1 files changed, 105 insertions, 0 deletions
diff --git a/libc/stdlib/strtoul.c b/libc/stdlib/strtoul.c
new file mode 100644
index 00000000..754e7db4
--- /dev/null
+++ b/libc/stdlib/strtoul.c
@@ -0,0 +1,105 @@
+/******************************************************************************
+ * Copyright (c) 2004, 2008 IBM Corporation
+ * All rights reserved.
+ * This program and the accompanying materials
+ * are made available under the terms of the BSD License
+ * which accompanies this distribution, and is available at
+ * http://www.opensource.org/licenses/bsd-license.php
+ *
+ * Contributors:
+ *     IBM Corporation - initial implementation
+ *****************************************************************************/
+
+#include <stdlib.h>
+
+unsigned long int strtoul(const char *S, char **PTR,int BASE)
+{
+	unsigned long rval = 0;
+	short int digit;
+	// *PTR is S, unless PTR is NULL, in which case i override it with my own ptr
+	char* ptr;
+	if (PTR == 0)
+	{
+		//override
+		PTR = &ptr;
+	}
+	// i use PTR to advance through the string
+	*PTR = (char *) S;
+	//check if BASE is ok
+	if ((BASE < 0) || BASE > 36)
+	{
+		return 0;
+	}
+	// ignore white space at beginning of S
+	while ((**PTR == ' ')
+			|| (**PTR == '\t')
+			|| (**PTR == '\n')
+			|| (**PTR == '\r')
+			)
+	{
+		(*PTR)++;
+	}
+	// if BASE is 0... determine the base from the first chars...
+	if (BASE == 0)
+	{
+		// if S starts with "0x", BASE = 16, else 10
+		if ((**PTR == '0') && (*((*PTR)+1) == 'x'))
+		{
+			BASE = 16;
+			(*PTR)++;
+			(*PTR)++;
+		}
+		else
+		{
+			BASE = 10;
+		}
+	}
+	if (BASE == 16)
+	{
+		// S may start with "0x"
+		if ((**PTR == '0') && (*((*PTR)+1) == 'x'))
+		{
+			(*PTR)++;
+			(*PTR)++;
+		}
+	}
+	//until end of string
+	while (**PTR)
+	{
+		if (((**PTR) >= '0') && ((**PTR) <='9'))
+		{
+			//digit (0..9)
+			digit = **PTR - '0';
+		}
+		else if (((**PTR) >= 'a') && ((**PTR) <='z'))
+		{
+			//alphanumeric digit lowercase(a (10) .. z (35) )
+			digit = (**PTR - 'a') + 10;
+		}
+		else if (((**PTR) >= 'A') && ((**PTR) <='Z'))
+		{
+			//alphanumeric digit uppercase(a (10) .. z (35) )
+			digit = (**PTR - 'A') + 10;
+		}
+		else
+		{
+			//end of parseable number reached...
+			break;
+		}
+		if (digit < BASE)
+		{
+			rval = (rval * BASE) + digit;
+		}
+		else
+		{
+			//digit found, but its too big for current base
+			//end of parseable number reached...
+			break;
+		}
+		//next...
+		(*PTR)++;
+	}
+	//done
+	return rval;
+}
+