add simd string quote seeking

src/string_decoder.rs

@@ -59,6 +59,98 @@ where
  let mut found_escape = false;
  let mut ascii_only = true;
 
+ #[cfg(any(target_arch = "aarch64", target_arch = "x86_64"))]
+ 'simd: {
+ #[cfg(target_arch = "aarch64")]
+ mod impl_ {
+ pub use std::arch::aarch64::{
+ vceqq_u8 as simd_eq, vcltq_u8 as simd_lt, vdupq_n_u8 as simd_duplicate, vld1q_u8 as simd_load,
+ vorrq_u8 as simd_or, *,
+ };
+
+ pub const SIMD_STEP: usize = 16;
+
+ pub fn is_vector_nonzero(vec: uint8x16_t) -> bool {
+ unsafe { vmaxvq_u8(vec) != 0 }
+ }
+
+ pub unsafe fn simd_is_ascii_non_control(vec: uint8x16_t) -> uint8x16_t {
+ simd_or(vcltq_u8(vec, vdupq_n_u8(32)), vcgeq_u8(vec, vdupq_n_u8(128)))
+ }
+ }
+
+ #[cfg(target_arch = "x86_64")]
+ mod impl_ {
+ pub use std::arch::x86_64::{_mm_cmpeq_epi8 as simd_eq, _mm_or_si128 as simd_or, *};
+
+ pub const SIMD_STEP: usize = 16;
+
+ pub fn is_vector_nonzero(vec: __m128i) -> bool {
+ unsafe { _mm_testz_si128(vec, vec) == 0 }
+ }
+
+ pub unsafe fn simd_duplicate(val: u8) -> __m128i {
+ _mm_set1_epi8(val as i8)
+ }
+
+ pub unsafe fn simd_load(ptr: *const u8) -> __m128i {
+ _mm_loadu_si128(ptr as *const __m128i)
+ }
+
+ pub unsafe fn simd_is_ascii_non_control(vec: __m128i) -> __m128i {
+ let is_lt_32 = _mm_cmplt_epi8(
+ // range-shift to unsigned
+ _mm_xor_si128(vec, _mm_set1_epi8(-128)),
+ _mm_xor_si128(_mm_set1_epi8(32), _mm_set1_epi8(-128)),
+ );
+ let is_ge_128 = _mm_cmplt_epi8(vec, _mm_set1_epi8(0));
+ _mm_or_si128(is_lt_32, is_ge_128)
+ }
+ }
+
+ use impl_::*;
+
+ #[cfg(target_arch = "x86_64")]
+ if !is_x86_feature_detected!("sse") {
+ break 'simd;
+ }
+
+ let simd_quote = unsafe { simd_duplicate(b'"') };
+ let simd_backslash = unsafe { simd_duplicate(b'\\') };
+
+ for remaining_chunk in data
+ .get(index..)
+ .into_iter()
+ .flat_map(|remaining| remaining.chunks_exact(SIMD_STEP))
+ {
+ let remaining_chunk_v = unsafe { simd_load(remaining_chunk.as_ptr()) };
+
+ let backslash = unsafe { simd_eq(remaining_chunk_v, simd_backslash) };
+ let mask = unsafe { simd_is_ascii_non_control(remaining_chunk_v) };
+ let backslash_or_mask = unsafe { simd_or(backslash, mask) };
+
+ // go slow if backslash or mask found
+ if is_vector_nonzero(backslash_or_mask) {
+ break 'simd;
+ }
+
+ // Compare the remaining chunk with the special characters
+ let compare_result = unsafe { simd_eq(remaining_chunk_v, simd_quote) };
+
+ // Check if any element in the comparison result is true
+ if is_vector_nonzero(compare_result) {
+ // Found a match, return the index
+ let j = unsafe { remaining_chunk.iter().position(|&x| x == b'"').unwrap_unchecked() };
+ return Ok((
+ StringOutput::Data(unsafe { std::str::from_utf8_unchecked(&data[start..index + j]) }),
+ index + j + 1,
+ ));
+ }
+
+ index += remaining_chunk.len();
+ }
+ }
+
  while let Some(next) = data.get(index) {
  match next {
  b'"' => {