package org.apache.maven.surefire.util.internal;
   
   /*
    * 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.
   */
  
  import java.nio.ByteBuffer;
  import java.nio.CharBuffer;
  import java.nio.charset.CharacterCodingException;
  import java.nio.charset.Charset;
  import java.util.StringTokenizer;
  
  /**
   * <p>
   * Common {@link String java.lang.String} manipulation routines.
   * </p>
   * <br>
   * <p>
   * Originally from <a href="http://jakarta.apache.org/turbine/">Turbine</a> and the GenerationJavaCore library.
   * </p>
   * <br>
   * NOTE: This class is not part of any api and is public purely for technical reasons !
   *
   * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
   * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
   * @author <a href="mailto:gcoladonato@yahoo.com">Greg Coladonato</a>
   * @author <a href="mailto:bayard@generationjava.com">Henri Yandell</a>
   * @author <a href="mailto:ed@codehaus.org">Ed Korthof</a>
   * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
   * @author Stephen Colebourne
   * @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
   * @author Holger Krauth
   * @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a>
   * @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>
   * @version $Id: StringUtils.java 8001 2009-01-03 13:17:09Z vsiveton $
   * @since 1.0
   */
  public final class StringUtils
  {
      public static final String NL = System.getProperty( "line.separator" );
  
      private static final byte[] HEX_CHARS = {
                      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
  
      private static final Charset DEFAULT_CHARSET = Charset.defaultCharset();
  
      /**
       * TODO
       * Use JDK7 StandardCharsets
       */
      public static final Charset US_ASCII = Charset.forName( "US-ASCII" );
  
      // 8-bit charset Latin-1
      public static final Charset ISO_8859_1 = Charset.forName( "ISO-8859-1" );
  
      public static final Charset UTF_8 = Charset.forName( "UTF-8" );
  
      private StringUtils()
      {
          throw new IllegalStateException( "no instantiable constructor" );
      }
  
      public static String[] split( String text, String separator )
      {
          final StringTokenizer tok;
          if ( separator == null )
          {
              // Null separator means we're using StringTokenizer's default
              // delimiter, which comprises all whitespace characters.
              tok = new StringTokenizer( text );
          }
          else
          {
              tok = new StringTokenizer( text, separator );
          }
  
          String[] list = new String[tok.countTokens()];
          for ( int i = 0; tok.hasMoreTokens(); i++ )
          {
              list[i] = tok.nextToken();
          }
          return list;
      }
  
     /**
      * <p>
      * Checks if a (trimmed) String is {@code null} or blank.
      * </p>
      *
      * @param str the String to check
      * @return {@code true} if the String is {@code null}, or length zero once trimmed
      */
     public static boolean isBlank( String str )
     {
         return str == null || str.trim().isEmpty();
     }
 
     /**
      * <p>
      * Checks if a (trimmed) String is not {@code null} and not blank.
      * </p>
      *
      * @param str the String to check
      * @return {@code true} if the String is not {@code null} and length of trimmed {@code str} is not zero.
      */
     public static boolean isNotBlank( String str )
     {
         return !isBlank( str );
     }
 
     /**
      * Escape the specified string to a representation that only consists of nicely printable characters, without any
      * newlines and without a comma.
      * <p>
      * The reverse-method is {@link #unescapeString(StringBuilder, CharSequence)}.
      *
      * @param target target string buffer. The required space will be up to {@code str.getBytes().length * 5} chars.
      * @param str String to escape values in, may be {@code null}.
      */
     @SuppressWarnings( "checkstyle:magicnumber" )
     public static void escapeToPrintable( StringBuilder target, CharSequence str )
     {
         if ( target == null )
         {
             throw new IllegalArgumentException( "The target buffer must not be null" );
         }
         if ( str == null )
         {
             return;
         }
 
         for ( int i = 0; i < str.length(); i++ )
         {
             char c = str.charAt( i );
 
             // handle non-nicely printable chars and the comma
             if ( c < 32 || c > 126 || c == '\\' || c == ',' )
             {
                 target.append( '\\' );
                 target.append( (char) HEX_CHARS[( 0xF000 & c ) >> 12] );
                 target.append( (char) HEX_CHARS[( 0x0F00 & c ) >> 8] );
                 target.append( (char) HEX_CHARS[( 0x00F0 & c ) >> 4] );
                 target.append( (char) HEX_CHARS[( 0x000F & c )] );
             }
             else
             {
                 target.append( c );
             }
         }
     }
 
     /**
      * Reverses the effect of {@link #escapeToPrintable(StringBuilder, CharSequence)}.
      *
      * @param target target string buffer
      * @param str the String to un-escape, as created by {@link #escapeToPrintable(StringBuilder, CharSequence)}
      */
     public static void unescapeString( StringBuilder target, CharSequence str )
     {
         if ( target == null )
         {
             throw new IllegalArgumentException( "The target buffer must not be null" );
         }
         if ( str == null )
         {
             return;
         }
 
         for ( int i = 0; i < str.length(); i++ )
         {
             char ch = str.charAt( i );
 
             if ( ch == '\\' )
             {
                 target.append( (char) (
                                   digit( str.charAt( ++i ) ) << 12
                                 | digit( str.charAt( ++i ) ) << 8
                                 | digit( str.charAt( ++i ) ) << 4
                                 | digit( str.charAt( ++i ) )
                                 ) );
             }
             else
             {
                 target.append( ch );
             }
         }
     }
 
     private static int digit( char ch )
     {
         if ( ch >= 'a' )
         {
             return 10 + ch - 'a';
         }
         else if ( ch >= 'A' )
         {
             return 10 + ch - 'A';
         }
         else
         {
             return ch - '0';
         }
     }
 
