goldberg_emulator/overlay_experimental/System/StringView.hpp
2022-08-05 02:06:42 -04:00

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/*
* Copyright (C) Nemirtingas
* This file is part of System.
*
* System is free software; you can redistribute it
* and/or modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* System is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with System; if not, see
* <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <iterator>
#include <string>
#include <iostream>
#include <array>
namespace System {
template<typename char_type>
class BasicStringView {
const char_type* _string;
size_t _length;
using type = BasicStringView<char_type>;
public:
class iterator {
const char_type* _value;
public:
constexpr iterator(const iterator& o) : _value(o._value) {}
constexpr iterator(const char_type* value) : _value(value) {}
constexpr iterator& operator++() { ++_value; return *this; }
constexpr iterator operator++(int) { iterator retval = *this; ++(*this); return retval; }
constexpr iterator& operator--() { --_value; return *this; }
constexpr iterator operator--(int) { iterator retval = *this; --(*this); return retval; }
constexpr bool operator==(iterator other) const { return _value == other._value; }
constexpr bool operator!=(iterator other) const { return !(*this == other); }
constexpr const char_type& operator*() const { return *_value; }
// iterator traits
using difference_type = long;
using value_type = char_type;
using pointer = const char_type*;
using reference = const char_type&;
using iterator_category = std::random_access_iterator_tag;
};
constexpr BasicStringView() : _string(nullptr), _length(0)
{}
constexpr BasicStringView(const char_type* str, size_t length) : _string(str), _length(length)
{}
constexpr BasicStringView(std::basic_string<char_type, std::char_traits<char_type>, std::allocator<char_type>> const& str) : _string(str.data()), _length(str.length())
{}
template<size_t N>
constexpr BasicStringView(const char_type(&str)[N]) : _string(str), _length(N - 1)
{}
template<size_t N>
constexpr BasicStringView(std::array<char_type, N> const& str) : _string(&str.at[0]), _length(N)
{}
constexpr BasicStringView(type const& other) : _string(other._string), _length(other._length)
{}
constexpr BasicStringView(type&& other) : _string(other._string), _length(other._length)
{}
constexpr type& operator=(type const& other)
{
_string = other._string;
_length = other._length;
return *this;
}
constexpr type& operator=(type&& other)
{
_string = other._string;
_length = other._length;
return *this;
}
constexpr const char_type* data() const { return _string; }
constexpr bool empty() const { return _length == 0; }
constexpr size_t size() const { return _length; }
constexpr size_t length() const { return _length; }
constexpr const char_type& operator[](size_t index) const { return _string[index]; }
constexpr size_t find_first_of(type const& string, const size_t offset = 0) const
{
if(_length == 0)
return std::string::npos;
for (size_t i = offset; i < _length; ++i)
{
for (size_t j = 0; j < string._length; ++j)
{
if (_string[i] == string[j])
return i;
}
}
return std::string::npos;
}
constexpr size_t find_first_not_of(type const& string, const size_t offset = 0) const
{
if(_length == 0)
return std::string::npos;
for (size_t i = offset; i < _length; ++i)
{
for (size_t j = 0; j < string._length; ++j)
{
if (_string[i] == string[j])
break;
if (j == (string._length - 1))
return i;
}
}
return std::string::npos;
}
constexpr size_t find(type const& string, const size_t offset = 0) const
{
if (_length < string._length)
return std::string::npos;
for (size_t i = offset; i < (_length - string._length + 1); ++i)
{
for (size_t j = 0; j < string._length; ++j)
{
if (_string[i + j] != string[j])
break;
if (j == (string._length - 1))
return i;
}
}
return std::string::npos;
}
constexpr size_t find_not(type const& string, const size_t offset = 0) const
{
if (_length < string._length)
return std::string::npos;
for (size_t i = offset; i < (_length - string._length + 1); ++i)
{
for (size_t j = 0; j < string._length; ++j)
{
if (_string[i + j] == string[j])
break;
if (j == (string._length - 1))
return i;
}
}
return std::string::npos;
}
constexpr size_t count(char_type const c) const
{
size_t n = 0;
for (size_t i = 0; i < _length; ++i)
if (_string[i] == c)
++n;
return n;
}
constexpr type substr(size_t offset, size_t length = std::string::npos) const
{
if (offset >= _length)
return type();
return type(_string + offset, (_length - offset) > length ? length : _length - offset);
}
constexpr iterator begin() const
{
return iterator(_string);
}
constexpr iterator end() const
{
return iterator(_string + _length);
}
std::string to_string() const
{
return std::string(_string, _string + _length);
}
size_t copy(char_type* p, size_t p_size) const
{
size_t written = 0;
if (p != nullptr)
{
size_t to_write = (_length > p_size ? p_size : _length);
char_type* b = _string;
while (to_write--)
{
*p++ = *b++;
++written;
}
}
return written;
}
};
using StringView = BasicStringView<char>;
}
template<typename char_type>
std::basic_ostream<char_type>& operator<<(std::basic_ostream<char_type>& os, System::BasicStringView<char_type> const& sv)
{
return os.write(sv.data(), sv.length());
}
template<typename char_type>
std::basic_string<char_type> operator+(std::basic_string<char_type> const& str, System::BasicStringView<char_type> const& sv)
{
std::string r(str);
return r.append(sv.data(), sv.data() + sv.length());
}
template<typename char_type>
std::basic_string<char_type>& operator+=(std::basic_string<char_type>& str, System::BasicStringView<char_type> const& sv)
{
return str.append(sv.data(), sv.data() + sv.length());
}