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Util: Add GenericLexer class

master
Riyyi 2 years ago
parent
commit
4ce026ec78
  1. 55
      src/util/genericlexer.cpp
  2. 43
      src/util/genericlexer.h

55
src/util/genericlexer.cpp

@ -0,0 +1,55 @@
/*
* Copyright (C) 2022 Riyyi
*
* SPDX-License-Identifier: MIT
*/
#include <algorithm> // max, min
#include "util/genericlexer.h"
namespace Util {
GenericLexer::GenericLexer(std::string_view input)
: m_input(input)
{
}
GenericLexer::~GenericLexer()
{
}
// -----------------------------------------
size_t GenericLexer::tell() const
{
return m_index;
}
bool GenericLexer::isEOF() const
{
return m_index >= m_input.length();
}
char GenericLexer::peek(size_t offset) const
{
return m_input[std::max(std::min(m_index + offset, m_input.length()), (size_t)0)];
}
void GenericLexer::ignore(size_t count)
{
m_index += std::min(count, m_input.length() - m_index);
}
void GenericLexer::retreat(size_t count)
{
m_index -= std::min(count, m_index);
}
char GenericLexer::consume()
{
assert(!isEOF());
return m_input[m_index++];
}
} // namespace Util

43
src/util/genericlexer.h

@ -0,0 +1,43 @@
/*
* Copyright (C) 2022 Riyyi
*
* SPDX-License-Identifier: MIT
*/
#ifndef UTIL_GENERIC_LEXER_H
#define UTIL_GENERIC_LEXER_H
#include <cassert> // assert
#include <cstddef> // size_t
#include <string_view>
namespace Util {
class GenericLexer {
public:
GenericLexer(std::string_view input);
virtual ~GenericLexer();
// Position
size_t tell() const;
bool isEOF() const;
// Access
char peek(size_t offset = 0) const;
// Modifiers
void ignore(size_t count = 1);
void retreat(size_t count = 1);
char consume();
protected:
size_t m_index { 0 };
std::string_view m_input;
};
} // namespace Util
#endif // UTIL_GENERIC_LEXER_H
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