/*
	File       : BUF.C
	Description: Buffered File I/O
	Author     : Peter H. Michalicka
	Environment: HP-UX 8.05
*/

#include <stdio.h>
#ifndef WIN32
#include <unistd.h>
#endif
#include "tiff.h"

extern WorkFile t;
extern IMAGE im;
extern long *SOffs;
extern long *SBCs;
extern BYTE *iob;
extern int nstrip;
extern BYTE TIFFBitRevTable[256];

char *msg_fopen = "Cant open file <%s>";
char *msg_fwrite = "Cant write to file <%s>";
char *msg_fread = "Cant read from file <%s>";

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

	/* Code */

int open_ibuf(fnam)
char *fnam;
{
	t.fnam = fnam;

	if ((t.fpi = fopen(fnam, "rb")) == NULL)
		return error(msg_fopen, fnam);

	return TRUE;
}

int fillbuf()
{
	if ((t.ilen = fread((char *)t.ibuf, 1, BLKSIZE, t.fpi)) == 0)
		return error(msg_fread, t.fnam);
	t.ipos = 0;

	return TRUE;
}

int fillstrip()
{
	BYTE *ptr, *maxptr;

	t.ipos = 0;
	fseek(t.fpi, SOffs[nstrip], SEEK_SET);

	if ((t.ilen = fread((char *)iob, 1, SBCs[nstrip], t.fpi)) == 0)
		return error(msg_fread, t.fnam);

	ptr = iob;
	maxptr = ptr + t.ilen;

	if (im.FillOrder == 2) {
		do {
			*ptr = TIFFBitRevTable[*ptr];
		} while (++ptr < maxptr);
	}
	nstrip++;

	return TRUE;
}

void getbuf(size, ptr)
int size;	/* (I) .. get size Bytes to ptr */
BYTE *ptr;	/* (O) .. Buffer Pointer */
{
	int j = 0;

	if ((t.ipos+size) >= t.ilen) {
		while (t.ipos < t.ilen) {
			*ptr++ = t.ibuf[t.ipos++];
			j++;
		}
		t.ipos = 0;
		if ((t.ilen = fread((char *)t.ibuf, 1, BLKSIZE, t.fpi)) == 0)
			if ((size-j) != 0)
				error("Invalid End Of File", NULL);

		while (j < size) {
			*ptr++ = t.ibuf[t.ipos++];
			j++;
		}
	} else {
		while (j < size) {
			*ptr++ = t.ibuf[t.ipos++];
			j++;
	}	}
}