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Subject[PATCH] 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.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>

---

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.

compile-tested on x86.

diff --git a/lib/cmdline.c b/lib/cmdline.c
index f596c08..34129cf 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -116,7 +116,7 @@ char *get_options(const char *str, int nints, int *ints)
/**
* 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),
@@ -128,9 +128,11 @@ char *get_options(const char *str, int nints, int *ints)

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 +142,15 @@ unsigned long long memparse (char *ptr, char **retptr)
case 'K':
case 'k':
ret <<= 10;
- (*retptr)++;
+ endptr++;
default:
break;
}
+
+ if (retptr) {
+ *retptr = endptr;
+ }
+
return ret;
}

========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
Have classroom, will lecture.
http://crashcourse.ca Waterloo, Ontario, CANADA
========================================================================

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