From d7788151a0807d5d2d410e3f8944d8c8a651f8d2 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Wed, 30 Aug 2017 16:32:00 +0800 Subject: [PATCH] bitmap: provide to_le/from_le helpers Provide helpers to convert bitmaps to little endian format. It can be used when we want to send one bitmap via network to some other hosts. One thing to mention is that, these helpers only solve the problem of endianess, but it does not solve the problem of different word size on machines (the bitmaps managing same count of bits may contains different size when malloced). So we need to take care of the size alignment issue on the callers for now. Signed-off-by: Peter Xu Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- include/qemu/bitmap.h | 7 +++++++ util/bitmap.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+) diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h index 2718706edb..509eeddece 100644 --- a/include/qemu/bitmap.h +++ b/include/qemu/bitmap.h @@ -39,6 +39,8 @@ * bitmap_clear(dst, pos, nbits) Clear specified bit area * bitmap_test_and_clear_atomic(dst, pos, nbits) Test and clear area * bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area + * bitmap_to_le(dst, src, nbits) Convert bitmap to little endian + * bitmap_from_le(dst, src, nbits) Convert bitmap from little endian */ /* @@ -247,4 +249,9 @@ static inline unsigned long *bitmap_zero_extend(unsigned long *old, return new; } +void bitmap_to_le(unsigned long *dst, const unsigned long *src, + long nbits); +void bitmap_from_le(unsigned long *dst, const unsigned long *src, + long nbits); + #endif /* BITMAP_H */ diff --git a/util/bitmap.c b/util/bitmap.c index 90a42ff625..cb618c65a5 100644 --- a/util/bitmap.c +++ b/util/bitmap.c @@ -370,3 +370,35 @@ long slow_bitmap_count_one(const unsigned long *bitmap, long nbits) return result; } + +static void bitmap_to_from_le(unsigned long *dst, + const unsigned long *src, long nbits) +{ + long len = BITS_TO_LONGS(nbits); + +#ifdef HOST_WORDS_BIGENDIAN + long index; + + for (index = 0; index < len; index++) { +# if HOST_LONG_BITS == 64 + dst[index] = bswap64(src[index]); +# else + dst[index] = bswap32(src[index]); +# endif + } +#else + memcpy(dst, src, len * sizeof(unsigned long)); +#endif +} + +void bitmap_from_le(unsigned long *dst, const unsigned long *src, + long nbits) +{ + bitmap_to_from_le(dst, src, nbits); +} + +void bitmap_to_le(unsigned long *dst, const unsigned long *src, + long nbits) +{ + bitmap_to_from_le(dst, src, nbits); +}