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Subject[PATCH] video: add a clamp() macro to kernel.h and replace two existing defs
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Clamps a value to be within a given range with strict typechecking.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
akpm: I've submitted a clamp_t version previously for use in libata.
You may want to just roll this into that one so clamp/clamp_t go in
together.
drivers/media/video/bt8xx/bttvp.h | 2 --
drivers/media/video/usbvideo/vicam.c | 6 ------
include/linux/kernel.h | 13 +++++++++++++
3 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/media/video/bt8xx/bttvp.h b/drivers/media/video/bt8xx/bttvp.h
index 1305d31..b38e3a0 100644
--- a/drivers/media/video/bt8xx/bttvp.h
+++ b/drivers/media/video/bt8xx/bttvp.h
@@ -82,8 +82,6 @@
/* Limits scaled width, which must be a multiple of 4. */
#define MAX_HACTIVE (0x3FF & -4)

-#define clamp(x, low, high) min (max (low, x), high)
-
#define BTTV_NORMS (\
V4L2_STD_PAL | V4L2_STD_PAL_N | \
V4L2_STD_PAL_Nc | V4L2_STD_SECAM | \
diff --git a/drivers/media/video/usbvideo/vicam.c b/drivers/media/video/usbvideo/vicam.c
index da1ba02..938a60d 100644
--- a/drivers/media/video/usbvideo/vicam.c
+++ b/drivers/media/video/usbvideo/vicam.c
@@ -70,12 +70,6 @@

#define VICAM_HEADER_SIZE 64

-#define clamp( x, l, h ) max_t( __typeof__( x ), \
- ( l ), \
- min_t( __typeof__( x ), \
- ( h ), \
- ( x ) ) )
-
/* Not sure what all the bytes in these char
* arrays do, but they're necessary to make
* the camera work.
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 47924ce..09ee1e0 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -352,6 +352,19 @@ static inline int __attribute__ ((format (printf, 1, 2))) pr_debug(const char *
_x > _y ? _x : _y; })

/*
+ * Clamp a value to within a given range with strict type checking
+ */
+#define clamp(val,min,max) ({ \
+ typeof(val) __val = (val); \
+ typeof(min) __min = (min); \
+ typeof(max) __max = (max); \
+ (void) (&__val == &__min); \
+ (void) (&__val == &__max); \
+ __val = __val < __min ? __min: __val; \
+ __val > __max ? __max: __val; })
+
+
+/*
* ..and if you can't take the strict
* types, you can specify one yourself.
*
--
1.5.4.2.200.g99e75




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