Initial Jack import.

Change-Id: I953cf0a520195a7187d791b2885848ad0d5a9b43

1 files changed, 162 insertions, 0 deletions

diff --git a/dx/src/com/android/jack/dx/util/Leb128Utils.java b/dx/src/com/android/jack/dx/util/Leb128Utils.java
new file mode 100644
index 00000000..f6d85d1a
--- /dev/null
+++ b/dx/src/com/android/jack/dx/util/Leb128Utils.java
@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2008 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.jack.dx.util;
+
+/**
+ * Reads and writes DWARFv3 LEB 128 signed and unsigned integers. See DWARF v3
+ * section 7.6.
+ */
+public final class Leb128Utils {
+    /**
+     * This class is uninstantiable.
+     */
+    private Leb128Utils() {
+        // This space intentionally left blank.
+    }
+
+    /**
+     * Gets the number of bytes in the unsigned LEB128 encoding of the
+     * given value.
+     *
+     * @param value the value in question
+     * @return its write size, in bytes
+     */
+    public static int unsignedLeb128Size(int value) {
+        // TODO: This could be much cleverer.
+
+        int remaining = value >> 7;
+        int count = 0;
+
+        while (remaining != 0) {
+            remaining >>= 7;
+            count++;
+        }
+
+        return count + 1;
+    }
+
+    /**
+     * Gets the number of bytes in the signed LEB128 encoding of the
+     * given value.
+     *
+     * @param value the value in question
+     * @return its write size, in bytes
+     */
+    public static int signedLeb128Size(int value) {
+        // TODO: This could be much cleverer.
+
+        int remaining = value >> 7;
+        int count = 0;
+        boolean hasMore = true;
+        int end = ((value & Integer.MIN_VALUE) == 0) ? 0 : -1;
+
+        while (hasMore) {
+            hasMore = (remaining != end)
+                || ((remaining & 1) != ((value >> 6) & 1));
+
+            value = remaining;
+            remaining >>= 7;
+            count++;
+        }
+
+        return count;
+    }
+
+    /**
+     * Reads an signed integer from {@code in}.
+     */
+    public static int readSignedLeb128(ByteInput in) {
+        int result = 0;
+        int cur;
+        int count = 0;
+        int signBits = -1;
+
+        do {
+            cur = in.readByte() & 0xff;
+            result |= (cur & 0x7f) << (count * 7);
+            signBits <<= 7;
+            count++;
+        } while (((cur & 0x80) == 0x80) && count < 5);
+
+        if ((cur & 0x80) == 0x80) {
+            throw new DexException("invalid LEB128 sequence");
+        }
+
+        // Sign extend if appropriate
+        if (((signBits >> 1) & result) != 0 ) {
+            result |= signBits;
+        }
+
+        return result;
+    }
+
+    /**
+     * Reads an unsigned integer from {@code in}.
+     */
+    public static int readUnsignedLeb128(ByteInput in) {
+        int result = 0;
+        int cur;
+        int count = 0;
+
+        do {
+            cur = in.readByte() & 0xff;
+            result |= (cur & 0x7f) << (count * 7);
+            count++;
+        } while (((cur & 0x80) == 0x80) && count < 5);
+
+        if ((cur & 0x80) == 0x80) {
+            throw new DexException("invalid LEB128 sequence");
+        }
+
+        return result;
+    }
+
+    /**
+     * Writes {@code value} as an unsigned integer to {@code out}, starting at
+     * {@code offset}. Returns the number of bytes written.
+     */
+    public static void writeUnsignedLeb128(ByteOutput out, int value) {
+        int remaining = value >>> 7;
+
+        while (remaining != 0) {
+            out.writeByte((byte) ((value & 0x7f) | 0x80));
+            value = remaining;
+            remaining >>>= 7;
+        }
+
+        out.writeByte((byte) (value & 0x7f));
+    }
+
+    /**
+     * Writes {@code value} as a signed integer to {@code out}, starting at
+     * {@code offset}. Returns the number of bytes written.
+     */
+    public static void writeSignedLeb128(ByteOutput out, int value) {
+        int remaining = value >> 7;
+        boolean hasMore = true;
+        int end = ((value & Integer.MIN_VALUE) == 0) ? 0 : -1;
+
+        while (hasMore) {
+            hasMore = (remaining != end)
+                    || ((remaining & 1) != ((value >> 6) & 1));
+
+            out.writeByte((byte) ((value & 0x7f) | (hasMore ? 0x80 : 0)));
+            value = remaining;
+            remaining >>= 7;
+        }
+    }
+}