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/*
* Siren Encoder/Decoder library
*
* @author: Youness Alaoui <kakaroto@kakaroto.homelinux.net>
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "siren7.h"
#define PI 3.1415926
typedef struct
{
float cos;
float msin;
} dct_table_type;
static float dct_core_320[100];
static float dct_core_640[100];
static dct_table_type dct_table_5[5];
static dct_table_type dct_table_10[10];
static dct_table_type dct_table_20[20];
static dct_table_type dct_table_40[40];
static dct_table_type dct_table_80[80];
static dct_table_type dct_table_160[160];
static dct_table_type dct_table_320[320];
static dct_table_type dct_table_640[640];
static dct_table_type *dct_tables[8] = { dct_table_5,
dct_table_10,
dct_table_20,
dct_table_40,
dct_table_80,
dct_table_160,
dct_table_320,
dct_table_640
};
static int dct4_initialized = 0;
void
siren_dct4_init (void)
{
int i, j = 0;
double scale_320 = (float) sqrt (2.0 / 320);
double scale_640 = (float) sqrt (2.0 / 640);
double angle;
double scale;
/* set up dct4 tables */
for (i = 0; i < 10; i++) {
angle = (float) ((i + 0.5) * PI);
for (j = 0; j < 10; j++) {
dct_core_320[(i * 10) + j] =
(float) (scale_320 * cos ((j + 0.5) * angle / 10));
dct_core_640[(i * 10) + j] =
(float) (scale_640 * cos ((j + 0.5) * angle / 10));
}
}
for (i = 0; i < 8; i++) {
scale = (float) (PI / ((5 << i) * 4));
for (j = 0; j < (5 << i); j++) {
angle = (float) (j + 0.5) * scale;
dct_tables[i][j].cos = (float) cos (angle);
dct_tables[i][j].msin = (float) -sin (angle);
}
}
dct4_initialized = 1;
}
void
siren_dct4 (float *Source, float *Destination, int dct_length)
{
int log_length = 0;
float *dct_core = NULL;
dct_table_type **dct_table_ptr_ptr = NULL;
dct_table_type *dct_table_ptr = NULL;
float OutBuffer1[640];
float OutBuffer2[640];
float *Out_ptr;
float *NextOut_ptr;
float *In_Ptr = NULL;
float *In_Ptr_low = NULL;
float *In_Ptr_high = NULL;
float In_val_low;
float In_val_high;
float *Out_ptr_low = NULL;
float *Out_ptr_high = NULL;
float mult1, mult2, mult3, mult4, mult5, mult6, mult7, mult8, mult9, mult10;
int i, j;
if (dct4_initialized == 0)
siren_dct4_init ();
if (dct_length == 640) {
log_length = 5;
dct_core = dct_core_640;
} else {
log_length = 4;
dct_core = dct_core_320;
}
Out_ptr = OutBuffer1;
NextOut_ptr = OutBuffer2;
In_Ptr = Source;
for (i = 0; i <= log_length; i++) {
for (j = 0; j < (1 << i); j++) {
Out_ptr_low = Out_ptr + (j * (dct_length >> i));
Out_ptr_high = Out_ptr + ((j + 1) * (dct_length >> i));
do {
In_val_low = *In_Ptr++;
In_val_high = *In_Ptr++;
*Out_ptr_low++ = In_val_low + In_val_high;
*--Out_ptr_high = In_val_low - In_val_high;
} while (Out_ptr_low < Out_ptr_high);
}
In_Ptr = Out_ptr;
Out_ptr = NextOut_ptr;
NextOut_ptr = In_Ptr;
}
for (i = 0; i < (2 << log_length); i++) {
for (j = 0; j < 10; j++) {
mult1 = In_Ptr[(i * 10)] * dct_core[j * 10];
mult2 = In_Ptr[(i * 10) + 1] * dct_core[(j * 10) + 1];
mult3 = In_Ptr[(i * 10) + 2] * dct_core[(j * 10) + 2];
mult4 = In_Ptr[(i * 10) + 3] * dct_core[(j * 10) + 3];
mult5 = In_Ptr[(i * 10) + 4] * dct_core[(j * 10) + 4];
mult6 = In_Ptr[(i * 10) + 5] * dct_core[(j * 10) + 5];
mult7 = In_Ptr[(i * 10) + 6] * dct_core[(j * 10) + 6];
mult8 = In_Ptr[(i * 10) + 7] * dct_core[(j * 10) + 7];
mult9 = In_Ptr[(i * 10) + 8] * dct_core[(j * 10) + 8];
mult10 = In_Ptr[(i * 10) + 9] * dct_core[(j * 10) + 9];
Out_ptr[(i * 10) + j] = mult1 + mult2 + mult3 + mult4 +
mult5 + mult6 + mult7 + mult8 + mult9 + mult10;
}
}
In_Ptr = Out_ptr;
Out_ptr = NextOut_ptr;
NextOut_ptr = In_Ptr;
dct_table_ptr_ptr = dct_tables;
for (i = log_length; i >= 0; i--) {
dct_table_ptr_ptr++;
for (j = 0; j < (1 << i); j++) {
dct_table_ptr = *dct_table_ptr_ptr;
if (i == 0)
Out_ptr_low = Destination + (j * (dct_length >> i));
else
Out_ptr_low = Out_ptr + (j * (dct_length >> i));
Out_ptr_high = Out_ptr_low + (dct_length >> i);
In_Ptr_low = In_Ptr + (j * (dct_length >> i));
In_Ptr_high = In_Ptr_low + (dct_length >> (i + 1));
do {
*Out_ptr_low++ =
(*In_Ptr_low * (*dct_table_ptr).cos) -
(*In_Ptr_high * (*dct_table_ptr).msin);
*--Out_ptr_high =
(*In_Ptr_high++ * (*dct_table_ptr).cos) +
(*In_Ptr_low++ * (*dct_table_ptr).msin);
dct_table_ptr++;
*Out_ptr_low++ =
(*In_Ptr_low * (*dct_table_ptr).cos) +
(*In_Ptr_high * (*dct_table_ptr).msin);
*--Out_ptr_high =
(*In_Ptr_low++ * (*dct_table_ptr).msin) -
(*In_Ptr_high++ * (*dct_table_ptr).cos);
dct_table_ptr++;
} while (Out_ptr_low < Out_ptr_high);
}
In_Ptr = Out_ptr;
Out_ptr = NextOut_ptr;
NextOut_ptr = In_Ptr;
}
}
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