/* libFLAC - Free Lossless Audio Codec library
- * Copyright (C) 2000,2001 Josh Coalson
+ * Copyright (C) 2000,2001,2002,2003,2004,2005,2006,2007 Josh Coalson
*
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
*
- * This library 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
- * Library General Public License for more details.
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
*
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * - 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.
*/
-#include <assert.h>
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
#include <math.h>
+#include <string.h>
+#include "private/bitmath.h"
#include "private/fixed.h"
+#include "FLAC/assert.h"
#ifndef M_LN2
/* math.h in VC++ doesn't seem to have this (how Microsoft is that?) */
#endif
#define local_abs(x) ((unsigned)((x)<0? -(x) : (x)))
-unsigned FLAC__fixed_compute_best_predictor(const int32 data[], unsigned data_len, real residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
+#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, FLAC__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 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
+ order = 0;
+ else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
+ order = 1;
+ else if(total_error_2 < 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] = (FLAC__float)((total_error_0 > 0) ? log(M_LN2 * (FLAC__double)total_error_0 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[1] = (FLAC__float)((total_error_1 > 0) ? log(M_LN2 * (FLAC__double)total_error_1 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[2] = (FLAC__float)((total_error_2 > 0) ? log(M_LN2 * (FLAC__double)total_error_2 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[3] = (FLAC__float)((total_error_3 > 0) ? log(M_LN2 * (FLAC__double)total_error_3 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[4] = (FLAC__float)((total_error_4 > 0) ? log(M_LN2 * (FLAC__double)total_error_4 / (FLAC__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, FLAC__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
{
- int32 last_error_0 = data[-1];
- int32 last_error_1 = data[-1] - data[-2];
- int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
- int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
- int32 error_0, error_1, error_2, error_3, error_4;
- uint32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
+ 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_0 = data[i] ; total_error_0 += local_abs(error_0);
- error_1 = error_0 - last_error_0; total_error_1 += local_abs(error_1);
- error_2 = error_1 - last_error_1; total_error_2 += local_abs(error_2);
- error_3 = error_2 - last_error_2; total_error_3 += local_abs(error_3);
- error_4 = error_3 - last_error_3; total_error_4 += local_abs(error_4);
-
- /* WATCHOUT - total_error_* has been know to overflow when encoding
- * erratic signals when the bits-per-sample is large. We avoid the
- * speed penalty of watching for overflow, and instead rely on the
- * encoder's evaluation of the subframe to catch these cases.
- */
-
- last_error_0 = error_0;
- last_error_1 = error_1;
- last_error_2 = error_2;
- last_error_3 = error_3;
+ 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 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_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|) */
- residual_bits_per_sample[0] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_0 / (real) data_len) / M_LN2 : 0.0);
- residual_bits_per_sample[1] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_1 / (real) data_len) / M_LN2 : 0.0);
- residual_bits_per_sample[2] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_2 / (real) data_len) / M_LN2 : 0.0);
- residual_bits_per_sample[3] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_3 / (real) data_len) / M_LN2 : 0.0);
- residual_bits_per_sample[4] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_4 / (real) data_len) / M_LN2 : 0.0);
+ 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
+#if defined _MSC_VER || defined __MINGW32__
+ /* with MSVC you have to spoon feed it the casting */
+ residual_bits_per_sample[0] = (FLAC__float)((total_error_0 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_0 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[1] = (FLAC__float)((total_error_1 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_1 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[2] = (FLAC__float)((total_error_2 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_2 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[3] = (FLAC__float)((total_error_3 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_3 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[4] = (FLAC__float)((total_error_4 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_4 / (FLAC__double)data_len) / M_LN2 : 0.0);
