Move Base64Reader to utils package

Change-Id: Id46898c5cae268f05850d79938929b7707f27320

1 files changed, 117 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/utils/Base64Reader.java b/java/src/com/android/inputmethod/latin/utils/Base64Reader.java
new file mode 100644
index 000000000..3eca6e744
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/utils/Base64Reader.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+package com.android.inputmethod.latin.utils;
+
+import com.android.inputmethod.annotations.UsedForTesting;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.LineNumberReader;
+
+@UsedForTesting
+public class Base64Reader {
+    private final LineNumberReader mReader;
+
+    private String mLine;
+    private int mCharPos;
+    private int mByteCount;
+
+    @UsedForTesting
+    public Base64Reader(final LineNumberReader reader) {
+        mReader = reader;
+        reset();
+    }
+
+    @UsedForTesting
+    public void reset() {
+        mLine = null;
+        mCharPos = 0;
+        mByteCount = 0;
+    }
+
+    @UsedForTesting
+    public int getLineNumber() {
+        return mReader.getLineNumber();
+    }
+
+    @UsedForTesting
+    public int getByteCount() {
+        return mByteCount;
+    }
+
+    private void fillBuffer() throws IOException {
+        if (mLine == null || mCharPos >= mLine.length()) {
+            mLine = mReader.readLine();
+            mCharPos = 0;
+        }
+        if (mLine == null) {
+            throw new EOFException();
+        }
+    }
+
+    private int peekUint8() throws IOException {
+        fillBuffer();
+        final char c = mLine.charAt(mCharPos);
+        if (c >= 'A' && c <= 'Z')
+            return c - 'A' + 0;
+        if (c >= 'a' && c <= 'z')
+            return c - 'a' + 26;
+        if (c >= '0' && c <= '9')
+            return c - '0' + 52;
+        if (c == '+')
+            return 62;
+        if (c == '/')
+            return 63;
+        if (c == '=')
+            return 0;
+        throw new RuntimeException("Unknown character '" + c + "' in base64 at line "
+                + mReader.getLineNumber());
+    }
+
+    private int getUint8() throws IOException {
+        final int value = peekUint8();
+        mCharPos++;
+        return value;
+    }
+
+    @UsedForTesting
+    public int readUint8() throws IOException {
+        final int value1, value2;
+        switch (mByteCount % 3) {
+        case 0:
+            value1 = getUint8() << 2;
+            value2 = value1 | (peekUint8() >> 4);
+            break;
+        case 1:
+            value1 = (getUint8() & 0x0f) << 4;
+            value2 = value1 | (peekUint8() >> 2);
+            break;
+        default:
+            value1 = (getUint8() & 0x03) << 6;
+            value2 = value1 | getUint8();
+            break;
+        }
+        mByteCount++;
+        return value2;
+    }
+
+    @UsedForTesting
+    public short readInt16() throws IOException {
+        final int data = readUint8() << 8;
+        return (short)(data | readUint8());
+    }
+}