Adding JMCR-Stable version

[Benchmarks_CSolver.git] / JMCR-Stable / real-world application / MyDerby-10.3 / java / drda / org / apache / derby / impl / drda / DRDAString.java

diff --git a/JMCR-Stable/real-world application/MyDerby-10.3/java/drda/org/apache/derby/impl/drda/DRDAString.java b/JMCR-Stable/real-world application/MyDerby-10.3/java/drda/org/apache/derby/impl/drda/DRDAString.java
new file mode 100644 (file)
index 0000000..3db7014
--- /dev/null
+++ b/JMCR-Stable/real-world application/MyDerby-10.3/java/drda/org/apache/derby/impl/drda/DRDAString.java
@@ -0,0 +1,142 @@
+/*\r
+ * Derby - class org.apache.derby.impl.drda.DRDAString\r
+ *\r
+ * Licensed to the Apache Software Foundation (ASF) under one or more\r
+ * contributor license agreements.  See the NOTICE file distributed with\r
+ * this work for additional information regarding copyright ownership.\r
+ * The ASF licenses this file to You under the Apache License, Version 2.0\r
+ * (the "License"); you may not use this file except in compliance with\r
+ * the License.  You may obtain a copy of the License at\r
+ *\r
+ *   http://www.apache.org/licenses/LICENSE-2.0\r
+ *\r
+ * Unless required by applicable law or agreed to in writing, software\r
+ * distributed under the License is distributed on an "AS IS" BASIS,\r
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or\r
+ * implied. See the License for the specific language governing\r
+ * permissions and limitations under the License.\r
+ *\r
+ */\r
+\r
+package org.apache.derby.impl.drda;\r
+\r
+/**\r
+ * This class provides functionality for reusing buffers and strings\r
+ * when parsing DRDA packets. A byte array representing a string is\r
+ * stored internally. When the string is requested as a\r
+ * <code>String</code> object, the byte array is converted to a\r
+ * string, and the string is cached to avoid unnecessary conversion\r
+ * later.\r
+ */\r
+final class DRDAString {\r
+    /** Buffer representing the string. */\r
+    private byte[] buffer;\r
+    /** Object used to convert byte buffer to string. */\r
+    private final CcsidManager ccsidManager;\r
+\r
+    /** True if the contents were modified in the previous call to\r
+     * <code>setBytes</code>. */\r
+    private boolean modified;\r
+\r
+    /** The previously generated string. */\r
+    private String cachedString;\r
+\r
+    /**\r
+     * Create a new <code>DRDAString</code> instance.\r
+     *\r
+     * @param m a <code>CcsidManager</code> value specifying\r
+     * which encoding is used\r
+     */\r
+    DRDAString(CcsidManager m) {\r
+        this.buffer = new byte[0];\r
+        this.ccsidManager = m;\r
+        this.cachedString = null;\r
+    }\r
+\r
+    /**\r
+     * Check whether the internal buffer contains the same data as\r
+     * another byte buffer.\r
+     *\r
+     * @param buf a byte array\r
+     * @param offset start position in the byte array\r
+     * @param size how many bytes to read from the byte array\r
+     * @return <code>true</code> if the internal buffer contains the\r
+     * same data as the specified byte array\r
+     */\r
+    private boolean equalTo(byte[] buf, int offset, int size) {\r
+        int len = buffer.length;\r
+        if (len != size) return false;\r
+        for (int i = 0; i < len; ++i) {\r
+            if (buffer[i] != buf[i+offset]) return false;\r
+        }\r
+        return true;\r
+    }\r
+\r
+    /**\r
+     * Modify the internal byte buffer. If the new data is equal to\r
+     * the old data, the cached values are not cleared.\r
+     *\r
+     * @param src the new bytes\r
+     * @param offset start offset\r
+     * @param size number of bytes to use\r
+     */\r
+    public void setBytes(byte[] src, int offset, int size) {\r
+        if (equalTo(src, offset, size)) {\r
+            modified = false;\r
+            return;\r
+        }\r
+        if (buffer.length != size) {\r
+            buffer = new byte[size];\r
+        }\r
+        System.arraycopy(src, offset, buffer, 0, size);\r
+        modified = true;\r
+        cachedString = null;\r
+    }\r
+\r
+    /**\r
+     * Check whether the contents of the <code>DRDAString</code> were\r
+     * modified in the previous call to <code>setBytes()</code>.\r
+     *\r
+     * @return <code>true</code> if the contents were modified\r
+     */\r
+    public boolean wasModified() {\r
+        return modified;\r
+    }\r
+\r
+    /**\r
+     * Convert the internal byte array to a string. The string value\r
+     * is cached.\r
+     *\r
+     * @return a <code>String</code> value\r
+     */\r
+    public String toString() {\r
+        if (cachedString == null) {\r
+            cachedString =\r
+                ccsidManager.convertToUCS2(buffer);\r
+        }\r
+        return cachedString;\r
+    }\r
+\r
+    /**\r
+     * Return the length in bytes of the internal string\r
+     * representation.\r
+     *\r
+     * @return length of internal representation\r
+     */\r
+    public int length() {\r
+        return buffer.length;\r
+    }\r
+\r
+    /**\r
+     * Return the internal byte array. The returned array should not\r
+     * be modified, as it is used internally in\r
+     * <code>DRDAString</code>. The value of the array might be\r
+     * modified by subsequent calls to\r
+     * <code>DRDAString.setBytes()</code>.\r
+     *\r
+     * @return internal buffer\r
+     */\r
+    public byte[] getBytes() {\r
+        return buffer;\r
+    }\r
+}\r