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-rw-r--r--libmad/src/layer3.c2707
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diff --git a/libmad/src/layer3.c b/libmad/src/layer3.c
new file mode 100644
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--- /dev/null
+++ b/libmad/src/layer3.c
@@ -0,0 +1,2707 @@
+/*
+ * libmad - MPEG audio decoder library
+ * Copyright (C) 2000-2004 Underbit Technologies, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * $Id: layer3.c,v 1.43 2004/01/23 09:41:32 rob Exp $
+ */
+
+# ifdef HAVE_CONFIG_H
+# include "config.h"
+# endif
+
+# include "global.h"
+
+# include <stdlib.h>
+# include <string.h>
+
+# ifdef HAVE_ASSERT_H
+# include <assert.h>
+# endif
+
+# ifdef HAVE_LIMITS_H
+# include <limits.h>
+# else
+# define CHAR_BIT 8
+# endif
+
+# include "fixed.h"
+# include "bit.h"
+# include "stream.h"
+# include "frame.h"
+# include "huffman.h"
+# include "layer3.h"
+
+# ifdef _MSC_VER
+# pragma warning(push)
+# pragma warning(disable: 4244 4018)
+# endif
+
+/* --- Layer III ----------------------------------------------------------- */
+
+enum {
+ count1table_select = 0x01,
+ scalefac_scale = 0x02,
+ preflag = 0x04,
+ mixed_block_flag = 0x08
+};
+
+enum {
+ I_STEREO = 0x1,
+ MS_STEREO = 0x2
+};
+
+struct sideinfo {
+ unsigned int main_data_begin;
+ unsigned int private_bits;
+
+ unsigned char scfsi[2];
+
+ struct granule {
+ struct channel {
+ /* from side info */
+ unsigned short part2_3_length;
+ unsigned short big_values;
+ unsigned short global_gain;
+ unsigned short scalefac_compress;
+
+ unsigned char flags;
+ unsigned char block_type;
+ unsigned char table_select[3];
+ unsigned char subblock_gain[3];
+ unsigned char region0_count;
+ unsigned char region1_count;
+
+ /* from main_data */
+ unsigned char scalefac[39]; /* scalefac_l and/or scalefac_s */
+ } ch[2];
+ } gr[2];
+};
+
+/*
+ * scalefactor bit lengths
+ * derived from section 2.4.2.7 of ISO/IEC 11172-3
+ */
+static
+struct {
+ unsigned char slen1;
+ unsigned char slen2;
+} const sflen_table[16] = {
+ { 0, 0 }, { 0, 1 }, { 0, 2 }, { 0, 3 },
+ { 3, 0 }, { 1, 1 }, { 1, 2 }, { 1, 3 },
+ { 2, 1 }, { 2, 2 }, { 2, 3 }, { 3, 1 },
+ { 3, 2 }, { 3, 3 }, { 4, 2 }, { 4, 3 }
+};
+
+/*
+ * number of LSF scalefactor band values
+ * derived from section 2.4.3.2 of ISO/IEC 13818-3
+ */
+static
+unsigned char const nsfb_table[6][3][4] = {
+ { { 6, 5, 5, 5 },
+ { 9, 9, 9, 9 },
+ { 6, 9, 9, 9 } },
+
+ { { 6, 5, 7, 3 },
+ { 9, 9, 12, 6 },
+ { 6, 9, 12, 6 } },
+
+ { { 11, 10, 0, 0 },
+ { 18, 18, 0, 0 },
+ { 15, 18, 0, 0 } },
+
+ { { 7, 7, 7, 0 },
+ { 12, 12, 12, 0 },
+ { 6, 15, 12, 0 } },
+
+ { { 6, 6, 6, 3 },
+ { 12, 9, 9, 6 },
+ { 6, 12, 9, 6 } },
+
+ { { 8, 8, 5, 0 },
+ { 15, 12, 9, 0 },
+ { 6, 18, 9, 0 } }
+};
+
+/*
+ * MPEG-1 scalefactor band widths
+ * derived from Table B.8 of ISO/IEC 11172-3
+ */
+static
+unsigned char const sfb_48000_long[] = {
+ 4, 4, 4, 4, 4, 4, 6, 6, 6, 8, 10,
+ 12, 16, 18, 22, 28, 34, 40, 46, 54, 54, 192
+};
+
+static
+unsigned char const sfb_44100_long[] = {
+ 4, 4, 4, 4, 4, 4, 6, 6, 8, 8, 10,
+ 12, 16, 20, 24, 28, 34, 42, 50, 54, 76, 158
+};
+
+static
+unsigned char const sfb_32000_long[] = {
+ 4, 4, 4, 4, 4, 4, 6, 6, 8, 10, 12,
+ 16, 20, 24, 30, 38, 46, 56, 68, 84, 102, 26
+};
+
+static
+unsigned char const sfb_48000_short[] = {
+ 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 6,
+ 6, 6, 6, 6, 6, 10, 10, 10, 12, 12, 12, 14, 14,
+ 14, 16, 16, 16, 20, 20, 20, 26, 26, 26, 66, 66, 66
+};
+
+static
+unsigned char const sfb_44100_short[] = {
+ 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 6,
+ 6, 6, 8, 8, 8, 10, 10, 10, 12, 12, 12, 14, 14,
+ 14, 18, 18, 18, 22, 22, 22, 30, 30, 30, 56, 56, 56
+};
+
+static
+unsigned char const sfb_32000_short[] = {
+ 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 6,
+ 6, 6, 8, 8, 8, 12, 12, 12, 16, 16, 16, 20, 20,
+ 20, 26, 26, 26, 34, 34, 34, 42, 42, 42, 12, 12, 12
+};
+
+static
+unsigned char const sfb_48000_mixed[] = {
+ /* long */ 4, 4, 4, 4, 4, 4, 6, 6,
+ /* short */ 4, 4, 4, 6, 6, 6, 6, 6, 6, 10,
+ 10, 10, 12, 12, 12, 14, 14, 14, 16, 16,
+ 16, 20, 20, 20, 26, 26, 26, 66, 66, 66
+};
+
+static
+unsigned char const sfb_44100_mixed[] = {
+ /* long */ 4, 4, 4, 4, 4, 4, 6, 6,
+ /* short */ 4, 4, 4, 6, 6, 6, 8, 8, 8, 10,
+ 10, 10, 12, 12, 12, 14, 14, 14, 18, 18,
+ 18, 22, 22, 22, 30, 30, 30, 56, 56, 56
+};
+
+static
+unsigned char const sfb_32000_mixed[] = {
+ /* long */ 4, 4, 4, 4, 4, 4, 6, 6,
+ /* short */ 4, 4, 4, 6, 6, 6, 8, 8, 8, 12,
+ 12, 12, 16, 16, 16, 20, 20, 20, 26, 26,
+ 26, 34, 34, 34, 42, 42, 42, 12, 12, 12
+};
+
+/*
+ * MPEG-2 scalefactor band widths
+ * derived from Table B.2 of ISO/IEC 13818-3
+ */
+static
+unsigned char const sfb_24000_long[] = {
+ 6, 6, 6, 6, 6, 6, 8, 10, 12, 14, 16,
+ 18, 22, 26, 32, 38, 46, 54, 62, 70, 76, 36
+};
+
+static
+unsigned char const sfb_22050_long[] = {
+ 6, 6, 6, 6, 6, 6, 8, 10, 12, 14, 16,
+ 20, 24, 28, 32, 38, 46, 52, 60, 68, 58, 54
+};
+
+# define sfb_16000_long sfb_22050_long
+
+static
+unsigned char const sfb_24000_short[] = {
+ 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, 6, 6, 8,
+ 8, 8, 10, 10, 10, 12, 12, 12, 14, 14, 14, 18, 18,
+ 18, 24, 24, 24, 32, 32, 32, 44, 44, 44, 12, 12, 12
+};
+
+static
+unsigned char const sfb_22050_short[] = {
+ 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, 6, 6, 6,
+ 6, 6, 8, 8, 8, 10, 10, 10, 14, 14, 14, 18, 18,
+ 18, 26, 26, 26, 32, 32, 32, 42, 42, 42, 18, 18, 18
+};
+
+static
+unsigned char const sfb_16000_short[] = {
+ 4, 4, 4, 4, 4, 4, 4, 4, 4, 6, 6, 6, 8,
+ 8, 8, 10, 10, 10, 12, 12, 12, 14, 14, 14, 18, 18,
+ 18, 24, 24, 24, 30, 30, 30, 40, 40, 40, 18, 18, 18
+};
+
+static
+unsigned char const sfb_24000_mixed[] = {
+ /* long */ 6, 6, 6, 6, 6, 6,
+ /* short */ 6, 6, 6, 8, 8, 8, 10, 10, 10, 12,
+ 12, 12, 14, 14, 14, 18, 18, 18, 24, 24,
+ 24, 32, 32, 32, 44, 44, 44, 12, 12, 12
+};
+
+static
+unsigned char const sfb_22050_mixed[] = {
+ /* long */ 6, 6, 6, 6, 6, 6,
+ /* short */ 6, 6, 6, 6, 6, 6, 8, 8, 8, 10,
+ 10, 10, 14, 14, 14, 18, 18, 18, 26, 26,
+ 26, 32, 32, 32, 42, 42, 42, 18, 18, 18
+};
+
+static
+unsigned char const sfb_16000_mixed[] = {
+ /* long */ 6, 6, 6, 6, 6, 6,
+ /* short */ 6, 6, 6, 8, 8, 8, 10, 10, 10, 12,
+ 12, 12, 14, 14, 14, 18, 18, 18, 24, 24,
+ 24, 30, 30, 30, 40, 40, 40, 18, 18, 18
+};
+
+/*
+ * MPEG 2.5 scalefactor band widths
+ * derived from public sources
+ */
+# define sfb_12000_long sfb_16000_long
+# define sfb_11025_long sfb_12000_long
+
+static
+unsigned char const sfb_8000_long[] = {
+ 12, 12, 12, 12, 12, 12, 16, 20, 24, 28, 32,
+ 40, 48, 56, 64, 76, 90, 2, 2, 2, 2, 2
+};
+
+# define sfb_12000_short sfb_16000_short
+# define sfb_11025_short sfb_12000_short
+
+static
+unsigned char const sfb_8000_short[] = {
+ 8, 8, 8, 8, 8, 8, 8, 8, 8, 12, 12, 12, 16,
+ 16, 16, 20, 20, 20, 24, 24, 24, 28, 28, 28, 36, 36,
+ 36, 2, 2, 2, 2, 2, 2, 2, 2, 2, 26, 26, 26
+};
+
+# define sfb_12000_mixed sfb_16000_mixed
+# define sfb_11025_mixed sfb_12000_mixed
+
+/* the 8000 Hz short block scalefactor bands do not break after
+ the first 36 frequency lines, so this is probably wrong */
+static
+unsigned char const sfb_8000_mixed[] = {
+ /* long */ 12, 12, 12,
+ /* short */ 4, 4, 4, 8, 8, 8, 12, 12, 12, 16, 16, 16,
+ 20, 20, 20, 24, 24, 24, 28, 28, 28, 36, 36, 36,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 26, 26, 26
+};
+
+static
+struct {
+ unsigned char const *l;
+ unsigned char const *s;
+ unsigned char const *m;
+} const sfbwidth_table[9] = {
+ { sfb_48000_long, sfb_48000_short, sfb_48000_mixed },
+ { sfb_44100_long, sfb_44100_short, sfb_44100_mixed },
+ { sfb_32000_long, sfb_32000_short, sfb_32000_mixed },
+ { sfb_24000_long, sfb_24000_short, sfb_24000_mixed },
+ { sfb_22050_long, sfb_22050_short, sfb_22050_mixed },
+ { sfb_16000_long, sfb_16000_short, sfb_16000_mixed },
+ { sfb_12000_long, sfb_12000_short, sfb_12000_mixed },
+ { sfb_11025_long, sfb_11025_short, sfb_11025_mixed },
+ { sfb_8000_long, sfb_8000_short, sfb_8000_mixed }
+};
+
+/*
+ * scalefactor band preemphasis (used only when preflag is set)
+ * derived from Table B.6 of ISO/IEC 11172-3
+ */
+static
+unsigned char const pretab[22] = {
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2, 0
+};
+
+/*
+ * table for requantization
+ *
+ * rq_table[x].mantissa * 2^(rq_table[x].exponent) = x^(4/3)
+ */
+static
+struct fixedfloat {
+ unsigned long mantissa : 27;
+ unsigned short exponent : 5;
+} const rq_table[8207] = {
+# include "rq_table.dat"
+};
+
+/*
+ * fractional powers of two
+ * used for requantization and joint stereo decoding
+ *
+ * root_table[3 + x] = 2^(x/4)
+ */
+static
+mad_fixed_t const root_table[7] = {
+ MAD_F(0x09837f05) /* 2^(-3/4) == 0.59460355750136 */,
