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/* Copyright (c) 1992 AT&T - All rights reserved. */
#include <libc.h>
#include <libg.h>
#include "libgint.h"
#define CHUNK 6000
Bitmap*
rdbitmapfile(int fd)
{
char hdr[5*12+1];
unsigned char *data;
long dy, px;
unsigned long l, t, n;
long miny, maxy;
Rectangle r;
int ld;
Bitmap *b;
if(read(fd, hdr, 5*12)!=5*12)
berror("rdbitmapfile read");
ld = atoi(hdr+0*12);
r.min.x = atoi(hdr+1*12);
r.min.y = atoi(hdr+2*12);
r.max.x = atoi(hdr+3*12);
r.max.y = atoi(hdr+4*12);
if(ld<0 || ld>1)
berror("rdbitmapfile ldepth");
if(r.min.x>r.max.x || r.min.y>r.max.y)
berror("rdbitmapfile rectangle");
miny = r.min.y;
maxy = r.max.y;
px = 1<<(3-ld); /* pixels per byte */
/* set l to number of bytes of data per scan line */
if(r.min.x >= 0)
l = (r.max.x+px-1)/px - r.min.x/px;
else{ /* make positive before divide */
t = (-r.min.x)+px-1;
t = (t/px)*px;
l = (t+r.max.x+px-1)/px;
}
b = balloc(r, ld);
if(b == 0)
return 0;
data = (unsigned char *)malloc(CHUNK);
if(data == 0)
berror("rdbitmapfile malloc");
while(maxy > miny){
dy = maxy - miny;
if(dy*l > CHUNK)
dy = CHUNK/l;
n = dy*l;
if(read(fd, data, n) != n){
free(data);
bfree(b);
berror("rdbitmapfile read");
}
wrbitmap(b, miny, miny+dy, data);
miny += dy;
}
free(data);
return b;
}
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