1 #include <u.h>
2 #include <libc.h>
3 #include <draw.h>
4 #include <memdraw.h>
5 
6 int
7 _loadmemimage(Memimage *i, Rectangle r, uchar *data, int ndata)
8 {
9 	int y, l, lpart, rpart, mx, m, mr;
10 	uchar *q;
11 
12 	if(!rectinrect(r, i->r))
13 		return -1;
14 	l = bytesperline(r, i->depth);
15 	if(ndata < l*Dy(r))
16 		return -1;
17 	ndata = l*Dy(r);
18 	q = byteaddr(i, r.min);
19 	mx = 7/i->depth;
20 	lpart = (r.min.x & mx) * i->depth;
21 	rpart = (r.max.x & mx) * i->depth;
22 	m = 0xFF >> lpart;
23 	/* may need to do bit insertion on edges */
24 	if(l == 1){	/* all in one byte */
25 		if(rpart)
26 			m ^= 0xFF >> rpart;
27 		for(y=r.min.y; y<r.max.y; y++){
28 			*q ^= (*data^*q) & m;
29 			q += i->width*sizeof(u32int);
30 			data++;
31 		}
32 		return ndata;
33 	}
34 	if(lpart==0 && rpart==0){	/* easy case */
35 		for(y=r.min.y; y<r.max.y; y++){
36 			memmove(q, data, l);
37 			q += i->width*sizeof(u32int);
38 			data += l;
39 		}
40 		return ndata;
41 	}
42 	mr = 0xFF ^ (0xFF >> rpart);
43 	if(lpart!=0 && rpart==0){
44 		for(y=r.min.y; y<r.max.y; y++){
45 			*q ^= (*data^*q) & m;
46 			if(l > 1)
47 				memmove(q+1, data+1, l-1);
48 			q += i->width*sizeof(u32int);
49 			data += l;
50 		}
51 		return ndata;
52 	}
53 	if(lpart==0 && rpart!=0){
54 		for(y=r.min.y; y<r.max.y; y++){
55 			if(l > 1)
56 				memmove(q, data, l-1);
57 			q[l-1] ^= (data[l-1]^q[l-1]) & mr;
58 			q += i->width*sizeof(u32int);
59 			data += l;
60 		}
61 		return ndata;
62 	}
63 	for(y=r.min.y; y<r.max.y; y++){
64 		*q ^= (*data^*q) & m;
65 		if(l > 2)
66 			memmove(q+1, data+1, l-2);
67 		q[l-1] ^= (data[l-1]^q[l-1]) & mr;
68 		q += i->width*sizeof(u32int);
69 		data += l;
70 	}
71 	return ndata;
72 }