#124 Base64 encoding implementation

IRCClient/Utilities.cpp

@@ -6,9 +6,10 @@
 */
 
 #include "Utilities.h"
+#include <fmt/format.h>
+#include <cstdint>
 #include <sstream>
 #include <vector>
-#include <fmt/format.h>
 
 std::pair<std::string,std::string> FormatCTCPLine(std::string line)
 {
@@ -142,3 +143,53 @@ bool strEquals(const std::string& l, const std::string& r)
         }
     );
 }
+
+std::string toBase64(const std::string& input)
+{
+    static const char b64map[] = { 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
+                                   'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
+                                   'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
+                                   'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/' };
+
+    std::string ret;
+
+    for (auto i = 0; i < input.size(); i += 3) {
+        std::int_fast32_t seq{}; // Need only 24 bits of this
+        std::int_fast32_t a{}, b{}, c{}, d{};
+        bool cBlank{}, dBlank{};
+
+        seq |= input[i];
+        seq <<= 8;
+
+        if (i + 1 < input.size())
+            seq |= input[i + 1];
+        else
+            cBlank = true;
+        seq <<= 8;
+
+        if (i + 2 < input.size())
+            seq |= input[i + 2];
+        else
+            dBlank = true;
+
+        a = (seq & 0xFC0000) >> 18;
+        b = (seq & 0x3F000) >> 12;
+        c = (seq & 0xFC0) >> 6;
+        d = seq & 0x3F;
+
+        ret.push_back(b64map[a]);
+        ret.push_back(b64map[b]);
+
+        if (cBlank)
+            ret.push_back('=');
+        else
+            ret.push_back(b64map[c]);
+
+        if (dBlank)
+            ret.push_back('=');
+        else
+            ret.push_back(b64map[d]);
+    }
+
+    return ret;
+}

IRCClient/Utilities.h

@@ -20,5 +20,6 @@ std::string longIpToNormal(const std::string& longip);
 std::string normalIpToLong(const std::string& normalip);
 std::string concatenateModes(const std::unordered_map<char, std::string>& modes);
 bool strEquals(const std::string& l, const std::string& r);
+std::string toBase64(const std::string& input);
 
 #endif //IRCUTILITIES_H