a

libc/u16.c

@@ -0,0 +1,53 @@
+#include <u.h>
+#include <libc.h>
+static char t16e[] = "0123456789ABCDEF";
+
+int
+dec16(uchar *out, int lim, char *in, int n)
+{
+	int c, w = 0, i = 0;
+	uchar *start = out;
+	uchar *eout = out + lim;
+
+	while(n-- > 0){
+		c = *in++;
+		if('0' <= c && c <= '9')
+			c = c - '0';
+		else if('a' <= c && c <= 'z')
+			c = c - 'a' + 10;
+		else if('A' <= c && c <= 'Z')
+			c = c - 'A' + 10;
+		else
+			continue;
+		w = (w<<4) + c;
+		i++;
+		if(i == 2){
+			if(out + 1 > eout)
+				goto exhausted;
+			*out++ = w;
+			w = 0;
+			i = 0;
+		}
+	}
+exhausted:
+	return out - start;
+}
+
+int
+enc16(char *out, int lim, uchar *in, int n)
+{
+	uint c;
+	char *eout = out + lim;
+	char *start = out;
+
+	while(n-- > 0){
+		c = *in++;
+		if(out + 2 >= eout)
+			goto exhausted;
+		*out++ = t16e[c>>4];
+		*out++ = t16e[c&0xf];
+	}
+exhausted:
+	*out = 0;
+	return out - start;
+}