strfnd.h

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// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
 
#pragma once
 
#include <string>
#include <string_view>
 
// FIXME: convert this class to string_view
template <typename T>
class BasicStrfnd {
        typedef std::basic_string<T> String;
        String str;
        size_t pos;
public:
        BasicStrfnd(const String &s) { start(s); }
        BasicStrfnd(const T *ptr) { str = ptr; pos = 0; }
        BasicStrfnd(std::basic_string_view<T> sv) { str = sv; pos = 0; }
 
        void start(const String &s) { str = s; pos = 0; }
        size_t where() { return pos; }
        void to(size_t i) { pos = i; }
        bool at_end() { return pos >= str.size(); }
        String what() { return str; }
 
        String next(const String &sep)
        {
                if (pos >= str.size())
                        return String();
 
                size_t n;
                if (sep.empty() || (n = str.find(sep, pos)) == String::npos) {
                        n = str.size();
                }
                String ret = str.substr(pos, n - pos);
                pos = n + sep.size();
                return ret;
        }
 
        // Returns substr up to the next occurrence of sep that isn't escaped with esc ('\\')
        String next_esc(const String &sep, T esc=static_cast<T>('\\'))
        {
                if (pos >= str.size())
                        return String();
 
                size_t n, old_p = pos;
                do {
                        if (sep.empty() || (n = str.find(sep, pos)) == String::npos) {
                                pos = n = str.size();
                                break;
                        }
                        pos = n + sep.length();
                } while (n > 0 && str[n - 1] == esc);
 
                return str.substr(old_p, n - old_p);
        }
 
        void skip_over(const String &chars)
        {
                size_t p = str.find_first_not_of(chars, pos);
                if (p != String::npos)
                        pos = p;
        }
};
 
typedef BasicStrfnd<char> Strfnd;
typedef BasicStrfnd<wchar_t> WStrfnd;