[libfdt][PATCH v4] implement strnlen for systems that need it

[libfdt][PATCH v4] implement strnlen for systems that need it

[John Arbuckle]

Prior the Mac OS 10.7, the function strnlen() was not available. This patch
implements strnlen() on Mac OS X versions that are below 10.7.

Signed-off-by: John Arbuckle <programmingkidx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
v4 changes:
- Added check for definition of MAC_OS_X_VERSION_10_7
- Renamed strnlen to fdt_strnlen
- Added macro that defines strnlen as fdt_strnlen

v3 changes:
- Replaced loop with memchr()

v2 changes:
- Simplified the code to make it static inline'ed
- Changed the type of count to size_t

 libfdt/libfdt_env.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/libfdt/libfdt_env.h b/libfdt/libfdt_env.h
index 952056c..41fac04 100644
--- a/libfdt/libfdt_env.h
+++ b/libfdt/libfdt_env.h
@@ -109,4 +109,31 @@ static inline fdt64_t cpu_to_fdt64(uint64_t x)
 #undef CPU_TO_FDT16
 #undef EXTRACT_BYTE
 
+#ifdef __APPLE__
+#include <AvailabilityMacros.h>
+
+/* strnlen() is not available on Mac OS < 10.7 */
+# if !defined(MAC_OS_X_VERSION_10_7) || (MAC_OS_X_VERSION_MAX_ALLOWED < \
+                                         MAC_OS_X_VERSION_10_7)
+
+#define strnlen fdt_strnlen
+
+/*
+ * fdt_strnlen: returns the length of a string or max_count - which ever is
+ * smallest.
+ * Input 1 string: the string whose size is to be determined
+ * Input 2 max_count: the maximum value returned by this function
+ * Output: length of the string or max_count (the smallest of the two)
+ */
+static inline size_t fdt_strnlen(const char *string, size_t max_count)
+{
+    const char *p = memchr(string, 0, max_count);
+    return p ? p - string : max_count;
+}
+
+#endif /* !defined(MAC_OS_X_VERSION_10_7) || (MAC_OS_X_VERSION_MAX_ALLOWED <
+          MAC_OS_X_VERSION_10_7) */
+
+#endif /* __APPLE__ */
+
 #endif /* _LIBFDT_ENV_H */
-- 
2.10.2

Re: [libfdt][PATCH v4] implement strnlen for systems that need it

[David Gibson]

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On Wed, Oct 25, 2017 at 09:13:46PM -0400, John Arbuckle wrote:
> Prior the Mac OS 10.7, the function strnlen() was not available. This patch
> implements strnlen() on Mac OS X versions that are below 10.7.
> 
> Signed-off-by: John Arbuckle <programmingkidx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Applied, thanks.

> ---
> v4 changes:
> - Added check for definition of MAC_OS_X_VERSION_10_7
> - Renamed strnlen to fdt_strnlen
> - Added macro that defines strnlen as fdt_strnlen
> 
> v3 changes:
> - Replaced loop with memchr()
> 
> v2 changes:
> - Simplified the code to make it static inline'ed
> - Changed the type of count to size_t
> 
>  libfdt/libfdt_env.h | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/libfdt/libfdt_env.h b/libfdt/libfdt_env.h
> index 952056c..41fac04 100644
> --- a/libfdt/libfdt_env.h
> +++ b/libfdt/libfdt_env.h
> @@ -109,4 +109,31 @@ static inline fdt64_t cpu_to_fdt64(uint64_t x)
>  #undef CPU_TO_FDT16
>  #undef EXTRACT_BYTE
>  
> +#ifdef __APPLE__
> +#include <AvailabilityMacros.h>
> +
> +/* strnlen() is not available on Mac OS < 10.7 */
> +# if !defined(MAC_OS_X_VERSION_10_7) || (MAC_OS_X_VERSION_MAX_ALLOWED < \
> +                                         MAC_OS_X_VERSION_10_7)
> +
> +#define strnlen fdt_strnlen
> +
> +/*
> + * fdt_strnlen: returns the length of a string or max_count - which ever is
> + * smallest.
> + * Input 1 string: the string whose size is to be determined
> + * Input 2 max_count: the maximum value returned by this function
> + * Output: length of the string or max_count (the smallest of the two)
> + */
> +static inline size_t fdt_strnlen(const char *string, size_t max_count)
> +{
> +    const char *p = memchr(string, 0, max_count);
> +    return p ? p - string : max_count;
> +}
> +
> +#endif /* !defined(MAC_OS_X_VERSION_10_7) || (MAC_OS_X_VERSION_MAX_ALLOWED <
> +          MAC_OS_X_VERSION_10_7) */
> +
> +#endif /* __APPLE__ */
> +
>  #endif /* _LIBFDT_ENV_H */

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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