context: // **********************************************************************
  //
  // Copyright (c) 2003-2015 ZeroC, Inc. All rights reserved.
  //
  // This copy of Ice is licensed to you under the terms described in the
  // ICE_LICENSE file included in this distribution.
  //
  // **********************************************************************
  
  using System.Text;
  using System.Diagnostics;
  using System.Collections.Generic;
  
  namespace IceUtilInternal
  {
  
      public sealed class StringUtil
      {
          //
          // Return the index of the first character in str to
          // appear in match, starting from 0. Returns -1 if none is
          // found.
          //
          public static int findFirstOf(string str, string match)
          {
              return findFirstOf(str, match, 0);
          }
          
          //
          // Return the index of the first character in str to
          // appear in match, starting from start. Returns -1 if none is
          // found.
          //
          public static int findFirstOf(string str, string match, int start)
          {
              int len = str.Length;
              for(int i = start; i < len; i++)
              {
                  char ch = str[i];
                  if(match.IndexOf((char) ch) != -1)
                  {
                      return i;
                  }
              }
              
              return -1;
          }
          
          //
          // Return the index of the first character in str which does
          // not appear in match, starting from 0. Returns -1 if none is
          // found.
          //
          public static int findFirstNotOf(string str, string match)
          {
              return findFirstNotOf(str, match, 0);
          }
          
          //
          // Return the index of the first character in str which does
          // not appear in match, starting from start. Returns -1 if none is
          // found.
          //
          public static int findFirstNotOf(string str, string match, int start)
          {
              int len = str.Length;
              for(int i = start; i < len; i++)
              {
                  char ch = str[i];
                  if(match.IndexOf((char) ch) == -1)
                  {
                      return i;
                  }
              }
              
              return -1;
          }
          
          //
          // Write the byte b as an escape sequence if it isn't a printable ASCII
          // character and append the escape sequence to sb. Additional characters
          // that should be escaped can be passed in special. If b is any of these
          // characters, b is preceded by a backslash in sb.
          //
          private static void encodeChar(byte b, StringBuilder sb, string special)
          {
              switch((char)b)
              {
                  case '\\': 
                  {
                      sb.Append("\\\\");
                      break;
                  }
                  
                  case '\'': 
                  {
                      sb.Append("\\'");
                      break;
                  }
                  
                  case '"': 
                  {
                      sb.Append("\\\"");
                      break;
                  }
                  
                  case '\b': 
                  {
                      sb.Append("\\b");
                      break;
                  }
                  
                  case '\f': 
                  {
                      sb.Append("\\f");
                      break;
                  }
                  
                  case '\n': 
                  {
                      sb.Append("\\n");
                      break;
                  }
                  
                  case '\r': 
                  {
                      sb.Append("\\r");
                      break;
                  }
                  
                  case '\t': 
                  {
                      sb.Append("\\t");
                      break;
                  }
                  
                  default: 
                  {
                      if(!(b >= 32 && b <= 126))
                      {
                          sb.Append('\\');
                          string octal = System.Convert.ToString(b, 8);
                          //
                          // Add leading zeroes so that we avoid problems during
                          // decoding. For example, consider the encoded string
                          // \0013 (i.e., a character with value 1 followed by
                          // the character '3'). If the leading zeroes were omitted,
                          // the result would be incorrectly interpreted by the
                          // decoder as a single character with value 11.
                          //
                          for(int j = octal.Length; j < 3; j++)
                          {
                              sb.Append('0');
                          }
                          sb.Append(octal);
                      }
                      else if(special != null && special.IndexOf((char)b) != -1)
                      {
                          sb.Append('\\');
                          sb.Append((char)b);
                      }
                      else
                      {
                          sb.Append((char)b);
                      }
                  }
                  break;
              }
          }
          
          //
          // Add escape sequences (such as "\n", or "\007") to make a string
          // readable in ASCII. Any characters that appear in special are
          // prefixed with a backslash in the returned string.
          //
          public static string escapeString(string s, string special)
          {
              if(special != null)
              {
                  for(int i = 0; i < special.Length; ++i)
                  {
                      if((int)special[i] < 32 || (int)special[i] > 126)
                      {
                          throw new System.ArgumentException("special characters must be in ASCII range 32-126",
                                                             "special");
                      }
                  }
              }
  
              UTF8Encoding utf8 = new UTF8Encoding();
              byte[] bytes = utf8.GetBytes(s);
  
              StringBuilder result = new StringBuilder(bytes.Length);
              for(int i = 0; i < bytes.Length; i++)
              {
                  encodeChar(bytes[i], result, special);
              }
              
              return result.ToString();
          }
          
          private static char checkChar(string s, int pos)
          {
              char c = s[pos];
              if(!(c >= 32 && c <= 126))
              {
                  string msg;
                  if(pos > 0)
                  {
                      msg = "character after `" + s.Substring(0, pos) + "'";
                  }
                  else
                  {
                      msg = "first character";
                  }
                  msg += " is not a printable ASCII character (ordinal " + (int)c + ")";
                  throw new System.ArgumentException(msg);
              }
              return c;
          }
  
