/*
 *
 * File:	pack.c
 * Project:	libpict 1.1
 * Date:	Fri, May 19, 1995
 * (c) SPDsoft 1992-95
 *
 */
#include <string.h>
#include <stdio.h>
#include "pict.h"

#define	MAX_CF	127
#define	MIN_CF	-127
#define	MCFV	128	/*MAX_CF+1*/
#define	PSZ	BUFSIZ	/* Transm. optima a disco */

#if defined(__STDC__) || defined(THINK_C) || !defined(_SUN_)
#	define _SIGNED	signed
#else
#	ifndef _SIGNED
#	define _SIGNED
#	endif
#endif

U_char	packed[PSZ],
	*pEnd,
	*uEnd;

int i;

#define	GETp	{ if (p==pEnd)				\
		  {					\
			  incre=MIN2(psz,PSZ);		\
			  fread( (char*)packed,BYTE,(size_t)incre,file); \
			  psz -= incre;			\
			  p=packed; pEnd = p+incre;	\
		  }					\
		}
		
#define MIN3(a,b,c)	( i=((a)<(b)?(a):(b)),		\
			(i<(c)?i:(c) ))
		
#define MIN2(a,b)	 ((a)<(b)?(a):(b))


#ifdef  __STDC__
short int pack_bytes( U_char *unpacked, short int usz, FILE *file )
#else   /* __STDC__ */
short int pack_bytes( unpacked, usz, file )
	U_char *unpacked; short int usz; FILE *file ;
#endif  /* __STDC__ */
{
	U_char			*u, *p;		/* index unpacked, packed */
	_SIGNED char		*cf;		/* counter flag pointer */
	int			flgz;		/* zero flag */
	unsigned short int	incre,
				psz=0;

	u=unpacked;

	uEnd=unpacked+usz;
	pEnd=packed+PSZ-2;

	while( u<uEnd )
	{
		p=packed;
	
		cf=(_SIGNED char*)p++;
		*cf=0;
		*p=*u++;
	
		for(;( u<uEnd )&&( p<pEnd );u++)
		{
			flgz = (*u == *p);
			if((*cf==MIN_CF)||((*cf==MAX_CF)&&(!flgz)))
			{
				/* Nuevo bloque */
				cf=(_SIGNED char *)++p;
				(*cf) = 0;
				*(++p)=*u;
			}
			else
			{
				if(flgz) /* Mas de bloque rep */
				{
					(*cf)--;
					if(*cf>=0) /* camb. nuevo rep */
					{
						cf=(_SIGNED char*)p;
						(*cf)=-1;
						*(++p)=*u;
					}
				}
				else
				{
					if(*cf>=0) /* Mas de bloque no rep */
						(*cf)++;
					else	/* Nuevo bloque tipo ? */
					{
						cf=(_SIGNED char *)++p;
						(*cf)=0;
					}

					*(++p)=*u;
				}
			}
		} /* de for */

		p++;

/*
 *	esta funcion puede ( muy excepcionalmente ) hacer
 *	que los bytes empaquetados ocupen m.s que
 *	los originales, esto puede tener consecuencias
 *	fatales si se usa en ficheros PICT en los que
 *	rowBytes <= 0x00fa  ( desborda
 *	la variable corresponiente en el archivo )
 */	 
		if ( (int)(u-unpacked)*1.1 < (int)(p-packed ))
		/* esto se ejecutara rara vez */
		for(u=unpacked,p=packed;(u < uEnd)&&(p<pEnd);)
		{
			incre = MIN3(MCFV,uEnd-u,pEnd-p+1);
			for(*p++ = incre-1;incre>0;incre--)
					*p++ = *u++;
		}
	
		fwrite((char *)packed,(size_t)(p-packed),1,file);
		psz += p-packed ;
		unpacked = u;
	
	}/*while*/

	return psz;
}

#ifdef  __STDC__
short int unpack_bytes( U_char *unpacked, short int psz, FILE *file )
#else   /* __STDC__ */
short int unpack_bytes( unpacked, psz, file )
	U_char *unpacked; short int psz; FILE *file ;
#endif  /* __STDC__ */
{
	U_char			*u, *p;	/* index unpacked, packed */
	_SIGNED char		cf;	/* counter flag */
	unsigned short int	incre;

	pEnd=packed+PSZ;

	u=unpacked;
	p=pEnd;

	while((psz>0)||(p!=pEnd))
	{
		GETp;
		cf = (_SIGNED char) *p++;

		if(cf >=0)
		{
			for(;cf>=0;cf--)
			{
				GETp;	
				*u++ = *p++;
			}
		}
		else
		{
			GETp;
			for(;cf<=0;cf++) *u++ = *p;
			p++;
		}
	}

	return	u-unpacked;
}