+ MAD_F(0x0b504f33) /* 2^(-2/4) == 0.70710678118655 */,
+ MAD_F(0x0d744fcd) /* 2^(-1/4) == 0.84089641525371 */,
+ MAD_F(0x10000000) /* 2^( 0/4) == 1.00000000000000 */,
+ MAD_F(0x1306fe0a) /* 2^(+1/4) == 1.18920711500272 */,
+ MAD_F(0x16a09e66) /* 2^(+2/4) == 1.41421356237310 */,
+ MAD_F(0x1ae89f99) /* 2^(+3/4) == 1.68179283050743 */
+};
+
+/*
+ * coefficients for aliasing reduction
+ * derived from Table B.9 of ISO/IEC 11172-3
+ *
+ * c[] = { -0.6, -0.535, -0.33, -0.185, -0.095, -0.041, -0.0142, -0.0037 }
+ * cs[i] = 1 / sqrt(1 + c[i]^2)
+ * ca[i] = c[i] / sqrt(1 + c[i]^2)
+ */
+static
+mad_fixed_t const cs[8] = {
+ +MAD_F(0x0db84a81) /* +0.857492926 */, +MAD_F(0x0e1b9d7f) /* +0.881741997 */,
+ +MAD_F(0x0f31adcf) /* +0.949628649 */, +MAD_F(0x0fbba815) /* +0.983314592 */,
+ +MAD_F(0x0feda417) /* +0.995517816 */, +MAD_F(0x0ffc8fc8) /* +0.999160558 */,
+ +MAD_F(0x0fff964c) /* +0.999899195 */, +MAD_F(0x0ffff8d3) /* +0.999993155 */
+};
+
+static
+mad_fixed_t const ca[8] = {
+ -MAD_F(0x083b5fe7) /* -0.514495755 */, -MAD_F(0x078c36d2) /* -0.471731969 */,
+ -MAD_F(0x05039814) /* -0.313377454 */, -MAD_F(0x02e91dd1) /* -0.181913200 */,
+ -MAD_F(0x0183603a) /* -0.094574193 */, -MAD_F(0x00a7cb87) /* -0.040965583 */,
+ -MAD_F(0x003a2847) /* -0.014198569 */, -MAD_F(0x000f27b4) /* -0.003699975 */
+};
+
+/*
+ * IMDCT coefficients for short blocks
+ * derived from section 2.4.3.4.10.2 of ISO/IEC 11172-3
+ *
+ * imdct_s[i/even][k] = cos((PI / 24) * (2 * (i / 2) + 7) * (2 * k + 1))
+ * imdct_s[i /odd][k] = cos((PI / 24) * (2 * (6 + (i-1)/2) + 7) * (2 * k + 1))
+ */
+static
+mad_fixed_t const imdct_s[6][6] = {
+# include "imdct_s.dat"
+};
+
+# if !defined(ASO_IMDCT)
+/*
+ * windowing coefficients for long blocks
+ * derived from section 2.4.3.4.10.3 of ISO/IEC 11172-3
+ *
+ * window_l[i] = sin((PI / 36) * (i + 1/2))
+ */
+static
+mad_fixed_t const window_l[36] = {
+ MAD_F(0x00b2aa3e) /* 0.043619387 */, MAD_F(0x0216a2a2) /* 0.130526192 */,
+ MAD_F(0x03768962) /* 0.216439614 */, MAD_F(0x04cfb0e2) /* 0.300705800 */,
+ MAD_F(0x061f78aa) /* 0.382683432 */, MAD_F(0x07635284) /* 0.461748613 */,
+ MAD_F(0x0898c779) /* 0.537299608 */, MAD_F(0x09bd7ca0) /* 0.608761429 */,
+ MAD_F(0x0acf37ad) /* 0.675590208 */, MAD_F(0x0bcbe352) /* 0.737277337 */,
+ MAD_F(0x0cb19346) /* 0.793353340 */, MAD_F(0x0d7e8807) /* 0.843391446 */,
+
+ MAD_F(0x0e313245) /* 0.887010833 */, MAD_F(0x0ec835e8) /* 0.923879533 */,
+ MAD_F(0x0f426cb5) /* 0.953716951 */, MAD_F(0x0f9ee890) /* 0.976296007 */,
+ MAD_F(0x0fdcf549) /* 0.991444861 */, MAD_F(0x0ffc19fd) /* 0.999048222 */,
+ MAD_F(0x0ffc19fd) /* 0.999048222 */, MAD_F(0x0fdcf549) /* 0.991444861 */,
+ MAD_F(0x0f9ee890) /* 0.976296007 */, MAD_F(0x0f426cb5) /* 0.953716951 */,
+ MAD_F(0x0ec835e8) /* 0.923879533 */, MAD_F(0x0e313245) /* 0.887010833 */,
+
+ MAD_F(0x0d7e8807) /* 0.843391446 */, MAD_F(0x0cb19346) /* 0.793353340 */,
+ MAD_F(0x0bcbe352) /* 0.737277337 */, MAD_F(0x0acf37ad) /* 0.675590208 */,
+ MAD_F(0x09bd7ca0) /* 0.608761429 */, MAD_F(0x0898c779) /* 0.537299608 */,
+ MAD_F(0x07635284) /* 0.461748613 */, MAD_F(0x061f78aa) /* 0.382683432 */,
+ MAD_F(0x04cfb0e2) /* 0.300705800 */, MAD_F(0x03768962) /* 0.216439614 */,
+ MAD_F(0x0216a2a2) /* 0.130526192 */, MAD_F(0x00b2aa3e) /* 0.043619387 */,
+};
+# endif /* ASO_IMDCT */
+
+/*
+ * windowing coefficients for short blocks
+ * derived from section 2.4.3.4.10.3 of ISO/IEC 11172-3
+ *
+ * window_s[i] = sin((PI / 12) * (i + 1/2))
+ */
+static
+mad_fixed_t const window_s[12] = {
+ MAD_F(0x0216a2a2) /* 0.130526192 */, MAD_F(0x061f78aa) /* 0.382683432 */,
+ MAD_F(0x09bd7ca0) /* 0.608761429 */, MAD_F(0x0cb19346) /* 0.793353340 */,
+ MAD_F(0x0ec835e8) /* 0.923879533 */, MAD_F(0x0fdcf549) /* 0.991444861 */,
+ MAD_F(0x0fdcf549) /* 0.991444861 */, MAD_F(0x0ec835e8) /* 0.923879533 */,
+ MAD_F(0x0cb19346) /* 0.793353340 */, MAD_F(0x09bd7ca0) /* 0.608761429 */,
+ MAD_F(0x061f78aa) /* 0.382683432 */, MAD_F(0x0216a2a2) /* 0.130526192 */,
+};
+
+/*
+ * coefficients for intensity stereo processing
+ * derived from section 2.4.3.4.9.3 of ISO/IEC 11172-3
+ *
+ * is_ratio[i] = tan(i * (PI / 12))
+ * is_table[i] = is_ratio[i] / (1 + is_ratio[i])
+ */
+static
+mad_fixed_t const is_table[7] = {
+ MAD_F(0x00000000) /* 0.000000000 */,
+ MAD_F(0x0361962f) /* 0.211324865 */,
+ MAD_F(0x05db3d74) /* 0.366025404 */,
+ MAD_F(0x08000000) /* 0.500000000 */,
+ MAD_F(0x0a24c28c) /* 0.633974596 */,
+ MAD_F(0x0c9e69d1) /* 0.788675135 */,
+ MAD_F(0x10000000) /* 1.000000000 */
+};
+
+/*
+ * coefficients for LSF intensity stereo processing
+ * derived from section 2.4.3.2 of ISO/IEC 13818-3
+ *
+ * is_lsf_table[0][i] = (1 / sqrt(sqrt(2)))^(i + 1)
+ * is_lsf_table[1][i] = (1 / sqrt(2)) ^(i + 1)
+ */
+static
+mad_fixed_t const is_lsf_table[2][15] = {
+ {
+ MAD_F(0x0d744fcd) /* 0.840896415 */,
+ MAD_F(0x0b504f33) /* 0.707106781 */,
+ MAD_F(0x09837f05) /* 0.594603558 */,
+ MAD_F(0x08000000) /* 0.500000000 */,
+ MAD_F(0x06ba27e6) /* 0.420448208 */,
+ MAD_F(0x05a8279a) /* 0.353553391 */,
+ MAD_F(0x04c1bf83) /* 0.297301779 */,
+ MAD_F(0x04000000) /* 0.250000000 */,
+ MAD_F(0x035d13f3) /* 0.210224104 */,
+ MAD_F(0x02d413cd) /* 0.176776695 */,
+ MAD_F(0x0260dfc1) /* 0.148650889 */,
+ MAD_F(0x02000000) /* 0.125000000 */,
+ MAD_F(0x01ae89fa) /* 0.105112052 */,
+ MAD_F(0x016a09e6) /* 0.088388348 */,
+ MAD_F(0x01306fe1) /* 0.074325445 */
+ }, {
+ MAD_F(0x0b504f33) /* 0.707106781 */,
+ MAD_F(0x08000000) /* 0.500000000 */,
+ MAD_F(0x05a8279a) /* 0.353553391 */,
+ MAD_F(0x04000000) /* 0.250000000 */,
+ MAD_F(0x02d413cd) /* 0.176776695 */,
+ MAD_F(0x02000000) /* 0.125000000 */,
+ MAD_F(0x016a09e6) /* 0.088388348 */,
+ MAD_F(0x01000000) /* 0.062500000 */,
+ MAD_F(0x00b504f3) /* 0.044194174 */,
+ MAD_F(0x00800000) /* 0.031250000 */,
+ MAD_F(0x005a827a) /* 0.022097087 */,
+ MAD_F(0x00400000) /* 0.015625000 */,
+ MAD_F(0x002d413d) /* 0.011048543 */,
+ MAD_F(0x00200000) /* 0.007812500 */,
+ MAD_F(0x0016a09e) /* 0.005524272 */
+ }
+};
+
+/*
+ * NAME: III_sideinfo()
+ * DESCRIPTION: decode frame side information from a bitstream
+ */
+static
+enum mad_error III_sideinfo(struct mad_bitptr *ptr, unsigned int nch,
+ int lsf, struct sideinfo *si,
+ unsigned int *data_bitlen,
+ unsigned int *priv_bitlen)
+{
+ unsigned int ngr, gr, ch, i;
+ enum mad_error result = MAD_ERROR_NONE;
+
+ *data_bitlen = 0;
+ *priv_bitlen = lsf ? ((nch == 1) ? 1 : 2) : ((nch == 1) ? 5 : 3);
+
+ si->main_data_begin = mad_bit_read(ptr, lsf ? 8 : 9);
+ si->private_bits = mad_bit_read(ptr, *priv_bitlen);
+
+ ngr = 1;
+ if (!lsf) {
+ ngr = 2;
+
+ for (ch = 0; ch < nch; ++ch)
+ si->scfsi[ch] = mad_bit_read(ptr, 4);
+ }
+
+ for (gr = 0; gr < ngr; ++gr) {
+ struct granule *granule = &si->gr[gr];
+
+ for (ch = 0; ch < nch; ++ch) {
+ struct channel *channel = &granule->ch[ch];
+
+ channel->part2_3_length = mad_bit_read(ptr, 12);
+ channel->big_values = mad_bit_read(ptr, 9);
+ channel->global_gain = mad_bit_read(ptr, 8);
+ channel->scalefac_compress = mad_bit_read(ptr, lsf ? 9 : 4);
+
+ *data_bitlen += channel->part2_3_length;
+
+ if (channel->big_values > 288 && result == 0)
+ result = MAD_ERROR_BADBIGVALUES;
+
+ channel->flags = 0;
+
+ /* window_switching_flag */
+ if (mad_bit_read(ptr, 1)) {
+ channel->block_type = mad_bit_read(ptr, 2);
+
+ if (channel->block_type == 0 && result == 0)
+ result = MAD_ERROR_BADBLOCKTYPE;
+
+ if (!lsf && channel->block_type == 2 && si->scfsi[ch] && result == 0)
+ result = MAD_ERROR_BADSCFSI;
+
+ channel->region0_count = 7;
+ channel->region1_count = 36;
+
+ if (mad_bit_read(ptr, 1))
+ channel->flags |= mixed_block_flag;
+ else if (channel->block_type == 2)
+ channel->region0_count = 8;
+
+ for (i = 0; i < 2; ++i)
+ channel->table_select[i] = mad_bit_read(ptr, 5);
+
+# if defined(DEBUG)
+ channel->table_select[2] = 4; /* not used */
+# endif
+
+ for (i = 0; i < 3; ++i)
+ channel->subblock_gain[i] = mad_bit_read(ptr, 3);
+ }
+ else {
+ channel->block_type = 0;
+
+ for (i = 0; i < 3; ++i)
+ channel->table_select[i] = mad_bit_read(ptr, 5);
+
+ channel->region0_count = mad_bit_read(ptr, 4);
+ channel->region1_count = mad_bit_read(ptr, 3);
+ }
+
+ /* [preflag,] scalefac_scale, count1table_select */
+ channel->flags |= mad_bit_read(ptr, lsf ? 2 : 3);
+ }
+ }
+
+ return result;
+}
+
+/*
+ * NAME: III_scalefactors_lsf()
+ * DESCRIPTION: decode channel scalefactors for LSF from a bitstream
+ */
+static
+unsigned int III_scalefactors_lsf(struct mad_bitptr *ptr,
+ struct channel *channel,
+ struct channel *gr1ch, int mode_extension)
+{
+ struct mad_bitptr start;
+ unsigned int scalefac_compress, index, slen[4], part, n, i;
+ unsigned char const *nsfb;
+
+ start = *ptr;
+
+ scalefac_compress = channel->scalefac_compress;
+ index = (channel->block_type == 2) ?
