diff options
| -rw-r--r-- | src/helper/binarybuffer.h | 44 |
1 files changed, 41 insertions, 3 deletions
diff --git a/src/helper/binarybuffer.h b/src/helper/binarybuffer.h index e8931ab7..9e0cc9b7 100644 --- a/src/helper/binarybuffer.h +++ b/src/helper/binarybuffer.h @@ -29,6 +29,15 @@ * Support functions to access arbitrary bits in a byte array */ +/** + * Sets @c num bits in @c _buffer, starting at the @c first bit, + * using the bits in @c value. This routine fast-paths writes + * of little-endian, byte-aligned, 32-bit words. + * @param _buffer The buffer whose bits will be set. + * @param first The bit offset in @c _buffer to start writing (0-31). + * @param num The number of bits from @c value to copy (1-32). + * @param value Up to 32 bits that will be copied to _buffer. + */ static inline void buf_set_u32(void *_buffer, unsigned first, unsigned num, uint32_t value) { @@ -48,6 +57,15 @@ static inline void buf_set_u32(void *_buffer, } } } +/** + * Retrieves @c num bits from @c _buffer, starting at the @c first bit, + * returning the bits in a 32-bit word. This routine fast-paths reads + * of little-endian, byte-aligned, 32-bit words. + * @param _buffer The buffer whose bits will be read. + * @param first The bit offset in @c _buffer to start reading (0-31). + * @param num The number of bits from @c _buffer to read (1-32). + * @returns Up to 32-bits that were read from @c _buffer. + */ static inline uint32_t buf_get_u32(const void *_buffer, unsigned first, unsigned num) { @@ -68,16 +86,36 @@ static inline uint32_t buf_get_u32(const void *_buffer, } } -/// flip_u32 inverts the bit order inside a 32-bit word (31..0 -> 0..31) -uint32_t flip_u32(uint32_t value, unsigned num); +/** + * Inverts the ordering of bits inside a 32-bit word (e.g. 31..0 -> 0..31). + * This routine can be used to flip smaller data types by using smaller + * values for @c width. + * @param value The word to flip. + * @param width The number of bits in value (2-32). + * @returns A 32-bit word with @c value in reversed bit-order. + */ +uint32_t flip_u32(uint32_t value, unsigned width); bool buf_cmp(const void *buf1, const void *buf2, unsigned size); bool buf_cmp_mask(const void *buf1, const void *buf2, const void *mask, unsigned size); +/** + * Copies @c size bits out of @c from and into @c to. Any extra + * bits in the final byte will be set to zero. + * @param from The buffer to copy into @c to. + * @param to The buffer that will receive the copy of @c from. + * @param size The number of bits to copy. + */ void* buf_cpy(const void *from, void *to, unsigned size); -void* buf_set_ones(void *buf, unsigned count); +/** + * Set the contents of @c buf with @c count bits, all set to 1. + * @param buf The buffer to fill with ones. + * @param size The number of bits. + * @returns The original buffer (@c buf). + */ +void* buf_set_ones(void *buf, unsigned size); void* buf_set_buf(const void *src, unsigned src_start, void *dst, unsigned dst_start, unsigned len); |