Add base64 string encoder/decoder (#79)

* Add base64 string encoder/decoder Signed-off-by: Juan Lopez Fernandez <[email protected]> * Uncrustify Signed-off-by: Juan Lopez Fernandez <[email protected]> --------- Signed-off-by: Juan Lopez Fernandez <[email protected]>
eProsima · Aug 30, 2023 · 900874d · 900874d
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diff --git a/cpp_utils/include/cpp_utils/utils.hpp b/cpp_utils/include/cpp_utils/utils.hpp
@@ -289,11 +289,45 @@ CPP_UTILS_DllAPI
 std::set<Key> get_keys(
         const std::map<Key, Value>& map);
 
+/**
+ * @brief Get std::unordered_map keys.
+ *
+ * Obtain the set of keys relative to a std::unordered_map.
+ *
+ * @param map [in] map whose keys are returned
+ *
+ * @return map keys
+ */
 template <typename Key, typename Value>
 CPP_UTILS_DllAPI
 std::set<Key> get_keys(
         const std::unordered_map<Key, Value>& map);
 
+/**
+ * @brief Encode string using base64.
+ *
+ * @param in [in] string to encode
+ *
+ * @return string in base64
+ */
+CPP_UTILS_DllAPI
+std::string base64_encode(
+        const std::string& in);
+
+/**
+ * @brief Decode base64 string.
+ *
+ * @param in [in] string in base64 to decode
+ *
+ * @return decoded string
+ */
+CPP_UTILS_DllAPI
+std::string base64_decode(
+        const std::string& in);
+
+//! Set of characters used in base64 encoding/decoding algorithms
+const std::string base64_alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
 } /* namespace utils */
 } /* namespace eprosima */
 

diff --git a/cpp_utils/src/cpp/utils.cpp b/cpp_utils/src/cpp/utils.cpp
@@ -232,5 +232,63 @@ std::vector<std::string> split_string(
     return result;
 }
 
+// FROM: https://gist.github.com/williamdes/308b95ac9ef1ee89ae0143529c361d37
+std::string base64_encode(
+        const std::string& in)
+{
+    std::string out;
+
+    int val = 0, valb = -6;
+    for (unsigned char c : in)
+    {
+        val = (val << 8) + c;
+        valb += 8;
+        while (valb >= 0)
+        {
+            out.push_back(base64_alphabet[(val >> valb) & 0x3F]);
+            valb -= 6;
+        }
+    }
+    if (valb > -6)
+    {
+        out.push_back(base64_alphabet[((val << 8) >> (valb + 8)) & 0x3F]);
+    }
+    while (out.size() % 4)
+    {
+        out.push_back('=');
+    }
+    return out;
+}
+
+// FROM: https://gist.github.com/williamdes/308b95ac9ef1ee89ae0143529c361d37
+std::string base64_decode(
+        const std::string& in)
+{
+    std::string out;
+
+    std::vector<int> T(256, -1);
+    for (int i = 0; i < 64; i++)
+    {
+        T[base64_alphabet[i]] = i;
+    }
+
+    int val = 0, valb = -8;
+    for (unsigned char c : in)
+    {
+        if (T[c] == -1)
+        {
+            break;
+        }
+        val = (val << 6) + T[c];
+        valb += 6;
+        if (valb >= 0)
+        {
+            out.push_back(char((val >> valb) & 0xFF));
+            valb -= 8;
+        }
+    }
+    return out;
+}
+
 } /* namespace utils */
 } /* namespace eprosima */