SourceTools.cc

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//
// SourceTools.cc
//
// Created on August 27th 2018
//
// Copyright 2018 CFM (www.cfm.fr)
//
// Licensed 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.
//

#include "SourceTools.h"


namespace MetroCollect::MetricsSource {
    bool resetFile(std::ifstream& file, std::vector<char>& buffer, const std::string_view& path) {
        errno = 0;
        buffer.clear();
        buffer.resize(1024, '\0');
        file = std::ifstream(path.data(), std::ios::binary);
        if (errno) {
            perror(std::string(path).append(": Error opening file").c_str());
            errno = 0;
            return false;
        }

        file.clear();
        file.seekg(0);
        file.read(buffer.data(), buffer.size());
        if (errno) {
            perror(std::string(path).append(": Error reading file").c_str());
            errno = 0;
            return false;
        }

        while (!file.eof()) {
            buffer.resize(buffer.size() * 2, '\0');
            file.clear();
            file.seekg(0);
            file.read(buffer.data(), buffer.size());
        }
        buffer.resize(buffer.size() * 2, '\0');
        return true;
    }

    bool readFile(std::ifstream& file, std::vector<char>& buffer, const std::string_view& path) {
        errno = 0;
        file.clear();
        file.seekg(0);
        file.read(buffer.data(), buffer.size());
        if (errno) {
            perror(std::string(path).append(": Error reading file").c_str());
            errno = 0;
            return resetFile(file, buffer, path);
        }
        buffer[file.gcount()] = '\0';
        return true;
    }


    int alphanumCompare(const char* l, const char* r) {
        enum mode_t { STRING, NUMBER } mode = STRING;
        while (*l && *r) {
            switch (mode) {
                case STRING:
                    char l_char, r_char;
                    while ((l_char = *l) && (r_char = *r)) {
                        const bool l_digit = std::isdigit(l_char);
                        const bool r_digit = std::isdigit(r_char);
                        if (l_digit && r_digit) {
                            mode = NUMBER;
                            break;
                        }
                        if (l_digit)
                            return -1;
                        if (r_digit)
                            return +1;
                        const int diff = l_char - r_char;
                        if(diff != 0)
                            return diff;
                        ++l;
                        ++r;
                    }
                    break;
                case NUMBER:
                    char *end;
                    unsigned long l_int = std::strtoul(l, &end, 0);
                    l = end;
                    unsigned long r_int = std::strtoul(r, &end, 0);
                    r = end;
                    const long diff = l_int - r_int;
                    if(diff != 0)
                        return diff;
                    mode = STRING;
                    break;
            }
        }
        if (*r)
            return -1;
        if (*l)
            return +1;
        return 0;
    }
}