+ ((channel->flags & mixed_block_flag) ? 2 : 1) : 0;
+
+ if (!((mode_extension & I_STEREO) && gr1ch)) {
+ if (scalefac_compress < 400) {
+ slen[0] = (scalefac_compress >> 4) / 5;
+ slen[1] = (scalefac_compress >> 4) % 5;
+ slen[2] = (scalefac_compress % 16) >> 2;
+ slen[3] = scalefac_compress % 4;
+
+ nsfb = nsfb_table[0][index];
+ }
+ else if (scalefac_compress < 500) {
+ scalefac_compress -= 400;
+
+ slen[0] = (scalefac_compress >> 2) / 5;
+ slen[1] = (scalefac_compress >> 2) % 5;
+ slen[2] = scalefac_compress % 4;
+ slen[3] = 0;
+
+ nsfb = nsfb_table[1][index];
+ }
+ else {
+ scalefac_compress -= 500;
+
+ slen[0] = scalefac_compress / 3;
+ slen[1] = scalefac_compress % 3;
+ slen[2] = 0;
+ slen[3] = 0;
+
+ channel->flags |= preflag;
+
+ nsfb = nsfb_table[2][index];
+ }
+
+ n = 0;
+ for (part = 0; part < 4; ++part) {
+ for (i = 0; i < nsfb[part]; ++i)
+ channel->scalefac[n++] = mad_bit_read(ptr, slen[part]);
+ }
+
+ while (n < 39)
+ channel->scalefac[n++] = 0;
+ }
+ else { /* (mode_extension & I_STEREO) && gr1ch (i.e. ch == 1) */
+ scalefac_compress >>= 1;
+
+ if (scalefac_compress < 180) {
+ slen[0] = scalefac_compress / 36;
+ slen[1] = (scalefac_compress % 36) / 6;
+ slen[2] = (scalefac_compress % 36) % 6;
+ slen[3] = 0;
+
+ nsfb = nsfb_table[3][index];
+ }
+ else if (scalefac_compress < 244) {
+ scalefac_compress -= 180;
+
+ slen[0] = (scalefac_compress % 64) >> 4;
+ slen[1] = (scalefac_compress % 16) >> 2;
+ slen[2] = scalefac_compress % 4;
+ slen[3] = 0;
+
+ nsfb = nsfb_table[4][index];
+ }
+ else {
+ scalefac_compress -= 244;
+
+ slen[0] = scalefac_compress / 3;
+ slen[1] = scalefac_compress % 3;
+ slen[2] = 0;
+ slen[3] = 0;
+
+ nsfb = nsfb_table[5][index];
+ }
+
+ n = 0;
+ for (part = 0; part < 4; ++part) {
+ unsigned int max, is_pos;
+
+ max = (1 << slen[part]) - 1;
+
+ for (i = 0; i < nsfb[part]; ++i) {
+ is_pos = mad_bit_read(ptr, slen[part]);
+
+ channel->scalefac[n] = is_pos;
+ gr1ch->scalefac[n++] = (is_pos == max);
+ }
+ }
+
+ while (n < 39) {
+ channel->scalefac[n] = 0;
+ gr1ch->scalefac[n++] = 0; /* apparently not illegal */
+ }
+ }
+
+ return mad_bit_length(&start, ptr);
+}
+
+/*
+ * NAME: III_scalefactors()
+ * DESCRIPTION: decode channel scalefactors of one granule from a bitstream
+ */
+static
+unsigned int III_scalefactors(struct mad_bitptr *ptr, struct channel *channel,
+ struct channel const *gr0ch, unsigned int scfsi)
+{
+ struct mad_bitptr start;
+ unsigned int slen1, slen2, sfbi;
+
+ start = *ptr;
+
+ slen1 = sflen_table[channel->scalefac_compress].slen1;
+ slen2 = sflen_table[channel->scalefac_compress].slen2;
+
+ if (channel->block_type == 2) {
+ unsigned int nsfb;
+
+ sfbi = 0;
+
+ nsfb = (channel->flags & mixed_block_flag) ? 8 + 3 * 3 : 6 * 3;
+ while (nsfb--)
+ channel->scalefac[sfbi++] = mad_bit_read(ptr, slen1);
+
+ nsfb = 6 * 3;
+ while (nsfb--)
+ channel->scalefac[sfbi++] = mad_bit_read(ptr, slen2);
+
+ nsfb = 1 * 3;
+ while (nsfb--)
+ channel->scalefac[sfbi++] = 0;
+ }
+ else { /* channel->block_type != 2 */
+ if (scfsi & 0x8) {
+ for (sfbi = 0; sfbi < 6; ++sfbi)
+ channel->scalefac[sfbi] = gr0ch->scalefac[sfbi];
+ }
+ else {
+ for (sfbi = 0; sfbi < 6; ++sfbi)
+ channel->scalefac[sfbi] = mad_bit_read(ptr, slen1);
+ }
+
+ if (scfsi & 0x4) {
+ for (sfbi = 6; sfbi < 11; ++sfbi)
+ channel->scalefac[sfbi] = gr0ch->scalefac[sfbi];
+ }
+ else {
+ for (sfbi = 6; sfbi < 11; ++sfbi)
+ channel->scalefac[sfbi] = mad_bit_read(ptr, slen1);
+ }
+
+ if (scfsi & 0x2) {
+ for (sfbi = 11; sfbi < 16; ++sfbi)
+ channel->scalefac[sfbi] = gr0ch->scalefac[sfbi];
+ }
+ else {
+ for (sfbi = 11; sfbi < 16; ++sfbi)
+ channel->scalefac[sfbi] = mad_bit_read(ptr, slen2);
+ }
+
+ if (scfsi & 0x1) {
+ for (sfbi = 16; sfbi < 21; ++sfbi)
+ channel->scalefac[sfbi] = gr0ch->scalefac[sfbi];
+ }
+ else {
+ for (sfbi = 16; sfbi < 21; ++sfbi)
+ channel->scalefac[sfbi] = mad_bit_read(ptr, slen2);
+ }
+
+ channel->scalefac[21] = 0;
+ }
+
+ return mad_bit_length(&start, ptr);
+}
+
+/*
+ * The Layer III formula for requantization and scaling is defined by
+ * section 2.4.3.4.7.1 of ISO/IEC 11172-3, as follows:
+ *
+ * long blocks:
+ * xr[i] = sign(is[i]) * abs(is[i])^(4/3) *
+ * 2^((1/4) * (global_gain - 210)) *
+ * 2^-(scalefac_multiplier *
+ * (scalefac_l[sfb] + preflag * pretab[sfb]))
+ *
+ * short blocks:
+ * xr[i] = sign(is[i]) * abs(is[i])^(4/3) *
+ * 2^((1/4) * (global_gain - 210 - 8 * subblock_gain[w])) *
+ * 2^-(scalefac_multiplier * scalefac_s[sfb][w])
+ *
+ * where:
+ * scalefac_multiplier = (scalefac_scale + 1) / 2
+ *
+ * The routines III_exponents() and III_requantize() facilitate this
+ * calculation.
