gt:             count -= len;
context: /*
   *   
   *
   * Copyright  1990-2006 Sun Microsystems, Inc. All Rights Reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
   * 
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License version
   * 2 only, as published by the Free Software Foundation. 
   * 
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   * General Public License version 2 for more details (a copy is
   * included at /legal/license.txt). 
   * 
   * You should have received a copy of the GNU General Public License
   * version 2 along with this work; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA 
   * 
   * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
   * Clara, CA 95054 or visit www.sun.com if you need additional
   * information or have any questions. 
   */
  
  package java.lang;
  
  import com.sun.cldchi.jvm.JVM;
  
  /**
   * A string buffer implements a mutable sequence of characters. 
   * A string buffer is like a {@link String}, but can be modified. At any 
   * point in time it contains some particular sequence of characters, but 
   * the length and content of the sequence can be changed through certain 
   * method calls.
   * <p>
   * String buffers are safe for use by multiple threads. The methods 
   * are synchronized where necessary so that all the operations on any 
   * particular instance behave as if they occur in some serial order 
   * that is consistent with the order of the method calls made by each of 
   * the individual threads involved. 
   * <p>
   * String buffers are used by the compiler to implement the binary 
   * string concatenation operator <code>+</code>. For example, the code:
   * <p><blockquote><pre>
   *     x = "a" + 4 + "c"
   * </pre></blockquote><p>
   * is compiled to the equivalent of: 
   * <p><blockquote><pre>
   *     x = new StringBuffer().append("a").append(4).append("c")
   *                           .toString()
   * </pre></blockquote>
   * which creates a new string buffer (initially empty), appends the string
   * representation of each operand to the string buffer in turn, and then
   * converts the contents of the string buffer to a string. Overall, this avoids
   * creating many temporary strings.
   * <p>
   * The principal operations on a <code>StringBuffer</code> are the 
   * <code>append</code> and <code>insert</code> methods, which are 
   * overloaded so as to accept data of any type. Each effectively 
   * converts a given datum to a string and then appends or inserts the 
   * characters of that string to the string buffer. The 
   * <code>append</code> method always adds these characters at the end 
   * of the buffer; the <code>insert</code> method adds the characters at 
   * a specified point. 
   * <p>
   * For example, if <code>z</code> refers to a string buffer object 
   * whose current contents are "<code>start</code>", then 
   * the method call <code>z.append("le")</code> would cause the string 
   * buffer to contain "<code>startle</code>", whereas 
   * <code>z.insert(4, "le")</code> would alter the string buffer to 
   * contain "<code>starlet</code>". 
   * <p>
   * In general, if sb refers to an instance of a <code>StringBuffer</code>, 
   * then <code>sb.append(x)</code> has the same effect as 
   * <code>sb.insert(sb.length(),&nbsp;x)</code>.
   * <p>
   * Every string buffer has a capacity. As long as the length of the 
   * character sequence contained in the string buffer does not exceed 
   * the capacity, it is not necessary to allocate a new internal 
   * buffer array. If the internal buffer overflows, it is 
   * automatically made larger. 
   *
   * @version 1.60, 12/04/99 (CLDC 1.0, Spring 2000)
   * @see     java.io.ByteArrayOutputStream
   * @see     java.lang.String
   * @since   JDK1.0
   */
   
  public final class StringBuffer {
  
      /**
       * The value is used for character storage.
       * 
       * @serial
       */
      private char value[];
  
      /** 
       * The count is the number of characters in the buffer.
       * 
       * @serial
       */
      private int count;
  
      /**
       * A flag indicating whether the buffer is shared 
       *
       * @serial
       */
      private boolean shared;
  
      /**
       * Constructs a string buffer with no characters in it and an 
       * initial capacity of 16 characters. 
       */
      public StringBuffer() {
          value = new char[16];
      }
  
      /**
       * Constructs a string buffer with no characters in it and an 
       * initial capacity specified by the <code>length</code> argument. 
       *
       * @param      length   the initial capacity.
       * @exception  NegativeArraySizeException  if the <code>length</code>
       *               argument is less than <code>0</code>.
       */
      public StringBuffer(int length) {
          value = new char[length];
      }
  
