// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// with the License.  You may obtain a copy of the License at

//

//   http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing,

// software distributed under the License is distributed on an

// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

// KIND, either express or implied.  See the License for the

// specific language governing permissions and limitations

// under the License.

// Date: Tue Jun 23 15:03:24 CST 2015

#ifndef BUTIL_FIND_CSTR_H

#define BUTIL_FIND_CSTR_H

#include <string>

#include <map>

#include <algorithm>

#include "butil/thread_local.h"

// Find c-string in maps with std::string as keys without memory allocations.

// Example:

//   std::map<std::string, int> string_map;

//

//   string_map.find("hello");         // constructed a temporary std::string

//                                     // which needs memory allocation.

//

//   find_cstr(string_map, "hello");   // no allocation.

//

// You can specialize find_cstr for other maps.

// Possible prototypes are:

//   const_iterator find_cstr(const Map& map, const char* key);

//   iterator       find_cstr(Map& map, const char* key);

//   const_iterator find_cstr(const Map& map, const char* key, size_t length);

//   iterator       find_cstr(Map& map, const char* key, size_t length);

namespace butil {

struct StringMapThreadLocalTemp {

    bool initialized;

    char buf[sizeof(std::string)];

    static void delete_tls(void* buf) {

        StringMapThreadLocalTemp* temp = (StringMapThreadLocalTemp*)buf;

        if (temp->initialized) {

            temp->initialized = false;

            std::string* temp_string = (std::string*)temp->buf;

            temp_string->~basic_string();

        }

    }

    inline std::string* get_string(const char* key) {

        if (!initialized) {

            initialized = true;

            std::string* tmp = new (buf) std::string(key);

            thread_atexit(delete_tls, this);

            return tmp;

        } else {

            std::string* tmp = (std::string*)buf;

            tmp->assign(key);

            return tmp;

        }

    }

    inline std::string* get_string(const char* key, size_t length) {

        if (!initialized) {

            initialized = true;

            std::string* tmp = new (buf) std::string(key, length);

            thread_atexit(delete_tls, this);

            return tmp;

        } else {

            std::string* tmp = (std::string*)buf;

            tmp->assign(key, length);

            return tmp;

        }

    }

    inline std::string* get_lowered_string(const char* key) {

        std::string* tmp = get_string(key);

        std::transform(tmp->begin(), tmp->end(), tmp->begin(), ::tolower);

        return tmp;

    }

    inline std::string* get_lowered_string(const char* key, size_t length) {

        std::string* tmp = get_string(key, length);

        std::transform(tmp->begin(), tmp->end(), tmp->begin(), ::tolower);

        return tmp;

    }

};

extern thread_local StringMapThreadLocalTemp tls_stringmap_temp;

template <typename T, typename C, typename A>

typename std::map<std::string, T, C, A>::const_iterator

find_cstr(const std::map<std::string, T, C, A>& m, const char* key) {

    return m.find(*tls_stringmap_temp.get_string(key));

}

template <typename T, typename C, typename A>

typename std::map<std::string, T, C, A>::iterator

find_cstr(std::map<std::string, T, C, A>& m, const char* key) {

    return m.find(*tls_stringmap_temp.get_string(key));

}

template <typename T, typename C, typename A>

typename std::map<std::string, T, C, A>::const_iterator

find_cstr(const std::map<std::string, T, C, A>& m,

          const char* key, size_t length) {

    return m.find(*tls_stringmap_temp.get_string(key, length));

}

template <typename T, typename C, typename A>

typename std::map<std::string, T, C, A>::iterator

find_cstr(std::map<std::string, T, C, A>& m,

          const char* key, size_t length) {

    return m.find(*tls_stringmap_temp.get_string(key, length));

}

template <typename T, typename C, typename A>

typename std::map<std::string, T, C, A>::const_iterator

find_lowered_cstr(const std::map<std::string, T, C, A>& m, const char* key) {

    return m.find(*tls_stringmap_temp.get_lowered_string(key));

}

template <typename T, typename C, typename A>

typename std::map<std::string, T, C, A>::iterator

find_lowered_cstr(std::map<std::string, T, C, A>& m, const char* key) {

    return m.find(*tls_stringmap_temp.get_lowered_string(key));

}

template <typename T, typename C, typename A>

typename std::map<std::string, T, C, A>::const_iterator

find_lowered_cstr(const std::map<std::string, T, C, A>& m,

                  const char* key, size_t length) {

    return m.find(*tls_stringmap_temp.get_lowered_string(key, length));

}

template <typename T, typename C, typename A>

typename std::map<std::string, T, C, A>::iterator

find_lowered_cstr(std::map<std::string, T, C, A>& m,

                  const char* key, size_t length) {

    return m.find(*tls_stringmap_temp.get_lowered_string(key, length));

}

}  // namespace butil

#endif  // BUTIL_FIND_CSTR_H