     /**
      * Escapes the bytes in the array {@code input} to contain only 'printable' bytes.
      * <br>
      * Escaping is done by encoding the non-nicely printable bytes to {@code '\' + upperCaseHexBytes(byte)}.
      * <br>
      * The reverse-method is {@link #unescapeBytes(String, String)}.
      * <br>
      * The returned byte array is started with aligned sequence {@code header} and finished by {@code \n}.
      *
      * @param header prefix header
      * @param input input buffer
      * @param off offset in the input buffer
      * @param len number of bytes to copy from the input buffer
      * @return number of bytes written to {@code out}
      * @throws NullPointerException if the specified parameter {@code header} or {@code input} is null
      * @throws IndexOutOfBoundsException if {@code off} or {@code len} is out of range
      *         ({@code off < 0 || len < 0 || off >= input.length || len > input.length || off + len > input.length})
      */
     @SuppressWarnings( "checkstyle:magicnumber" )
     public static EncodedArray escapeBytesToPrintable( final byte[] header, final byte[] input, final int off,
                                                        final int len )
     {
         if ( input.length == 0 )
         {
             return EncodedArray.EMPTY;
         }
         if ( off < 0 || len < 0 || off >= input.length || len > input.length || off + len > input.length )
         {
             throw new IndexOutOfBoundsException(
                     "off < 0 || len < 0 || off >= input.length || len > input.length || off + len > input.length" );
         }
         // Hex-escaping can be up to 3 times length of a regular byte. Last character is '\n', see (+1).
         final byte[] encodeBytes = new byte[header.length + 3 * len + 1];
         System.arraycopy( header, 0, encodeBytes, 0, header.length );
         int outputPos = header.length;
         final int end = off + len;
         for ( int i = off; i < end; i++ )
         {
             final byte b = input[i];
 
             // handle non-nicely printable bytes
             if ( b < 32 || b > 126 || b == '\\' || b == ',' )
             {
                 final int upper = ( 0xF0 & b ) >> 4;
                 final int lower = ( 0x0F & b );
                 encodeBytes[outputPos++] = '\\';
                 encodeBytes[outputPos++] = HEX_CHARS[upper];
                 encodeBytes[outputPos++] = HEX_CHARS[lower];
             }
             else
             {
                 encodeBytes[outputPos++] = b;
             }
         }
         encodeBytes[outputPos++] = (byte) '\n';
 
         return new EncodedArray( encodeBytes, outputPos );
     }
 
     /**
      * Reverses the effect of {@link #escapeBytesToPrintable(byte[], byte[], int, int)}.
      *
      * @param str the input String
      * @param charsetName the charset name
      * @return the number of bytes written to {@code out}
      */
     public static ByteBuffer unescapeBytes( String str, String charsetName  )
     {
         int outPos = 0;
 
         if ( str == null )
         {
             return ByteBuffer.wrap( new byte[0] );
         }
 
         byte[] out = new byte[str.length()];
         for ( int i = 0; i < str.length(); i++ )
         {
             char ch = str.charAt( i );
 
             if ( ch == '\\' )
             {
                 int upper = digit( str.charAt( ++i ) );
                 int lower = digit( str.charAt( ++i ) );
                 out[outPos++] = (byte) ( upper << 4 | lower );
             }
             else
             {
                 out[outPos++] = (byte) ch;
             }
         }
 
         Charset sourceCharset = Charset.forName( charsetName );
         if ( !DEFAULT_CHARSET.equals( sourceCharset ) )
         {
             CharBuffer decodedFromSourceCharset;
             try
             {
                 decodedFromSourceCharset = sourceCharset.newDecoder().decode( ByteBuffer.wrap( out, 0, outPos ) );
                 return DEFAULT_CHARSET.encode( decodedFromSourceCharset );
             }
             catch ( CharacterCodingException e )
             {
                 // ignore and fall through to the non-recoded version
             }
         }
 
         return ByteBuffer.wrap( out, 0, outPos );
     }
 
     public static byte[] encodeStringForForkCommunication( String string )
     {
         return string.getBytes( ISO_8859_1 );
     }
 
     /**
      * Determines if {@code buffer} starts with specific literal(s).
      *
      * @param buffer     Examined StringBuffer
      * @param pattern    a pattern which should start in {@code buffer}
      * @return    {@code true} if buffer's literal starts with given {@code pattern}, or both are empty.
      */
     public static boolean startsWith( StringBuffer buffer, String pattern )
     {
         if ( buffer.length() < pattern.length() )
         {
             return false;
         }
         else
         {
             for ( int i = 0, len = pattern.length(); i < len; i++ )
             {
                 if ( buffer.charAt( i ) != pattern.charAt( i ) )
                 {
                     return false;
                 }
             }
             return true;
         }
     }
 
     /**
      * Escaped string to byte array with offset 0 and certain length.
      */
     public static final class EncodedArray
     {
         private static final EncodedArray EMPTY = new EncodedArray( new byte[]{}, 0 );
 
         private final byte[] array;
         private final int size;
 
         private EncodedArray( byte[] array, int size )
         {
             this.array = array;
             this.size = size;
         }
 
         public byte[] getArray()
         {
             return array;
         }
 
         public int getSize()
         {
             return size;
         }
     }
 }