      /**
       * Constructs a string buffer so that it represents the same 
       * sequence of characters as the string argument; in other
       * words, the initial contents of the string buffer is a copy of the 
       * argument string. The initial capacity of the string buffer is 
       * <code>16</code> plus the length of the string argument. 
       *
       * @param   str   the initial contents of the buffer.
       */
      public StringBuffer(String str) {
          this(str.length() + 16);
          append(str);
      }
  
      /**
       * Returns the length (character count) of this string buffer.
       *
       * @return  the length of the sequence of characters currently 
       *          represented by this string buffer.
       */
      public int length() {
          return count;
      }
  
      /**
       * Returns the current capacity of the String buffer. The capacity
       * is the amount of storage available for newly inserted
       * characters; beyond which an allocation will occur.
       *
       * @return  the current capacity of this string buffer.
       */
      public int capacity() {
          return value.length;
      }
  
      /**
       * Copies the buffer value.  This is normally only called when shared
       * is true.  It should only be called from a synchronized method.
       */
      private final void copy() {
          char newValue[] = new char[value.length];
          JVM.unchecked_char_arraycopy(value, 0, newValue, 0, count);
          value = newValue;
          shared = false;
      }
  
      /**
       * Ensures that the capacity of the buffer is at least equal to the
       * specified minimum.
       * If the current capacity of this string buffer is less than the 
       * argument, then a new internal buffer is allocated with greater 
       * capacity. The new capacity is the larger of: 
       * <ul>
       * <li>The <code>minimumCapacity</code> argument. 
       * <li>Twice the old capacity, plus <code>2</code>. 
       * </ul>
       * If the <code>minimumCapacity</code> argument is nonpositive, this
       * method takes no action and simply returns.
       *
       * @param   minimumCapacity   the minimum desired capacity.
       */
      public synchronized void ensureCapacity(int minimumCapacity) {
          if (minimumCapacity > value.length) {
              expandCapacity(minimumCapacity);
          }
      }
  
      /**
       * This implements the expansion semantics of ensureCapacity but is
       * unsynchronized for use internally by methods which are already
       * synchronized.
       *
       * @see java.lang.StringBuffer#ensureCapacity(int)
       */
      private void expandCapacity(int minimumCapacity) {
          int newCapacity = (value.length + 1) * 2;
          if (newCapacity < 0) {
              newCapacity = Integer.MAX_VALUE;
          } else if (minimumCapacity > newCapacity) {
              newCapacity = minimumCapacity;
          }
          
          char newValue[] = new char[newCapacity];
          JVM.unchecked_char_arraycopy(value, 0, newValue, 0, count);
          value = newValue;
          shared = false;
      }
  
      /**
       * Sets the length of this String buffer.
       * This string buffer is altered to represent a new character sequence 
       * whose length is specified by the argument. For every nonnegative 
       * index <i>k</i> less than <code>newLength</code>, the character at 
       * index <i>k</i> in the new character sequence is the same as the 
       * character at index <i>k</i> in the old sequence if <i>k</i> is less 
       * than the length of the old character sequence; otherwise, it is the 
       * null character <code>'\u0000'</code>. 
       *  
       * In other words, if the <code>newLength</code> argument is less than 
       * the current length of the string buffer, the string buffer is 
       * truncated to contain exactly the number of characters given by the 
       * <code>newLength</code> argument. 
       * <p>
       * If the <code>newLength</code> argument is greater than or equal 
       * to the current length, sufficient null characters 
       * (<code>'&#92;u0000'</code>) are appended to the string buffer so that 
       * length becomes the <code>newLength</code> argument. 
       * <p>
       * The <code>newLength</code> argument must be greater than or equal 
       * to <code>0</code>. 
       *
       * @param      newLength   the new length of the buffer.
       * @exception  IndexOutOfBoundsException  if the
       *               <code>newLength</code> argument is negative.
       * @see        java.lang.StringBuffer#length()
       */
      public synchronized void setLength(int newLength) {
          if (newLength < 0) {
              throw new StringIndexOutOfBoundsException(
  /* #ifdef VERBOSE_EXCEPTIONS */
  /// skipped                       newLength
  /* #endif */
              );
          }
          
          if (newLength > value.length) {
              expandCapacity(newLength);
          }
  
          if (count < newLength) {
              if (shared) copy();
              for (; count < newLength; count++) {
                  value[count] = '\0';
              }
          } else {
              count = newLength;
              if (shared) {
                  if (newLength > 0) {
                      copy();
                  } else {
                      // If newLength is zero, assume the StringBuffer is being
                      // stripped for reuse; Make new buffer of default size
                      value = new char[16];
                      shared = false;
                  }
              }
          }
      }
  
