1 // Copyright 2011 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef V8_PARSING_DUPLICATE_FINDER_H_ 6 #define V8_PARSING_DUPLICATE_FINDER_H_ 7 8 #include "src/base/hashmap.h" 9 #include "src/collector.h" 10 11 namespace v8 { 12 namespace internal { 13 14 // DuplicateFinder discovers duplicate symbols. 15 class DuplicateFinder { 16 public: 17 DuplicateFinder() : backing_store_(16), map_(&Match) {} 18 19 bool AddOneByteSymbol(Vector<const uint8_t> key); 20 bool AddTwoByteSymbol(Vector<const uint16_t> key); 21 22 private: 23 bool AddSymbol(Vector<const uint8_t> key, bool is_one_byte); 24 // Backs up the key and its length in the backing store. 25 // The backup is stored with a base 127 encoding of the 26 // length (plus a bit saying whether the string is one byte), 27 // followed by the bytes of the key. 28 uint8_t* BackupKey(Vector<const uint8_t> key, bool is_one_byte); 29 30 // Compare two encoded keys (both pointing into the backing store) 31 // for having the same base-127 encoded lengths and representation. 32 // and then having the same 'length' bytes following. 33 static bool Match(void* first, void* second); 34 35 // Creates a hash from a sequence of bytes. 36 static uint32_t Hash(Vector<const uint8_t> key, bool is_one_byte); 37 38 // Backing store used to store strings used as hashmap keys. 39 SequenceCollector<unsigned char> backing_store_; 40 base::CustomMatcherHashMap map_; 41 }; 42 43 } // namespace internal 44 } // namespace v8 45 46 #endif // V8_PARSING_DUPLICATE_FINDER_H_ 47
