Re: [PATCH 3/3] ewah: support platforms that require aligned reads
Jeff King wrote: --- a/ewah/ewah_io.c +++ b/ewah/ewah_io.c @@ -112,23 +112,38 @@ int ewah_serialize(struct ewah_bitmap *self, int fd) [...] +#if __BYTE_ORDER != __BIG_ENDIAN Is this portable? On a platform without __BYTE_ORDER or __BIG_ENDIAN defined, it is interpreted as #if 0 != 0 which means that such platforms are assumed to be big endian. Does Mingw define __BYTE_ORDER, for example? + { + size_t i; + for (i = 0; i self-buffer_size; ++i) + self-buffer[i] = ntohll(self-buffer[i]); + } +#endif It's tempting to guard with something like if (ntohl(1) != 1) { ... } The optimizer can tell if this is true or false at compile time, so it shouldn't slow anything down. With that change, Reviewed-by: Jonathan Nieder jrnie...@gmail.com Thanks for the quick fix. diff --git i/ewah/ewah_io.c w/ewah/ewah_io.c index 4a7fae6..5a527a4 100644 --- i/ewah/ewah_io.c +++ w/ewah/ewah_io.c @@ -135,13 +135,11 @@ int ewah_read_mmap(struct ewah_bitmap *self, void *map, size_t len) memcpy(self-buffer, ptr, self-buffer_size * sizeof(uint64_t)); ptr += self-buffer_size * sizeof(uint64_t); -#if __BYTE_ORDER != __BIG_ENDIAN - { + if (ntohl(1) != 1) { size_t i; for (i = 0; i self-buffer_size; ++i) self-buffer[i] = ntohll(self-buffer[i]); } -#endif self-rlw = self-buffer + get_be32(ptr); -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 3/3] ewah: support platforms that require aligned reads
On Fri, Jan 24, 2014 at 12:44 AM, Jonathan Nieder jrnie...@gmail.com wrote: --- a/ewah/ewah_io.c +++ b/ewah/ewah_io.c @@ -112,23 +112,38 @@ int ewah_serialize(struct ewah_bitmap *self, int fd) [...] +#if __BYTE_ORDER != __BIG_ENDIAN Is this portable? We explicitly set the __BYTE_ORDER macros in `compat/bswap.h`. In fact, this preprocessor conditional is the same one that we use when choosing what version of the `ntohl` macro to define, so that's why I decided to use it here. -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 3/3] ewah: support platforms that require aligned reads
Vicent Martà wrote: On Fri, Jan 24, 2014 at 12:44 AM, Jonathan Nieder jrnie...@gmail.com wrote: +#if __BYTE_ORDER != __BIG_ENDIAN Is this portable? We explicitly set the __BYTE_ORDER macros in `compat/bswap.h`. In fact, this preprocessor conditional is the same one that we use when choosing what version of the `ntohl` macro to define, so that's why I decided to use it here. Ah, thanks. Sorry I missed that. So feel free to add my reviewed-by to the patch without my tweak, too. -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html