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smalliff.c
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C/C++ Source or Header
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1988-03-19
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3KB
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118 lines
#include <functions.h>
#include <intuition/intuition.h> /* Nice because it includes everything else */
#include <libraries/dos.h>
#include "smalliff.h"
/* Ali T. Ozer, Oct, Nov 1987 */
/* This code to read IFF pictures originally from D. John Hodgson's "view"
** program. LIMITATIONS : no masking, CATS/LISTS/PROPS. CAMG chunks
** are supported.
*/
/* Original Copyright:
** VIEW.C - tiny ILBM viewer; (c) 1986 DJH
*/
#define CRead(f,src,sz) if (Read (f, src, sz) == -1L) return (0);
int ReadILBM (fp, pic)
struct FileHandle *fp; /* An already "Open"ed AmigaDOS file handle */
PicInfoStruct *pic;
{
unsigned char cmap[MAXCOLORS][3];
ChunkHeader header;
ID id;
int cnt;
CRead(fp, &header, (long)sizeof(ChunkHeader));
if (header.ckID != ID_FORM) return (0); /* Not IFF */
CRead(fp, &id, (long)sizeof(id));
if (id != ID_ILBM) return (0); /* Not ILBM */
while (1) {
CRead(fp, &header, (long)sizeof(header));
if (header.ckID == ID_BODY) break;
switch(header.ckID) {
case ID_BMHD: CRead(fp, &(pic->bmhd), (long) sizeof(BitMapHeader)); break;
case ID_CMAP: CRead(fp, &(cmap[0][0]), header.ckSize);
pic->colorcount = (UBYTE)(header.ckSize/3); break;
case ID_CAMG: CRead(fp, &(pic->viewmodes), header.ckSize); break;
default: Seek(fp, WordAlign(header.ckSize), OFFSET_CURRENT); break;
}
}
pic->rawsourcesize = header.ckSize;
if ((pic->rawsource = AllocMem (header.ckSize, NULL)) == NULL)
return (0); /* Not enough memory */
CRead(fp, pic->rawsource, header.ckSize);
/* make some forced assumptions if CAMG chunk unavailable */
if (pic->viewmodes == NULL) {
if (pic->bmhd.w > MAXWIDTH) pic->viewmodes |= HIRES;
if (pic->bmhd.h > MAXHEIGHT) pic->viewmodes |= LACE;
}
for (cnt = 0; cnt < pic->colorcount; cnt++) {
pic->colortable[cnt] =
(((UWORD)cmap[cnt][0]) << 4L) |
(((UWORD)cmap[cnt][1])) |
(((UWORD)cmap[cnt][2]) >> 4L);
};
return (1);
}
Expand(bm, bmhd, sourcebuf) /* Fast line decompress/deinterleave */
struct BitMap *bm;
BitMapHeader *bmhd;
register char *sourcebuf;
{
register char n,*destbuf; /* in order of preferred allocation */
register short plane,rowbytes;
short linelen,i,curloc;
linelen=bmhd->w/8;
curloc = 0;
for (i=0;i<bmhd->h;i++) { /* process n lines/screen */
for (plane=0;plane<bmhd->nPlanes;plane++) { /* process n planes/line */
destbuf=(char *)(bm->Planes[plane])+curloc;
if (bmhd->compression == cmpByteRun1) { /* compressed screen? */
rowbytes=linelen;
while (rowbytes) { /* unpack until 1 scan-line complete */
n=*sourcebuf++; /* fetch block run marker */
/* uncompressed block? copy n bytes verbatim */
if (n>=0) {
movmem(sourcebuf,destbuf,(unsigned int)++n); rowbytes-=n;
destbuf+=n; sourcebuf+=n;
}
else { /* compressed block? expand n duplicate bytes */
n=-n+1; rowbytes-=n;
setmem(destbuf,(unsigned int)n,(unsigned int)*sourcebuf++);
destbuf+=n;
}
} /* finish unpacking line */
}
else { /* uncompressed? just copy */
movmem(sourcebuf,destbuf,(unsigned int)linelen);
sourcebuf+=linelen; destbuf+=linelen;
}
} /* finish interleaved planes, lines */
curloc += linelen;
}
}