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simplifying the find_next_json_quotable_character fnc for neon processors (#2613)

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Daniel Lemire
2026-02-25 01:06:08 -05:00
committed by GitHub
parent 6cf1bdba43
commit 3cd9875f1f
1 changed files with 5 additions and 21 deletions
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include/simdjson/generic/builder/json_string_builder-inl.h
+5 -21
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@@ -191,28 +191,12 @@ find_next_json_quotable_character(const std::string_view view,
needs_escape = vorrq_u8(needs_escape, vceqq_u8(word, v92));
needs_escape = vorrq_u8(needs_escape, vcltq_u8(word, v32));
if (vmaxvq_u32(vreinterpretq_u32_u8(needs_escape)) != 0) {
// Found quotable character - extract exact byte position using ctz
uint64x2_t as64 = vreinterpretq_u64_u8(needs_escape);
uint64_t lo = vgetq_lane_u64(as64, 0);
uint64_t hi = vgetq_lane_u64(as64, 1);
const uint8x8_t res = vshrn_n_u16(vreinterpretq_u16_u8(needs_escape), 4);
const uint64_t mask = vget_lane_u64(vreinterpret_u64_u8(res), 0);
if(mask != 0) {
size_t offset = ptr - reinterpret_cast<const uint8_t *>(view.data());
#ifdef _MSC_VER
unsigned long trailing_zero = 0;
if (lo != 0) {
_BitScanForward64(&trailing_zero, lo);
return offset + trailing_zero / 8;
} else {
_BitScanForward64(&trailing_zero, hi);
return offset + 8 + trailing_zero / 8;
}
#else
if (lo != 0) {
return offset + __builtin_ctzll(lo) / 8;
} else {
return offset + 8 + __builtin_ctzll(hi) / 8;
}
#endif
auto trailing_zero = trailing_zeroes(mask);
return offset + (trailing_zero >> 2);
}
ptr += 16;
remaining -= 16;