imported from ant 1.7 source distribution

[vamsas.git] / src / org / apache / tools / zip / ZipLong.java

diff --git a/src/org/apache/tools/zip/ZipLong.java b/src/org/apache/tools/zip/ZipLong.java
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+++ b/src/org/apache/tools/zip/ZipLong.java
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+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one or more
+ *  contributor license agreements.  See the NOTICE file distributed with
+ *  this work for additional information regarding copyright ownership.
+ *  The ASF licenses this file to You 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 org.apache.tools.zip;
+
+/**
+ * Utility class that represents a four byte integer with conversion
+ * rules for the big endian byte order of ZIP files.
+ *
+ */
+public final class ZipLong implements Cloneable {
+
+    private long value;
+
+    /**
+     * Create instance from a number.
+     * @param value the long to store as a ZipLong
+     * @since 1.1
+     */
+    public ZipLong(long value) {
+        this.value = value;
+    }
+
+    /**
+     * Create instance from bytes.
+     * @param bytes the bytes to store as a ZipLong
+     * @since 1.1
+     */
+    public ZipLong (byte[] bytes) {
+        this(bytes, 0);
+    }
+
+    /**
+     * Create instance from the four bytes starting at offset.
+     * @param bytes the bytes to store as a ZipLong
+     * @param offset the offset to start
+     * @since 1.1
+     */
+    public ZipLong (byte[] bytes, int offset) {
+        value = ZipLong.getValue(bytes, offset);
+    }
+
+    /**
+     * Get value as four bytes in big endian byte order.
+     * @since 1.1
+     * @return value as four bytes in big endian order
+     */
+    public byte[] getBytes() {
+        return ZipLong.getBytes(value);
+    }
+
+    /**
+     * Get value as Java long.
+     * @since 1.1
+     * @return value as a long
+     */
+    public long getValue() {
+        return value;
+    }
+
+    /**
+     * Get value as four bytes in big endian byte order.
+     * @param value the value to convert
+     * @return value as four bytes in big endian byte order
+     */
+    public static byte[] getBytes(long value) {
+        byte[] result = new byte[4];
+        result[0] = (byte) ((value & 0xFF));
+        result[1] = (byte) ((value & 0xFF00) >> 8);
+        result[2] = (byte) ((value & 0xFF0000) >> 16);
+        result[3] = (byte) ((value & 0xFF000000L) >> 24);
+        return result;
+    }
+
+    /**
+     * Helper method to get the value as a Java long from four bytes starting at given array offset
+     * @param bytes the array of bytes
+     * @param offset the offset to start
+     * @return the correspondanding Java long value
+     */
+    public static long getValue(byte[] bytes, int offset) {
+        long value = (bytes[offset + 3] << 24) & 0xFF000000L;
+        value += (bytes[offset + 2] << 16) & 0xFF0000;
+        value += (bytes[offset + 1] << 8) & 0xFF00;
+        value += (bytes[offset] & 0xFF);
+        return value;
+    }
+
+    /**
+     * Helper method to get the value as a Java long from a four-byte array
+     * @param bytes the array of bytes
+     * @return the correspondanding Java long value
+     */
+    public static long getValue(byte[] bytes) {
+        return getValue(bytes, 0);
+    }
+
+    /**
+     * Override to make two instances with same value equal.
+     * @param o an object to compare
+     * @return true if the objects are equal
+     * @since 1.1
+     */
+    public boolean equals(Object o) {
+        if (o == null || !(o instanceof ZipLong)) {
+            return false;
+        }
+        return value == ((ZipLong) o).getValue();
+    }
+
+    /**
+     * Override to make two instances with same value equal.
+     * @return the value stored in the ZipLong
+     * @since 1.1
+     */
+    public int hashCode() {
+        return (int) value;
+    }
+}