vgmstream/src/coding/SASSC_decoder.c

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#include "coding.h"
#include "../util.h"
/* Activision / EXAKT Entertainment's DPCM for Supercar Street Challenge */
#if 0
To build table:
int32_t bring_round(int32_t v)
{
return v | (v >> 12);
}
for (i=0x00;i<0x20;i++)
SASSC_steps[i] = bring_round(i<<4);
for (i=0x20;i<0x40;i++)
SASSC_steps[i] = bring_round(((i-0x20)*7+0x20)<<4);
for (i=0x40;i<0x60;i++)
SASSC_steps[i] = bring_round(((i-0x40)*24+0x100)<<4);
for (i=0x60;i<0x80;i++)
SASSC_steps[i] = bring_round(((i-0x60)*96+0x400)<<4);
for (i=0x80;i<0xFF;i++)
SASSC_steps[i] = -SASSC_steps[i-0x80];
SASSC_steps[0xFF] = SASSC_steps[0x7F];
#endif
int32_t SASSC_steps[256] =
{
0, 16, 32, 48, 64, 80, 96, 112,
128, 144, 160, 176, 192, 208, 224, 240,
256, 272, 288, 304, 320, 336, 352, 368,
384, 400, 416, 432, 448, 464, 480, 496,
512, 624, 736, 848, 960, 1072, 1184, 1296,
1408, 1520, 1632, 1744, 1856, 1968, 2080, 2192,
2304, 2416, 2528, 2640, 2752, 2864, 2976, 3088,
3200, 3312, 3424, 3536, 3648, 3760, 3872, 3984,
4097, 4481, 4865, 5249, 5633, 6017, 6401, 6785,
7169, 7553, 7937, 8322, 8706, 9090, 9474, 9858,
10242, 10626, 11010, 11394, 11778, 12162, 12547, 12931,
13315, 13699, 14083, 14467, 14851, 15235, 15619, 16003,
16388, 17924, 19460, 20997, 22533, 24069, 25606, 27142,
28679, 30215, 31751, 33288, 34824, 36360, 37897, 39433,
40970, 42506, 44042, 45579, 47115, 48651, 50188, 51724,
53261, 54797, 56333, 57870, 59406, 60942, 62479, 64015,
0, -16, -32, -48, -64, -80, -96, -112,
-128, -144, -160, -176, -192, -208, -224, -240,
-256, -272, -288, -304, -320, -336, -352, -368,
-384, -400, -416, -432, -448, -464, -480, -496,
-512, -624, -736, -848, -960, -1072, -1184, -1296,
-1408, -1520, -1632, -1744, -1856, -1968, -2080, -2192,
-2304, -2416, -2528, -2640, -2752, -2864, -2976, -3088,
-3200, -3312, -3424, -3536, -3648, -3760, -3872, -3984,
-4097, -4481, -4865, -5249, -5633, -6017, -6401, -6785,
-7169, -7553, -7937, -8322, -8706, -9090, -9474, -9858,
-10242, -10626, -11010, -11394, -11778, -12162, -12547, -12931,
-13315, -13699, -14083, -14467, -14851, -15235, -15619, -16003,
-16388, -17924, -19460, -20997, -22533, -24069, -25606, -27142,
-28679, -30215, -31751, -33288, -34824, -36360, -37897, -39433,
-40970, -42506, -44042, -45579, -47115, -48651, -50188, -51724,
-53261, -54797, -56333, -57870, -59406, -60942, -62479, 64015,
};
void decode_SASSC(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
int i;
int32_t sample_count;
int32_t hist = stream->adpcm_history1_32;
for(i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
hist = hist + SASSC_steps[(uint8_t)read_8bit(stream->offset+i,stream->streamfile)];
outbuf[sample_count] = clamp16(hist);
}
stream->adpcm_history1_32 = hist;
}