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tweaking the approach

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This commit is contained in:
Daniel Lemire
2024-11-25 21:10:25 -05:00
parent a14b63e654
commit db5323a972
11 changed files with 214 additions and 16 deletions
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src/generic/stage2/stringparsing.h
+12 -15
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@@ -241,28 +241,25 @@ simdjson_warn_unused size_t write_string_escaped(const std::string_view input, c
// need escaping.
size_t i = 0;
size_t pos = 0;
if(input.size() >= sizeof(simd8<uint8_t>)) {
if(input.size() >= escaping::BYTES_PROCESSED) {
auto vec_processing = [input,out]() -> size_t {
size_t i = 0;
size_t pos = 0;
for(;input.size() - i >= sizeof(simd8<uint8_t>); i += sizeof(simd8<uint8_t>)) {
simd8<uint8_t> vinput(reinterpret_cast<const uint8_t *>(input.data()) + i);
// instead of doing it register by register, we could regroup, but consider
// that we expect most strings to be short.
if(((vinput <= 31) | (vinput == '\\') | (vinput == '"')).any()) {
return i; // We have a character that needs escaping
// We could be more carefully and identify the character that needs escaping.
for(;input.size() - i >= escaping::BYTES_PROCESSED; i += escaping::BYTES_PROCESSED) {
escaping vinput = escaping::copy_and_find(reinterpret_cast<const uint8_t *>(input.data()) + i, reinterpret_cast<uint8_t *>(out) + pos);
if(vinput.has_escape()) {
return i + vinput.escape_index(); // We have a character that needs escaping
}
vinput.store(reinterpret_cast<uint8_t *>(out) + pos);
pos += sizeof(simd8<uint8_t>);
pos += escaping::BYTES_PROCESSED;
}
if(i == input.size()) { return input.size(); }
simd8<uint8_t> vinput(reinterpret_cast<const uint8_t *>(input.data()) + input.size() - sizeof(simd8<uint8_t>));
if(((vinput <= 31) | (vinput == '\\') | (vinput == '"')).any()) {
return i; // We have a character that needs escaping
// We could be more carefully and identify the character that needs escaping.
// We virtually backtrack so we can load a full vector register
i = input.size() - escaping::BYTES_PROCESSED;
pos = i;
escaping vinput = escaping::copy_and_find(reinterpret_cast<const uint8_t *>(input.data()) + i, reinterpret_cast<uint8_t *>(out) + pos);
if(vinput.has_escape()) {
return i + vinput.escape_index(); // We have a character that needs escaping
}
vinput.store(reinterpret_cast<uint8_t *>(out) + input.size() - sizeof(simd8<uint8_t>));
return input.size();
};
i = vec_processing();