Initial revision
diff --git a/src/libdraw/creadimage.c b/src/libdraw/creadimage.c
new file mode 100644
index 0000000..99c4275
--- /dev/null
+++ b/src/libdraw/creadimage.c
@@ -0,0 +1,113 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+
+Image *
+creadimage(Display *d, int fd, int dolock)
+{
+ char hdr[5*12+1];
+ Rectangle r;
+ int m, nb, miny, maxy, new, ldepth, ncblock;
+ uchar *buf, *a;
+ Image *i;
+ u32int chan;
+
+ if(readn(fd, hdr, 5*12) != 5*12)
+ return nil;
+
+ /*
+ * distinguish new channel descriptor from old ldepth.
+ * channel descriptors have letters as well as numbers,
+ * while ldepths are a single digit formatted as %-11d.
+ */
+ new = 0;
+ for(m=0; m<10; m++){
+ if(hdr[m] != ' '){
+ new = 1;
+ break;
+ }
+ }
+ if(hdr[11] != ' '){
+ werrstr("creadimage: bad format");
+ return nil;
+ }
+ if(new){
+ hdr[11] = '\0';
+ if((chan = strtochan(hdr)) == 0){
+ werrstr("creadimage: bad channel string %s", hdr);
+ return nil;
+ }
+ }else{
+ ldepth = ((int)hdr[10])-'0';
+ if(ldepth<0 || ldepth>3){
+ werrstr("creadimage: bad ldepth %d", ldepth);
+ return nil;
+ }
+ chan = drawld2chan[ldepth];
+ }
+ 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(r.min.x>r.max.x || r.min.y>r.max.y){
+ werrstr("creadimage: bad rectangle");
+ return nil;
+ }
+
+ if(dolock)
+ lockdisplay(d);
+ i = allocimage(d, r, chan, 0, 0);
+ if(dolock)
+ unlockdisplay(d);
+ if(i == nil)
+ return nil;
+ ncblock = _compblocksize(r, i->depth);
+ buf = malloc(ncblock);
+ if(buf == nil)
+ goto Errout;
+ miny = r.min.y;
+ while(miny != r.max.y){
+ if(readn(fd, hdr, 2*12) != 2*12){
+ Errout:
+ if(dolock)
+ lockdisplay(d);
+ Erroutlock:
+ freeimage(i);
+ if(dolock)
+ unlockdisplay(d);
+ free(buf);
+ return nil;
+ }
+ maxy = atoi(hdr+0*12);
+ nb = atoi(hdr+1*12);
+ if(maxy<=miny || r.max.y<maxy){
+ werrstr("creadimage: bad maxy %d", maxy);
+ goto Errout;
+ }
+ if(nb<=0 || ncblock<nb){
+ werrstr("creadimage: bad count %d", nb);
+ goto Errout;
+ }
+ if(readn(fd, buf, nb)!=nb)
+ goto Errout;
+ if(dolock)
+ lockdisplay(d);
+ a = bufimage(i->display, 21+nb);
+ if(a == nil)
+ goto Erroutlock;
+ a[0] = 'Y';
+ BPLONG(a+1, i->id);
+ BPLONG(a+5, r.min.x);
+ BPLONG(a+9, miny);
+ BPLONG(a+13, r.max.x);
+ BPLONG(a+17, maxy);
+ if(!new) /* old image: flip the data bits */
+ _twiddlecompressed(buf, nb);
+ memmove(a+21, buf, nb);
+ if(dolock)
+ unlockdisplay(d);
+ miny = maxy;
+ }
+ free(buf);
+ return i;
+}