          //
          // Decode the character or escape sequence starting at start and return it.
          // end marks the one-past-the-end position of the substring to be scanned.
          // nextStart is set to the index of the first character following the decoded
          // character or escape sequence.
          //
          private static char decodeChar(string s, int start, int end, out int nextStart)
          {
              Debug.Assert(start >= 0);
              Debug.Assert(start < end);
              Debug.Assert(end <= s.Length);
  
              char c;
  
              if(s[start] != '\\')
              {
                  c = checkChar(s, start++);
              }
              else
              {
                  if(start + 1 == end)
                  {
                      throw new System.ArgumentException("trailing backslash");
                  }
                  switch(s[++start])
                  {
                      case '\\': 
                      case '\'': 
                      case '"': 
                      {
                          c = s[start++];
                          break;
                      }
                      case 'b': 
                      {
                          ++start;
                          c = '\b';
                          break;
                      }
                      case 'f': 
                      {
                          ++start;
                          c = '\f';
                          break;
                      }
                      case 'n': 
                      {
                          ++start;
                          c = '\n';
                          break;
                      }
                      case 'r': 
                      {
                          ++start;
                          c = '\r';
                          break;
                      }
                      case 't': 
                      {
                          ++start;
                          c = '\t';
                          break;
                      }
                      case '0':
                      case '1':
                      case '2':
                      case '3':
                      case '4':
                      case '5':
                      case '6':
                      case '7':
                      {
                          int val = 0;
                          for(int j = 0; j < 3 && start < end; ++j)
                          {
                              int charVal = s[start++] - '0';
                              if(charVal < 0 || charVal > 7)
                              {
                                  --start;
                                  break;
                              }
                              val = val * 8 + charVal;
                          }
                          if(val > 255)
                          {
                              string msg = "octal value \\" + System.Convert.ToString(val, 8) + " (" + val +
                                  ") is out of range";
                              throw new System.ArgumentException(msg, "s");
                          }
                          c = System.Convert.ToChar(val);
                          break;
                      }
                      default:
                      {
                          c = checkChar(s, start++);
                          break;
                      }
                  }
              }
              nextStart = start;
              return c;
          }
  
          //
          // Remove escape sequences from s and append the result to sb.
          // Return true if successful, false otherwise.
          //
          private static void decodeString(string s, int start, int end, StringBuilder sb)
          {
              while(start < end)
              {
                  sb.Append(decodeChar(s, start, end, out start));
              }
          }
  
          //
          // Remove escape sequences added by escapeString. Throws System.ArgumentException
          // for an invalid input string.
          //
          public static string unescapeString(string s, int start, int end)
          {
              Debug.Assert(start >= 0 && start <= end && end <= s.Length);
  
              StringBuilder sb = new StringBuilder();
              decodeString(s, start, end, sb);
              string decodedString = sb.ToString();
  
              byte[] arr = new byte[decodedString.Length];
              for(int i = 0; i < arr.Length; ++i)
              {
                  arr[i] = (byte)decodedString[i];
              }
  
              UTF8Encoding utf8 = new UTF8Encoding(false, true);
              return utf8.GetString(arr, 0, arr.Length); // May raise ArgumentException.
          }
  
          //
          // Split string helper; returns null for unmatched quotes
          //
          static public string[] splitString(string str, string delim)
          {
              List<string> l = new List<string>();
              char[] arr = new char[str.Length];
              int pos = 0;
  
              int n = 0;
              char quoteChar = '\0';
              while(pos < str.Length)
              {
                  if(quoteChar == '\0' && (str[pos] == '"' || str[pos] == '\''))
                  {
                      quoteChar = str[pos++];
                      continue; // Skip the quote.
                  }
                  else if(quoteChar == '\0' && str[pos] == '\\' && pos + 1 < str.Length &&
                          (str[pos + 1] == '\'' || str[pos + 1] == '"'))
                  {
                      ++pos; // Skip the backslash
                  }
                  else if(quoteChar != '\0' && str[pos] == '\\' && pos + 1 < str.Length && str[pos + 1] == quoteChar)
                  {
                      ++pos; // Skip the backslash
                  }
                  else if(quoteChar != '\0' && str[pos] == quoteChar)
                  {
                      ++pos;
                      quoteChar = '\0';
                      continue; // Skip the quote.
                  }
                  else if(delim.IndexOf(str[pos]) != -1)
                  {
                      if(quoteChar == '\0')
                      {
                          ++pos;
                          if(n > 0)
                          {
                              l.Add(new string(arr, 0, n));
                              n = 0;
                          }
                          continue;
                      }
                  }
                  
  
gt:                 if(pos < str.Length)