+ */
+
+/*
+ * NAME: III_exponents()
+ * DESCRIPTION: calculate scalefactor exponents
+ */
+static
+void III_exponents(struct channel const *channel,
+ unsigned char const *sfbwidth, signed int exponents[39])
+{
+ signed int gain;
+ unsigned int scalefac_multiplier, sfbi;
+
+ gain = (signed int) channel->global_gain - 210;
+ scalefac_multiplier = (channel->flags & scalefac_scale) ? 2 : 1;
+
+ if (channel->block_type == 2) {
+ unsigned int l;
+ signed int gain0, gain1, gain2;
+
+ sfbi = l = 0;
+
+ if (channel->flags & mixed_block_flag) {
+ unsigned int premask;
+
+ premask = (channel->flags & preflag) ? ~0 : 0;
+
+ /* long block subbands 0-1 */
+
+ while (l < 36) {
+ exponents[sfbi] = gain -
+ (signed int) ((channel->scalefac[sfbi] + (pretab[sfbi] & premask)) <<
+ scalefac_multiplier);
+
+ l += sfbwidth[sfbi++];
+ }
+ }
+
+ /* this is probably wrong for 8000 Hz short/mixed blocks */
+
+ gain0 = gain - 8 * (signed int) channel->subblock_gain[0];
+ gain1 = gain - 8 * (signed int) channel->subblock_gain[1];
+ gain2 = gain - 8 * (signed int) channel->subblock_gain[2];
+
+ while (l < 576) {
+ exponents[sfbi + 0] = gain0 -
+ (signed int) (channel->scalefac[sfbi + 0] << scalefac_multiplier);
+ exponents[sfbi + 1] = gain1 -
+ (signed int) (channel->scalefac[sfbi + 1] << scalefac_multiplier);
+ exponents[sfbi + 2] = gain2 -
+ (signed int) (channel->scalefac[sfbi + 2] << scalefac_multiplier);
+
+ l += 3 * sfbwidth[sfbi];
+ sfbi += 3;
+ }
+ }
+ else { /* channel->block_type != 2 */
+ if (channel->flags & preflag) {
+ for (sfbi = 0; sfbi < 22; ++sfbi) {
+ exponents[sfbi] = gain -
+ (signed int) ((channel->scalefac[sfbi] + pretab[sfbi]) <<
+ scalefac_multiplier);
+ }
+ }
+ else {
+ for (sfbi = 0; sfbi < 22; ++sfbi) {
+ exponents[sfbi] = gain -
+ (signed int) (channel->scalefac[sfbi] << scalefac_multiplier);
+ }
+ }
+ }
+}
+
+/*
+ * NAME: III_requantize()
+ * DESCRIPTION: requantize one (positive) value
+ */
+static
+mad_fixed_t III_requantize(unsigned int value, signed int exp)
+{
+ mad_fixed_t requantized;
+ signed int frac;
+ struct fixedfloat const *power;
+
+ frac = exp % 4; /* assumes sign(frac) == sign(exp) */
+ exp /= 4;
+
+ power = &rq_table[value];
+ requantized = power->mantissa;
+ exp += power->exponent;
+
+ if (exp < 0) {
+ if (-exp >= sizeof(mad_fixed_t) * CHAR_BIT) {
+ /* underflow */
+ requantized = 0;
+ }
+ else {
+ requantized += 1L << (-exp - 1);
+ requantized >>= -exp;
+ }
+ }
+ else {
+ if (exp >= 5) {
+ /* overflow */
+# if defined(DEBUG)
+ fprintf(stderr, "requantize overflow (%f * 2^%d)\n",
+ mad_f_todouble(requantized), exp);
+# endif
+ requantized = MAD_F_MAX;
+ }
+ else
+ requantized <<= exp;
+ }
+
+ return frac ? mad_f_mul(requantized, root_table[3 + frac]) : requantized;
+}
+
+/* we must take care that sz >= bits and sz < sizeof(long) lest bits == 0 */
+# define MASK(cache, sz, bits) \
+ (((cache) >> ((sz) - (bits))) & ((1 << (bits)) - 1))
+# define MASK1BIT(cache, sz) \
+ ((cache) & (1 << ((sz) - 1)))
+
+/*
+ * NAME: III_huffdecode()
+ * DESCRIPTION: decode Huffman code words of one channel of one granule
+ */
+static
+enum mad_error III_huffdecode(struct mad_bitptr *ptr, mad_fixed_t xr[576],
+ struct channel *channel,
+ unsigned char const *sfbwidth,
+ unsigned int part2_length)
+{
+ signed int exponents[39], exp;
+ signed int const *expptr;
+ struct mad_bitptr peek;
+ signed int bits_left, cachesz;
+ register mad_fixed_t *xrptr;
+ mad_fixed_t const *sfbound;
+ register unsigned long bitcache;
+
+ bits_left = (signed) channel->part2_3_length - (signed) part2_length;
+ if (bits_left < 0)
+ return MAD_ERROR_BADPART3LEN;
+
+ III_exponents(channel, sfbwidth, exponents);
+
+ peek = *ptr;
+ mad_bit_skip(ptr, bits_left);
+
+ /* align bit reads to byte boundaries */
+ cachesz = mad_bit_bitsleft(&peek);
+ cachesz += ((32 - 1 - 24) + (24 - cachesz)) & ~7;
+
+ bitcache = mad_bit_read(&peek, cachesz);
+ bits_left -= cachesz;
+
+ xrptr = &xr[0];
+
+ /* big_values */
+ {
+ unsigned int region, rcount;
+ struct hufftable const *entry;
+ union huffpair const *table;
+ unsigned int linbits, startbits, big_values, reqhits;
+ mad_fixed_t reqcache[16];
+
+ sfbound = xrptr + *sfbwidth++;
+ rcount = channel->region0_count + 1;
+
+ entry = &mad_huff_pair_table[channel->table_select[region = 0]];
+ table = entry->table;
+ linbits = entry->linbits;
+ startbits = entry->startbits;
+
+ if (table == 0)
+ return MAD_ERROR_BADHUFFTABLE;
+
+ expptr = &exponents[0];
+ exp = *expptr++;
+ reqhits = 0;
+
+ big_values = channel->big_values;
+
+ while (big_values-- && cachesz + bits_left > 0) {
+ union huffpair const *pair;
+ unsigned int clumpsz, value;
+ register mad_fixed_t requantized;
+
+ if (xrptr == sfbound) {
+ sfbound += *sfbwidth++;
+
+ /* change table if region boundary */
+
+ if (--rcount == 0) {
+ if (region == 0)
+ rcount = channel->region1_count + 1;
+ else
+ rcount = 0; /* all remaining */
+
+ entry = &mad_huff_pair_table[channel->table_select[++region]];
+ table = entry->table;
+ linbits = entry->linbits;
+ startbits = entry->startbits;
+
+ if (table == 0)
+ return MAD_ERROR_BADHUFFTABLE;
+ }
+
+ if (exp != *expptr) {
+ exp = *expptr;
+ reqhits = 0;
+ }
+
+ ++expptr;
+ }
+
+ if (cachesz < 21) {
+ unsigned int bits;
+
+ bits = ((32 - 1 - 21) + (21 - cachesz)) & ~7;
+ bitcache = (bitcache << bits) | mad_bit_read(&peek, bits);
+ cachesz += bits;
+ bits_left -= bits;
+ }
+
+ /* hcod (0..19) */
+
+ clumpsz = startbits;
+ pair = &table[MASK(bitcache, cachesz, clumpsz)];
+
+ while (!pair->final) {
+ cachesz -= clumpsz;
+
+ clumpsz = pair->ptr.bits;
+ pair = &table[pair->ptr.offset + MASK(bitcache, cachesz, clumpsz)];
+ }
+
+ cachesz -= pair->value.hlen;
+
+ if (linbits) {
+ /* x (0..14) */
+
+ value = pair->value.x;
+
+ switch (value) {
+ case 0:
+ xrptr[0] = 0;
+ break;
+
+ case 15:
+ if (cachesz < linbits + 2) {
+ bitcache = (bitcache << 16) | mad_bit_read(&peek, 16);
+ cachesz += 16;
+ bits_left -= 16;
+ }
+
+ value += MASK(bitcache, cachesz, linbits);
+ cachesz -= linbits;
+
+ requantized = III_requantize(value, exp);
+ goto x_final;
+
+ default:
+ if (reqhits & (1 << value))
+ requantized = reqcache[value];
+ else {
+ reqhits |= (1 << value);
+ requantized = reqcache[value] = III_requantize(value, exp);
+ }
+
+ x_final:
+ xrptr[0] = MASK1BIT(bitcache, cachesz--) ?
+ -requantized : requantized;
+ }
+
+ /* y (0..14) */
+
+ value = pair->value.y;
+
+ switch (value) {
+ case 0:
+ xrptr[1] = 0;
+ break;
+
+ case 15:
+ if (cachesz < linbits + 1) {
+ bitcache = (bitcache << 16) | mad_bit_read(&peek, 16);
+ cachesz += 16;
+ bits_left -= 16;
+ }
+
+ value += MASK(bitcache, cachesz, linbits);
+ cachesz -= linbits;
+
+ requantized = III_requantize(value, exp);
+ goto y_final;
+
+ default:
+ if (reqhits & (1 << value))
+ requantized = reqcache[value];
+ else {
+ reqhits |= (1 << value);
+ requantized = reqcache[value] = III_requantize(value, exp);
+ }
+
+ y_final:
+ xrptr[1] = MASK1BIT(bitcache, cachesz--) ?
+ -requantized : requantized;
+ }
+ }
+ else {
+ /* x (0..1) */
+
+ value = pair->value.x;
+
+ if (value == 0)
+ xrptr[0] = 0;
+ else {
+ if (reqhits & (1 << value))
+ requantized = reqcache[value];
+ else {
+ reqhits |= (1 << value);
+ requantized = reqcache[value] = III_requantize(value, exp);
+ }
+
+ xrptr[0] = MASK1BIT(bitcache, cachesz--) ?
+ -requantized : requantized;
+ }
+
+ /* y (0..1) */
+
+ value = pair->value.y;
+
+ if (value == 0)
+ xrptr[1] = 0;
+ else {
+ if (reqhits & (1 << value))
+ requantized = reqcache[value];
+ else {
+ reqhits |= (1 << value);
+ requantized = reqcache[value] = III_requantize(value, exp);
+ }
+
+ xrptr[1] = MASK1BIT(bitcache, cachesz--) ?
+ -requantized : requantized;
+ }
+ }
+
+ xrptr += 2;
+ }
+ }
+
+ if (cachesz + bits_left < 0)
+ return MAD_ERROR_BADHUFFDATA; /* big_values overrun */
+
+ /* count1 */
+ {
+ union huffquad const *table;
+ register mad_fixed_t requantized;
+
+ table = mad_huff_quad_table[channel->flags & count1table_select];
+
+ requantized = III_requantize(1, exp);
+
+ while (cachesz + bits_left > 0 && xrptr <= &xr[572]) {
+ union huffquad const *quad;
+
+ /* hcod (1..6) */
+
+ if (cachesz < 10) {
+ bitcache = (bitcache << 16) | mad_bit_read(&peek, 16);
+ cachesz += 16;
+ bits_left -= 16;
+ }
+
+ quad = &table[MASK(bitcache, cachesz, 4)];
+
+ /* quad tables guaranteed to have at most one extra lookup */
+ if (!quad->final) {
+ cachesz -= 4;
+
+ quad = &table[quad->ptr.offset +
+ MASK(bitcache, cachesz, quad->ptr.bits)];
+ }
+
+ cachesz -= quad->value.hlen;
+
+ if (xrptr == sfbound) {
+ sfbound += *sfbwidth++;
+
+ if (exp != *expptr) {
+ exp = *expptr;
+ requantized = III_requantize(1, exp);
+ }
+
+ ++expptr;
+ }
+
+ /* v (0..1) */
+
+ xrptr[0] = quad->value.v ?
+ (MASK1BIT(bitcache, cachesz--) ? -requantized : requantized) : 0;
+
+ /* w (0..1) */
+
+ xrptr[1] = quad->value.w ?
+ (MASK1BIT(bitcache, cachesz--) ? -requantized : requantized) : 0;
+
+ xrptr += 2;
+
+ if (xrptr == sfbound) {
+ sfbound += *sfbwidth++;
+
+ if (exp != *expptr) {
+ exp = *expptr;
+ requantized = III_requantize(1, exp);
+ }
+
+ ++expptr;
+ }
+
+ /* x (0..1) */
+
+ xrptr[0] = quad->value.x ?
+ (MASK1BIT(bitcache, cachesz--) ? -requantized : requantized) : 0;
+
+ /* y (0..1) */
+
+ xrptr[1] = quad->value.y ?