      /**
       * The specified character of the sequence currently represented by 
       * the string buffer, as indicated by the <code>index</code> argument, 
       * is returned. The first character of a string buffer is at index 
       * <code>0</code>, the next at index <code>1</code>, and so on, for 
       * array indexing. 
       * <p>
       * The index argument must be greater than or equal to 
       * <code>0</code>, and less than the length of this string buffer. 
       *
       * @param      index   the index of the desired character.
       * @return     the character at the specified index of this string buffer.
       * @exception  IndexOutOfBoundsException  if <code>index</code> is 
       *             negative or greater than or equal to <code>length()</code>.
       * @see        java.lang.StringBuffer#length()
       */
      public synchronized char charAt(int index) {
          if ((index < 0) || (index >= count)) {
              throw new StringIndexOutOfBoundsException(
  /* #ifdef VERBOSE_EXCEPTIONS */
  /// skipped                       index
  /* #endif */
              );
          }
          return value[index];
      }
  
      /**
       * Characters are copied from this string buffer into the 
       * destination character array <code>dst</code>. The first character to 
       * be copied is at index <code>srcBegin</code>; the last character to 
       * be copied is at index <code>srcEnd-1</code>. The total number of 
       * characters to be copied is <code>srcEnd-srcBegin</code>. The 
       * characters are copied into the subarray of <code>dst</code> starting 
       * at index <code>dstBegin</code> and ending at index:
       * <p><blockquote><pre>
       * dstbegin + (srcEnd-srcBegin) - 1
       * </pre></blockquote>
       *
       * @param      srcBegin   start copying at this offset in the string buffer.
       * @param      srcEnd     stop copying at this offset in the string buffer.
       * @param      dst        the array to copy the data into.
       * @param      dstBegin   offset into <code>dst</code>.
       * @exception  NullPointerException if <code>dst</code> is 
       *             <code>null</code>.
       * @exception  IndexOutOfBoundsException  if any of the following is true:
       *             <ul>
       *             <li><code>srcBegin</code> is negative
       *             <li><code>dstBegin</code> is negative
       *             <li>the <code>srcBegin</code> argument is greater than 
       *             the <code>srcEnd</code> argument.
       *             <li><code>srcEnd</code> is greater than 
       *             <code>this.length()</code>, the current length of this 
       *             string buffer.
       *             <li><code>dstBegin+srcEnd-srcBegin</code> is greater than 
       *             <code>dst.length</code>
       *             </ul>
       */
      public synchronized void getChars(int srcBegin, int srcEnd, char dst[], int dstBegin) {
          if (srcBegin < 0) {
              throw new StringIndexOutOfBoundsException(
  /* #ifdef VERBOSE_EXCEPTIONS */
  /// skipped                       srcBegin
  /* #endif */
              );
          }
          if ((srcEnd < 0) || (srcEnd > count)) {
              throw new StringIndexOutOfBoundsException(
  /* #ifdef VERBOSE_EXCEPTIONS */
  /// skipped                       srcEnd
  /* #endif */
              );
          }
          if (srcBegin > srcEnd) {
              throw new StringIndexOutOfBoundsException(
  /* #ifdef VERBOSE_EXCEPTIONS */
  /// skipped                       "srcBegin > srcEnd"
  /* #endif */
              );
          }
          // NOTE: dst not checked, cannot use unchecked arraycopy
          System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin);
      }
  
