ladybird/Userland/Libraries/LibRegex/RegexLexer.h
Gunnar Beutner d476144565 Userland: Allow building SerenityOS with -funsigned-char
Some of the code assumed that chars were always signed while that is
not the case on ARM hosts.

Also, some of the code tried to use EOF (-1) in a way similar to what
fgetc() does, however instead of storing the characters in an int
variable a char was used.

While this seemed to work it also meant that character 0xFF would be
incorrectly seen as an end-of-file.

Careful reading of fgetc() reveals that fgetc() stores character
data in an int where valid characters are in the range of 0-255 and
the EOF value is explicitly outside of that range (usually -1).
2021-06-13 18:52:58 +02:00

91 lines
2.5 KiB
C++

/*
* Copyright (c) 2020, Emanuel Sprung <emanuel.sprung@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Forward.h>
#include <AK/StringView.h>
namespace regex {
#define ENUMERATE_REGEX_TOKENS \
__ENUMERATE_REGEX_TOKEN(Eof) \
__ENUMERATE_REGEX_TOKEN(Char) \
__ENUMERATE_REGEX_TOKEN(Circumflex) \
__ENUMERATE_REGEX_TOKEN(Period) \
__ENUMERATE_REGEX_TOKEN(LeftParen) \
__ENUMERATE_REGEX_TOKEN(RightParen) \
__ENUMERATE_REGEX_TOKEN(LeftCurly) \
__ENUMERATE_REGEX_TOKEN(RightCurly) \
__ENUMERATE_REGEX_TOKEN(LeftBracket) \
__ENUMERATE_REGEX_TOKEN(RightBracket) \
__ENUMERATE_REGEX_TOKEN(Asterisk) \
__ENUMERATE_REGEX_TOKEN(EscapeSequence) \
__ENUMERATE_REGEX_TOKEN(Dollar) \
__ENUMERATE_REGEX_TOKEN(Pipe) \
__ENUMERATE_REGEX_TOKEN(Plus) \
__ENUMERATE_REGEX_TOKEN(Comma) \
__ENUMERATE_REGEX_TOKEN(Slash) \
__ENUMERATE_REGEX_TOKEN(EqualSign) \
__ENUMERATE_REGEX_TOKEN(HyphenMinus) \
__ENUMERATE_REGEX_TOKEN(Colon) \
__ENUMERATE_REGEX_TOKEN(Questionmark)
enum class TokenType {
#define __ENUMERATE_REGEX_TOKEN(x) x,
ENUMERATE_REGEX_TOKENS
#undef __ENUMERATE_REGEX_TOKEN
};
class Token {
public:
Token() = default;
Token(const TokenType type, const size_t start_position, const StringView value)
: m_type(type)
, m_position(start_position)
, m_value(value)
{
}
TokenType type() const { return m_type; }
const StringView& value() const { return m_value; }
size_t position() const { return m_position; }
const char* name() const;
static const char* name(const TokenType);
private:
TokenType m_type { TokenType::Eof };
size_t m_position { 0 };
StringView m_value { nullptr };
};
class Lexer {
public:
Lexer() = default;
explicit Lexer(const StringView source);
Token next();
void reset();
void back(size_t offset);
void set_source(const StringView source) { m_source = source; }
bool try_skip(char);
char skip();
const auto& source() const { return m_source; }
private:
ALWAYS_INLINE int peek(size_t offset = 0) const;
ALWAYS_INLINE void consume();
StringView m_source {};
size_t m_position { 0 };
size_t m_previous_position { 0 };
Token m_current_token { TokenType::Eof, 0, StringView(nullptr) };
int m_current_char { 0 };
};
}
using regex::Lexer;