Fix javac --incremental by using jmake for dependency analysis

third_party/jmake/src/org/pantsbuild/jmake/Base64.java

+/* Copyright (c) 2002-2013 Sun Microsystems, Inc. All rights reserved
+ *
+ * This program is distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+package org.pantsbuild.jmake;
+
+import java.util.Arrays;
+
+
+/**
+ * JMake needs to run against old versions of Java, that may not have JAXB's
+ * javax.xml.bind.DatatypeConverter. And we don't want JMake to depend on third-party external libraries,
+ * especially not just for this.  So we implement a lightweight Base64 converter here ourselves.
+
+ * Note that sun.misc.BASE64Encoder is not official API and can go away at any time. Plus it inserts
+ * line breaks into its emitted string, which is not what we want. So we can't use that either.
+ */
+
+public class Base64 {
+    // The easiest way to grok this code is to think of Base64 as the following chain of
+    // conversions (ignoring padding issues):
+    // 3 bytes -> 24 bits -> 4 6-bit nibbles -> 4 indexes from 0-63 -> 4 characters.
+    private static final char[] indexToDigit =
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
+    private static final int[] digitToIndex = new int[128];
+    static {
+        assert(indexToDigit.length == 64);
+        Arrays.fill(digitToIndex, -1);
+        for (int i = 0; i < indexToDigit.length; i++) digitToIndex[(int)indexToDigit[i]] = i;
+    }
+
+    private Base64() {}
+
+    public static char[] encode(byte[] in) {
+        char[] ret = new char[(in.length + 2) / 3 * 4];
+        int p = 0;
+        int i = 0;
+        while (i < in.length) {
+            // Lowest 24 bits count.
+            int bits = (in[i++] & 0xff) << 16 | (i < in.length ? in[i++] & 0xff : 0) << 8 | (i < in.length ? in[i++] & 0xff : 0);
+            ret[p++] = indexToDigit[(bits & 0xfc0000) >> 18];
+            ret[p++] = indexToDigit[(bits & 0x3f000) >> 12];
+            ret[p++] = indexToDigit[(bits & 0xfc0) >> 6];
+            ret[p++] = indexToDigit[bits & 0x3f];
+        }
+        assert(p == ret.length);
+        int padding = (3 - in.length % 3) % 3;
+        for (int j = ret.length - padding; j < ret.length; j++) ret[j] = '=';
+        return ret;
+    }
+
+    public static byte[] decode(char[] in) {
+        if (in.length % 4 != 0) throw new IllegalArgumentException("Base64-encoded string must be of length that is a multiple of 4.");
+        int len = in.length;
+        while(len > 0 && in[len - 1] == '=') len--;
+        int padding = in.length - len;
+        byte[] ret = new byte[in.length / 4 * 3 - padding];
+        int i = 0;
+        int p = 0;
+        while (i < len) {
+            char c0 = in[i++];
+            char c1 = in[i++];
+            char c2 = i < len ? in[i++] : 'A';
+            char c3 = i < len ? in[i++] : 'A';
+            if (c0 > 127 || c1 > 127 || c2 > 127 || c3 > 127) throw new IllegalArgumentException("Invalid Base64 digit in: " + c0 + c1 + c2 + c3);
+            int n0 = digitToIndex[c0];
+            int n1 = digitToIndex[c1];
+            int n2 = digitToIndex[c2];
+            int n3 = digitToIndex[c3];
+            if (n0 < 0 || n1 < 0 || n2 < 0 || n3 < 0) throw new IllegalArgumentException("Invalid Base64 digit in: " + c0 + c1 + c2 + c3);
+            int bits = (n0 << 18) | (n1 << 12) | (n2 << 6) | n3;
+            ret[p++] = (byte)((bits & 0xff0000) >> 16);
+            if (p < ret.length) ret[p++] = (byte)((bits & 0xff00) >> 8);
+            if (p < ret.length) ret[p++] = (byte)(bits & 0xff);
+        }
+        return ret;
+    }
+}