      /**
       * The character at the specified index of this string buffer is set 
       * to <code>ch</code>. The string buffer is altered to represent a new 
       * character sequence that is identical to the old character sequence, 
       * except that it contains the character <code>ch</code> at position 
       * <code>index</code>. 
       * <p>
       * The offset argument must be greater than or equal to 
       * <code>0</code>, and less than the length of this string buffer. 
       *
       * @param      index   the index of the character to modify.
       * @param      ch      the new character.
       * @exception  IndexOutOfBoundsException  if <code>index</code> is 
       *             negative or greater than or equal to <code>length()</code>.
       * @see        java.lang.StringBuffer#length()
       */
      public synchronized void setCharAt(int index, char ch) {
          if ((index < 0) || (index >= count)) {
              throw new StringIndexOutOfBoundsException(
  /* #ifdef VERBOSE_EXCEPTIONS */
  /// skipped                       index
  /* #endif */
              );
          }
          if (shared) copy();
          value[index] = ch;
      }
  
      /**
       * Appends the string representation of the <code>Object</code> 
       * argument to this string buffer. 
       * <p>
       * The argument is converted to a string as if by the method 
       * <code>String.valueOf</code>, and the characters of that 
       * string are then appended to this string buffer. 
       *
       * @param   obj   an <code>Object</code>.
       * @return  a reference to this <code>StringBuffer</code> object.
       * @see     java.lang.String#valueOf(java.lang.Object)
       * @see     java.lang.StringBuffer#append(java.lang.String)
       */
      public synchronized StringBuffer append(Object obj) {
          return append(String.valueOf(obj));
      }
  
      /**
       * Appends the string to this string buffer. 
       * <p>
       * The characters of the <code>String</code> argument are appended, in 
       * order, to the contents of this string buffer, increasing the 
       * length of this string buffer by the length of the argument. 
       * If <code>str</code> is <code>null</code>, then the four characters 
       * <code>"null"</code> are appended to this string buffer.
       * <p>
       * Let <i>n</i> be the length of the old character sequence, the one 
       * contained in the string buffer just prior to execution of the 
       * <code>append</code> method. Then the character at index <i>k</i> in 
       * the new character sequence is equal to the character at index <i>k</i> 
       * in the old character sequence, if <i>k</i> is less than <i>n</i>; 
       * otherwise, it is equal to the character at index <i>k-n</i> in the 
       * argument <code>str</code>.
       *
       * @param   str   a string.
       * @return  a reference to this <code>StringBuffer</code>.
       */
       public synchronized StringBuffer append(String str) {
         if (str == null) {
             str = String.valueOf(str);
         }
   
         int len = str.length();
         int newcount = count + len;
         if (newcount > value.length)
             expandCapacity(newcount);
         str.getChars(0, len, value, count);
         count = newcount;
         return this;
       }
   
      /**
       * Appends the string representation of the <code>char</code> array 
       * argument to this string buffer. 
       * <p>
       * The characters of the array argument are appended, in order, to 
       * the contents of this string buffer. The length of this string 
       * buffer increases by the length of the argument. 
       * <p>
       * The overall effect is exactly as if the argument were converted to 
       * a string by the method {@link String#valueOf(char[])} and the 
       * characters of that string were then {@link #append(String) appended} 
       * to this <code>StringBuffer</code> object.
       *
       * @param   str   the characters to be appended.
       * @return  a reference to this <code>StringBuffer</code> object.
       */
      public synchronized StringBuffer append(char str[]) {
          int len = str.length;
          int newcount = count + len;
          if (newcount > value.length)
              expandCapacity(newcount);
          JVM.unchecked_char_arraycopy(str, 0, value, count, len);
          count = newcount;
          return this;
      }
  
      /**
       * Appends the string representation of a subarray of the 
       * <code>char</code> array argument to this string buffer. 
       * <p>
       * Characters of the character array <code>str</code>, starting at 
       * index <code>offset</code>, are appended, in order, to the contents 
       * of this string buffer. The length of this string buffer increases 
       * by the value of <code>len</code>. 
       * <p>
       * The overall effect is exactly as if the arguments were converted to 
       * a string by the method {@link String#valueOf(char[],int,int)} and the
       * characters of that string were then {@link #append(String) appended} 
       * to this <code>StringBuffer</code> object.
       *
       * @param   str      the characters to be appended.
       * @param   offset   the index of the first character to append.
       * @param   len      the number of characters to append.
       * @return  a reference to this <code>StringBuffer</code> object.
       */
      public synchronized StringBuffer append(char str[], int offset, int len) {
          int newcount = count + len;
          if (newcount > value.length)
              expandCapacity(newcount);
          // NOTE: str and offset not checked, cannot use unchecked arraycopy
          System.arraycopy(str, offset, value, count, len);
          count = newcount;
          return this;
      }
  
