1 files changed, 64 insertions, 0 deletions
diff --git a/libXg/rdbitmapfile.c b/libXg/rdbitmapfile.c
new file mode 100644
index 0000000..ae8ec52
--- /dev/null
+++ b/libXg/rdbitmapfile.c
@@ -0,0 +1,64 @@
+/* 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;
+}