contains_word.cpp

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/*******************************************************************************
 * tlx/string/contains_word.cpp
 *
 * Part of tlx - http://panthema.net/tlx
 *
 * Copyright (C) 2016-2017 Timo Bingmann <[email protected]>
 *
 * All rights reserved. Published under the Boost Software License, Version 1.0
 ******************************************************************************/

#include <tlx/string/contains_word.hpp>

namespace tlx {

static inline bool is_white(char c) {
    return c == ' ' || c == '\n' || c == '\t' || c == '\r';
}

bool contains_word(const std::string& str, const char* word) {

    // all strings contain the empty word
    if (*word == 0)
        return true;

    std::string::const_iterator it = str.begin();

    while (it != str.end())
    {
        // skip over whitespace
        while (is_white(*it)) {
            if (++it == str.end()) return false;
        }

        // check if this non-whitespace matches the string
        const char* wi = word;
        while (*it == *wi) {
            ++it, ++wi;
            if (*wi == 0) {
                if (it == str.end() || is_white(*it))
                    return true;
                else break;
            }
            if (it == str.end()) return false;
        }

        // skip over not matching whitespace
        while (!is_white(*it)) {
            if (++it == str.end()) return false;
        }
    }

    return false;
}

bool contains_word(const std::string& str, const std::string& word) {

    // all strings contain the empty word
    if (word.empty())
        return true;

    std::string::const_iterator it = str.begin();

    while (it != str.end())
    {
        // skip over whitespace
        while (is_white(*it)) {
            if (++it == str.end()) return false;
        }

        // check if this non-whitespace matches the string
        std::string::const_iterator wi = word.begin();
        while (*it == *wi) {
            ++it, ++wi;
            if (wi == word.end()) {
                if (it == str.end() || is_white(*it))
                    return true;
                else break;
            }
            if (it == str.end()) return false;
        }

        // skip over not matching whitespace
        while (!is_white(*it)) {
            if (++it == str.end()) return false;
        }
    }

    return false;
}

} // namespace tlx

/******************************************************************************/