+#else
+ residual_bits_per_sample[0] = (FLAC__float)((total_error_0 > 0) ? log(M_LN2 * (FLAC__double)total_error_0 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[1] = (FLAC__float)((total_error_1 > 0) ? log(M_LN2 * (FLAC__double)total_error_1 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[2] = (FLAC__float)((total_error_2 > 0) ? log(M_LN2 * (FLAC__double)total_error_2 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[3] = (FLAC__float)((total_error_3 > 0) ? log(M_LN2 * (FLAC__double)total_error_3 / (FLAC__double)data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[4] = (FLAC__float)((total_error_4 > 0) ? log(M_LN2 * (FLAC__double)total_error_4 / (FLAC__double)data_len) / M_LN2 : 0.0);
+#endif
+#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 int32 data[], unsigned data_len, unsigned order, int32 residual[])
+void FLAC__fixed_compute_residual(const FLAC__int32 data[], unsigned data_len, unsigned order, FLAC__int32 residual[])
{
- unsigned i;
+ const int idata_len = (int)data_len;
+ int i;
switch(order) {
case 0:
- for(i = 0; i < data_len; i++) {
- residual[i] = data[i];
- }
+ FLAC__ASSERT(sizeof(residual[0]) == sizeof(data[0]));
+ memcpy(residual, data, sizeof(residual[0])*data_len);
break;
case 1:
- for(i = 0; i < data_len; i++) {
+ for(i = 0; i < idata_len; i++)
residual[i] = data[i] - data[i-1];
- }
break;
case 2:
- for(i = 0; i < data_len; i++) {
- /* == data[i] - 2*data[i-1] + data[i-2] */
+ for(i = 0; i < idata_len; i++)
+#if 1 /* OPT: may be faster with some compilers on some systems */
residual[i] = data[i] - (data[i-1] << 1) + data[i-2];
- }
+#else
+ residual[i] = data[i] - 2*data[i-1] + data[i-2];
+#endif
break;
case 3:
- for(i = 0; i < data_len; i++) {
- /* == data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3] */
+ for(i = 0; i < idata_len; i++)
+#if 1 /* OPT: may be faster with some compilers on some systems */
residual[i] = data[i] - (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) - data[i-3];
- }
+#else
+ residual[i] = data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3];
+#endif
break;
case 4:
- for(i = 0; i < data_len; i++) {
- /* == data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4] */
+ for(i = 0; i < idata_len; i++)
+#if 1 /* OPT: may be faster with some compilers on some systems */
residual[i] = data[i] - ((data[i-1]+data[i-3])<<2) + ((data[i-2]<<2) + (data[i-2]<<1)) + data[i-4];
- }
+#else
+ residual[i] = data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4];
+#endif
break;
default:
- assert(0);
+ FLAC__ASSERT(0);
}
}
-void FLAC__fixed_restore_signal(const int32 residual[], unsigned data_len, unsigned order, int32 data[])
+void FLAC__fixed_restore_signal(const FLAC__int32 residual[], unsigned data_len, unsigned order, FLAC__int32 data[])
{
- unsigned i;
+ int i, idata_len = (int)data_len;
switch(order) {
case 0:
- for(i = 0; i < data_len; i++) {
- data[i] = residual[i];
- }
+ FLAC__ASSERT(sizeof(residual[0]) == sizeof(data[0]));
+ memcpy(data, residual, sizeof(residual[0])*data_len);
break;
case 1:
- for(i = 0; i < data_len; i++) {
+ for(i = 0; i < idata_len; i++)
data[i] = residual[i] + data[i-1];
- }
break;
case 2:
- for(i = 0; i < data_len; i++) {
- /* == residual[i] + 2*data[i-1] - data[i-2] */
+ for(i = 0; i < idata_len; i++)
+#if 1 /* OPT: may be faster with some compilers on some systems */
data[i] = residual[i] + (data[i-1]<<1) - data[i-2];
- }
+#else
+ data[i] = residual[i] + 2*data[i-1] - data[i-2];
+#endif
break;
case 3:
- for(i = 0; i < data_len; i++) {
- /* residual[i] + 3*data[i-1] - 3*data[i-2]) + data[i-3] */
+ for(i = 0; i < idata_len; i++)
+#if 1 /* OPT: may be faster with some compilers on some systems */
data[i] = residual[i] + (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) + data[i-3];
- }
+#else
+ data[i] = residual[i] + 3*data[i-1] - 3*data[i-2] + data[i-3];
+#endif
break;
case 4:
- for(i = 0; i < data_len; i++) {
- /* == residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4] */
+ for(i = 0; i < idata_len; i++)
+#if 1 /* OPT: may be faster with some compilers on some systems */
data[i] = residual[i] + ((data[i-1]+data[i-3])<<2) - ((data[i-2]<<2) + (data[i-2]<<1)) - data[i-4];
- }
+#else
+ data[i] = residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4];
+#endif
break;
default:
- assert(0);
+ FLAC__ASSERT(0);
}
}
projects / platform / upstream / flac.git / blobdiff