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| #include <iostream>
#include <string>
using namespace std;
char getBase64Char(int x) {
return "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"[x];
}
char getAsciiChar(int x) {
return x;
}
int findBase64Char(char x) {
string str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
return str.find(x);
}
int findAsciiChar(char x) {
return x;
}
string bitConversion(string str, const int inputSize, const int outputSize, char (*getChar)(int), int (*findChar)(char)) {
const int bufferSize = 16;
string result = "";
unsigned short buffer = 0;
int offset = 0, strLen = str.length();
for(int i=0; i<strLen; ++i) {
buffer += findChar(str[i]) << (bufferSize-offset-inputSize);
offset += inputSize;
while(offset >= outputSize) {
result += getChar(buffer>>(bufferSize-outputSize));
buffer <<= outputSize;
offset -= outputSize;
}
}
if(offset) {
result += getChar(buffer>>(bufferSize-outputSize));
}
return result;
}
string base64Encode(string str) {
const int strLen = str.length();
string result = bitConversion(str, 8, 6, getBase64Char, findAsciiChar);
if(strLen % 3 == 1) {
result += "==";
}
else if(strLen % 3 == 2) {
result += "=";
}
return result;
}
string base64Decode(string str) {
const int strLen = str.length();
if(str[strLen-2] == '=') {
str.resize(strLen-2);
}
else if(str[strLen-1] == '=') {
str.resize(strLen-1);
}
return bitConversion(str, 6, 8, getAsciiChar, findBase64Char);
}
int main() {
string str = "";
while(true) {
printf("Input:");
getline(cin, str);
str = base64Encode(str);
printf("Encode: %s\n", str.c_str());
str = base64Decode(str);
printf("Decode: %s\n", str.c_str());
}
return 0;
}
|