+ (MASK1BIT(bitcache, cachesz--) ? -requantized : requantized) : 0;
+
+ xrptr += 2;
+ }
+
+ if (cachesz + bits_left < 0) {
+# if 0 && defined(DEBUG)
+ fprintf(stderr, "huffman count1 overrun (%d bits)\n",
+ -(cachesz + bits_left));
+# endif
+
+ /* technically the bitstream is misformatted, but apparently
+ some encoders are just a bit sloppy with stuffing bits */
+
+ xrptr -= 4;
+ }
+ }
+
+ assert(-bits_left <= MAD_BUFFER_GUARD * CHAR_BIT);
+
+# if 0 && defined(DEBUG)
+ if (bits_left < 0)
+ fprintf(stderr, "read %d bits too many\n", -bits_left);
+ else if (cachesz + bits_left > 0)
+ fprintf(stderr, "%d stuffing bits\n", cachesz + bits_left);
+# endif
+
+ /* rzero */
+ while (xrptr < &xr[576]) {
+ xrptr[0] = 0;
+ xrptr[1] = 0;
+
+ xrptr += 2;
+ }
+
+ return MAD_ERROR_NONE;
+}
+
+# undef MASK
+# undef MASK1BIT
+
+/*
+ * NAME: III_reorder()
+ * DESCRIPTION: reorder frequency lines of a short block into subband order
+ */
+static
+void III_reorder(mad_fixed_t xr[576], struct channel const *channel,
+ unsigned char const sfbwidth[39])
+{
+ mad_fixed_t tmp[32][3][6];
+ unsigned int sb, l, f, w, sbw[3], sw[3];
+
+ /* this is probably wrong for 8000 Hz mixed blocks */
+
+ sb = 0;
+ if (channel->flags & mixed_block_flag) {
+ sb = 2;
+
+ l = 0;
+ while (l < 36)
+ l += *sfbwidth++;
+ }
+
+ for (w = 0; w < 3; ++w) {
+ sbw[w] = sb;
+ sw[w] = 0;
+ }
+
+ f = *sfbwidth++;
+ w = 0;
+
+ for (l = 18 * sb; l < 576; ++l) {
+ if (f-- == 0) {
+ f = *sfbwidth++ - 1;
+ w = (w + 1) % 3;
+ }
+
+ tmp[sbw[w]][w][sw[w]++] = xr[l];
+
+ if (sw[w] == 6) {
+ sw[w] = 0;
+ ++sbw[w];
+ }
+ }
+
+ memcpy(&xr[18 * sb], &tmp[sb], (576 - 18 * sb) * sizeof(mad_fixed_t));
+}
+
+/*
+ * NAME: III_stereo()
+ * DESCRIPTION: perform joint stereo processing on a granule
+ */
+static
+enum mad_error III_stereo(mad_fixed_t xr[2][576],
+ struct granule const *granule,
+ struct mad_header *header,
+ unsigned char const *sfbwidth)
+{
+ short modes[39];
+ unsigned int sfbi, l, n, i;
+
+ if (granule->ch[0].block_type !=
+ granule->ch[1].block_type ||
+ (granule->ch[0].flags & mixed_block_flag) !=
+ (granule->ch[1].flags & mixed_block_flag))
+ return MAD_ERROR_BADSTEREO;
+
+ for (i = 0; i < 39; ++i)
+ modes[i] = header->mode_extension;
+
+ /* intensity stereo */
+
+ if (header->mode_extension & I_STEREO) {
+ struct channel const *right_ch = &granule->ch[1];
+ mad_fixed_t const *right_xr = xr[1];
+ unsigned int is_pos;
+
+ header->flags |= MAD_FLAG_I_STEREO;
+
+ /* first determine which scalefactor bands are to be processed */
+
+ if (right_ch->block_type == 2) {
+ unsigned int lower, start, max, bound[3], w;
+
+ lower = start = max = bound[0] = bound[1] = bound[2] = 0;
+
+ sfbi = l = 0;
+
+ if (right_ch->flags & mixed_block_flag) {
+ while (l < 36) {
+ n = sfbwidth[sfbi++];
+
+ for (i = 0; i < n; ++i) {
+ if (right_xr[i]) {
+ lower = sfbi;
+ break;
+ }
+ }
+
+ right_xr += n;
+ l += n;
+ }
+
+ start = sfbi;
+ }
+
+ w = 0;
+ while (l < 576) {
+ n = sfbwidth[sfbi++];
+
+ for (i = 0; i < n; ++i) {
+ if (right_xr[i]) {
+ max = bound[w] = sfbi;
+ break;
+ }
+ }
+
+ right_xr += n;
+ l += n;
+ w = (w + 1) % 3;
+ }
+
+ if (max)
+ lower = start;
+
+ /* long blocks */
+
+ for (i = 0; i < lower; ++i)
+ modes[i] = header->mode_extension & ~I_STEREO;
+
+ /* short blocks */
+
+ w = 0;
+ for (i = start; i < max; ++i) {
+ if (i < bound[w])
+ modes[i] = header->mode_extension & ~I_STEREO;
+
+ w = (w + 1) % 3;
+ }
+ }
+ else { /* right_ch->block_type != 2 */
+ unsigned int bound;
+
+ bound = 0;
+ for (sfbi = l = 0; l < 576; l += n) {
+ n = sfbwidth[sfbi++];
+
+ for (i = 0; i < n; ++i) {
+ if (right_xr[i]) {
+ bound = sfbi;
+ break;
+ }
+ }
+
+ right_xr += n;
+ }
+
+ for (i = 0; i < bound; ++i)
+ modes[i] = header->mode_extension & ~I_STEREO;
+ }
+
+ /* now do the actual processing */
+
+ if (header->flags & MAD_FLAG_LSF_EXT) {
+ unsigned char const *illegal_pos = granule[1].ch[1].scalefac;
+ mad_fixed_t const *lsf_scale;
+
+ /* intensity_scale */
+ lsf_scale = is_lsf_table[right_ch->scalefac_compress & 0x1];
+
+ for (sfbi = l = 0; l < 576; ++sfbi, l += n) {
+ n = sfbwidth[sfbi];
+
+ if (!(modes[sfbi] & I_STEREO))
+ continue;
+
+ if (illegal_pos[sfbi]) {
+ modes[sfbi] &= ~I_STEREO;
+ continue;
+ }
+
+ is_pos = right_ch->scalefac[sfbi];
+
+ for (i = 0; i < n; ++i) {
+ register mad_fixed_t left;
+
+ left = xr[0][l + i];
+
+ if (is_pos == 0)
+ xr[1][l + i] = left;
+ else {
+ register mad_fixed_t opposite;
+
+ opposite = mad_f_mul(left, lsf_scale[(is_pos - 1) / 2]);
+
+ if (is_pos & 1) {
+ xr[0][l + i] = opposite;
+ xr[1][l + i] = left;
+ }
+ else
+ xr[1][l + i] = opposite;
+ }
+ }
+ }
+ }
+ else { /* !(header->flags & MAD_FLAG_LSF_EXT) */
+ for (sfbi = l = 0; l < 576; ++sfbi, l += n) {
+ n = sfbwidth[sfbi];
+
+ if (!(modes[sfbi] & I_STEREO))
+ continue;
+
+ is_pos = right_ch->scalefac[sfbi];
+
+ if (is_pos >= 7) { /* illegal intensity position */
+ modes[sfbi] &= ~I_STEREO;
+ continue;
+ }
+
+ for (i = 0; i < n; ++i) {
+ register mad_fixed_t left;
+
+ left = xr[0][l + i];
+
+ xr[0][l + i] = mad_f_mul(left, is_table[ is_pos]);
+ xr[1][l + i] = mad_f_mul(left, is_table[6 - is_pos]);
+ }
+ }
+ }
+ }
+
+ /* middle/side stereo */
+
+ if (header->mode_extension & MS_STEREO) {
+ register mad_fixed_t invsqrt2;
+
+ header->flags |= MAD_FLAG_MS_STEREO;
+
+ invsqrt2 = root_table[3 + -2];
+
+ for (sfbi = l = 0; l < 576; ++sfbi, l += n) {
+ n = sfbwidth[sfbi];
+
+ if (modes[sfbi] != MS_STEREO)
+ continue;
+
+ for (i = 0; i < n; ++i) {
+ register mad_fixed_t m, s;
+
+ m = xr[0][l + i];
+ s = xr[1][l + i];
+
+ xr[0][l + i] = mad_f_mul(m + s, invsqrt2); /* l = (m + s) / sqrt(2) */
+ xr[1][l + i] = mad_f_mul(m - s, invsqrt2); /* r = (m - s) / sqrt(2) */
+ }
+ }
+ }
+
+ return MAD_ERROR_NONE;
+}
+
+/*
+ * NAME: III_aliasreduce()
+ * DESCRIPTION: perform frequency line alias reduction
+ */
+static
+void III_aliasreduce(mad_fixed_t xr[576], int lines)
+{
+ mad_fixed_t const *bound;
+ int i;
+
+ bound = &xr[lines];
+ for (xr += 18; xr < bound; xr += 18) {
+ for (i = 0; i < 8; ++i) {
+ register mad_fixed_t a, b;
+ register mad_fixed64hi_t hi;
+ register mad_fixed64lo_t lo;
+
+ a = xr[-1 - i];
+ b = xr[ i];
+
+# if defined(ASO_ZEROCHECK)
+ if (a | b) {
+# endif
+ MAD_F_ML0(hi, lo, a, cs[i]);
+ MAD_F_MLA(hi, lo, -b, ca[i]);
+
+ xr[-1 - i] = MAD_F_MLZ(hi, lo);
+
+ MAD_F_ML0(hi, lo, b, cs[i]);
+ MAD_F_MLA(hi, lo, a, ca[i]);
+
+ xr[ i] = MAD_F_MLZ(hi, lo);
+# if defined(ASO_ZEROCHECK)
+ }
+# endif
+ }
+ }
+}
+
+# if defined(ASO_IMDCT)
+void III_imdct_l(mad_fixed_t const [18], mad_fixed_t [36], unsigned int);
+# else
+# if 1
+static
+void fastsdct(mad_fixed_t const x[9], mad_fixed_t y[18])
+{
+ mad_fixed_t a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12;
+ mad_fixed_t a13, a14, a15, a16, a17, a18, a19, a20, a21, a22, a23, a24, a25;
+ mad_fixed_t m0, m1, m2, m3, m4, m5, m6, m7;
+
+ enum {
+ c0 = MAD_F(0x1f838b8d), /* 2 * cos( 1 * PI / 18) */
+ c1 = MAD_F(0x1bb67ae8), /* 2 * cos( 3 * PI / 18) */
+ c2 = MAD_F(0x18836fa3), /* 2 * cos( 4 * PI / 18) */
+ c3 = MAD_F(0x1491b752), /* 2 * cos( 5 * PI / 18) */
+ c4 = MAD_F(0x0af1d43a), /* 2 * cos( 7 * PI / 18) */
+ c5 = MAD_F(0x058e86a0), /* 2 * cos( 8 * PI / 18) */
+ c6 = -MAD_F(0x1e11f642) /* 2 * cos(16 * PI / 18) */
+ };
+
+ a0 = x[3] + x[5];
+ a1 = x[3] - x[5];
+ a2 = x[6] + x[2];
+ a3 = x[6] - x[2];
+ a4 = x[1] + x[7];
+ a5 = x[1] - x[7];
+ a6 = x[8] + x[0];
+ a7 = x[8] - x[0];
+
+ a8 = a0 + a2;
+ a9 = a0 - a2;
+ a10 = a0 - a6;
+ a11 = a2 - a6;
+ a12 = a8 + a6;
+ a13 = a1 - a3;
+ a14 = a13 + a7;
+ a15 = a3 + a7;
+ a16 = a1 - a7;
+ a17 = a1 + a3;
+
+ m0 = mad_f_mul(a17, -c3);
+ m1 = mad_f_mul(a16, -c0);
+ m2 = mad_f_mul(a15, -c4);
+ m3 = mad_f_mul(a14, -c1);
+ m4 = mad_f_mul(a5, -c1);
+ m5 = mad_f_mul(a11, -c6);
+ m6 = mad_f_mul(a10, -c5);
+ m7 = mad_f_mul(a9, -c2);
+
+ a18 = x[4] + a4;
+ a19 = 2 * x[4] - a4;
+ a20 = a19 + m5;
+ a21 = a19 - m5;
+ a22 = a19 + m6;
+ a23 = m4 + m2;
+ a24 = m4 - m2;
+ a25 = m4 + m1;
+
+ /* output to every other slot for convenience */
+
+ y[ 0] = a18 + a12;
+ y[ 2] = m0 - a25;
+ y[ 4] = m7 - a20;
+ y[ 6] = m3;
+ y[ 8] = a21 - m6;
+ y[10] = a24 - m1;
+ y[12] = a12 - 2 * a18;
+ y[14] = a23 + m0;
+ y[16] = a22 + m7;
+}
+
+static inline
+void sdctII(mad_fixed_t const x[18], mad_fixed_t X[18])
+{
+ mad_fixed_t tmp[9];
+ int i;
+
+ /* scale[i] = 2 * cos(PI * (2 * i + 1) / (2 * 18)) */
+ static mad_fixed_t const scale[9] = {
+ MAD_F(0x1fe0d3b4), MAD_F(0x1ee8dd47), MAD_F(0x1d007930),
+ MAD_F(0x1a367e59), MAD_F(0x16a09e66), MAD_F(0x125abcf8),
+ MAD_F(0x0d8616bc), MAD_F(0x08483ee1), MAD_F(0x02c9fad7)
+ };
+
+ /* divide the 18-point SDCT-II into two 9-point SDCT-IIs */
+
+ /* even input butterfly */
+
+ for (i = 0; i < 9; i += 3) {
+ tmp[i + 0] = x[i + 0] + x[18 - (i + 0) - 1];
+ tmp[i + 1] = x[i + 1] + x[18 - (i + 1) - 1];
+ tmp[i + 2] = x[i + 2] + x[18 - (i + 2) - 1];
+ }
+
+ fastsdct(tmp, &X[0]);
+
+ /* odd input butterfly and scaling */
+
+ for (i = 0; i < 9; i += 3) {
+ tmp[i + 0] = mad_f_mul(x[i + 0] - x[18 - (i + 0) - 1], scale[i + 0]);
+ tmp[i + 1] = mad_f_mul(x[i + 1] - x[18 - (i + 1) - 1], scale[i + 1]);
+ tmp[i + 2] = mad_f_mul(x[i + 2] - x[18 - (i + 2) - 1], scale[i + 2]);
+ }
+
+ fastsdct(tmp, &X[1]);
+
+ /* output accumulation */
+
+ for (i = 3; i < 18; i += 8) {
+ X[i + 0] -= X[(i + 0) - 2];
+ X[i + 2] -= X[(i + 2) - 2];
+ X[i + 4] -= X[(i + 4) - 2];
+ X[i + 6] -= X[(i + 6) - 2];
+ }
+}
+
+static inline
+void dctIV(mad_fixed_t const y[18], mad_fixed_t X[18])
+{
+ mad_fixed_t tmp[18];
+ int i;
+
+ /* scale[i] = 2 * cos(PI * (2 * i + 1) / (4 * 18)) */
+ static mad_fixed_t const scale[18] = {
+ MAD_F(0x1ff833fa), MAD_F(0x1fb9ea93), MAD_F(0x1f3dd120),
+ MAD_F(0x1e84d969), MAD_F(0x1d906bcf), MAD_F(0x1c62648b),
+ MAD_F(0x1afd100f), MAD_F(0x1963268b), MAD_F(0x1797c6a4),
+ MAD_F(0x159e6f5b), MAD_F(0x137af940), MAD_F(0x11318ef3),
+ MAD_F(0x0ec6a507), MAD_F(0x0c3ef153), MAD_F(0x099f61c5),
+ MAD_F(0x06ed12c5), MAD_F(0x042d4544), MAD_F(0x0165547c)
