1 files changed, 70 insertions, 0 deletions
diff --git a/appl/lib/convcs/gb2312_btos.b b/appl/lib/convcs/gb2312_btos.b
new file mode 100644
index 00000000..8a06a75f
--- /dev/null
+++ b/appl/lib/convcs/gb2312_btos.b
@@ -0,0 +1,70 @@
+implement Btos;
+
+include "sys.m";
+include "convcs.m";
+
+GBMAX : con 8795;
+
+GBDATA : con "/lib/convcs/gb2312";
+
+MAXINT : con 16r7fffffff;
+BADCHAR : con 16rFFFD;
+
+gbmap := "";
+
+init(nil : string): string
+{
+	sys := load Sys Sys->PATH;
+	fd := sys->open(GBDATA, Sys->OREAD);
+	if (fd == nil)
+		return sys->sprint("%s: %r", GBDATA);
+
+	buf := array[GBMAX * Sys->UTFmax] of byte;
+	nread := 0;
+	for (;nread < len buf;) {
+		n := sys->read(fd, buf[nread:], Sys->ATOMICIO);
+		if (n <= 0)
+			break;
+		nread += n;
+	}
+	gbmap = string buf[:nread];
+	if (len gbmap != GBMAX) {
+		gbmap = nil;
+		return sys->sprint("%s: corrupt data", GBDATA);
+	}
+	return nil;
+}
+
+btos(nil : Convcs->State, b : array of byte, n : int) : (Convcs->State, string, int)
+{
+	nbytes := 0;
+	str := "";
+
+	if (n == -1)
+		n = MAXINT;
+
+	font := -1;
+	for (i := 0; i < len b && len str < n; i++) {
+		c := int b[i];
+		ch := Sys->UTFerror;
+		if (font == -1) {
+			# idle state
+			if (c >= 16rA1) {
+				font = c;
+				continue;
+			}
+			ch = c;
+		} else {
+			# seen a font spec
+			if (c >= 16rA1) {
+				ix := (font - 16rA0)*100 + (c-16rA0);
+				ch = gbmap[ix];
+			}
+			font = -1;
+		}
+		str[len str] = ch;
+		nbytes = i + 1;
+	}
+	return (nil, str, nbytes);
+}
+