pub fn count_words(data: &[u8]) -> u64Expand description
Count words using SIMD-accelerated whitespace detection + popcount.
A word is a maximal run of non-whitespace bytes (GNU wc definition). Word starts are transitions from whitespace to non-whitespace.
On x86_64, uses SSE2 range comparisons to detect whitespace in 16-byte
vectors: (0x09 <= b <= 0x0D) || (b == 0x20). Four vectors are processed
per iteration (64 bytes), with movemask combining into a 64-bit bitmask
for popcount-based word boundary detection.
Fallback: scalar 64-byte block bitmask approach with table lookup.