Adding support for Reset in StringTokenizerT and HttpHeadersIterator....

base/string_tokenizer.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_STRING_TOKENIZER_H_
 #define BASE_STRING_TOKENIZER_H_
 
 #include <string>
 
 // StringTokenizerT is a simple string tokenizer class.  It works like an
@@ skipping 123 matching lines @@
         token_is_delim_ = true;
         return true;
       }
       // else skip over delim
     }
     while (token_end_ != end_ && AdvanceOne(&state, *token_end_))
       ++token_end_;
     return true;
   }
 
+  // Start iterating through tokens from the beginning of the string.
+  void Reset() {
+    token_end_ = start_pos_;
+  }
+
   // Returns true if token is a delimiter.  When the tokenizer is constructed
   // with the RETURN_DELIMS option, this method can be used to check if the
   // returned token is actually a delimiter.
   bool token_is_delim() const { return token_is_delim_; }
 
   // If GetNext() returned true, then these methods may be used to read the
   // value of the token.
   const_iterator token_begin() const { return token_begin_; }
   const_iterator token_end() const { return token_end_; }
   str token() const { return str(token_begin_, token_end_); }
 
  private:
   void Init(const_iterator string_begin,
             const_iterator string_end,
             const str& delims) {
+    start_pos_ = string_begin;
     token_end_ = string_begin;
     end_ = string_end;
     delims_ = delims;
     options_ = 0;
   }
 
   bool IsDelim(char_type c) const {
     return delims_.find(c) != str::npos;
   }
 
@@ skipping 19 matching lines @@
         state->in_quote = false;
       }
     } else {
       if (IsDelim(c))
         return false;
       state->in_quote = IsQuote(state->quote_char = c);
     }
     return true;
   }
 
+  const_iterator start_pos_;
   const_iterator token_begin_;
   const_iterator token_end_;
   const_iterator end_;
   str delims_;
   str quotes_;
   int options_;
   bool token_is_delim_;
 };
 
 typedef StringTokenizerT<std::string, std::string::const_iterator>
     StringTokenizer;
 typedef StringTokenizerT<std::wstring, std::wstring::const_iterator>
     WStringTokenizer;
 typedef StringTokenizerT<std::string, const char*> CStringTokenizer;
 
 #endif  // BASE_STRING_TOKENIZER_H_