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winamp/Src/external_dependencies/openmpt-trunk/include/lame/mpglib/layer1.c

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/*
* layer1.c: Mpeg Layer-1 audio decoder
*
* Copyright (C) 1999-2010 The L.A.M.E. project
*
* Initially written by Michael Hipp, see also AUTHORS and README.
*
* 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.
*
* 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.
*
* 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.
*/
/* $Id: layer1.c,v 1.31 2017/08/23 13:22:23 robert Exp $ */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <assert.h>
#include "common.h"
#include "decode_i386.h"
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif
#include "layer1.h"
static int gd_are_hip_tables_layer1_initialized = 0;
void
hip_init_tables_layer1(void)
{
if (gd_are_hip_tables_layer1_initialized) {
return;
}
gd_are_hip_tables_layer1_initialized = 1;
}
typedef struct sideinfo_layer_I_struct
{
unsigned char allocation[SBLIMIT][2];
unsigned char scalefactor[SBLIMIT][2];
} sideinfo_layer_I;
static int
I_step_one(PMPSTR mp, sideinfo_layer_I* si)
{
struct frame *fr = &(mp->fr);
int jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext << 2) + 4 : 32;
int i;
int illegal_value_detected = 0;
unsigned char const ba15 = 15; /* bit pattern not allowed, looks like sync(?) */
memset(si, 0, sizeof(*si));
assert(fr->stereo == 1 || fr->stereo == 2);
if (fr->stereo == 2) {
for (i = 0; i < jsbound; i++) {
unsigned char b0 = get_leq_8_bits(mp, 4); /* values 0-15 */
unsigned char b1 = get_leq_8_bits(mp, 4); /* values 0-15 */
si->allocation[i][0] = b0;
si->allocation[i][1] = b1;
if (b0 == ba15 || b1 == ba15)
illegal_value_detected = 1;
}
for (i = jsbound; i < SBLIMIT; i++) {
unsigned char b = get_leq_8_bits(mp, 4); /* values 0-15 */
si->allocation[i][0] = b;
si->allocation[i][1] = b;
if (b == ba15)
illegal_value_detected = 1;
}
for (i = 0; i < SBLIMIT; i++) {
unsigned char n0 = si->allocation[i][0];
unsigned char n1 = si->allocation[i][1];
unsigned char b0 = n0 ? get_leq_8_bits(mp, 6) : 0; /* values 0-63 */
unsigned char b1 = n1 ? get_leq_8_bits(mp, 6) : 0; /* values 0-63 */
si->scalefactor[i][0] = b0;
si->scalefactor[i][1] = b1;
}
}
else {
for (i = 0; i < SBLIMIT; i++) {
unsigned char b0 = get_leq_8_bits(mp, 4); /* values 0-15 */
si->allocation[i][0] = b0;
if (b0 == ba15)
illegal_value_detected = 1;
}
for (i = 0; i < SBLIMIT; i++) {
unsigned char n0 = si->allocation[i][0];
unsigned char b0 = n0 ? get_leq_8_bits(mp, 6) : 0; /* values 0-63 */
si->scalefactor[i][0] = b0;
}
}
return illegal_value_detected;
}
static void
I_step_two(PMPSTR mp, sideinfo_layer_I *si, real fraction[2][SBLIMIT])
{
double r0, r1;
struct frame *fr = &(mp->fr);
int ds_limit = fr->down_sample_sblimit;
int i;
assert(fr->stereo == 1 || fr->stereo == 2);
if (fr->stereo == 2) {
int jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext << 2) + 4 : 32;
for (i = 0; i < jsbound; i++) {
unsigned char i0 = si->scalefactor[i][0];
unsigned char i1 = si->scalefactor[i][1];
unsigned char n0 = si->allocation[i][0];
unsigned char n1 = si->allocation[i][1];
assert( i0 < 64 );
assert( i1 < 64 );
assert( n0 < 16 );
assert( n1 < 16 );
if (n0 > 0) {
unsigned short v = get_leq_16_bits(mp, n0 + 1); /* 0-65535 */
r0 = (((-1) << n0) + v + 1) * muls[n0 + 1][i0];
}
else {
r0 = 0;
}
if (n1 > 0) {
unsigned short v = get_leq_16_bits(mp, n1 + 1); /* 0-65535 */
r1 = (((-1) << n1) + v + 1) * muls[n1 + 1][i1];
}
else {
r1 = 0;
}
fraction[0][i] = (real)r0;
fraction[1][i] = (real)r1;
}
for (i = jsbound; i < SBLIMIT; i++) {
unsigned char i0 = si->scalefactor[i][0];
unsigned char i1 = si->scalefactor[i][1];
unsigned char n = si->allocation[i][0];
assert( i0 < 64 );
assert( i1 < 64 );
assert( n < 16 );
if (n > 0) {
unsigned short v = get_leq_16_bits(mp, n + 1); /* 0-65535 */
unsigned int w = (((-1) << n) + v + 1);
r0 = w * muls[n + 1][i0];
r1 = w * muls[n + 1][i1];
}
else {
r0 = r1 = 0;
}
fraction[0][i] = (real)r0;
fraction[1][i] = (real)r1;
}
for (i = ds_limit; i < SBLIMIT; i++) {
fraction[0][i] = 0.0;
fraction[1][i] = 0.0;
}
}
else {
for (i = 0; i < SBLIMIT; i++) {
unsigned char n = si->allocation[i][0];
unsigned char j = si->scalefactor[i][0];
assert( j < 64 );
assert( n < 16 );
if (n > 0) {
unsigned short v = get_leq_16_bits(mp, n + 1);
r0 = (((-1) << n) + v + 1) * muls[n + 1][j];
}
else {
r0 = 0;
}
fraction[0][i] = (real)r0;
}
for (i = ds_limit; i < SBLIMIT; i++) {
fraction[0][i] = 0.0;
}
}
}
int
decode_layer1_sideinfo(PMPSTR mp)
{
(void) mp;
/* FIXME: extract side information and check values */
return 0;
}
int
decode_layer1_frame(PMPSTR mp, unsigned char *pcm_sample, int *pcm_point)
{
real fraction[2][SBLIMIT]; /* FIXME: change real -> double ? */
sideinfo_layer_I si;
struct frame *fr = &(mp->fr);
int single = fr->single;
int i, clip = 0;
if (I_step_one(mp, &si)) {
lame_report_fnc(mp->report_err, "hip: Aborting layer 1 decode, illegal bit allocation value\n");
return -1;
}
if (fr->stereo == 1 || single == 3)
single = 0;
if (single >= 0) {
/* decoding one of possibly two channels */
for (i = 0; i < SCALE_BLOCK; i++) {
I_step_two(mp, &si, fraction);
clip += synth_1to1_mono(mp, (real *) fraction[single], pcm_sample, pcm_point);
}
}
else {
for (i = 0; i < SCALE_BLOCK; i++) {
int p1 = *pcm_point;
I_step_two(mp, &si, fraction);
clip += synth_1to1(mp, (real *) fraction[0], 0, pcm_sample, &p1);
clip += synth_1to1(mp, (real *) fraction[1], 1, pcm_sample, pcm_point);
}
}
return clip;
}
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