lib: pull base-guessing logic to helper function

The default base is 10 unless there is a leading zero, in which
case the base will be guessed as 8.

The base will only be guesed as 16 when the string starts with '0x'
the third character is a valid hex digit.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 42 insertions, 38 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 4c6674a41ed..1a9c6b9b494 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' && isxdigit(cp[2]))
+                        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);
 
 /**