Initial checkin of "foundation" library for future stagefright development.

Change-Id: I11714dcaa647d0437a13e4c5b953b35e712da8f3

1 files changed, 139 insertions, 0 deletions

diff --git a/media/libstagefright/foundation/base64.cpp b/media/libstagefright/foundation/base64.cpp
new file mode 100644
index 0000000..d5fb4e0
--- /dev/null
+++ b/media/libstagefright/foundation/base64.cpp
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * 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 "base64.h"
+
+#include "ABuffer.h"
+#include "ADebug.h"
+
+namespace android {
+
+sp<ABuffer> decodeBase64(const AString &s) {
+    if ((s.size() % 4) != 0) {
+        return NULL;
+    }
+
+    size_t n = s.size();
+    size_t padding = 0;
+    if (n >= 1 && s.c_str()[n - 1] == '=') {
+        padding = 1;
+
+        if (n >= 2 && s.c_str()[n - 2] == '=') {
+            padding = 2;
+        }
+    }
+
+    size_t outLen = 3 * s.size() / 4 - padding;
+
+    sp<ABuffer> buffer = new ABuffer(outLen);
+
+    uint8_t *out = buffer->data();
+    size_t j = 0;
+    uint32_t accum = 0;
+    for (size_t i = 0; i < n; ++i) {
+        char c = s.c_str()[i];
+        unsigned value;
+        if (c >= 'A' && c <= 'Z') {
+            value = c - 'A';
+        } else if (c >= 'a' && c <= 'z') {
+            value = 26 + c - 'a';
+        } else if (c >= '0' && c <= '9') {
+            value = 52 + c - '0';
+        } else if (c == '+') {
+            value = 62;
+        } else if (c == '/') {
+            value = 63;
+        } else if (c != '=') {
+            return NULL;
+        } else {
+            if (i < n - padding) {
+                return NULL;
+            }
+
+            value = 0;
+        }
+
+        accum = (accum << 6) | value;
+
+        if (((i + 1) % 4) == 0) {
+            out[j++] = (accum >> 16);
+
+            if (j < outLen) { out[j++] = (accum >> 8) & 0xff; } 
+            if (j < outLen) { out[j++] = accum & 0xff; }
+
+            accum = 0;
+        }
+    }
+
+    return buffer;
+}
+
+static char encode6Bit(unsigned x) {
+    if (x <= 25) {
+        return 'A' + x;
+    } else if (x <= 51) {
+        return 'a' + x - 26;
+    } else if (x <= 61) {
+        return '0' + x - 52;
+    } else if (x == 62) {
+        return '+';
+    } else {
+        return '/';
+    }
+}
+
+void encodeBase64(
+        const void *_data, size_t size, AString *out) {
+    out->clear();
+
+    const uint8_t *data = (const uint8_t *)_data;
+
+    size_t i;
+    for (i = 0; i < (size / 3) * 3; i += 3) {
+        uint8_t x1 = data[i];
+        uint8_t x2 = data[i + 1];
+        uint8_t x3 = data[i + 2];
+
+        out->append(encode6Bit(x1 >> 2));
+        out->append(encode6Bit((x1 << 4 | x2 >> 4) & 0x3f));
+        out->append(encode6Bit((x2 << 2 | x3 >> 6) & 0x3f));
+        out->append(encode6Bit(x3 & 0x3f));
+    }
+    switch (size % 3) {
+        case 0:
+            break;
+        case 2:
+        {
+            uint8_t x1 = data[i];
+            uint8_t x2 = data[i + 1];
+            out->append(encode6Bit(x1 >> 2));
+            out->append(encode6Bit((x1 << 4 | x2 >> 4) & 0x3f));
+            out->append(encode6Bit((x2 << 2) & 0x3f));
+            out->append('=');
+            break;
+        }
+        default:
+        {
+            uint8_t x1 = data[i];
+            out->append(encode6Bit(x1 >> 2));
+            out->append(encode6Bit((x1 << 4) & 0x3f));
+            out->append("==");
+            break;
+        }
+    }
+}
+
+}  // namespace android