+ };
+
+ /* scaling */
+
+ for (i = 0; i < 18; i += 3) {
+ tmp[i + 0] = mad_f_mul(y[i + 0], scale[i + 0]);
+ tmp[i + 1] = mad_f_mul(y[i + 1], scale[i + 1]);
+ tmp[i + 2] = mad_f_mul(y[i + 2], scale[i + 2]);
+ }
+
+ /* SDCT-II */
+
+ sdctII(tmp, X);
+
+ /* scale reduction and output accumulation */
+
+ X[0] /= 2;
+ for (i = 1; i < 17; i += 4) {
+ X[i + 0] = X[i + 0] / 2 - X[(i + 0) - 1];
+ X[i + 1] = X[i + 1] / 2 - X[(i + 1) - 1];
+ X[i + 2] = X[i + 2] / 2 - X[(i + 2) - 1];
+ X[i + 3] = X[i + 3] / 2 - X[(i + 3) - 1];
+ }
+ X[17] = X[17] / 2 - X[16];
+}
+
+/*
+ * NAME: imdct36
+ * DESCRIPTION: perform X[18]->x[36] IMDCT using Szu-Wei Lee's fast algorithm
+ */
+static inline
+void imdct36(mad_fixed_t const x[18], mad_fixed_t y[36])
+{
+ mad_fixed_t tmp[18];
+ int i;
+
+ /* DCT-IV */
+
+ dctIV(x, tmp);
+
+ /* convert 18-point DCT-IV to 36-point IMDCT */
+
+ for (i = 0; i < 9; i += 3) {
+ y[i + 0] = tmp[9 + (i + 0)];
+ y[i + 1] = tmp[9 + (i + 1)];
+ y[i + 2] = tmp[9 + (i + 2)];
+ }
+ for (i = 9; i < 27; i += 3) {
+ y[i + 0] = -tmp[36 - (9 + (i + 0)) - 1];
+ y[i + 1] = -tmp[36 - (9 + (i + 1)) - 1];
+ y[i + 2] = -tmp[36 - (9 + (i + 2)) - 1];
+ }
+ for (i = 27; i < 36; i += 3) {
+ y[i + 0] = -tmp[(i + 0) - 27];
+ y[i + 1] = -tmp[(i + 1) - 27];
+ y[i + 2] = -tmp[(i + 2) - 27];
+ }
+}
+# else
+/*
+ * NAME: imdct36
+ * DESCRIPTION: perform X[18]->x[36] IMDCT
+ */
+static inline
+void imdct36(mad_fixed_t const X[18], mad_fixed_t x[36])
+{
+ mad_fixed_t t0, t1, t2, t3, t4, t5, t6, t7;
+ mad_fixed_t t8, t9, t10, t11, t12, t13, t14, t15;
+ register mad_fixed64hi_t hi;
+ register mad_fixed64lo_t lo;
+
+ MAD_F_ML0(hi, lo, X[4], MAD_F(0x0ec835e8));
+ MAD_F_MLA(hi, lo, X[13], MAD_F(0x061f78aa));
+
+ t6 = MAD_F_MLZ(hi, lo);
+
+ MAD_F_MLA(hi, lo, (t14 = X[1] - X[10]), -MAD_F(0x061f78aa));
+ MAD_F_MLA(hi, lo, (t15 = X[7] + X[16]), -MAD_F(0x0ec835e8));
+
+ t0 = MAD_F_MLZ(hi, lo);
+
+ MAD_F_MLA(hi, lo, (t8 = X[0] - X[11] - X[12]), MAD_F(0x0216a2a2));
+ MAD_F_MLA(hi, lo, (t9 = X[2] - X[9] - X[14]), MAD_F(0x09bd7ca0));
+ MAD_F_MLA(hi, lo, (t10 = X[3] - X[8] - X[15]), -MAD_F(0x0cb19346));
+ MAD_F_MLA(hi, lo, (t11 = X[5] - X[6] - X[17]), -MAD_F(0x0fdcf549));
+
+ x[7] = MAD_F_MLZ(hi, lo);
+ x[10] = -x[7];
+
+ MAD_F_ML0(hi, lo, t8, -MAD_F(0x0cb19346));
+ MAD_F_MLA(hi, lo, t9, MAD_F(0x0fdcf549));
+ MAD_F_MLA(hi, lo, t10, MAD_F(0x0216a2a2));
+ MAD_F_MLA(hi, lo, t11, -MAD_F(0x09bd7ca0));
+
+ x[19] = x[34] = MAD_F_MLZ(hi, lo) - t0;
+
+ t12 = X[0] - X[3] + X[8] - X[11] - X[12] + X[15];
+ t13 = X[2] + X[5] - X[6] - X[9] - X[14] - X[17];
+
+ MAD_F_ML0(hi, lo, t12, -MAD_F(0x0ec835e8));
+ MAD_F_MLA(hi, lo, t13, MAD_F(0x061f78aa));
+
+ x[22] = x[31] = MAD_F_MLZ(hi, lo) + t0;
+
+ MAD_F_ML0(hi, lo, X[1], -MAD_F(0x09bd7ca0));
+ MAD_F_MLA(hi, lo, X[7], MAD_F(0x0216a2a2));
+ MAD_F_MLA(hi, lo, X[10], -MAD_F(0x0fdcf549));
+ MAD_F_MLA(hi, lo, X[16], MAD_F(0x0cb19346));
+
+ t1 = MAD_F_MLZ(hi, lo) + t6;
+
+ MAD_F_ML0(hi, lo, X[0], MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[2], MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[3], -MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[6], MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[8], -MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[9], MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[11], MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[14], MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[15], -MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0f9ee890));
+
+ x[6] = MAD_F_MLZ(hi, lo) + t1;
+ x[11] = -x[6];
+
+ MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[2], -MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[3], MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[5], MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[6], MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[8], -MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[9], -MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[12], -MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[14], MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[15], MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[17], MAD_F(0x04cfb0e2));
+
+ x[23] = x[30] = MAD_F_MLZ(hi, lo) + t1;
+
+ MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[2], MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[3], -MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[5], MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[6], MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[8], -MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[9], -MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[11], MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[14], MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[15], MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0acf37ad));
+
+ x[18] = x[35] = MAD_F_MLZ(hi, lo) - t1;
+
+ MAD_F_ML0(hi, lo, X[4], MAD_F(0x061f78aa));
+ MAD_F_MLA(hi, lo, X[13], -MAD_F(0x0ec835e8));
+
+ t7 = MAD_F_MLZ(hi, lo);
+
+ MAD_F_MLA(hi, lo, X[1], -MAD_F(0x0cb19346));
+ MAD_F_MLA(hi, lo, X[7], MAD_F(0x0fdcf549));
+ MAD_F_MLA(hi, lo, X[10], MAD_F(0x0216a2a2));
+ MAD_F_MLA(hi, lo, X[16], -MAD_F(0x09bd7ca0));
+
+ t2 = MAD_F_MLZ(hi, lo);
+
+ MAD_F_MLA(hi, lo, X[0], MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[2], MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[3], -MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[5], MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[6], -MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[8], -MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[9], MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[12], MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[14], MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[15], MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[17], MAD_F(0x0f426cb5));
+
+ x[5] = MAD_F_MLZ(hi, lo);
+ x[12] = -x[5];
+
+ MAD_F_ML0(hi, lo, X[0], MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[2], -MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[3], MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[6], -MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[8], MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[9], -MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[11], MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[12], -MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[14], MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[15], MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0bcbe352));
+
+ x[0] = MAD_F_MLZ(hi, lo) + t2;
+ x[17] = -x[0];
+
+ MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[2], -MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[3], -MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[5], MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[6], MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[8], MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[9], MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[11], -MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[14], -MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[15], -MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[17], -MAD_F(0x03768962));
+
+ x[24] = x[29] = MAD_F_MLZ(hi, lo) + t2;
+
+ MAD_F_ML0(hi, lo, X[1], -MAD_F(0x0216a2a2));
+ MAD_F_MLA(hi, lo, X[7], -MAD_F(0x09bd7ca0));
+ MAD_F_MLA(hi, lo, X[10], MAD_F(0x0cb19346));
+ MAD_F_MLA(hi, lo, X[16], MAD_F(0x0fdcf549));
+
+ t3 = MAD_F_MLZ(hi, lo) + t7;
+
+ MAD_F_ML0(hi, lo, X[0], MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[2], MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[3], -MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[5], -MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[6], MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[8], MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[9], -MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[12], MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[14], MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[15], -MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0ffc19fd));
+
+ x[8] = MAD_F_MLZ(hi, lo) + t3;
+ x[9] = -x[8];
+
+ MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[2], MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[3], MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[6], -MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[8], MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[9], MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[11], -MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[14], -MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[15], MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[17], MAD_F(0x07635284));
+
+ x[21] = x[32] = MAD_F_MLZ(hi, lo) + t3;
+
+ MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[2], MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[3], MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[6], -MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[8], MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[9], MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[12], MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[14], MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[15], -MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0898c779));
+
+ x[20] = x[33] = MAD_F_MLZ(hi, lo) - t3;
+
+ MAD_F_ML0(hi, lo, t14, -MAD_F(0x0ec835e8));
+ MAD_F_MLA(hi, lo, t15, MAD_F(0x061f78aa));
+
+ t4 = MAD_F_MLZ(hi, lo) - t7;
+
+ MAD_F_ML0(hi, lo, t12, MAD_F(0x061f78aa));
+ MAD_F_MLA(hi, lo, t13, MAD_F(0x0ec835e8));
+
+ x[4] = MAD_F_MLZ(hi, lo) + t4;
+ x[13] = -x[4];
+
+ MAD_F_ML0(hi, lo, t8, MAD_F(0x09bd7ca0));
+ MAD_F_MLA(hi, lo, t9, -MAD_F(0x0216a2a2));
+ MAD_F_MLA(hi, lo, t10, MAD_F(0x0fdcf549));
+ MAD_F_MLA(hi, lo, t11, -MAD_F(0x0cb19346));
+
+ x[1] = MAD_F_MLZ(hi, lo) + t4;
+ x[16] = -x[1];
+
+ MAD_F_ML0(hi, lo, t8, -MAD_F(0x0fdcf549));
