/* $XConsortium: etiff2.c,v 1.3 94/04/17 20:34:31 rws Exp $ */
/**** module etiff2.c ****/
/******************************************************************************

Copyright (c) 1993, 1994  X Consortium

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******************************************************************************

	etiff2.c -- DDXIE module for encoding tiff2 format

	Ben Fahy, AGE Logic, Sept 1993 

******************************************************************************/

#include "fax.h"
#define _TIFF2
#include "fencode.h"
#include "xiemd.h"
#define FETABS_OWNER
#include "fetabs.h"

/************************************************************************/
encode_tiff2(state)
FaxEncodeState *state;
{
/* stuff exchanged with state variable */
register int goal;
register unsigned char *byteptr;
register unsigned char *endptr;
register int bitpos;
register int width;
register int stager;
int rl;
register int a0_color;
Tiff2EncodePvt	*epvt;

/* stuff exchanged with private state variable */
register int index;
register int nvals;
register int *counts;
register int nbits;
int rlcode;
int terminating;
register int codelength;

register int 	lines_coded=0;
register int	lines_to_code=0;
int old_rl;

	if (state == (FaxEncodeState *) NULL)
		return(-1);

	/* set up initial bitstream for the very first output strip */
	if (!state->bits.started) {
	    if (state->strip_state != StripStateNew)  {
	        state->encoder_done = ENCODE_ERROR_StripStateNotNew;
	       	return(-1);
	    }
	    
	    state->bits.byteptr = (unsigned char *)state->strip;
	    state->bits.endptr  = state->bits.byteptr + state->strip_size;
	    	/* record end of output strip */

	    state->bits.bitpos = 0;
	    state->bits.started = 1;
	    state->strip_state = StripStateInUse; 
	}

	/* or, reset bitstream for a new output strip */
	if (state->magic_needs)  {
	  if (state->strip_state == StripStateNew)  {
	    state->strip_state = StripStateInUse;
	    state->bits.byteptr = (unsigned char *)state->strip;
	    state->bits.endptr  = state->bits.byteptr + state->strip_size;
	    	/* record end of output strip */
	    state->bits.started = 1;
	  }
	  else {
	     /* no new strip?? But... I *need* more data! */
	      state->encoder_done = ENCODE_ERROR_BadMagic;
	      return(-1);
	  }
	  state->magic_needs = 0;
	}

	localize_state(state);


/***	Main Encoding Loop	***/
	while (1) {

	  switch(goal) {

	  case ENCODE_FAX_GOAL_StartNewLine:
	    /* every new line we need to compute its runlength data */

	    if (lines_coded >= state->nl_tocode) {
		/* We have read the whole input strip, need more data  */
		save_state_and_return(state);
	    }

	    /* get the sequence of white and black run lengths */
	    nvals = encode_runs(
		state->i_lines[lines_coded],	/* input data */
		width,				/* # of bits  */
		counts,				/* where to put lengths */
		state->radiometric,		/* if 1, white is 1 */
		width
	    );
	    if (nvals < 0) {
	        state->encoder_done = ENCODE_ERROR_EncodeRunsFailure;
		save_state_and_return(state);
	    }
	    a0_color = WHITE;
	    index = 0;
	    a0_color = WHITE;

	  case ENCODE_FAX_GOAL_OutputNextRunLength:
	    rl = counts[index++];
	    old_rl = rl;

	  case ENCODE_FAX_GOAL_DeduceCode:
	    nbits = deduce_code(a0_color,&rl,&rlcode,&terminating);
		/* should be a macro but for now, a function */
	    
	    /* shift code over so it merges with stager contents */
	    stager |= (rlcode << (16-bitpos));
	    bitpos += nbits;

	    if (bitpos >=8) {
		goal = ENCODE_FAX_GOAL_FlushStager;
		break;
	    }
	    if (terminating) {
		/* all done with this runlength */
		if (index < nvals) {
		    a0_color = ~a0_color;
	  	    goal = ENCODE_FAX_GOAL_OutputNextRunLength;
		    break;
		}
		else {
	  	    goal = ENCODE_FAX_GOAL_FinishLine;
		    break;
		}
	    }
	    /* go around the loop again */
	    goal = ENCODE_FAX_GOAL_DeduceCode;
	    old_rl = rl;
	    break;

	  case ENCODE_FAX_GOAL_FlushStager:
	    if (byteptr >= endptr) {
	        state->strip_state = StripStateDone;
	        state->magic_needs = 1;
		save_state_and_return(state);
	    }
	    /* if here, we know it is safe to flush at least one byte */
	    *byteptr++ = (stager&0xff000000) >> 24;
	    stager <<= 8;
	    bitpos -= 8;
	    
