/*
	File       : RLC.C
	Description: Convert BitMap to INTEL RLC
	Author     : Peter H. Michalicka
	Environment: HP-UX 8.05
*/

#include <stdio.h>
#include <string.h>

#include "tiff.h"
#include "vma.h"

WORD ic;	/* actual RLC column */
WORD rn;	/* actual RUN count */
WORD rb[32767];	/* RUN buffer */
int ii;		/* rb[ii] */
int is_start;	/* Start of RUN encounterd */
BYTE cb;

	/* external vars */

extern char *msg_fwrite;

	/* external functions */

#ifdef ANSI
int error(char *s1, char *s2);
#endif

static int iblkofs, blkofs, nblk, iline;
static char *ptr;

	/* Code */

void rlc_init(v)
vma *v;
{
	v->LineNo = 1;
	v->mbd[0].blkno = v->nblocks = nblk = blkofs = 0;
	ptr = v->bl[0];

	/* set defaults */

	ic = RLC_START;
	rb[0] = rn = 0;
	ii = 1;
	is_start = FALSE;
}

int put_buf(v, n, wp)
vma *v;
int n;
WORD *wp;
{
	n <<= 1;

	if ((blkofs + n) >= v->blocksize) {   /* check if fit to block */
		if (fwrite(ptr, v->blocksize, 1, v->fp) != 1)
			return error(msg_fwrite, v->fn);
		v->nblocks++;
		if (++nblk >= v->rblocks)      /* check resident blocks */
			nblk = 0;
		v->mbd[nblk].blkno = v->nblocks;
		ptr = v->bl[nblk];
		blkofs = 0;
	}
	iblkofs = blkofs;
	memcpy(ptr + blkofs, wp, n);
	blkofs += n;

	v->ofs[v->LineNo].blkno = (WORD)v->nblocks;
	v->ofs[v->LineNo].offset = (WORD)iblkofs;
	v->LineNo++;

	return TRUE;
}

int end_vma(v)
vma *v;
{
   if (blkofs)
      return fwrite(ptr, v->blocksize, 1, v->fp);   /* write last block */

   return TRUE;
}

int end_rlc(v)	/* set black runend to white */
vma *v;
{
	int i, n, jp;
	WORD re;

	if (is_start)
		rb[ii++] = ic;
	if (rn) {
		rb[0] = rn;	/* RUN count */
		ii--;		/* last inserted run */
		jp = rn << 1;	/* RUN = (sw,ew) */
		jp++;		/* 1st entry = RUN count */
	} else
		jp = 1;

	for (i = rn, n = 2; i ; i--) {
		rb[n]++; /* set black end to white end */
		n += 2;
	}
	if (! put_buf(v, jp, rb))
		return 0;

	ic = RLC_START;
	rb[0] = rn = 0;
	ii = 1;
	is_start = FALSE;

	return 1;
}

int end2rlc(v) /* dont correct white end */
vma *v;
{
	int i, n, jp;
	WORD re;

	if (is_start)
		rb[ii++] = ic;
	if (rn) {
		rb[0] = rn;	/* RUN count */
		ii--;		/* last inserted run */
		jp = rn << 1;	/* RUN = (sw,ew) */
		jp++;		/* 1st entry = RUN count */
	} else
		jp = 1;

	if (! put_buf(v, jp, rb))
		return 0;

	ic = RLC_START;
	rb[0] = rn = 0;
	ii = 1;
	is_start = FALSE;

	return 1;
}

void to_rlc()	/* process BYTE cb */
{
	WORD jp;		/* BitsPos of BYTE cb */

	if (cb) {
		if (! is_start) {
			if (cb == 0xFF) {
				rn++;	/* RUN count */
				is_start = TRUE;
				rb[ii++] = ic;
			} else { /* cb != 0xFF */
				jp = 0;	/* Bit 0 */
				while (jp < 8) {
					if ((cb & 0x80) != 0x00) { /* Bit reached */
						rn++;	/* RUN count */
						is_start = TRUE;
						rb[ii++] = ic + jp;
						while (++jp < 8) {
							cb <<= 1;
							if ((cb & 0x80) == 0x00) { /* RUN ends */
								rb[ii++] = ic + jp;
								is_start = FALSE;
								break;	/* inner while */
							}
						} /* wend */
					}
					cb <<= 1;
					jp++;
			}	}
		} else if (cb != 0xFF) { /* RUN continues */
			jp = 0;	/* Bit 0 */
			while (jp < 8) {
				if ((cb & 0x80) == 0x00) { /* empty Bit */
					rb[ii++] = ic + jp;
					is_start = FALSE;
					while (++jp < 8) {
						cb <<= 1;
						if ((cb & 0x80) != 0x00) { /* Bit reached */
							rn++;	/* RUN count */
							is_start = TRUE;
							rb[ii++] = ic + jp;
							break;	/* inner while */
						}
					} /* wend */
				}
				cb <<= 1;
				jp++;
			} /* wend */
		} /* else  cb == 0xFF  && RUN continues*/
	} else if (is_start) { /* cb == '0x00' */
		rb[ii++] = ic;
		is_start = FALSE;
	}
	ic += 8;
}