+ MAD_F_MLA(hi, lo, t9, -MAD_F(0x0cb19346));
+ MAD_F_MLA(hi, lo, t10, -MAD_F(0x09bd7ca0));
+ MAD_F_MLA(hi, lo, t11, -MAD_F(0x0216a2a2));
+
+ x[25] = x[28] = MAD_F_MLZ(hi, lo) + t4;
+
+ MAD_F_ML0(hi, lo, X[1], -MAD_F(0x0fdcf549));
+ MAD_F_MLA(hi, lo, X[7], -MAD_F(0x0cb19346));
+ MAD_F_MLA(hi, lo, X[10], -MAD_F(0x09bd7ca0));
+ MAD_F_MLA(hi, lo, X[16], -MAD_F(0x0216a2a2));
+
+ t5 = MAD_F_MLZ(hi, lo) - t6;
+
+ MAD_F_ML0(hi, lo, X[0], MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[2], MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[3], MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[5], MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[6], MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[8], -MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[9], MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[11], -MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[12], MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[14], -MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[15], MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0d7e8807));
+
+ x[2] = MAD_F_MLZ(hi, lo) + t5;
+ x[15] = -x[2];
+
+ MAD_F_ML0(hi, lo, X[0], MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[2], MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[3], MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[5], MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[6], -MAD_F(0x00b2aa3e));
+ MAD_F_MLA(hi, lo, X[8], MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[9], -MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[11], MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[14], MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[15], -MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[17], MAD_F(0x0e313245));
+
+ x[3] = MAD_F_MLZ(hi, lo) + t5;
+ x[14] = -x[3];
+
+ MAD_F_ML0(hi, lo, X[0], -MAD_F(0x0ffc19fd));
+ MAD_F_MLA(hi, lo, X[2], -MAD_F(0x0f9ee890));
+ MAD_F_MLA(hi, lo, X[3], -MAD_F(0x0f426cb5));
+ MAD_F_MLA(hi, lo, X[5], -MAD_F(0x0e313245));
+ MAD_F_MLA(hi, lo, X[6], -MAD_F(0x0d7e8807));
+ MAD_F_MLA(hi, lo, X[8], -MAD_F(0x0bcbe352));
+ MAD_F_MLA(hi, lo, X[9], -MAD_F(0x0acf37ad));
+ MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0898c779));
+ MAD_F_MLA(hi, lo, X[12], -MAD_F(0x07635284));
+ MAD_F_MLA(hi, lo, X[14], -MAD_F(0x04cfb0e2));
+ MAD_F_MLA(hi, lo, X[15], -MAD_F(0x03768962));
+ MAD_F_MLA(hi, lo, X[17], -MAD_F(0x00b2aa3e));
+
+ x[26] = x[27] = MAD_F_MLZ(hi, lo) + t5;
+}
+# endif
+
+/*
+ * NAME: III_imdct_l()
+ * DESCRIPTION: perform IMDCT and windowing for long blocks
+ */
+static
+void III_imdct_l(mad_fixed_t const X[18], mad_fixed_t z[36],
+ unsigned int block_type)
+{
+ unsigned int i;
+
+ /* IMDCT */
+
+ imdct36(X, z);
+
+ /* windowing */
+
+ switch (block_type) {
+ case 0: /* normal window */
+# if defined(ASO_INTERLEAVE1)
+ {
+ register mad_fixed_t tmp1, tmp2;
+
+ tmp1 = window_l[0];
+ tmp2 = window_l[1];
+
+ for (i = 0; i < 34; i += 2) {
+ z[i + 0] = mad_f_mul(z[i + 0], tmp1);
+ tmp1 = window_l[i + 2];
+ z[i + 1] = mad_f_mul(z[i + 1], tmp2);
+ tmp2 = window_l[i + 3];
+ }
+
+ z[34] = mad_f_mul(z[34], tmp1);
+ z[35] = mad_f_mul(z[35], tmp2);
+ }
+# elif defined(ASO_INTERLEAVE2)
+ {
+ register mad_fixed_t tmp1, tmp2;
+
+ tmp1 = z[0];
+ tmp2 = window_l[0];
+
+ for (i = 0; i < 35; ++i) {
+ z[i] = mad_f_mul(tmp1, tmp2);
+ tmp1 = z[i + 1];
+ tmp2 = window_l[i + 1];
+ }
+
+ z[35] = mad_f_mul(tmp1, tmp2);
+ }
+# elif 1
+ for (i = 0; i < 36; i += 4) {
+ z[i + 0] = mad_f_mul(z[i + 0], window_l[i + 0]);
+ z[i + 1] = mad_f_mul(z[i + 1], window_l[i + 1]);
+ z[i + 2] = mad_f_mul(z[i + 2], window_l[i + 2]);
+ z[i + 3] = mad_f_mul(z[i + 3], window_l[i + 3]);
+ }
+# else
+ for (i = 0; i < 36; ++i) z[i] = mad_f_mul(z[i], window_l[i]);
+# endif
+ break;
+
+ case 1: /* start block */
+ for (i = 0; i < 18; i += 3) {
+ z[i + 0] = mad_f_mul(z[i + 0], window_l[i + 0]);
+ z[i + 1] = mad_f_mul(z[i + 1], window_l[i + 1]);
+ z[i + 2] = mad_f_mul(z[i + 2], window_l[i + 2]);
+ }
+ /* (i = 18; i < 24; ++i) z[i] unchanged */
+ for (i = 24; i < 30; ++i) z[i] = mad_f_mul(z[i], window_s[i - 18]);
+ for (i = 30; i < 36; ++i) z[i] = 0;
+ break;
+
+ case 3: /* stop block */
+ for (i = 0; i < 6; ++i) z[i] = 0;
+ for (i = 6; i < 12; ++i) z[i] = mad_f_mul(z[i], window_s[i - 6]);
+ /* (i = 12; i < 18; ++i) z[i] unchanged */
+ for (i = 18; i < 36; i += 3) {
+ z[i + 0] = mad_f_mul(z[i + 0], window_l[i + 0]);
+ z[i + 1] = mad_f_mul(z[i + 1], window_l[i + 1]);
+ z[i + 2] = mad_f_mul(z[i + 2], window_l[i + 2]);
+ }
+ break;
+ }
+}
+# endif /* ASO_IMDCT */
+
+/*
+ * NAME: III_imdct_s()
+ * DESCRIPTION: perform IMDCT and windowing for short blocks
+ */
+static
+void III_imdct_s(mad_fixed_t const X[18], mad_fixed_t z[36])
+{
+ mad_fixed_t y[36], *yptr;
+ mad_fixed_t const *wptr;
+ int w, i;
+ register mad_fixed64hi_t hi;
+ register mad_fixed64lo_t lo;
+
+ /* IMDCT */
+
+ yptr = &y[0];
+
+ for (w = 0; w < 3; ++w) {
+ register mad_fixed_t const (*s)[6];
+
+ s = imdct_s;
+
+ for (i = 0; i < 3; ++i) {
+ MAD_F_ML0(hi, lo, X[0], (*s)[0]);
+ MAD_F_MLA(hi, lo, X[1], (*s)[1]);
+ MAD_F_MLA(hi, lo, X[2], (*s)[2]);
+ MAD_F_MLA(hi, lo, X[3], (*s)[3]);
+ MAD_F_MLA(hi, lo, X[4], (*s)[4]);
+ MAD_F_MLA(hi, lo, X[5], (*s)[5]);
+
+ yptr[i + 0] = MAD_F_MLZ(hi, lo);
+ yptr[5 - i] = -yptr[i + 0];
+
+ ++s;
+
+ MAD_F_ML0(hi, lo, X[0], (*s)[0]);
+ MAD_F_MLA(hi, lo, X[1], (*s)[1]);
+ MAD_F_MLA(hi, lo, X[2], (*s)[2]);
+ MAD_F_MLA(hi, lo, X[3], (*s)[3]);
+ MAD_F_MLA(hi, lo, X[4], (*s)[4]);
+ MAD_F_MLA(hi, lo, X[5], (*s)[5]);
+
+ yptr[ i + 6] = MAD_F_MLZ(hi, lo);
+ yptr[11 - i] = yptr[i + 6];
+
+ ++s;
+ }
+
+ yptr += 12;
+ X += 6;
+ }
+
+ /* windowing, overlapping and concatenation */
+
+ yptr = &y[0];
+ wptr = &window_s[0];
+
+ for (i = 0; i < 6; ++i) {
+ z[i + 0] = 0;
+ z[i + 6] = mad_f_mul(yptr[ 0 + 0], wptr[0]);
+
+ MAD_F_ML0(hi, lo, yptr[ 0 + 6], wptr[6]);
+ MAD_F_MLA(hi, lo, yptr[12 + 0], wptr[0]);
+
+ z[i + 12] = MAD_F_MLZ(hi, lo);
+
+ MAD_F_ML0(hi, lo, yptr[12 + 6], wptr[6]);
+ MAD_F_MLA(hi, lo, yptr[24 + 0], wptr[0]);
+
+ z[i + 18] = MAD_F_MLZ(hi, lo);
+
+ z[i + 24] = mad_f_mul(yptr[24 + 6], wptr[6]);
+ z[i + 30] = 0;
+
+ ++yptr;
+ ++wptr;
+ }
+}
+
+/*
+ * NAME: III_overlap()
+ * DESCRIPTION: perform overlap-add of windowed IMDCT outputs
+ */
+static
+void III_overlap(mad_fixed_t const output[36], mad_fixed_t overlap[18],
+ mad_fixed_t sample[18][32], unsigned int sb)
+{
+ unsigned int i;
+
+# if defined(ASO_INTERLEAVE2)
+ {
+ register mad_fixed_t tmp1, tmp2;
+
+ tmp1 = overlap[0];
+ tmp2 = overlap[1];
+
+ for (i = 0; i < 16; i += 2) {
+ sample[i + 0][sb] = output[i + 0 + 0] + tmp1;
+ overlap[i + 0] = output[i + 0 + 18];
+ tmp1 = overlap[i + 2];
+
+ sample[i + 1][sb] = output[i + 1 + 0] + tmp2;
+ overlap[i + 1] = output[i + 1 + 18];
+ tmp2 = overlap[i + 3];
+ }
+
+ sample[16][sb] = output[16 + 0] + tmp1;
+ overlap[16] = output[16 + 18];
+ sample[17][sb] = output[17 + 0] + tmp2;
+ overlap[17] = output[17 + 18];
+ }
+# elif 0
+ for (i = 0; i < 18; i += 2) {
+ sample[i + 0][sb] = output[i + 0 + 0] + overlap[i + 0];
+ overlap[i + 0] = output[i + 0 + 18];
+
+ sample[i + 1][sb] = output[i + 1 + 0] + overlap[i + 1];
+ overlap[i + 1] = output[i + 1 + 18];
+ }
+# else
+ for (i = 0; i < 18; ++i) {
+ sample[i][sb] = output[i + 0] + overlap[i];
+ overlap[i] = output[i + 18];
+ }
+# endif
+}
+
+/*
+ * NAME: III_overlap_z()
+ * DESCRIPTION: perform "overlap-add" of zero IMDCT outputs
+ */
+static inline
+void III_overlap_z(mad_fixed_t overlap[18],
+ mad_fixed_t sample[18][32], unsigned int sb)
+{
+ unsigned int i;
+
+# if defined(ASO_INTERLEAVE2)
+ {
+ register mad_fixed_t tmp1, tmp2;
+
+ tmp1 = overlap[0];
+ tmp2 = overlap[1];
+
+ for (i = 0; i < 16; i += 2) {
+ sample[i + 0][sb] = tmp1;
+ overlap[i + 0] = 0;
+ tmp1 = overlap[i + 2];
+
+ sample[i + 1][sb] = tmp2;
+ overlap[i + 1] = 0;
+ tmp2 = overlap[i + 3];
+ }
+
+ sample[16][sb] = tmp1;
+ overlap[16] = 0;
+ sample[17][sb] = tmp2;
+ overlap[17] = 0;
+ }
+# else
+ for (i = 0; i < 18; ++i) {
+ sample[i][sb] = overlap[i];
+ overlap[i] = 0;
+ }
+# endif
+}
+
+/*
+ * NAME: III_freqinver()
+ * DESCRIPTION: perform subband frequency inversion for odd sample lines
+ */
+static
+void III_freqinver(mad_fixed_t sample[18][32], unsigned int sb)
+{
+ unsigned int i;
+
+# if 1 || defined(ASO_INTERLEAVE1) || defined(ASO_INTERLEAVE2)
+ {
+ register mad_fixed_t tmp1, tmp2;
+
+ tmp1 = sample[1][sb];
+ tmp2 = sample[3][sb];
+
+ for (i = 1; i < 13; i += 4) {
+ sample[i + 0][sb] = -tmp1;
+ tmp1 = sample[i + 4][sb];
+ sample[i + 2][sb] = -tmp2;
+ tmp2 = sample[i + 6][sb];
+ }
+
+ sample[13][sb] = -tmp1;
+ tmp1 = sample[17][sb];
+ sample[15][sb] = -tmp2;
+ sample[17][sb] = -tmp1;
+ }
+# else
+ for (i = 1; i < 18; i += 2)
+ sample[i][sb] = -sample[i][sb];
+# endif
+}
+
+/*
+ * NAME: III_decode()
+ * DESCRIPTION: decode frame main_data
+ */
+static
+enum mad_error III_decode(struct mad_bitptr *ptr, struct mad_frame *frame,
+ struct sideinfo *si, unsigned int nch)
+{
+ struct mad_header *header = &frame->header;
+ unsigned int sfreqi, ngr, gr;
+
+ {
+ unsigned int sfreq;
+
+ sfreq = header->samplerate;
+ if (header->flags & MAD_FLAG_MPEG_2_5_EXT)
+ sfreq *= 2;
+
+ /* 48000 => 0, 44100 => 1, 32000 => 2,
+ 24000 => 3, 22050 => 4, 16000 => 5 */
+ sfreqi = ((sfreq >> 7) & 0x000f) +
+ ((sfreq >> 15) & 0x0001) - 8;
+
+ if (header->flags & MAD_FLAG_MPEG_2_5_EXT)
+ sfreqi += 3;
+ }
+
+ /* scalefactors, Huffman decoding, requantization */
+
+ ngr = (header->flags & MAD_FLAG_LSF_EXT) ? 1 : 2;
+
+ for (gr = 0; gr < ngr; ++gr) {
+ struct granule *granule = &si->gr[gr];
+ unsigned char const *sfbwidth[2];
+ mad_fixed_t xr[2][576];
+ unsigned int ch;
+ enum mad_error error;
+
+ for (ch = 0; ch < nch; ++ch) {
+ struct channel *channel = &granule->ch[ch];
+ unsigned int part2_length;
+
+ sfbwidth[ch] = sfbwidth_table[sfreqi].l;
+ if (channel->block_type == 2) {
+ sfbwidth[ch] = (channel->flags & mixed_block_flag) ?
