[Suspend2][ 11/13] [Suspend2] snprintf_used function

[Nigel Cunningham <nigel@suspend2.net>]

The normal snprintf function tells you how many characters would have been
appended to a buffer if it was large enough. For Suspend2, we want to know
how many characters were actually added. This variant of the routine does
that.

Signed-off-by: Nigel Cunningham <nigel@suspend2.net>

 include/linux/kernel.h |    2 ++
 lib/vsprintf.c         |   23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index f4fc576..5e99865 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -108,6 +108,8 @@ extern int vsprintf(char *buf, const cha
 	__attribute__ ((format (printf, 2, 0)));
 extern int snprintf(char * buf, size_t size, const char * fmt, ...)
 	__attribute__ ((format (printf, 3, 4)));
+extern int snprintf_used(char *buffer, int buffer_size,
+		const char *fmt, ...);
 extern int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 	__attribute__ ((format (printf, 3, 0)));
 extern int scnprintf(char * buf, size_t size, const char * fmt, ...)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index b07db5c..fccee2c 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -236,6 +236,29 @@ static char * number(char * buf, char * 
 	return buf;
 }
 
+/*
+ * vsnprintf_used
+ *
+ * Functionality    : Print a string with parameters to a buffer of a 
+ *                    limited size. Unlike vsnprintf, we return the number
+ *                    of bytes actually put in the buffer, not the number
+ *                    that would have been put in if it was big enough.
+ */
+int snprintf_used(char *buffer, int buffer_size, const char *fmt, ...)
+{
+	int result;
+	va_list args;
+
+	if (!buffer_size)
+		return 0;
+
+	va_start(args, fmt);
+	result = vsnprintf(buffer, buffer_size, fmt, args);
+	va_end(args);
+
+	return result > buffer_size ? buffer_size : result;
+}
+
 /**
  * vsnprintf - Format a string and place it in a buffer
  * @buf: The buffer to place the result into

--
Nigel Cunningham		nigel at suspend2 dot net