	    if (bitpos >= 8) {
		/* go around the loop again, trying to flush more */
		break;
	    }
	    /* if here, we have flushed stager to the point there is	*/
	    /* at most a partial byte of data left in it.		*/
	    if (terminating) {
		/* all done with this runlength */
		if (index < nvals) {
		    a0_color = ~a0_color;
	  	    goal = ENCODE_FAX_GOAL_OutputNextRunLength;
		    break;
		}
		else {
	  	    goal = ENCODE_FAX_GOAL_FinishLine;
		    break;
		}
	    }
	    /* not done with this runlength yet */
	    goal = ENCODE_FAX_GOAL_DeduceCode;
	    break;

	  case ENCODE_FAX_GOAL_FinishLine:
	     if (bitpos) {
		/* have to flush stager */
	        if (byteptr >= endptr) {
	       	    state->strip_state = StripStateDone;
	       	    state->magic_needs = 1;
		    save_state_and_return(state);
	        }
		/* make sure nothing bogus is happening */
		if (bitpos > 8) {
		    state->encoder_done = ENCODE_ERROR_BadStager;
		    save_state_and_return(state);
		}

	        *byteptr++ = (stager&0xff000000) >> 24;
	        stager <<= 8;
	        bitpos = 0;
	     }
	     ++lines_coded;
	     goal = ENCODE_FAX_GOAL_StartNewLine;
	     break;

	  default:
	    state->encoder_done = ENCODE_ERROR_BadMagic;
	    save_state_and_return(state);
	    break;

	  } /* end of switch(goal) in main decoding loop */

	} /* end of main encoding loop */
}
/************************************************************************/
int encode_runs(src,nbits,counts,white_is_one,width)
LogInt *src;
unsigned int *counts;
register int nbits;
register int white_is_one;
register int width;
{
register unsigned int white_count=0,black_count=0;
register int i,current_is_white=1;
register int n_runs=0;
register int total=0;

register LogInt test_bit = LOGLEFT;
	/* LOGLEFT = the logically left-most bit in a word in 	*/
	/* the server, we allways fill the logically left-most	*/
	/* bit in a word first,  the logically right-most last	*/

/***	handle first bit differently than others	***/

    if (white_is_one) {	
	for (i=0; i<nbits; ++i) {
	   if (!test_bit) 
		test_bit = LOGLEFT;
	   
	   if (current_is_white) {
	        if (LOG_tstbit(src,i))
		   ++white_count;
		else {
		   counts[n_runs++] = white_count;
		   total += white_count;
		   current_is_white = 0;
		   black_count = 1;
		}
	   }  	/* end current_is_white */
	   else {
	        if (!LOG_tstbit(src,i))
		   ++black_count;
		else {
		   counts[n_runs++] = black_count;
		   total += black_count;
		   current_is_white = 1;
		   white_count = 1;
		}
	   }  	/* end current_is_not_white */

	   LOGRIGHT(test_bit);
		/* go to the next-filled bit in the word */

	}  /* end for (i<nbits)    */
    }      /* end if (white_is_one) */

    else {			/* white is zero */
	for (i=0; i<nbits; ++i) {
	   if (!test_bit) 
		test_bit = LOGLEFT;
	   
	   if (current_is_white) {
	        if (!LOG_tstbit(src,i))
		   ++white_count;
		else {
		   counts[n_runs++] = white_count;
		   total += white_count;
		   current_is_white = 0;
		   black_count = 1;
		}
	   }  	/* end current_is_white */
	   else {
	        if (LOG_tstbit(src,i))
		   ++black_count;
		else {
		   counts[n_runs++] = black_count;
		   total += black_count;
		   current_is_white = 1;
		   white_count = 1;
		}
	   }  	/* end current_is_not_white */

	   LOGRIGHT(test_bit);
		/* go to the next-filled bit in the word */

	}  /* end for (i<nbits)    */

    }      /* end else (!white_is_one) */

    if (current_is_white && white_count)  {
	counts[n_runs++] = white_count;
	total += white_count;
    }
    else if (!current_is_white && black_count)  {
	counts[n_runs++] = black_count;
	total += black_count;
    }
    if (total != width) 
       	return(-1);
    else
    	return(n_runs);
}
/************************************************************************/
int deduce_code(a0_color,rl,rlcode,terminating)
int a0_color,*rl,*rlcode,*terminating; 
{
int nbits;
ShiftedCodes *table;

	if (a0_color == WHITE)
		table = ShiftedWhites;
	else
		table = ShiftedBlacks;

	if (*rl < 0) 
		return(-1);

	if (*rl <= 63) {
		*terminating = 1;
		*rlcode = table[*rl].code;
		nbits = table[*rl].nbits;
		*rl = 0;
	}
	else if (*rl <= 2560) {
		*terminating = 0;
		*rlcode = table[63 +  (*rl >> 6)].code;
		nbits   = table[63 +  (*rl >> 6)].nbits;
		*rl %= 64;
	}
	else {
		*terminating = 0;
		*rlcode = table[63 + 2560/64].code;
		nbits   = table[63 + 2560/64].nbits;
		*rl -= 2560;
	}
	return(nbits);
}
/************************************************************************/