      /**
       * Appends the string representation of the <code>boolean</code> 
       * argument to the string buffer. 
       * <p>
       * The argument is converted to a string as if by the method 
       * <code>String.valueOf</code>, and the characters of that 
       * string are then appended to this string buffer. 
       *
       * @param   b   a <code>boolean</code>.
       * @return  a reference to this <code>StringBuffer</code>.
       * @see     java.lang.String#valueOf(boolean)
       * @see     java.lang.StringBuffer#append(java.lang.String)
       */
      public StringBuffer append(boolean b) {
          return append(String.valueOf(b));
      }
  
      /**
       * Appends the string representation of the <code>char</code> 
       * argument to this string buffer. 
       * <p>
       * The argument is appended to the contents of this string buffer. 
       * The length of this string buffer increases by <code>1</code>. 
       * <p>
       * The overall effect is exactly as if the argument were converted to 
       * a string by the method {@link String#valueOf(char)} and the character 
       * in that string were then {@link #append(String) appended} to this 
       * <code>StringBuffer</code> object.
       *
       * @param   c   a <code>char</code>.
       * @return  a reference to this <code>StringBuffer</code> object.
       */
      public synchronized StringBuffer append(char c) {
          int newcount = count + 1;
          if (newcount > value.length)
              expandCapacity(newcount);
          value[count++] = c;
          return this;
      }
  
      /**
       * Appends the string representation of the <code>int</code> 
       * argument to this string buffer. 
       * <p>
       * The argument is converted to a string as if by the method 
       * <code>String.valueOf</code>, and the characters of that 
       * string are then appended to this string buffer. 
       *
       * @param   i   an <code>int</code>.
       * @return  a reference to this <code>StringBuffer</code> object.
       * @see     java.lang.String#valueOf(int)
       * @see     java.lang.StringBuffer#append(java.lang.String)
       */
     public StringBuffer append(int i) {
         return append(String.valueOf(i));
     }
  
      /**
       * Appends the string representation of the <code>long</code> 
       * argument to this string buffer. 
       * <p>
       * The argument is converted to a string as if by the method 
       * <code>String.valueOf</code>, and the characters of that 
       * string are then appended to this string buffer. 
       *
       * @param   l   a <code>long</code>.
       * @return  a reference to this <code>StringBuffer</code> object.
       * @see     java.lang.String#valueOf(long)
       * @see     java.lang.StringBuffer#append(java.lang.String)
       */
      public StringBuffer append(long l) {
          return append(String.valueOf(l));
      }
  
      /**
       * Removes the characters in a substring of this <code>StringBuffer</code>.
       * The substring begins at the specified <code>start</code> and extends to
       * the character at index <code>end - 1</code> or to the end of the
       * <code>StringBuffer</code> if no such character exists. If
       * <code>start</code> is equal to <code>end</code>, no changes are made.
       *
       * @param      start  The beginning index, inclusive.
       * @param      end    The ending index, exclusive.
       * @return     This string buffer.
       * @exception  StringIndexOutOfBoundsException  if <code>start</code>
       *             is negative, greater than <code>length()</code>, or
       *             greater than <code>end</code>.
       * @since      1.2
       */
      public synchronized StringBuffer delete(int start, int end) {
          if (start < 0)
              throw new StringIndexOutOfBoundsException(
  /* #ifdef VERBOSE_EXCEPTIONS */
  /// skipped                       start
  /* #endif */
              );
          if (end > count)
              end = count;
          if (start > end)
              throw new StringIndexOutOfBoundsException();
  
          int len = end - start;
          if (len > 0) {
              if (shared)
                  copy();
              JVM.unchecked_char_arraycopy(value, start+len, 
                                           value, start, count-end);
  