1 files changed, 66 insertions, 0 deletions
diff --git a/src/support/base64.h b/src/support/base64.h
new file mode 100644
index 000000000..0c87c37c1
--- /dev/null
+++ b/src/support/base64.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2019 WebAssembly Community Group participants
+ *
+ * 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.
+ */
+
+#ifndef wasm_support_base64_h
+#define wasm_support_base64_h
+
+#include <cassert>
+#include <string>
+#include <vector>
+
+inline std::string base64Encode(std::vector<char> &data) {
+  std::string ret;
+  size_t i = 0;
+
+  const char* alphabet =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "abcdefghijklmnopqrstuvwxyz"
+    "0123456789+/";
+
+  while (i + 3 <= data.size()) {
+    uint32_t bits =
+      (((uint32_t)(uint8_t) data[i + 0]) << 16) |
+      (((uint32_t)(uint8_t) data[i + 1]) << 8) |
+      (((uint32_t)(uint8_t) data[i + 2]) << 0);
+    ret += alphabet[(bits >> 18) & 0x3f];
+    ret += alphabet[(bits >> 12) & 0x3f];
+    ret += alphabet[(bits >> 6) & 0x3f];
+    ret += alphabet[(bits >> 0) & 0x3f];
+    i += 3;
+  }
+
+  if (i + 2 == data.size()) {
+    uint32_t bits =
+      (((uint32_t)(uint8_t) data[i + 0]) << 8) |
+      (((uint32_t)(uint8_t) data[i + 1]) << 0);
+    ret += alphabet[(bits >> 10) & 0x3f];
+    ret += alphabet[(bits >> 4) & 0x3f];
+    ret += alphabet[(bits << 2) & 0x3f];
+    ret += '=';
+  } else if (i + 1 == data.size()) {
+    uint32_t bits = (uint32_t)(uint8_t) data[i + 0];
+    ret += alphabet[(bits >> 2) & 0x3f];
+    ret += alphabet[(bits << 4) & 0x3f];
+    ret += '=';
+    ret += '=';
+  } else {
+    assert(i == data.size());
+  }
+
+  return ret;
+}
+
+#endif // wasm_support_base64_h