Implement tick events compression in a log file.

src/utils.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 344 matching lines @@
     qsort(start(),
           length(),
           sizeof(T),
           reinterpret_cast<RawComparer>(cmp));
   }
 
   void Sort() {
     Sort(PointerValueCompare<T>);
   }
 
+  void Truncate(int length) {
+    ASSERT(length <= length_);
+    length_ = length;
+  }
+
   // Releases the array underlying this vector. Once disposed the
   // vector is empty.
   void Dispose() {
     if (is_empty()) return;
     DeleteArray(start_);
     start_ = NULL;
     length_ = 0;
   }
 
   inline Vector<T> operator+(int offset) {
@@ skipping 190 matching lines @@
 #endif
   while (dest < limit) {
     *dest++ = static_cast<sinkchar>(*src++);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_UTILS_H_