// ========================================================================
   // Copyright (c) 2004-2009 Mort Bay Consulting Pty. Ltd.
   // ------------------------------------------------------------------------
   // All rights reserved. This program and the accompanying materials
   // are made available under the terms of the Eclipse Public License v1.0
   // and Apache License v2.0 which accompanies this distribution.
   // The Eclipse Public License is available at 
   // http://www.eclipse.org/legal/epl-v10.html
   // The Apache License v2.0 is available at
  // http://www.opensource.org/licenses/apache2.0.php
  // You may elect to redistribute this code under either of these licenses. 
  // ========================================================================
  
  package org.eclipse.jetty.util;
  
  import java.io.UnsupportedEncodingException;
  import java.nio.charset.Charset;
  
  import org.eclipse.jetty.util.log.Log;
  
  // ====================================================================
  /** Fast String Utilities.
   *
   * These string utilities provide both conveniance methods and
   * performance improvements over most standard library versions. The
   * main aim of the optimizations is to avoid object creation unless
   * absolutely required.
   *
   * 
   */
  public class StringUtil
  {
      public static final String ALL_INTERFACES="0.0.0.0";
      public static final String CRLF="\015\012";
      public static final String __LINE_SEPARATOR=
          System.getProperty("line.separator","\n");
         
      public static final String __ISO_8859_1="ISO-8859-1";
      public final static String __UTF8="UTF-8";
      public final static String __UTF8Alt="UTF8";
      public final static String __UTF16="UTF-16";
      
      public final static Charset __UTF8_CHARSET;
      public final static Charset __ISO_8859_1_CHARSET;
      
      static
      {
          __UTF8_CHARSET=Charset.forName(__UTF8);
          __ISO_8859_1_CHARSET=Charset.forName(__ISO_8859_1);
      }
      
      private static char[] lowercases = {
            '\000','\001','\002','\003','\004','\005','\006','\007',
            '\010','\011','\012','\013','\014','\015','\016','\017',
            '\020','\021','\022','\023','\024','\025','\026','\027',
            '\030','\031','\032','\033','\034','\035','\036','\037',
            '\040','\041','\042','\043','\044','\045','\046','\047',
            '\050','\051','\052','\053','\054','\055','\056','\057',
            '\060','\061','\062','\063','\064','\065','\066','\067',
            '\070','\071','\072','\073','\074','\075','\076','\077',
            '\100','\141','\142','\143','\144','\145','\146','\147',
            '\150','\151','\152','\153','\154','\155','\156','\157',
            '\160','\161','\162','\163','\164','\165','\166','\167',
            '\170','\171','\172','\133','\134','\135','\136','\137',
            '\140','\141','\142','\143','\144','\145','\146','\147',
            '\150','\151','\152','\153','\154','\155','\156','\157',
            '\160','\161','\162','\163','\164','\165','\166','\167',
            '\170','\171','\172','\173','\174','\175','\176','\177' };
  
      /* ------------------------------------------------------------ */
      /**
       * fast lower case conversion. Only works on ascii (not unicode)
       * @param s the string to convert
       * @return a lower case version of s
       */
      public static String asciiToLowerCase(String s)
      {
          char[] c = null;
          int i=s.length();
  
          // look for first conversion
          while (i-->0)
          {
              char c1=s.charAt(i);
              if (c1<=127)
              {
                  char c2=lowercases[c1];
                  if (c1!=c2)
                  {
                      c=s.toCharArray();
                      c[i]=c2;
                      break;
                  }
              }
          }
  
          while (i-->0)
          {
              if(c[i]<=127)
                 c[i] = lowercases[c[i]];
         }
         
         return c==null?s:new String(c);
     }
 
 
     /* ------------------------------------------------------------ */
     public static boolean startsWithIgnoreCase(String s,String w)
     {
         if (w==null)
             return true;
         
         if (s==null || s.length()<w.length())
             return false;
         
         for (int i=0;i<w.length();i++)
         {
             char c1=s.charAt(i);
             char c2=w.charAt(i);
             if (c1!=c2)
             {
                 if (c1<=127)
                     c1=lowercases[c1];
                 if (c2<=127)
                     c2=lowercases[c2];
                 if (c1!=c2)
                     return false;
             }
         }
         return true;
     }
     
     /* ------------------------------------------------------------ */
     public static boolean endsWithIgnoreCase(String s,String w)
     {
         if (w==null)
             return true;
 
         if (s==null)
             return false;
             
         int sl=s.length();
         int wl=w.length();
         
         if (sl<wl)
             return false;
         
         for (int i=wl;i-->0;)
         {
             char c1=s.charAt(--sl);
             char c2=w.charAt(i);
             if (c1!=c2)
             {
                 if (c1<=127)
                     c1=lowercases[c1];
                 if (c2<=127)
                     c2=lowercases[c2];
                 if (c1!=c2)
                     return false;
             }
         }
         return true;
     }
     
