/* libFLAC - Free Lossless Audio Codec library * Copyright (C) 2000-2009 Josh Coalson * Copyright (C) 2011-2022 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) … #ifdef local_abs64 #undef local_abs64 #endif #define local_abs64(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; uint32_t 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, (uint32_t)(-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; uint32_t 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, (uint32_t)(-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 uint32_t FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], uint32_t data_len, float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #else uint32_t FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], uint32_t data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #endif { … } #ifndef FLAC__INTEGER_ONLY_LIBRARY uint32_t FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], uint32_t data_len, float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #else uint32_t FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], uint32_t data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #endif { … } #ifndef FLAC__INTEGER_ONLY_LIBRARY #define CHECK_ORDER_IS_VALID(macro_order) … #else #define CHECK_ORDER_IS_VALID … #endif #ifndef FLAC__INTEGER_ONLY_LIBRARY uint32_t FLAC__fixed_compute_best_predictor_limit_residual(const FLAC__int32 data[], uint32_t data_len, float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #else uint32_t FLAC__fixed_compute_best_predictor_limit_residual(const FLAC__int32 data[], uint32_t data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #endif { … } #ifndef FLAC__INTEGER_ONLY_LIBRARY uint32_t FLAC__fixed_compute_best_predictor_limit_residual_33bit(const FLAC__int64 data[], uint32_t data_len, float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #else uint32_t FLAC__fixed_compute_best_predictor_limit_residual_33bit(const FLAC__int64 data[], uint32_t data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #endif { … } void FLAC__fixed_compute_residual(const FLAC__int32 data[], uint32_t data_len, uint32_t order, FLAC__int32 residual[]) { … } void FLAC__fixed_compute_residual_wide(const FLAC__int32 data[], uint32_t data_len, uint32_t order, FLAC__int32 residual[]) { … } void FLAC__fixed_compute_residual_wide_33bit(const FLAC__int64 data[], uint32_t data_len, uint32_t order, FLAC__int32 residual[]) { … } #ifdef FUZZING_BUILD_MODE_NO_SANITIZE_SIGNED_INTEGER_OVERFLOW /* The attribute below is to silence the undefined sanitizer of oss-fuzz. * Because fuzzing feeds bogus predictors and residual samples to the * decoder, having overflows in this section is unavoidable. Also, * because the calculated values are audio path only, there is no * potential for security problems */ __attribute__((no_sanitize("signed-integer-overflow"))) #endif void FLAC__fixed_restore_signal(const FLAC__int32 residual[], uint32_t data_len, uint32_t order, FLAC__int32 data[]) { … } void FLAC__fixed_restore_signal_wide(const FLAC__int32 residual[], uint32_t data_len, uint32_t order, FLAC__int32 data[]) { … } #ifdef FUZZING_BUILD_MODE_NO_SANITIZE_SIGNED_INTEGER_OVERFLOW /* The attribute below is to silence the undefined sanitizer of oss-fuzz. * Because fuzzing feeds bogus predictors and residual samples to the * decoder, having overflows in this section is unavoidable. Also, * because the calculated values are audio path only, there is no * potential for security problems */ __attribute__((no_sanitize("signed-integer-overflow"))) #endif void FLAC__fixed_restore_signal_wide_33bit(const FLAC__int32 residual[], uint32_t data_len, uint32_t order, FLAC__int64 data[]) { … }
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