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LibRegex: Use a match table for character classes

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Generate a sorted, compressed series of ranges in a match table for
character classes, and use a binary search to find the matches.
This is about a 3-4x speedup for character class match performance. :^)
This commit is contained in:
Ali Mohammad Pur 2021-10-03 19:01:25 +03:30 • committed by Andreas Kling
parent 478b36c37b
commit 8f722302d9
6 changed files with 232 additions and 35 deletions
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47
Userland/Libraries/LibRegex/RegexByteCode.cpp
View file

@ -7,6 +7,7 @@
#include "RegexByteCode.h"
#include "AK/StringBuilder.h"
#include "RegexDebug.h"
#include <AK/BinarySearch.h>
#include <AK/CharacterTypes.h>
#include <AK/Debug.h>
#include <LibUnicode/CharacterTypes.h>
@ -491,6 +492,38 @@ ALWAYS_INLINE ExecutionResult OpCode_Compare::execute(MatchInput const& input, M
compare_character_class(input, state, character_class, ch, current_inversion_state(), inverse_matched);
} else if (compare_type == CharacterCompareType::LookupTable) {
if (input.view.length() <= state.string_position)
return ExecutionResult::Failed_ExecuteLowPrioForks;
auto count = m_bytecode->at(offset++);
auto range_data = m_bytecode->spans().slice(offset, count);
offset += count;
auto ch = input.view.substring_view(state.string_position, 1)[0];
auto matching_range = binary_search(range_data, ch, nullptr, [insensitive = input.regex_options & AllFlags::Insensitive](auto needle, CharRange range) {
auto from = range.from;
auto to = range.to;
if (insensitive) {
from = to_ascii_lowercase(from);
to = to_ascii_lowercase(to);
needle = to_ascii_lowercase(needle);
}
if (needle > range.to)
return 1;
if (needle < range.from)
return -1;
return 0;
});
if (matching_range) {
if (current_inversion_state())
inverse_matched = true;
else
advance_string_position(state, input.view, ch);
}
} else if (compare_type == CharacterCompareType::CharRange) {
if (input.view.length() <= state.string_position)
return ExecutionResult::Failed_ExecuteLowPrioForks;
@ -816,6 +849,10 @@ Vector<CompareTypeAndValuePair> OpCode_Compare::flat_compares() const
} else if (compare_type == CharacterCompareType::CharRange) {
auto value = m_bytecode->at(offset++);
result.append({ compare_type, value });
} else if (compare_type == CharacterCompareType::LookupTable) {
auto count = m_bytecode->at(offset++);
for (size_t i = 0; i < count; ++i)
result.append({ CharacterCompareType::CharRange, m_bytecode->at(offset++) });
} else {
result.append({ compare_type, 0 });
}
@ -884,6 +921,16 @@ Vector<String> const OpCode_Compare::variable_arguments_to_string(Optional<Match
result.empend(String::formatted(
"compare against: '{}'",
input.value().view.substring_view(string_start_offset, state().string_position > view.length() ? 0 : 1).to_string()));
} else if (compare_type == CharacterCompareType::LookupTable) {
auto count = m_bytecode->at(offset++);
for (size_t j = 0; j < count; ++j) {
auto range = (CharRange)m_bytecode->at(offset++);
result.append(String::formatted("{:x}-{:x}", range.from, range.to));
}
if (!view.is_null() && view.length() > state().string_position)
result.empend(String::formatted(
"compare against: '{}'",
input.value().view.substring_view(string_start_offset, state().string_position > view.length() ? 0 : 1).to_string()));
}
}
return result;