1 files changed, 59 insertions, 0 deletions
diff --git a/appl/cmd/sum.b b/appl/cmd/sum.b
new file mode 100644
index 00000000..7e7a1335
--- /dev/null
+++ b/appl/cmd/sum.b
@@ -0,0 +1,59 @@
+implement Sum;
+
+include "sys.m";
+include "draw.m";
+include "crc.m";
+
+Sum : module
+{
+	init : fn(nil : ref Draw->Context, argv : list of string);
+};
+
+init(nil : ref Draw->Context, argv : list of string)
+{
+	sys := load Sys Sys->PATH;
+	stderr := sys->fildes(2);
+	crcm := load Crc Crc->PATH;
+	crcs := crcm->init(0, 0);
+	a := tl argv;
+	buf := array[Sys->ATOMICIO] of byte;
+	err := 0;
+	for ( ; a != nil; a = tl a) {
+		s := hd a;
+		(ok, d) := sys->stat(s);
+		if (ok < 0) {
+			sys->fprint(stderr, "sum: cannot get status of %s: %r\n", s);
+			err = 1;
+			continue;
+		}
+		if (d.mode & Sys->DMDIR)
+			continue;
+		fd := sys->open(s, Sys->OREAD);
+		if (fd == nil) {
+			sys->fprint(stderr, "sum: cannot open %s: %r\n", s);
+			err = 1;
+			continue;
+		}
+		crc := 0;
+		nbytes := big 0;
+		while((nr := sys->read(fd, buf, len buf)) > 0){
+			crc = crcm->crc(crcs, buf, nr);
+			nbytes += big nr;
+		}
+		if(nr < 0) {
+			sys->fprint(stderr, "sum: error reading %s: %r\n", s);
+			err = 1;
+		}
+		# encode the length but make n==0 not 0
+		l := int (nbytes & big 16rFFFFFFFF);
+		buf[0] = byte((l>>24)^16rCC);
+		buf[1] = byte((l>>16)^16r55);
+		buf[2] = byte((l>>8)^16rCC);
+		buf[3] = byte(l^16r55);
+		crc = crcm->crc(crcs, buf, 4);
+		sys->print("%.8ux %6bd %s\n", crc, nbytes, s);
+		crcm->reset(crcs);
+	}
+	if(err)
+		raise "fail:error";
+}