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-rw-r--r--media/gmp-clearkey/0.1/ClearKeyBase64.cpp99
1 files changed, 99 insertions, 0 deletions
diff --git a/media/gmp-clearkey/0.1/ClearKeyBase64.cpp b/media/gmp-clearkey/0.1/ClearKeyBase64.cpp
new file mode 100644
index 000000000..c4c530a34
--- /dev/null
+++ b/media/gmp-clearkey/0.1/ClearKeyBase64.cpp
@@ -0,0 +1,99 @@
+/*
+ * Copyright 2015, Mozilla Foundation and contributors
+ *
+ * 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.
+ */
+
+#include "ClearKeyBase64.h"
+
+#include <algorithm>
+
+using namespace std;
+
+/**
+* Take a base64-encoded string, convert (in-place) each character to its
+* corresponding value in the [0x00, 0x3f] range, and truncate any padding.
+*/
+static bool
+Decode6Bit(string& aStr)
+{
+ for (size_t i = 0; i < aStr.length(); i++) {
+ if (aStr[i] >= 'A' && aStr[i] <= 'Z') {
+ aStr[i] -= 'A';
+ }
+ else if (aStr[i] >= 'a' && aStr[i] <= 'z') {
+ aStr[i] -= 'a' - 26;
+ }
+ else if (aStr[i] >= '0' && aStr[i] <= '9') {
+ aStr[i] -= '0' - 52;
+ }
+ else if (aStr[i] == '-' || aStr[i] == '+') {
+ aStr[i] = 62;
+ }
+ else if (aStr[i] == '_' || aStr[i] == '/') {
+ aStr[i] = 63;
+ }
+ else {
+ // Truncate '=' padding at the end of the aString.
+ if (aStr[i] != '=') {
+ aStr.erase(i, string::npos);
+ return false;
+ }
+ aStr[i] = '\0';
+ aStr.resize(i);
+ break;
+ }
+ }
+
+ return true;
+}
+
+bool
+DecodeBase64(const string& aEncoded, vector<uint8_t>& aOutDecoded)
+{
+ if (aEncoded.empty()) {
+ aOutDecoded.clear();
+ return true;
+ }
+ if (aEncoded.size() == 1) {
+ // Invalid Base64 encoding.
+ return false;
+ }
+ string encoded = aEncoded;
+ if (!Decode6Bit(encoded)) {
+ return false;
+ }
+
+ // The number of bytes we haven't yet filled in the current byte, mod 8.
+ int shift = 0;
+
+ aOutDecoded.resize((encoded.size() * 3) / 4);
+ vector<uint8_t>::iterator out = aOutDecoded.begin();
+ for (size_t i = 0; i < encoded.length(); i++) {
+ if (!shift) {
+ *out = encoded[i] << 2;
+ }
+ else {
+ *out |= encoded[i] >> (6 - shift);
+ out++;
+ if (out == aOutDecoded.end()) {
+ // Hit last 6bit octed in encoded, which is padding and can be ignored.
+ break;
+ }
+ *out = encoded[i] << (shift + 2);
+ }
+ shift = (shift + 2) % 8;
+ }
+
+ return true;
+} \ No newline at end of file