/***

 * CopyPolicy: GNU Public License 2 applies

 * Copyright (C) by Monty (xiphmont@mit.edu)

 *

 * Gapa analysis support code for paranoia

 *

 ***/

#include <string.h>

#include "p_block.h"

#include "cdda_paranoia.h"

#include "gap.h"

/**** Gap analysis code ***************************************************/

long i_paranoia_overlap_r(int16_t *buffA,int16_t *buffB,

			  long offsetA, long offsetB){

  long beginA=offsetA;

  long beginB=offsetB;

  for(;beginA>=0 && beginB>=0;beginA--,beginB--)

    if(buffA[beginA]!=buffB[beginB])break;

  beginA++;

  beginB++;

  return(offsetA-beginA);

}

long i_paranoia_overlap_f(int16_t *buffA,int16_t *buffB,

			  long offsetA, long offsetB,

			  long sizeA,long sizeB){

  long endA=offsetA;

  long endB=offsetB;

  for(;endA

    if(buffA[endA]!=buffB[endB])break;

  return(endA-offsetA);

}

int i_stutter_or_gap(int16_t *A, int16_t *B,long offA, long offB,

		     long gap){

  long a1=offA;

  long b1=offB;

  if(a1<0){

    b1-=a1;

    gap+=a1;

    a1=0;

  }

  return(memcmp(A+a1,B+b1,gap*2));

}

/* riftv is the first value into the rift -> or <- */

void i_analyze_rift_f(int16_t *A,int16_t *B,

		      long sizeA, long sizeB,

		      long aoffset, long boffset, 

		      long *matchA,long *matchB,long *matchC){

  long apast=sizeA-aoffset;

  long bpast=sizeB-boffset;

  long i;

  *matchA=0, *matchB=0, *matchC=0;

  /* Look for three possible matches... (A) Ariftv->B, (B) Briftv->A and 

     (c) AB->AB. */

  for(i=0;;i++){

    if(i

      if(i_paranoia_overlap_f(A,B,aoffset,boffset+i,sizeA,sizeB)>=MIN_WORDS_RIFT){

	*matchA=i;

	break;

      }

    if(i

      if(i_paranoia_overlap_f(A,B,aoffset+i,boffset,sizeA,sizeB)>=MIN_WORDS_RIFT){

	*matchB=i;

	break;

      }

      if(i

	if(i_paranoia_overlap_f(A,B,aoffset+i,boffset+i,sizeA,sizeB)>=MIN_WORDS_RIFT){

	  *matchC=i;

	  break;

	}

    }else

      if(i>=bpast)break;

  }

  if(*matchA==0 && *matchB==0 && *matchC==0)return;

  if(*matchC)return;

  if(*matchA){

    if(i_stutter_or_gap(A,B,aoffset-*matchA,boffset,*matchA))

      return;

    *matchB=-*matchA; /* signify we need to remove n bytes from B */

    *matchA=0;

    return;

  }else{

    if(i_stutter_or_gap(B,A,boffset-*matchB,aoffset,*matchB))

      return;

    *matchA=-*matchB;

    *matchB=0;

    return;

  }

}

/* riftv must be first even val of rift moving back */

void i_analyze_rift_r(int16_t *A,int16_t *B,

		      long sizeA, long sizeB,

		      long aoffset, long boffset, 

		      long *matchA,long *matchB,long *matchC){

  long apast=aoffset+1;

  long bpast=boffset+1;

  long i;

  *matchA=0, *matchB=0, *matchC=0;

  /* Look for three possible matches... (A) Ariftv->B, (B) Briftv->A and 

     (c) AB->AB. */

  for(i=0;;i++){

    if(i

      if(i_paranoia_overlap_r(A,B,aoffset,boffset-i)>=MIN_WORDS_RIFT){

	*matchA=i;

	break;

      }

    if(i

      if(i_paranoia_overlap_r(A,B,aoffset-i,boffset)>=MIN_WORDS_RIFT){

	*matchB=i;

	break;

      }      

      if(i

	if(i_paranoia_overlap_r(A,B,aoffset-i,boffset-i)>=MIN_WORDS_RIFT){

	  *matchC=i;

	  break;

	}

    }else

      if(i>=bpast)break;

  }

  if(*matchA==0 && *matchB==0 && *matchC==0)return;

  if(*matchC)return;

  if(*matchA){

    if(i_stutter_or_gap(A,B,aoffset+1,boffset-*matchA+1,*matchA))

      return;

    *matchB=-*matchA; /* signify we need to remove n bytes from B */

    *matchA=0;

    return;

  }else{

    if(i_stutter_or_gap(B,A,boffset+1,aoffset-*matchB+1,*matchB))

      return;

    *matchA=-*matchB;

    *matchB=0;

    return;

  }

}

void  analyze_rift_silence_f(int16_t *A,int16_t *B,long sizeA,long sizeB,

			     long aoffset, long boffset,

			     long *matchA, long *matchB){

  *matchA=-1;

  *matchB=-1;

  sizeA=prna_min(sizeA,aoffset+MIN_WORDS_RIFT);

  sizeB=prna_min(sizeB,boffset+MIN_WORDS_RIFT);

  aoffset++;

  boffset++;

  while(aoffset

    if(A[aoffset]!=A[aoffset-1]){

      *matchA=0;

      break;

    }

    aoffset++;

  }

  while(boffset

    if(B[boffset]!=B[boffset-1]){

      *matchB=0;

      break;

    }

    boffset++;

  }

}