */ + FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6); + FLAC__ASSERT(fracbits >= -3); + + /* now shift the decimal point into place */ + if(fracbits < 16) + return rbps << (16-fracbits); + else if(fracbits > 16) + return rbps >> (fracbits-16); + else + return rbps; +} + +static FLAC__fixedpoint local__compute_rbps_wide_integerized(FLAC__uint64 err, FLAC__uint32 n) +{ + FLAC__uint32 rbps; + unsigned bits; /* the number of bits required to represent a number */ + int fracbits; /* the number of bits of rbps that comprise the fractional part */ + + FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint)); + FLAC__ASSERT(err > 0); + FLAC__ASSERT(n > 0); + + FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE); + if(err <= n) + return 0; + /* + * The above two things tell us 1) n fits in 16 bits; 2) err/n > 1. + * These allow us later to know we won't lose too much precision in the + * fixed-point division (err<<fracbits)/n. + */ + + fracbits = (8*sizeof(err)) - (FLAC__bitmath_ilog2_wide(err)+1); + + err <<= fracbits; + err /= n; + /* err now holds err/n with fracbits fractional bits */ + + /* + * Whittle err down to 16 bits max. 16 significant bits is enough for + * our purposes. + */ + FLAC__ASSERT(err > 0); + bits = FLAC__bitmath_ilog2_wide(err)+1; + if(bits > 16) { + err >>= (bits-16); + fracbits -= (bits-16); + } + rbps = (FLAC__uint32)err; + + /* Multiply by fixed-point version of ln(2), with 16 fractional bits */ + rbps *= FLAC__FP_LN2; + fracbits += 16; + FLAC__ASSERT(fracbits >= 0); + + /* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */ + { + const int f = fracbits & 3; + if(f) { + rbps >>= f; + fracbits -= f; + } + } + + rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1)); + + if(rbps == 0) + return 0; + + /* + * The return value must have 16 fractional bits. Since the whole part + * of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits + * must be >= -3, these assertion allows us to be able to shift rbps + * left if necessary to get 16 fracbits without losing any bits of the + * whole part of rbps. + * + * There is a slight chance due to accumulated error that the whole part + * will require 6 bits, so we use 6 in the assertion. Really though as + * long as it fits in 13 bits (32 - (16 - (-3))) we are fine. + */ + FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6); + FLAC__ASSERT(fracbits >= -3); + + /* now shift the decimal point into place */ + if(fracbits < 16) + return rbps << (16-fracbits); + else if(fracbits > 16) + return rbps >> (fracbits-16); + else + return rbps; +} +#endif + +#ifndef FLAC__INTEGER_ONLY_LIBRARY +unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) +#else +unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) +#endif +{ + FLAC__int32 last_error_0 = data[-1]; + FLAC__int32 last_error_1 = data[-1] - data[-2]; + FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]); + FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]); + FLAC__int32 error, save; + FLAC__uint32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0; + unsigned i, order; + + for(i = 0; i < data_len; i++) { + error = data[i] ; total_error_0 += local_abs(error); save = error; + error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error; + error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error; + error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error; + error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save; + } + + if(total_error_0 < flac_min(flac_min(flac_min(total_error_1, total_error_2), total_error_3), total_error_4)) + order = 0; + else if(total_error_1 < flac_min(flac_min(total_error_2, total_error_3), total_error_4)) + order = 1; + else if(total_error_2 < flac_min(total_error_3, total_error_4)) + order = 2; + else if(total_error_3 < total_error_4) + order = 3; + else + order = 4; + + /* Estimate the expected number of bits per residual signal sample. */ + /* 'total_error*' is linearly related to the variance of the residual */ + /* signal, so we use it directly to compute E(|x|) */ + FLAC__ASSERT(data_len > 0 || total_error_0 == 0); + FLAC__ASSERT(data_len > 0 || total_error_1 == 0); + FLAC__ASSERT(data_len > 0 || total_error_2 == 0); + FLAC__ASSERT(data_len > 0 || total_error_3 == 0); + FLAC__ASSERT(data_len > 0 || total_error_4 == 0); +#ifndef FLAC__INTEGER_ONLY_LIBRARY + residual_bits_per_sample[0] = (float)((total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double)data_len) / M_LN2 : 0.0); + residual_bits_per_sample[1] = (float)((total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double)data_len) / M_LN2 : 0.0); + residual_bits_per_sample[2] = (float)((total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double)data_len) / M_LN2 : 0.0); + residual_bits_per_sample[3] = (float)((total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double)data_len) / M_LN2 : 0.0); + residual_bits_per_sample[4] = (float)((total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (double)data_len) / M_LN2 : 0.0); +#else + residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_integerized(total_error_0, data_len) : 0; + residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_integerized(total_error_1, data_len) : 0; + residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_integerized(total_error_2, data_len) : 0; + residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_integerized(total_error_3, data_len) : 0; + residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_integerized(total_error_4, data_len) : 0; +#endif + + return order; +} + +#ifndef FLAC__INTEGER_ONLY_LIBRARY +unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) +#else +unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) +#endif +{ + FLAC__int32 last_error_0 = data[-1]; + FLAC__int32 last_error_1 = data[-1] - data[-2]; + FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]); + FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]); + FLAC__int32 error, save; + /* total_error_* are 64-bits to avoid overflow when encoding + * erratic signals when the bits-per-sample and blocksize are + * large. + */ + FLAC__uint64 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0; + unsigned i, order; + + for(i = 0; i < data_len; i++) { + error = data[i] ; total_error_0 += local_abs(error); save = error; + error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error; + error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error; + error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error; + error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save; + } + + if(total_error_0 < flac_min(flac_min(flac_min(total_error_1, total_error_2), total_error_3), total_error_4)) + order = 0; + else if(total_error_1 < flac_min(flac_min(total_error_2, total_error_3), total_error_4)) + order = 1; + else if(total_error_2 < flac_min(total_error_3, total_error_4)) + order = 2; + else if(total_error_3 < total_error_4) + order = 3; + else + order = 4; + + /* Estimate the expected number of bits per residual signal sample. */ + /* 'total_error*' is linearly related to the variance of the residual */ + /* signal, so we use it directly to compute E(|x|) */ + FLAC__ASSERT(data_len > 0 || total_error_0 == 0); + FLAC__ASSERT(data_len > 0 || total_error_1 == 0); + FLAC__ASSERT(data_len > 0 || total_error_2 == 0); + FLAC__ASSERT(data_len > 0 || total_error_3 == 0); + FLAC__ASSERT(data_len > 0 || total_error_4 == 0); +#ifndef FLAC__INTEGER_ONLY_LIBRARY + residual_bits_per_sample[0] = (float)((total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double)data_len) / M_LN2 : 0.0); + residual_bits_per_sample[1] = (float)((total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double)data_len) / M_LN2 : 0.0); + residual_bits_per_sample[2] = (float)((total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double)data_len) / M_LN2 : 0.0); + residual_bits_per_sample[3] = (float)((total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double)data_len) / M_LN2 : 0.0); + residual_bits_per_sample[4] = (float)((total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (double)data_len) / M_LN2 : 0.0); +#else + residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_wide_integerized(total_error_0, data_len) : 0; + residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_wide_integerized(total_error_1, data_len) : 0; + residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_wide_integerized(total_error_2, data_len) : 0; + residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_wide_integerized(total_error_3, data_len) : 0; + residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_wide_integerized(total_error_4, data_len) : 0; +#endif + + return order; +} + +void FLAC__fixed_compute_residual(const FLAC__int32 data[], unsigned data_len, unsigned order, FLAC__int32 residual[]) +{ + const int idata_len = (int)data_len; + int i; + + switch(order) { + case 0: + FLAC__ASSERT(sizeof(residual[0]) == sizeof(data[0])); + memcpy(residual, data, sizeof(residual[0])*data_len); + break; + case 1: + for(i = 0; i < idata_len; i++) + residual[i] = data[i] - data[i-1]; + break; + case 2: + for(i = 0; i < idata_len; i++) + residual[i] = data[i] - 2*data[i-1] + data[i-2]; + break; + case 3: + for(i = 0; i < idata_len; i++) + residual[i] = data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3]; + break; + case 4: + for(i = 0; i < idata_len; i++) + residual[i] = data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4]; + break; + default: + FLAC__ASSERT(0); + } +} + +void FLAC__fixed_restore_signal(const FLAC__int32 residual[], unsigned data_len, unsigned order, FLAC__int32 data[]) +{ + int i, idata_len = (int)data_len; + + switch(order) { + case 0: + FLAC__ASSERT(sizeof(residual[0]) == sizeof(data[0])); + memcpy(data, residual, sizeof(residual[0])*data_len); + break; + case 1: + for(i = 0; i < idata_len; i++) + data[i] = residual[i] + data[i-1]; + break; + case 2: + for(i = 0; i < idata_len; i++) + data[i] = residual[i] + 2*data[i-1] - data[i-2]; + break; + case 3: + for(i = 0; i < idata_len; i++) + data[i] = residual[i] + 3*data[i-1] - 3*data[i-2] + data[i-3]; + break; + case 4: + for(i = 0; i < idata_len; i++) + data[i] = residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4]; + break; + default: + FLAC__ASSERT(0); + } +} |