     /* ------------------------------------------------------------ */
     /**
      * returns the next index of a character from the chars string
      */
     public static int indexFrom(String s,String chars)
     {
         for (int i=0;i<s.length();i++)
            if (chars.indexOf(s.charAt(i))>=0)
               return i;
         return -1;
     }
     
     /* ------------------------------------------------------------ */
     /**
      * replace substrings within string.
      */
     public static String replace(String s, String sub, String with)
     {
         int c=0;
         int i=s.indexOf(sub,c);
         if (i == -1)
             return s;
     
         StringBuilder buf = new StringBuilder(s.length()+with.length());
 
         do
         {
             buf.append(s.substring(c,i));
             buf.append(with);
             c=i+sub.length();
         } while ((i=s.indexOf(sub,c))!=-1);
 
         if (c<s.length())
             buf.append(s.substring(c,s.length()));
 
         return buf.toString();
         
     }
 
 
     /* ------------------------------------------------------------ */
     /** Remove single or double quotes.
      */
     public static String unquote(String s)
     {
         return QuotedStringTokenizer.unquote(s);
     }
 
 
     /* ------------------------------------------------------------ */
     /** Append substring to StringBuilder 
      * @param buf StringBuilder to append to
      * @param s String to append from
      * @param offset The offset of the substring
      * @param length The length of the substring
      */
     public static void append(StringBuilder buf,
                               String s,
                               int offset,
                               int length)
     {
         synchronized(buf)
         {
             int end=offset+length;
             for (int i=offset; i<end;i++)
             {
                 if (i>=s.length())
                     break;
                 buf.append(s.charAt(i));
             }
         }
     }
 
     
     /* ------------------------------------------------------------ */
     /**
      * append hex digit
      * 
      */
     public static void append(StringBuilder buf,byte b,int base)
     {
         int bi=0xff&b;
         int c='0'+(bi/base)%base;
         if (c>'9')
             c= 'a'+(c-'0'-10);
         buf.append((char)c);
         c='0'+bi%base;
         if (c>'9')
             c= 'a'+(c-'0'-10);
         buf.append((char)c);
     }
 
     /* ------------------------------------------------------------ */
     public static void append2digits(StringBuffer buf,int i)
     {
         if (i<100)
         {
             buf.append((char)(i/10+'0'));
             buf.append((char)(i%10+'0'));
         }
     }
     
     /* ------------------------------------------------------------ */
     public static void append2digits(StringBuilder buf,int i)
     {
         if (i<100)
         {
             buf.append((char)(i/10+'0'));
             buf.append((char)(i%10+'0'));
         }
     }
     
     /* ------------------------------------------------------------ */
     /** Return a non null string.
      * @param s String
      * @return The string passed in or empty string if it is null. 
      */
     public static String nonNull(String s)
     {
         if (s==null)
             return "";
         return s;
     }
     
     /* ------------------------------------------------------------ */
     public static boolean equals(String s,char[] buf, int offset, int length)
     {
         if (s.length()!=length)
             return false;
         for (int i=0;i<length;i++)
             if (buf[offset+i]!=s.charAt(i))
                 return false;
         return true;
     }
 
     /* ------------------------------------------------------------ */
     public static String toUTF8String(byte[] b,int offset,int length)
     {
         try
         {
             return new String(b,offset,length,__UTF8);
         }
         catch (UnsupportedEncodingException e)
         {
             throw new IllegalArgumentException(e);
         }
     }
 
     /* ------------------------------------------------------------ */
     public static String toString(byte[] b,int offset,int length,String charset)
     {
         try
         {
             return new String(b,offset,length,charset);
         }
         catch (UnsupportedEncodingException e)
         {
             throw new IllegalArgumentException(e);
         }
     }
 
 
     /* ------------------------------------------------------------ */
     public static boolean isUTF8(String charset)
     {
         return charset==__UTF8||__UTF8.equalsIgnoreCase(charset)||__UTF8Alt.equalsIgnoreCase(charset);
     }
 
 
     /* ------------------------------------------------------------ */
     public static String printable(String name)
     {
         if (name==null)
             return null;
         StringBuilder buf = new StringBuilder(name.length());
         for (int i=0;i<name.length();i++)
         {
             char c=name.charAt(i);
             if (!Character.isISOControl(c))
                 buf.append(c);
         }
         return buf.toString();
     }
     
