[C++知识库]字符串与二进制编码/base64编码互相转换的小工具

网上东西太多了，原来不想写的，网上东西太多太杂了，找半天不一定有用，所以本文主要保存两个简单的小工具，后期也会进行扩展和完善。

字符串与二进制的互转：

bool StringToBianery2(const string& input, string* output) {
    for(int i = 0 ; i < input.length(); i++){
        string temprst = "";
        int temp = (int)input[i];
        int count = 0;
        while(temp > 0){
            if(temp %  2 == 0){
                temprst += '0';
            }else{
                temprst += '1';
            }
            temp /= 2;
            count++;
        }
        if(count < 8){
            for(int j = 0 ; j < (8-count); j++){
                temprst += '0';
            }
        }
        //反转
        int index = 0;
        string temprst2 = "";
        for(int j = 7; j >= 0; j--){
            temprst2 += temprst[j];
            index++;
        }
        *output += temprst2;
    }
    return output->empty() == false;
}

bool Bianery2ToString(const string& input, string* output){
    int strlen = 0;
    while(strlen < input.length()){
        int temp = 0 , count = 7;
        for(int j = strlen; j < strlen+8; j++){
            if(input[j] == '1'){
                temp += pow(2, count);
            }
            count--;
        }
        char rsttemp = (char)temp;
        *output += rsttemp;
        strlen = strlen + 8;
    }
    return output->empty() == false;
}

字符串与base64编码的互转

boost中有实现base64编码的方式，所以做一个小封装

bool Base64Encode(const string& input, string* output) {
    typedef boost::archive::iterators::base64_from_binary<boost::archive::iterators::transform_width<string::const_iterator, 6, 8> > Base64EncodeIterator;
    stringstream result;
    copy(Base64EncodeIterator(input.begin()) , Base64EncodeIterator(input.end()), ostream_iterator<char>(result));
    size_t equal_count = (3 - input.length() % 3) % 3;
    for (size_t i = 0; i < equal_count; i++) {
        result.put('=');
    }
    *output = result.str();
    return output->empty() == false;
}

bool Base64Decode(const string& input, string* output) {
    typedef boost::archive::iterators::transform_width<boost::archive::iterators::binary_from_base64<string::const_iterator>, 8, 6> Base64DecodeIterator;
    stringstream result;
    try {
        copy(Base64DecodeIterator(input.begin()) , Base64DecodeIterator(input.end()), ostream_iterator<char>(result));
    } catch(...) {
        return false;
    }
    *output = result.str();
    return output->empty() == false;
}