simdjson/src/haswell/dom_parser_implementation.cpp

167 lines
6.5 KiB
C++

#include "haswell/begin_implementation.h"
#include "haswell/dom_parser_implementation.h"
#include "generic/stage2/jsoncharutils.h"
//
// Stage 1
//
namespace SIMDJSON_IMPLEMENTATION {
namespace {
using namespace simd;
struct json_character_block {
static simdjson_really_inline json_character_block classify(const simd::simd8x64<uint8_t>& in);
// ASCII white-space ('\r','\n','\t',' ')
simdjson_really_inline uint64_t whitespace() const;
// non-quote structural characters (comma, colon, braces, brackets)
simdjson_really_inline uint64_t op() const;
// neither a structural character nor a white-space, so letters, numbers and quotes
simdjson_really_inline uint64_t scalar() const;
uint64_t _whitespace; // ASCII white-space ('\r','\n','\t',' ')
uint64_t _op; // structural characters (comma, colon, braces, brackets but not quotes)
};
simdjson_really_inline uint64_t json_character_block::whitespace() const { return _whitespace; }
simdjson_really_inline uint64_t json_character_block::op() const { return _op; }
simdjson_really_inline uint64_t json_character_block::scalar() const { return ~(op() | whitespace()); }
// This identifies structural characters (comma, colon, braces, brackets),
// and ASCII white-space ('\r','\n','\t',' ').
simdjson_really_inline json_character_block json_character_block::classify(const simd::simd8x64<uint8_t>& in) {
// These lookups rely on the fact that anything < 127 will match the lower 4 bits, which is why
// we can't use the generic lookup_16.
const auto whitespace_table = simd8<uint8_t>::repeat_16(' ', 100, 100, 100, 17, 100, 113, 2, 100, '\t', '\n', 112, 100, '\r', 100, 100);
// The 6 operators (:,[]{}) have these values:
//
// , 2C
// : 3A
// [ 5B
// { 7B
// ] 5D
// } 7D
//
// If you use | 0x20 to turn [ and ] into { and }, the lower 4 bits of each character is unique.
// We exploit this, using a simd 4-bit lookup to tell us which character match against, and then
// match it (against | 0x20).
//
// To prevent recognizing other characters, everything else gets compared with 0, which cannot
// match due to the | 0x20.
//
// NOTE: Due to the | 0x20, this ALSO treats <FF> and <SUB> (control characters 0C and 1A) like ,
// and :. This gets caught in stage 2, which checks the actual character to ensure the right
// operators are in the right places.
const auto op_table = simd8<uint8_t>::repeat_16(
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, ':', '{', // : = 3A, [ = 5B, { = 7B
',', '}', 0, 0 // , = 2C, ] = 5D, } = 7D
);
// We compute whitespace and op separately. If later code only uses one or the
// other, given the fact that all functions are aggressively inlined, we can
// hope that useless computations will be omitted. This is namely case when
// minifying (we only need whitespace).
const uint64_t whitespace = in.eq({
_mm256_shuffle_epi8(whitespace_table, in.chunks[0]),
_mm256_shuffle_epi8(whitespace_table, in.chunks[1])
});
// Turn [ and ] into { and }
const simd8x64<uint8_t> curlified{
in.chunks[0] | 0x20,
in.chunks[1] | 0x20
};
const uint64_t op = curlified.eq({
_mm256_shuffle_epi8(op_table, in.chunks[0]),
_mm256_shuffle_epi8(op_table, in.chunks[1])
});
return { whitespace, op };
}
simdjson_really_inline bool is_ascii(const simd8x64<uint8_t>& input) {
return input.reduce_or().is_ascii();
}
SIMDJSON_UNUSED simdjson_really_inline simd8<bool> must_be_continuation(const simd8<uint8_t> prev1, const simd8<uint8_t> prev2, const simd8<uint8_t> prev3) {
simd8<uint8_t> is_second_byte = prev1.saturating_sub(0b11000000u-1); // Only 11______ will be > 0
simd8<uint8_t> is_third_byte = prev2.saturating_sub(0b11100000u-1); // Only 111_____ will be > 0
simd8<uint8_t> is_fourth_byte = prev3.saturating_sub(0b11110000u-1); // Only 1111____ will be > 0
// Caller requires a bool (all 1's). All values resulting from the subtraction will be <= 64, so signed comparison is fine.
return simd8<int8_t>(is_second_byte | is_third_byte | is_fourth_byte) > int8_t(0);
}
simdjson_really_inline simd8<bool> must_be_2_3_continuation(const simd8<uint8_t> prev2, const simd8<uint8_t> prev3) {
simd8<uint8_t> is_third_byte = prev2.saturating_sub(0b11100000u-1); // Only 111_____ will be > 0
simd8<uint8_t> is_fourth_byte = prev3.saturating_sub(0b11110000u-1); // Only 1111____ will be > 0
// Caller requires a bool (all 1's). All values resulting from the subtraction will be <= 64, so signed comparison is fine.
return simd8<int8_t>(is_third_byte | is_fourth_byte) > int8_t(0);
}
} // unnamed namespace
} // namespace SIMDJSON_IMPLEMENTATION
#include "generic/stage1/utf8_lookup4_algorithm.h"
#include "generic/stage1/json_structural_indexer.h"
#include "generic/stage1/utf8_validator.h"
//
// Stage 2
//
#include "haswell/stringparsing.h"
#include "haswell/numberparsing.h"
#include "generic/stage2/tape_builder.h"
//
// Implementation-specific overrides
//
namespace SIMDJSON_IMPLEMENTATION {
namespace {
namespace stage1 {
simdjson_really_inline uint64_t json_string_scanner::find_escaped(uint64_t backslash) {
if (!backslash) { uint64_t escaped = prev_escaped; prev_escaped = 0; return escaped; }
return find_escaped_branchless(backslash);
}
} // namespace stage1
} // unnamed namespace
SIMDJSON_WARN_UNUSED error_code implementation::minify(const uint8_t *buf, size_t len, uint8_t *dst, size_t &dst_len) const noexcept {
return haswell::stage1::json_minifier::minify<128>(buf, len, dst, dst_len);
}
SIMDJSON_WARN_UNUSED error_code dom_parser_implementation::stage1(const uint8_t *_buf, size_t _len, bool streaming) noexcept {
this->buf = _buf;
this->len = _len;
return haswell::stage1::json_structural_indexer::index<128>(_buf, _len, *this, streaming);
}
SIMDJSON_WARN_UNUSED bool implementation::validate_utf8(const char *buf, size_t len) const noexcept {
return haswell::stage1::generic_validate_utf8(buf,len);
}
SIMDJSON_WARN_UNUSED error_code dom_parser_implementation::stage2(dom::document &_doc) noexcept {
return stage2::tape_builder::parse_document<false>(*this, _doc);
}
SIMDJSON_WARN_UNUSED error_code dom_parser_implementation::stage2_next(dom::document &_doc) noexcept {
return stage2::tape_builder::parse_document<true>(*this, _doc);
}
SIMDJSON_WARN_UNUSED error_code dom_parser_implementation::parse(const uint8_t *_buf, size_t _len, dom::document &_doc) noexcept {
auto error = stage1(_buf, _len, false);
if (error) { return error; }
return stage2(_doc);
}
} // namespace SIMDJSON_IMPLEMENTATION
#include "generic/ondemand.h"
#include "haswell/end_implementation.h"