/**************************************
**
** F16.C : Code to read 16-bit fractal data sets.  Uses
** strictly Targa16 type 10 files (run-length encoded 16-bit RGB).
*/

/* Lee Daniel Crocker	   CompuServe: 73407,2030   <== Preferred
** 1380 Jewett Ave.		  BIX: lcrocker
** Pittsburg, CA  94565        Usenet: ...!ames!pacbell!sactoh0!siva!lee
**
** This code is hereby placed in the public domain.  You are free to
** use, modify, usurp, laugh at, destroy, or otherwise abuse it in any
** way you see fit.
**
** "If you steal from one author it's plagiarism; if you steal from
** many it's research."  --Wilson Mizner
*/

/* 16 bit .tga files were generated for continuous potential "potfile"s
   from version 9.? thru version 14.  Replaced by double row gif type
   file (.pot) in version 15.  Delete this code after a few more revs.
   The part which wrote 16 bit .tga files has already been deleted.
*/

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include "targa_lc.h"
#include "prototyp.h"

#ifndef XFRACT
extern char rlebuf[258];    /* RLE-state variables */
#else
char rlebuf[258];    /* RLE-state variables */
#endif
static int state, count, bufp;

/**************************************
**
** Open previously saved Targa16 type 10 file filling in hs, vs, and
** csize with values in the header.  If *csize is not zero, the block
** pointed to by cp is filled with the comment block.  The caller
** _must_ allocate 256 bytes for this purpose before calling.
*/

FILE *t16_open(char *fname, int *hs, int *vs, int *csize, U8 *cp)
{
    char filename[64];
    U8 header[HEADERSIZE];
    FILE *fp;

    strcpy(filename, fname);
    if (strchr(filename, '.') == NULL) strcat(filename, ".TGA");
    if ((fp = fopen(filename, READMODE)) == NULL) return NULL;

    fread(header, HEADERSIZE, 1, fp);
    if ((header[O_FILETYPE] != T_RLERGB) || (header[O_ESIZE] != 16)) {
	fclose(fp);
	return NULL;
    }
    GET16(header[O_HSIZE], *hs);
    GET16(header[O_VSIZE], *vs);
    if (*csize = header[O_COMMENTLEN]) fread(cp, *csize, 1, fp);

    state = count = bufp = 0;
    return fp;
}

int t16_getline(FILE *fp, int hs, U16 *data)
{
    int i;

    for (i=0; i<hs; ++i) {
	if (state == 0) {
	    bufp = 0;
	    if ((count = getc(fp)) > 127) {
		state = 1;
		count -= 127;
		fread(rlebuf, 2, 1, fp);
	    } else {
		state = 2;
		++count;
		fread(rlebuf, 2, count, fp);
	    }
	}
	GET16(rlebuf[bufp], data[i]);
	if (--count == 0) state = 0;
	if (state == 2) bufp += 2;
    }
    return 0;
}