lib: allow memparse() to accept a NULL and ignorable second parm
Extend memparse() to allow the caller to use a NULL second parameter, which
would represent no interest in returning the address of the end of the parsed
string.
In numerous cases, callers invoke memparse() to parse a possibly-suffixed
string (such as "64K" or "2G" or whatever) and define a character pointer to
accept the end pointer being returned by memparse() even though they have no
interest in it and promptly throw it away.
This (backward-compatible) enhancement allows callers to use NULL in the cases
where they just don't care about getting back that end pointer.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/cmdline.c b/lib/cmdline.c
index f596c08d..5ba8a94 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -116,7 +116,7 @@
/**
* memparse - parse a string with mem suffixes into a number
* @ptr: Where parse begins
- * @retptr: (output) Pointer to next char after parse completes
+ * @retptr: (output) Optional pointer to next char after parse completes
*
* Parses a string into a number. The number stored at @ptr is
* potentially suffixed with %K (for kilobytes, or 1024 bytes),
@@ -126,11 +126,13 @@
* megabyte, or one gigabyte, respectively.
*/
-unsigned long long memparse (char *ptr, char **retptr)
+unsigned long long memparse(char *ptr, char **retptr)
{
- unsigned long long ret = simple_strtoull (ptr, retptr, 0);
+ char *endptr; /* local pointer to end of parsed string */
- switch (**retptr) {
+ unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
+
+ switch (*endptr) {
case 'G':
case 'g':
ret <<= 10;
@@ -140,10 +142,14 @@
case 'K':
case 'k':
ret <<= 10;
- (*retptr)++;
+ endptr++;
default:
break;
}
+
+ if (retptr)
+ *retptr = endptr;
+
return ret;
}