1 files changed, 72 insertions, 0 deletions
diff --git a/src/libdraw/md-load.c b/src/libdraw/md-load.c
new file mode 100644
index 00000000..6788fa90
--- /dev/null
+++ b/src/libdraw/md-load.c
@@ -0,0 +1,72 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+
+int
+_loadmemimage(Memimage *i, Rectangle r, uchar *data, int ndata)
+{
+	int y, l, lpart, rpart, mx, m, mr;
+	uchar *q;
+
+	if(!rectinrect(r, i->r))
+		return -1;
+	l = bytesperline(r, i->depth);
+	if(ndata < l*Dy(r))
+		return -1;
+	ndata = l*Dy(r);
+	q = byteaddr(i, r.min);
+	mx = 7/i->depth;
+	lpart = (r.min.x & mx) * i->depth;
+	rpart = (r.max.x & mx) * i->depth;
+	m = 0xFF >> lpart;
+	/* may need to do bit insertion on edges */
+	if(l == 1){	/* all in one byte */
+		if(rpart)
+			m ^= 0xFF >> rpart;
+		for(y=r.min.y; y<r.max.y; y++){
+			*q ^= (*data^*q) & m;
+			q += i->width*sizeof(u32int);
+			data++;
+		}
+		return ndata;
+	}
+	if(lpart==0 && rpart==0){	/* easy case */
+		for(y=r.min.y; y<r.max.y; y++){
+			memmove(q, data, l);
+			q += i->width*sizeof(u32int);
+			data += l;
+		}
+		return ndata;
+	}
+	mr = 0xFF ^ (0xFF >> rpart);
+	if(lpart!=0 && rpart==0){
+		for(y=r.min.y; y<r.max.y; y++){
+			*q ^= (*data^*q) & m;
+			if(l > 1)
+				memmove(q+1, data+1, l-1);
+			q += i->width*sizeof(u32int);
+			data += l;
+		}
+		return ndata;
+	}
+	if(lpart==0 && rpart!=0){
+		for(y=r.min.y; y<r.max.y; y++){
+			if(l > 1)
+				memmove(q, data, l-1);
+			q[l-1] ^= (data[l-1]^q[l-1]) & mr;
+			q += i->width*sizeof(u32int);
+			data += l;
+		}
+		return ndata;
+	}
+	for(y=r.min.y; y<r.max.y; y++){
+		*q ^= (*data^*q) & m;
+		if(l > 2)
+			memmove(q+1, data+1, l-2);
+		q[l-1] ^= (data[l-1]^q[l-1]) & mr;
+		q += i->width*sizeof(u32int);
+		data += l;
+	}
+	return ndata;
+}