+ sfbwidth_table[sfreqi].m : sfbwidth_table[sfreqi].s;
+ }
+
+ if (header->flags & MAD_FLAG_LSF_EXT) {
+ part2_length = III_scalefactors_lsf(ptr, channel,
+ ch == 0 ? 0 : &si->gr[1].ch[1],
+ header->mode_extension);
+ }
+ else {
+ part2_length = III_scalefactors(ptr, channel, &si->gr[0].ch[ch],
+ gr == 0 ? 0 : si->scfsi[ch]);
+ }
+
+ error = III_huffdecode(ptr, xr[ch], channel, sfbwidth[ch], part2_length);
+ if (error)
+ return error;
+ }
+
+ /* joint stereo processing */
+
+ if (header->mode == MAD_MODE_JOINT_STEREO && header->mode_extension) {
+ error = III_stereo(xr, granule, header, sfbwidth[0]);
+ if (error)
+ return error;
+ }
+
+ /* reordering, alias reduction, IMDCT, overlap-add, frequency inversion */
+
+ for (ch = 0; ch < nch; ++ch) {
+ struct channel const *channel = &granule->ch[ch];
+ mad_fixed_t (*sample)[32] = &frame->sbsample[ch][18 * gr];
+ unsigned int sb, l, i, sblimit;
+ mad_fixed_t output[36];
+
+ if (channel->block_type == 2) {
+ III_reorder(xr[ch], channel, sfbwidth[ch]);
+
+# if !defined(OPT_STRICT)
+ /*
+ * According to ISO/IEC 11172-3, "Alias reduction is not applied for
+ * granules with block_type == 2 (short block)." However, other
+ * sources suggest alias reduction should indeed be performed on the
+ * lower two subbands of mixed blocks. Most other implementations do
+ * this, so by default we will too.
+ */
+ if (channel->flags & mixed_block_flag)
+ III_aliasreduce(xr[ch], 36);
+# endif
+ }
+ else
+ III_aliasreduce(xr[ch], 576);
+
+ l = 0;
+
+ /* subbands 0-1 */
+
+ if (channel->block_type != 2 || (channel->flags & mixed_block_flag)) {
+ unsigned int block_type;
+
+ block_type = channel->block_type;
+ if (channel->flags & mixed_block_flag)
+ block_type = 0;
+
+ /* long blocks */
+ for (sb = 0; sb < 2; ++sb, l += 18) {
+ III_imdct_l(&xr[ch][l], output, block_type);
+ III_overlap(output, (*frame->overlap)[ch][sb], sample, sb);
+ }
+ }
+ else {
+ /* short blocks */
+ for (sb = 0; sb < 2; ++sb, l += 18) {
+ III_imdct_s(&xr[ch][l], output);
+ III_overlap(output, (*frame->overlap)[ch][sb], sample, sb);
+ }
+ }
+
+ III_freqinver(sample, 1);
+
+ /* (nonzero) subbands 2-31 */
+
+ i = 576;
+ while (i > 36 && xr[ch][i - 1] == 0)
+ --i;
+
+ sblimit = 32 - (576 - i) / 18;
+
+ if (channel->block_type != 2) {
+ /* long blocks */
+ for (sb = 2; sb < sblimit; ++sb, l += 18) {
+ III_imdct_l(&xr[ch][l], output, channel->block_type);
+ III_overlap(output, (*frame->overlap)[ch][sb], sample, sb);
+
+ if (sb & 1)
+ III_freqinver(sample, sb);
+ }
+ }
+ else {
+ /* short blocks */
+ for (sb = 2; sb < sblimit; ++sb, l += 18) {
+ III_imdct_s(&xr[ch][l], output);
+ III_overlap(output, (*frame->overlap)[ch][sb], sample, sb);
+
+ if (sb & 1)
+ III_freqinver(sample, sb);
+ }
+ }
+
+ /* remaining (zero) subbands */
+
+ for (sb = sblimit; sb < 32; ++sb) {
+ III_overlap_z((*frame->overlap)[ch][sb], sample, sb);
+
+ if (sb & 1)
+ III_freqinver(sample, sb);
+ }
+ }
+ }
+
+ return MAD_ERROR_NONE;
+}
+
+/*
+ * NAME: layer->III()
+ * DESCRIPTION: decode a single Layer III frame
+ */
+int mad_layer_III(struct mad_stream *stream, struct mad_frame *frame)
+{
+ struct mad_header *header = &frame->header;
+ unsigned int nch, priv_bitlen, next_md_begin = 0;
+ unsigned int si_len, data_bitlen, md_len;
+ unsigned int frame_space, frame_used, frame_free;
+ struct mad_bitptr ptr;
+ struct sideinfo si;
+ enum mad_error error;
+ int result = 0;
+
+ /* allocate Layer III dynamic structures */
+
+ if (stream->main_data == 0) {
+ stream->main_data = malloc(MAD_BUFFER_MDLEN);
+ if (stream->main_data == 0) {
+ stream->error = MAD_ERROR_NOMEM;
+ return -1;
+ }
+ }
+
+ if (frame->overlap == 0) {
+ frame->overlap = calloc(2 * 32 * 18, sizeof(mad_fixed_t));
+ if (frame->overlap == 0) {
+ stream->error = MAD_ERROR_NOMEM;
+ return -1;
+ }
+ }
+
+ nch = MAD_NCHANNELS(header);
+ si_len = (header->flags & MAD_FLAG_LSF_EXT) ?
+ (nch == 1 ? 9 : 17) : (nch == 1 ? 17 : 32);
+
+ /* check frame sanity */
+
+ if (stream->next_frame - mad_bit_nextbyte(&stream->ptr) <
+ (signed int) si_len) {
+ stream->error = MAD_ERROR_BADFRAMELEN;
+ stream->md_len = 0;
+ return -1;
+ }
+
+ /* check CRC word */
+
+ if (header->flags & MAD_FLAG_PROTECTION) {
+ header->crc_check =
+ mad_bit_crc(stream->ptr, si_len * CHAR_BIT, header->crc_check);
+
+ if (header->crc_check != header->crc_target &&
+ !(frame->options & MAD_OPTION_IGNORECRC)) {
+ stream->error = MAD_ERROR_BADCRC;
+ result = -1;
+ }
+ }
+
+ /* decode frame side information */
+
+ error = III_sideinfo(&stream->ptr, nch, header->flags & MAD_FLAG_LSF_EXT,
+ &si, &data_bitlen, &priv_bitlen);
+ if (error && result == 0) {
+ stream->error = error;
+ result = -1;
+ }
+
+ header->flags |= priv_bitlen;
+ header->private_bits |= si.private_bits;
+
+ /* find main_data of next frame */
+
+ {
+ struct mad_bitptr peek;
+ unsigned long header;
+
+ mad_bit_init(&peek, stream->next_frame);
+
+ header = mad_bit_read(&peek, 32);
+ if ((header & 0xffe60000L) /* syncword | layer */ == 0xffe20000L) {
+ if (!(header & 0x00010000L)) /* protection_bit */
+ mad_bit_skip(&peek, 16); /* crc_check */
+
+ next_md_begin =
+ mad_bit_read(&peek, (header & 0x00080000L) /* ID */ ? 9 : 8);
+ }
+
+ mad_bit_finish(&peek);
+ }
+
+ /* find main_data of this frame */
+
+ frame_space = stream->next_frame - mad_bit_nextbyte(&stream->ptr);
+
+ if (next_md_begin > si.main_data_begin + frame_space)
+ next_md_begin = 0;
+
+ md_len = si.main_data_begin + frame_space - next_md_begin;
+
+ frame_used = 0;
+
+ if (si.main_data_begin == 0) {
+ ptr = stream->ptr;
+ stream->md_len = 0;
+
+ frame_used = md_len;
+ }
+ else {
+ if (si.main_data_begin > stream->md_len) {
+ if (result == 0) {
+ stream->error = MAD_ERROR_BADDATAPTR;
+ result = -1;
+ }
+ }
+ else {
+ mad_bit_init(&ptr,
+ *stream->main_data + stream->md_len - si.main_data_begin);
+
+ if (md_len > si.main_data_begin) {
+ assert(stream->md_len + md_len -
+ si.main_data_begin <= MAD_BUFFER_MDLEN);
+
+ memcpy(*stream->main_data + stream->md_len,
+ mad_bit_nextbyte(&stream->ptr),
+ frame_used = md_len - si.main_data_begin);
+ stream->md_len += frame_used;
+ }
+ }
+ }
+
+ frame_free = frame_space - frame_used;
+
+ /* decode main_data */
+
+ if (result == 0) {
+ error = III_decode(&ptr, frame, &si, nch);
+ if (error) {
+ stream->error = error;
+ result = -1;
+ }
+
+ /* designate ancillary bits */
+
+ stream->anc_ptr = ptr;
+ stream->anc_bitlen = md_len * CHAR_BIT - data_bitlen;
+ }
+
+# if 0 && defined(DEBUG)
+ fprintf(stderr,
+ "main_data_begin:%u, md_len:%u, frame_free:%u, "
+ "data_bitlen:%u, anc_bitlen: %u\n",
+ si.main_data_begin, md_len, frame_free,
+ data_bitlen, stream->anc_bitlen);
+# endif
+
+ /* preload main_data buffer with up to 511 bytes for next frame(s) */
+
+ if (frame_free >= next_md_begin) {
+ memcpy(*stream->main_data,
+ stream->next_frame - next_md_begin, next_md_begin);
+ stream->md_len = next_md_begin;
+ }
+ else {
+ if (md_len < si.main_data_begin) {
+ unsigned int extra;
+
+ extra = si.main_data_begin - md_len;
+ if (extra + frame_free > next_md_begin)
+ extra = next_md_begin - frame_free;
+
+ if (extra < stream->md_len) {
+ memmove(*stream->main_data,
+ *stream->main_data + stream->md_len - extra, extra);
+ stream->md_len = extra;
+ }
+ }
+ else
+ stream->md_len = 0;
+
+ memcpy(*stream->main_data + stream->md_len,
+ stream->next_frame - frame_free, frame_free);
+ stream->md_len += frame_free;
+ }
+
+ return result;
+}
+
+# ifdef _MSC_VER
+# pragma warning(pop)
+# endif