void m4ri_build_code(int *ord, int *inc, int l) {
int i,j;
for(i=0 ; i < TWOPOW(l) ; i++) {
ord[i] = m4ri_gray_code(i, l);
}
for(i = l ; i>0 ; i--) {
for(j=1 ; j < TWOPOW(i) + 1 ; j++) {
inc[j *TWOPOW(l-i) -1 ] = l - i;
}
}
}
void m4ri_build_all_codes() {
if (codebook) {
return;
}
int k;
codebook=(code**)m4ri_mm_calloc(MAXKAY+1, sizeof(code *));
for(k=1 ; k<MAXKAY+1; k++) {
codebook[k] = (code *)m4ri_mm_calloc(sizeof(code),1);
codebook[k]->ord =(int *)m4ri_mm_calloc(TWOPOW(k),sizeof(int));
codebook[k]->inc =(int *)m4ri_mm_calloc(TWOPOW(k),sizeof(int));
m4ri_build_code(codebook[k]->ord, codebook[k]->inc, k);
}
}
float quantize(int bits, float input, float maxval)
{
unsigned long quantval = 0;
int sign;
float output;
sign = (input < 0);
input = fabs(input);
//quantize to bit code
if (input >= maxval) {
quantval = (long)(TWOPOW(bits - 1) - 1);
} else {
quantval = (long)(
(
(unsigned long)(TWOPOW(bits-1) +
(TWOPOW(bits-1)-1)) * input/maxval + 1.0
) / 2.0
);
}
if (sign) { quantval |= TWOPOW(bits - 1); }
//dequantize back to float
if (quantval & TWOPOW(bits - 1)) {
sign = -1;
quantval &= TWOPOW(bits - 1) - 1;
} else {
sign = 1;
}
output = sign * 2.0 * maxval * ((float)quantval / (TWOPOW(bits) - 1));
return output;
}
static inline int log2_floor(int n){
int i;
for(i=0;TWOPOW(i)<=n;i++){}
return i;
}
