Initial revision

From-SVN: r26263

libjava/java/io/StringReader.java

@@ -0,0 +1,139 @@
+/* Copyright (C) 1998, 1999  Cygnus Solutions
+
+   This file is part of libgcj.
+
+This software is copyrighted work licensed under the terms of the
+Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
+details.  */
+ 
+package java.io;
+
+/**
+ * @author Warren Levy <warrenl@cygnus.com>
+ * @date October 19, 1998.  
+ */
+/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
+ * "The Java Language Specification", ISBN 0-201-63451-1
+ * plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
+ * Status:  Believed complete and correct
+ */
+ 
+public class StringReader extends Reader
+{
+  /* A String provided by the creator of the stream. */
+  private String buf;
+
+  /* Position of the next char in buf to be read. */
+  private int pos;
+
+  /* The currently marked position in the stream. */
+  private int markedPos;
+
+  /* The index in buf one greater than the last valid character. */
+  private int count;
+
+  public StringReader(String buffer)
+  {
+    super();
+    buf = buffer;
+
+    count = buffer.length();
+    markedPos = pos = 0;
+  }
+
+  public void close()
+  {
+    synchronized (lock)
+    {
+      buf = null;
+    }
+  }
+
+  public void mark(int readAheadLimit) throws IOException
+  {
+    synchronized (lock)
+    {
+      if (buf == null)
+        throw new IOException();
+
+      // readAheadLimit is ignored per Java Class Lib. book, p. 1692.
+      markedPos = pos;
+    }
+  }
+
+  public boolean markSupported()
+  {
+    return true;
+  }
+
+  public int read() throws IOException
+  {
+    synchronized (lock)
+    {
+      if (buf == null)
+        throw new IOException();
+
+      if (pos < count)
+        return ((int) buf.charAt(pos++)) & 0xFFFF;
+      return -1;
+    }
+  }
+
+  public int read(char[] b, int off, int len) throws IOException
+  {
+    synchronized (lock)
+    {
+      if (buf == null)
+        throw new IOException();
+
+      /* Don't need to check pos value, arraycopy will check it. */
+      if (off < 0 || len < 0 || off + len > b.length)
+        throw new ArrayIndexOutOfBoundsException();
+
+      if (pos >= count)
+        return -1;
+
+      int lastChar = Math.min(count, pos + len);
+      buf.getChars(pos, lastChar, b, off);
+      int numChars = lastChar - pos;
+      pos = lastChar;
+      return numChars;
+    }
+  }
+
+  public boolean ready() // TODO12: throws IOException
+  {
+    // TODO12: The JCL specifically says this returns true even if the
+    // reader has been closed, whereas the online 1.2 doc specifically
+    // says to throw an IOException if closed.
+    return true;
+  }
+
+  public void reset() throws IOException
+  {
+    synchronized (lock)
+    {
+      if (buf == null)
+        throw new IOException();
+
+      pos = markedPos;
+    }
+  }
+
+  public long skip(long n) throws IOException
+  {
+    synchronized (lock)
+    {
+      if (buf == null)
+        throw new IOException();
+
+      // Even though the var numChars is a long, in reality it can never
+      // be larger than an int since the result of subtracting 2 positive
+      // ints will always fit in an int.  Since we have to return a long
+      // anyway, numChars might as well just be a long.
+      long numChars = Math.min((long) (count - pos), n < 0 ? 0L : n);
+      pos += numChars;
+      return numChars;
+    }
+  }
+}