/*	decode_ntom.c: N->M down/up sampling. Not optimized for speed.	copyright 1995-2006 by the mpg123 project - free software under the terms of the LGPL 2.1	see COPYING and AUTHORS files in distribution or http://mpg123.de	initially written by Michael Hipp*/#include <stdlib.h>#include <math.h>#include <string.h>#include "config.h"#include "mpg123.h"#define WRITE_SAMPLE(samples,sum,clip) \  if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \  else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \  else { *(samples) = sum; }#define NTOM_MUL (32768)static unsigned long ntom_val[2] = { NTOM_MUL>>1,NTOM_MUL>>1 };static unsigned long ntom_step = NTOM_MUL;void synth_ntom_set_step(long m,long n){	if(param.verbose > 1)		fprintf(stderr,"Init rate converter: %ld->%ld\n",m,n);	if(n >= 96000 || m >= 96000 || m == 0 || n == 0) {		fprintf(stderr,"NtoM converter: illegal rates\n");		exit(1);	}	n *= NTOM_MUL;	ntom_step = n / m;	if(ntom_step > 8*NTOM_MUL) {		fprintf(stderr,"max. 1:8 conversion allowed!\n");		exit(1);	}	ntom_val[0] = ntom_val[1] = NTOM_MUL>>1;}int synth_ntom_8bit(real *bandPtr,int channel,unsigned char *samples,int *pnt){  short samples_tmp[8*64];  short *tmp1 = samples_tmp + channel;  int i,ret;  int pnt1 = 0;  ret = synth_ntom(bandPtr,channel,(unsigned char *) samples_tmp,&pnt1);  samples += channel + *pnt;  for(i=0;i<(pnt1>>2);i++) {    *samples = conv16to8[*tmp1>>AUSHIFT];    samples += 2;    tmp1 += 2;  }  *pnt += pnt1>>1;  return ret;}int synth_ntom_8bit_mono(real *bandPtr,unsigned char *samples,int *pnt){  short samples_tmp[8*64];  short *tmp1 = samples_tmp;  int i,ret;  int pnt1 = 0;  ret = synth_ntom(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);  samples += *pnt;  for(i=0;i<(pnt1>>2);i++) {    *samples++ = conv16to8[*tmp1>>AUSHIFT];    tmp1 += 2;  }  *pnt += pnt1 >> 2;    return ret;}int synth_ntom_8bit_mono2stereo(real *bandPtr,unsigned char *samples,int *pnt){  short samples_tmp[8*64];  short *tmp1 = samples_tmp;  int i,ret;  int pnt1 = 0;  ret = synth_ntom(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);  samples += *pnt;  for(i=0;i<(pnt1>>2);i++) {    *samples++ = conv16to8[*tmp1>>AUSHIFT];    *samples++ = conv16to8[*tmp1>>AUSHIFT];    tmp1 += 2;  }  *pnt += pnt1 >> 1;  return ret;}int synth_ntom_mono(real *bandPtr,unsigned char *samples,int *pnt){  short samples_tmp[8*64];  short *tmp1 = samples_tmp;  int i,ret;  int pnt1 = 0;  ret = synth_ntom(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);  samples += *pnt;  for(i=0;i<(pnt1>>2);i++) {    *( (short *)samples) = *tmp1;    samples += 2;    tmp1 += 2;  }  *pnt += pnt1 >> 1;  return ret;}int synth_ntom_mono2stereo(real *bandPtr,unsigned char *samples,int *pnt){  int i,ret;  int pnt1 = *pnt;  ret = synth_ntom(bandPtr,0,samples,pnt);  samples += pnt1;    for(i=0;i<((*pnt-pnt1)>>2);i++) {    ((short *)samples)[1] = ((short *)samples)[0];    samples+=4;  }  return ret;}int synth_ntom(real *bandPtr,int channel,unsigned char *out,int *pnt){  static real buffs[2][2][0x110];  static const int step = 2;  static int bo = 1;  short *samples = (short *) (out + *pnt);  real *b0,(*buf)[0x110];  int clip = 0;   int bo1;  int ntom;  if(have_eq_settings)	do_equalizer(bandPtr,channel);  if(!channel) {    bo--;    bo &= 0xf;    buf = buffs[0];    ntom = ntom_val[1] = ntom_val[0];  }  else {    samples++;    out += 2; /* to compute the right *pnt value */    buf = buffs[1];    ntom = ntom_val[1];  }  if(bo & 0x1) {    b0 = buf[0];    bo1 = bo;    dct64(buf[1]+((bo+1)&0xf),buf[0]+bo,bandPtr);  }  else {    b0 = buf[1];    bo1 = bo+1;    dct64(buf[0]+bo,buf[1]+bo+1,bandPtr);  }  {    register int j;    real *window = decwin + 16 - bo1;     for (j=16;j;j--,window+=0x10)    {      real sum;      ntom += ntom_step;      if(ntom < NTOM_MUL) {        window += 16;        b0 += 16;        continue;      }      sum  = *window++ * *b0++;      sum -= *window++ * *b0++;      sum += *window++ * *b0++;      sum -= *window++ * *b0++;      sum += *window++ * *b0++;      sum -= *window++ * *b0++;      sum += *window++ * *b0++;      sum -= *window++ * *b0++;      sum += *window++ * *b0++;      sum -= *window++ * *b0++;      sum += *window++ * *b0++;      sum -= *window++ * *b0++;      sum += *window++ * *b0++;      sum -= *window++ * *b0++;      sum += *window++ * *b0++;      sum -= *window++ * *b0++;      while(ntom >= NTOM_MUL) {        WRITE_SAMPLE(samples,sum,clip);        samples += step;        ntom -= NTOM_MUL;      }    }    ntom += ntom_step;    if(ntom >= NTOM_MUL)    {      real sum;      sum  = window[0x0] * b0[0x0];      sum += window[0x2] * b0[0x2];      sum += window[0x4] * b0[0x4];      sum += window[0x6] * b0[0x6];      sum += window[0x8] * b0[0x8];      sum += window[0xA] * b0[0xA];      sum += window[0xC] * b0[0xC];      sum += window[0xE] * b0[0xE];      while(ntom >= NTOM_MUL) {        WRITE_SAMPLE(samples,sum,clip);        samples += step;        ntom -= NTOM_MUL;      }    }    b0-=0x10,window-=0x20;    window += bo1<<1;    for (j=15;j;j--,b0-=0x20,window-=0x10)    {      real sum;      ntom += ntom_step;      if(ntom < NTOM_MUL) {        window -= 16;        b0 += 16;        continue;      }      sum = -*(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      sum -= *(--window) * *b0++;      while(ntom >= NTOM_MUL) {        WRITE_SAMPLE(samples,sum,clip);        samples += step;        ntom -= NTOM_MUL;      }    }  }  ntom_val[channel] = ntom;  *pnt = ((unsigned char *) samples - out);  return clip;}