     /* ------------------------------------------------------------ */
     public static String printable(byte[] b)
     {
         StringBuilder buf = new StringBuilder();
         for (int i=0;i<b.length;i++)
         {
             char c=(char)b[i];
             if (Character.isWhitespace(c)|| c>' ' && c<0x7f)
                 buf.append(c);
             else 
             {
                 buf.append("0x");
                 TypeUtil.toHex(b[i],buf);
             }
         }
         return buf.toString();
     }
     
     public static byte[] getBytes(String s)
     {
         try
         {
             return s.getBytes(__ISO_8859_1);
         }
         catch(Exception e)
         {
             Log.warn(e);
             return s.getBytes();
         }
     }
     
     public static byte[] getBytes(String s,String charset)
     {
         try
         {
             return s.getBytes(charset);
         }
         catch(Exception e)
         {
             Log.warn(e);
             return s.getBytes();
         }
     }
     
     
     
     /**
      * Converts a binary SID to a string SID
      * 
      * http://en.wikipedia.org/wiki/Security_Identifier
      * 
      * S-1-IdentifierAuthority-SubAuthority1-SubAuthority2-...-SubAuthorityn
      */
     public static String sidBytesToString(byte[] sidBytes)
     {
         StringBuilder sidString = new StringBuilder();
         
         // Identify this as a SID
         sidString.append("S-");
         
         // Add SID revision level (expect 1 but may change someday)
         sidString.append(Byte.toString(sidBytes[0])).append('-');
         
         StringBuilder tmpBuilder = new StringBuilder();
         
         // crunch the six bytes of issuing authority value
         for (int i = 2; i <= 7; ++i)
         {
             tmpBuilder.append(Integer.toHexString(sidBytes[i] & 0xFF));
         }
         
         sidString.append(Long.parseLong(tmpBuilder.toString(), 16)); // '-' is in the subauth loop
    
         // the number of subAuthorities we need to attach
         int subAuthorityCount = sidBytes[1];
 
         // attach each of the subAuthorities
         for (int i = 0; i < subAuthorityCount; ++i)
         {
             int offset = i * 4;
             tmpBuilder.setLength(0);
             // these need to be zero padded hex and little endian
             tmpBuilder.append(String.format("%02X%02X%02X%02X", 
                     (sidBytes[11 + offset] & 0xFF),
                     (sidBytes[10 + offset] & 0xFF),
                     (sidBytes[9 + offset] & 0xFF),
                     (sidBytes[8 + offset] & 0xFF)));  
             sidString.append('-').append(Long.parseLong(tmpBuilder.toString(), 16));
         }
         
         return sidString.toString();
     }
     
     /**
      * Converts a string SID to a binary SID
      * 
      * http://en.wikipedia.org/wiki/Security_Identifier
      * 
      * S-1-IdentifierAuthority-SubAuthority1-SubAuthority2-...-SubAuthorityn
      */
     public static byte[] sidStringToBytes( String sidString )
     {
         String[] sidTokens = sidString.split("-");
         
         int subAuthorityCount = sidTokens.length - 3; // S-Rev-IdAuth-
         
         int byteCount = 0;
         byte[] sidBytes = new byte[1 + 1 + 6 + (4 * subAuthorityCount)];
         
         // the revision byte
         sidBytes[byteCount++] = (byte)Integer.parseInt(sidTokens[1]);
 
         // the # of sub authorities byte
         sidBytes[byteCount++] = (byte)subAuthorityCount;
 
         // the certAuthority
         String hexStr = Long.toHexString(Long.parseLong(sidTokens[2]));
         
         while( hexStr.length() < 12) // pad to 12 characters
         {
             hexStr = "0" + hexStr;
         }
 
         // place the certAuthority 6 bytes
         for ( int i = 0 ; i < hexStr.length(); i = i + 2)
         {
             sidBytes[byteCount++] = (byte)Integer.parseInt(hexStr.substring(i, i + 2),16);
         }
                 
         
         for ( int i = 3; i < sidTokens.length ; ++i)
         {
             hexStr = Long.toHexString(Long.parseLong(sidTokens[i]));
             
             while( hexStr.length() < 8) // pad to 8 characters
             {
                 hexStr = "0" + hexStr;
             }     
             
             // place the inverted sub authorities, 4 bytes each
             for ( int j = hexStr.length(); j > 0; j = j - 2)
             {          
                 sidBytes[byteCount++] = (byte)Integer.parseInt(hexStr.substring(j-2, j),16);
             }
         }
       
         return sidBytes;
     }
 }