[PATCH v2 1/3] Add string parsing function get_next_ulong

[Stefan Assmann <sassmann@xxxxxxxxx>]

Adding this function to allow easy parsing of unsigned long values from the
beginning of strings. Convenience function to parse pointers from the kernel
command line.

Signed-off-by: Stefan Assmann <sassmann@xxxxxxxxx>
Acked-by: Tony Luck <tony.luck@xxxxxxxxx>
Acked-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 include/linux/kernel.h |    1 +
 lib/cmdline.c          |   35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 00cec4d..98c1916 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -280,6 +280,7 @@ extern int vsscanf(const char *, const char *, va_list)
 
 extern int get_option(char **str, int *pint);
 extern char *get_options(const char *str, int nints, int *ints);
+extern int get_next_ulong(char **str, unsigned long *val, char sep, int base);
 extern unsigned long long memparse(const char *ptr, char **retptr);
 
 extern int core_kernel_text(unsigned long addr);
diff --git a/lib/cmdline.c b/lib/cmdline.c
index f5f3ad8..82a6616 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -114,6 +114,41 @@ char *get_options(const char *str, int nints, int *ints)
 }
 
 /**
+ *	get_next_ulong - Parse unsigned long at the beginning of a string
+ *	@strp: (output) String to be parsed
+ *	@val: (output) unsigned long carrying the result
+ *	@sep: character specifying the separator
+ *	@base: number system of the parsed value
+ *
+ *	This function parses an unsigned long value at the beginning of a
+ *	string. The string may begin with a separator or an unsigned long
+ *	value.
+ *	After the function is run val will contain the parsed value and strp
+ *	will point to the character *after* the parsed unsigned long.
+ *
+ *	In the error case 0 is returned, val and *strp stay unaltered.
+ *	Otherwise return 1.
+ */
+int get_next_ulong(char **strp, unsigned long *val, char sep, int base)
+{
+	char *tmp;
+
+	if (!strp || !(*strp))
+		return 0;
+
+	tmp = *strp;
+	if (*tmp == sep)
+		tmp++;
+
+	*val = simple_strtoul(tmp, strp, base);
+
+	if (tmp == *strp)
+		return 0; /* no new value parsed */
+	else
+		return 1;
+}
+
+/**
  *	memparse - parse a string with mem suffixes into a number
  *	@ptr: Where parse begins
  *	@retptr: (output) Optional pointer to next char after parse completes
-- 
1.7.4

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