diff options
Diffstat (limited to 'src/helper/binarybuffer.h')
-rw-r--r-- | src/helper/binarybuffer.h | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/src/helper/binarybuffer.h b/src/helper/binarybuffer.h index 3fbfea49..c2d643b1 100644 --- a/src/helper/binarybuffer.h +++ b/src/helper/binarybuffer.h @@ -58,6 +58,45 @@ static inline void buf_set_u32(void *_buffer, } } } + +/** + * 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, 64-bit words. + * @param _buffer The buffer whose bits will be set. + * @param first The bit offset in @c _buffer to start writing (0-63). + * @param num The number of bits from @c value to copy (1-64). + * @param value Up to 64 bits that will be copied to _buffer. + */ +static inline void buf_set_u64(void *_buffer, + unsigned first, unsigned num, uint64_t value) +{ + uint8_t *buffer = (uint8_t *)_buffer; + + if ((num == 32) && (first == 0)) { + buffer[3] = (value >> 24) & 0xff; + buffer[2] = (value >> 16) & 0xff; + buffer[1] = (value >> 8) & 0xff; + buffer[0] = (value >> 0) & 0xff; + } else if ((num == 64) && (first == 0)) { + buffer[7] = (value >> 56) & 0xff; + buffer[6] = (value >> 48) & 0xff; + buffer[5] = (value >> 40) & 0xff; + buffer[4] = (value >> 32) & 0xff; + buffer[3] = (value >> 24) & 0xff; + buffer[2] = (value >> 16) & 0xff; + buffer[1] = (value >> 8) & 0xff; + buffer[0] = (value >> 0) & 0xff; + } else { + for (unsigned i = first; i < first + num; i++) { + if (((value >> (i - first)) & 1) == 1) + buffer[i / 8] |= 1 << (i % 8); + else + buffer[i / 8] &= ~(1 << (i % 8)); + } + } +} + /** * 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 @@ -88,6 +127,45 @@ static inline uint32_t buf_get_u32(const void *_buffer, } /** + * Retrieves @c num bits from @c _buffer, starting at the @c first bit, + * returning the bits in a 64-bit word. This routine fast-paths reads + * of little-endian, byte-aligned, 64-bit words. + * @param _buffer The buffer whose bits will be read. + * @param first The bit offset in @c _buffer to start reading (0-63). + * @param num The number of bits from @c _buffer to read (1-64). + * @returns Up to 64-bits that were read from @c _buffer. + */ +static inline uint64_t buf_get_u64(const void *_buffer, + unsigned first, unsigned num) +{ + uint8_t *buffer = (uint8_t *)_buffer; + + if ((num == 32) && (first == 0)) { + return 0 + ((((uint32_t)buffer[3]) << 24) | /* Note - zero plus is to avoid a checkpatch bug */ + (((uint32_t)buffer[2]) << 16) | + (((uint32_t)buffer[1]) << 8) | + (((uint32_t)buffer[0]) << 0)); + } else if ((num == 64) && (first == 0)) { + return 0 + ((((uint64_t)buffer[7]) << 56) | /* Note - zero plus is to avoid a checkpatch bug */ + (((uint64_t)buffer[6]) << 48) | + (((uint64_t)buffer[5]) << 40) | + (((uint64_t)buffer[4]) << 32) | + (((uint64_t)buffer[3]) << 24) | + (((uint64_t)buffer[2]) << 16) | + (((uint64_t)buffer[1]) << 8) | + (((uint64_t)buffer[0]) << 0)); + } else { + uint64_t result = 0; + for (unsigned i = first; i < first + num; i++) { + if (((buffer[i / 8] >> (i % 8)) & 1) == 1) + result = result | ((uint64_t)1 << (uint64_t)(i - first)); + } + return result; + } +} + + +/** * 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. |