[PATCH 1/3] lib: pull base-guessing logic to helper function

[PATCH 1/3] lib: pull base-guessing logic to helper function

[Harvey Harrison]

There is a small behavior change in this patch, previously, when
no base was specified and the string began with 0x? the base would
be guessed as 8, unless isxdigit(?) was true.  This would then return
0 as 'x' was larger than 8.  Now, the base is always guessed as 16 if
the string starts with '0x'

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
 lib/vsprintf.c |   84 +++++++++++++++++++++++++++++--------------------------
 1 files changed, 44 insertions(+), 40 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index c399bc1..3f8c428 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -32,6 +32,18 @@
 /* Works only for digits and letters, but small and fast */
 #define TOLOWER(x) ((x) | 0x20)
 
+static unsigned int simple_guess_base(const char *cp)
+{
+	if (cp[0] == '0') {
+		if (TOLOWER(cp[1]) == 'x')
+			return 16;
+		else
+			return 8;
+	} else {
+		return 10;
+	}
+}
+
 /**
  * simple_strtoul - convert a string to an unsigned long
  * @cp: The start of the string
@@ -40,32 +52,28 @@
  */
 unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
 {
-	unsigned long result = 0,value;
+	unsigned long result = 0;
 
-	if (!base) {
-		base = 10;
-		if (*cp == '0') {
-			base = 8;
-			cp++;
-			if ((TOLOWER(*cp) == 'x') && isxdigit(cp[1])) {
-				cp++;
-				base = 16;
-			}
-		}
-	} else if (base == 16) {
-		if (cp[0] == '0' && TOLOWER(cp[1]) == 'x')
-			cp += 2;
-	}
-	while (isxdigit(*cp) &&
-	       (value = isdigit(*cp) ? *cp-'0' : TOLOWER(*cp)-'a'+10) < base) {
-		result = result*base + value;
+	if (!base)
+		base = simple_guess_base(cp);
+
+	if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
+		cp += 2;
+
+	while (isxdigit(*cp)) {
+		unsigned int value;
+
+		value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
+		if (value >= base)
+			break;
+		result = result * base + value;
 		cp++;
 	}
+
 	if (endp)
 		*endp = (char *)cp;
 	return result;
 }
-
 EXPORT_SYMBOL(simple_strtoul);
 
 /**
@@ -91,32 +99,28 @@ EXPORT_SYMBOL(simple_strtol);
  */
 unsigned long long simple_strtoull(const char *cp,char **endp,unsigned int base)
 {
-	unsigned long long result = 0,value;
+	unsigned long long result = 0;
 
-	if (!base) {
-		base = 10;
-		if (*cp == '0') {
-			base = 8;
-			cp++;
-			if ((TOLOWER(*cp) == 'x') && isxdigit(cp[1])) {
-				cp++;
-				base = 16;
-			}
-		}
-	} else if (base == 16) {
-		if (cp[0] == '0' && TOLOWER(cp[1]) == 'x')
-			cp += 2;
-	}
-	while (isxdigit(*cp)
-	 && (value = isdigit(*cp) ? *cp-'0' : TOLOWER(*cp)-'a'+10) < base) {
-		result = result*base + value;
+	if (!base)
+		base = simple_guess_base(cp);
+
+	if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
+		cp += 2;
+
+	while (isxdigit(*cp)) {
+		unsigned int value;
+
+		value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
+		if (value >= base)
+			break;
+		result = result * base + value;
 		cp++;
 	}
+
 	if (endp)
 		*endp = (char *)cp;
 	return result;
 }
-
 EXPORT_SYMBOL(simple_strtoull);
 
 /**
-- 
1.6.0.2.405.g3cc38

Re: [PATCH 1/3] lib: pull base-guessing logic to helper function

[Andrew Morton]

On Wed, 17 Sep 2008 11:22:02 -0700
Harvey Harrison <harvey.harrison@gmail.com> wrote:

> There is a small behavior change in this patch, previously, when
> no base was specified and the string began with 0x? the base would
> be guessed as 8, unless isxdigit(?) was true.  This would then return
> 0 as 'x' was larger than 8.  Now, the base is always guessed as 16 if
> the string starts with '0x'

hm.  I'd call that a bugfix.