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ladybird/Libraries/LibRegex/Regex.h

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LibRegex: Add a regular expression library This commit is a mix of several commits, squashed into one because the commits before 'Move regex to own Library and fix all the broken stuff' were not fixable in any elegant way. The commits are listed below for "historical" purposes: - AK: Add options/flags and Errors for regular expressions Flags can be provided for any possible flavour by adding a new scoped enum. Handling of flags is done by templated Options class and the overloaded '|' and '&' operators. - AK: Add Lexer for regular expressions The lexer parses the input and extracts tokens needed to parse a regular expression. - AK: Add regex Parser and PosixExtendedParser This patchset adds a abstract parser class that can be derived to implement different parsers. A parser produces bytecode to be executed within the regex matcher. - AK: Add regex matcher This patchset adds an regex matcher based on the principles of the T-REX VM. The bytecode pruduced by the respective Parser is put into the matcher and the VM will recursively execute the bytecode according to the available OpCodes. Possible improvement: the recursion could be replaced by multi threading capabilities. To match a Regular expression, e.g. for the Posix standard regular expression matcher use the following API: ``` Pattern<PosixExtendedParser> pattern("^.*$"); auto result = pattern.match("Well, hello friends!\nHello World!"); // Match whole needle EXPECT(result.count == 1); EXPECT(result.matches.at(0).view.starts_with("Well")); EXPECT(result.matches.at(0).view.end() == "!"); result = pattern.match("Well, hello friends!\nHello World!", PosixFlags::Multiline); // Match line by line EXPECT(result.count == 2); EXPECT(result.matches.at(0).view == "Well, hello friends!"); EXPECT(result.matches.at(1).view == "Hello World!"); EXPECT(pattern.has_match("Well,....")); // Just check if match without a result, which saves some resources. ``` - AK: Rework regex to work with opcodes objects This patchsets reworks the matcher to work on a more structured base. For that an abstract OpCode class and derived classes for the specific OpCodes have been added. The respective opcode logic is contained in each respective execute() method. - AK: Add benchmark for regex - AK: Some optimization in regex for runtime and memory - LibRegex: Move regex to own Library and fix all the broken stuff Now regex works again and grep utility is also in place for testing. This commit also fixes the use of regex.h in C by making `regex_t` an opaque (-ish) type, which makes its behaviour consistent between C and C++ compilers. Previously, <regex.h> would've blown C compilers up, and even if it didn't, would've caused a leak in C code, and not in C++ code (due to the existence of `OwnPtr` inside the struct). To make this whole ordeal easier to deal with (for now), this pulls the definitions of `reg*()` into LibRegex. pros: - The circular dependency between LibC and LibRegex is broken - Eaiser to test (without accidentally pulling in the host's libc!) cons: - Using any of the regex.h functions will require the user to link -lregex - The symbols will be missing from libc, which will be a big surprise down the line (especially with shared libs). Co-Authored-By: Ali Mohammad Pur <ali.mpfard@gmail.com>
2020-04-26 12:45:10 +00:00
/*
* Copyright (c) 2020, Emanuel Sprung <emanuel.sprung@gmail.com>
*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 08:24:48 +00:00
* SPDX-License-Identifier: BSD-2-Clause
LibRegex: Add a regular expression library This commit is a mix of several commits, squashed into one because the commits before 'Move regex to own Library and fix all the broken stuff' were not fixable in any elegant way. The commits are listed below for "historical" purposes: - AK: Add options/flags and Errors for regular expressions Flags can be provided for any possible flavour by adding a new scoped enum. Handling of flags is done by templated Options class and the overloaded '|' and '&' operators. - AK: Add Lexer for regular expressions The lexer parses the input and extracts tokens needed to parse a regular expression. - AK: Add regex Parser and PosixExtendedParser This patchset adds a abstract parser class that can be derived to implement different parsers. A parser produces bytecode to be executed within the regex matcher. - AK: Add regex matcher This patchset adds an regex matcher based on the principles of the T-REX VM. The bytecode pruduced by the respective Parser is put into the matcher and the VM will recursively execute the bytecode according to the available OpCodes. Possible improvement: the recursion could be replaced by multi threading capabilities. To match a Regular expression, e.g. for the Posix standard regular expression matcher use the following API: ``` Pattern<PosixExtendedParser> pattern("^.*$"); auto result = pattern.match("Well, hello friends!\nHello World!"); // Match whole needle EXPECT(result.count == 1); EXPECT(result.matches.at(0).view.starts_with("Well")); EXPECT(result.matches.at(0).view.end() == "!"); result = pattern.match("Well, hello friends!\nHello World!", PosixFlags::Multiline); // Match line by line EXPECT(result.count == 2); EXPECT(result.matches.at(0).view == "Well, hello friends!"); EXPECT(result.matches.at(1).view == "Hello World!"); EXPECT(pattern.has_match("Well,....")); // Just check if match without a result, which saves some resources. ``` - AK: Rework regex to work with opcodes objects This patchsets reworks the matcher to work on a more structured base. For that an abstract OpCode class and derived classes for the specific OpCodes have been added. The respective opcode logic is contained in each respective execute() method. - AK: Add benchmark for regex - AK: Some optimization in regex for runtime and memory - LibRegex: Move regex to own Library and fix all the broken stuff Now regex works again and grep utility is also in place for testing. This commit also fixes the use of regex.h in C by making `regex_t` an opaque (-ish) type, which makes its behaviour consistent between C and C++ compilers. Previously, <regex.h> would've blown C compilers up, and even if it didn't, would've caused a leak in C code, and not in C++ code (due to the existence of `OwnPtr` inside the struct). To make this whole ordeal easier to deal with (for now), this pulls the definitions of `reg*()` into LibRegex. pros: - The circular dependency between LibC and LibRegex is broken - Eaiser to test (without accidentally pulling in the host's libc!) cons: - Using any of the regex.h functions will require the user to link -lregex - The symbols will be missing from libc, which will be a big surprise down the line (especially with shared libs). Co-Authored-By: Ali Mohammad Pur <ali.mpfard@gmail.com>
2020-04-26 12:45:10 +00:00
*/
#pragma once
#include <LibRegex/Forward.h>
#include <LibRegex/RegexDebug.h>
#include <LibRegex/RegexMatcher.h>
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