src/libfreeswan/ttoul.c

@@ -0,0 +1,91 @@
+/*
+ * convert from text form of unsigned long to binary
+ * Copyright (C) 2000  Henry Spencer.
+ * 
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Library General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/lgpl.txt>.
+ * 
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
+ * License for more details.
+ *
+ * RCSID $Id: ttoul.c,v 1.1 2004/03/15 20:35:26 as Exp $
+ */
+#include "internal.h"
+#include "freeswan.h"
+
+/*
+ - ttoul - convert text substring to unsigned long number
+ */
+const char *			/* NULL for success, else string literal */
+ttoul(src, srclen, base, resultp)
+const char *src;
+size_t srclen;			/* 0 means strlen(src) */
+int base;			/* 0 means figure it out */
+unsigned long *resultp;
+{
+	const char *stop;
+	static char hex[] = "0123456789abcdef";
+	static char uchex[] = "0123456789ABCDEF";
+	int d;
+	char c;
+	char *p;
+	unsigned long r;
+	unsigned long rlimit;
+	int dlimit;
+
+	if (srclen == 0)
+		srclen = strlen(src);
+	if (srclen == 0)
+		return "empty string";
+
+	if (base == 0) {
+		if (srclen > 2 && *src == '0' &&
+					(*(src+1) == 'x' || *(src+1) == 'X'))
+			return ttoul(src+2, srclen-2, 16, resultp);
+		if (srclen > 1 && *src == '0')
+			return ttoul(src+1, srclen-1, 8, resultp);
+		return ttoul(src, srclen, 10, resultp);
+	}
+	if (base != 8 && base != 10 && base != 16)
+		return "unsupported number base";
+
+	r = 0;
+	stop = src + srclen;
+	if (base == 16) {
+		while (src < stop) {
+			c = *src++;
+			p = strchr(hex, c);
+			if (p != NULL)
+				d = p - hex;
+			else {
+				p = strchr(uchex, c);
+				if (p == NULL)
+					return "non-hex digit in hex number";
+				d = p - uchex;
+			}
+			r = (r << 4) | d;
+		}
+		/* defer length check to catch invalid digits first */
+		if (srclen > sizeof(unsigned long) * 2)
+			return "hex number too long";
+	} else {
+		rlimit = ULONG_MAX / base;
+		dlimit = (int)(ULONG_MAX - rlimit*base);
+		while (src < stop) {
+			c = *src++;
+			d = c - '0';
+			if (d < 0 || d >= base)
+				return "non-digit in number";
+			if (r > rlimit || (r == rlimit && d > dlimit))
+				return "unsigned-long overflow";
+			r = r*base + d;
+		}
+	}
+
+	*resultp = r;
+	return NULL;
+}