1 files changed, 114 insertions, 0 deletions
diff --git a/dx/src/com/android/dx/util/Mutf8.java b/dx/src/com/android/dx/util/Mutf8.java
new file mode 100644
index 0000000..fe55724
--- /dev/null
+++ b/dx/src/com/android/dx/util/Mutf8.java
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2011 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.dx.util;
+
+import java.io.UTFDataFormatException;
+
+/**
+ * Modified UTF-8 as described in the dex file format spec.
+ *
+ * <p>Derived from libcore's MUTF-8 encoder at java.nio.charset.ModifiedUtf8.
+ */
+public final class Mutf8 {
+    private Mutf8() {}
+
+    /**
+     * Decodes bytes from {@code in} into {@code out} until a delimiter 0x00 is
+     * encountered. Returns a new string containing the decoded characters.
+     */
+    public static String decode(ByteInput in, char[] out) throws UTFDataFormatException {
+        int s = 0;
+        while (true) {
+            char a = (char) (in.readByte() & 0xff);
+            if (a == 0) {
+                return new String(out, 0, s);
+            }
+            out[s] = a;
+            if (a < '\u0080') {
+                s++;
+            } else if ((a & 0xe0) == 0xc0) {
+                int b = in.readByte() & 0xff;
+                if ((b & 0xC0) != 0x80) {
+                    throw new UTFDataFormatException("bad second byte");
+                }
+                out[s++] = (char) (((a & 0x1F) << 6) | (b & 0x3F));
+            } else if ((a & 0xf0) == 0xe0) {
+                int b = in.readByte() & 0xff;
+                int c = in.readByte() & 0xff;
+                if (((b & 0xC0) != 0x80) || ((c & 0xC0) != 0x80)) {
+                    throw new UTFDataFormatException("bad second or third byte");
+                }
+                out[s++] = (char) (((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F));
+            } else {
+                throw new UTFDataFormatException("bad byte");
+            }
+        }
+    }
+
+    /**
+     * Returns the number of bytes the modified UTF8 representation of 's' would take.
+     */
+    private static long countBytes(String s, boolean shortLength) throws UTFDataFormatException {
+        long result = 0;
+        final int length = s.length();
+        for (int i = 0; i < length; ++i) {
+            char ch = s.charAt(i);
+            if (ch != 0 && ch <= 127) { // U+0000 uses two bytes.
+                ++result;
+            } else if (ch <= 2047) {
+                result += 2;
+            } else {
+                result += 3;
+            }
+            if (shortLength && result > 65535) {
+                throw new UTFDataFormatException("String more than 65535 UTF bytes long");
+            }
+        }
+        return result;
+    }
+
+    /**
+     * Encodes the modified UTF-8 bytes corresponding to {@code s} into  {@code
+     * dst}, starting at {@code offset}.
+     */
+    public static void encode(byte[] dst, int offset, String s) {
+        final int length = s.length();
+        for (int i = 0; i < length; i++) {
+            char ch = s.charAt(i);
+            if (ch != 0 && ch <= 127) { // U+0000 uses two bytes.
+                dst[offset++] = (byte) ch;
+            } else if (ch <= 2047) {
+                dst[offset++] = (byte) (0xc0 | (0x1f & (ch >> 6)));
+                dst[offset++] = (byte) (0x80 | (0x3f & ch));
+            } else {
+                dst[offset++] = (byte) (0xe0 | (0x0f & (ch >> 12)));
+                dst[offset++] = (byte) (0x80 | (0x3f & (ch >> 6)));
+                dst[offset++] = (byte) (0x80 | (0x3f & ch));
+            }
+        }
+    }
+
+    /**
+     * Returns an array containing the <i>modified UTF-8</i> form of {@code s}.
+     */
+    public static byte[] encode(String s) throws UTFDataFormatException {
+        int utfCount = (int) countBytes(s, true);
+        byte[] result = new byte[utfCount];
+        encode(result, 0, s);
+        return result;
+    }
+}