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// Copyright 2011 the V8 project 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 V8_PARSING_DUPLICATE_FINDER_H_
#define V8_PARSING_DUPLICATE_FINDER_H_
#include "src/base/hashmap.h"
#include "src/collector.h"
namespace v8 {
namespace internal {
class UnicodeCache;
// DuplicateFinder discovers duplicate symbols.
class DuplicateFinder {
public:
explicit DuplicateFinder(UnicodeCache* constants)
: unicode_constants_(constants), backing_store_(16), map_(&Match) {}
int AddOneByteSymbol(Vector<const uint8_t> key, int value);
int AddTwoByteSymbol(Vector<const uint16_t> key, int value);
// Add a a number literal by converting it (if necessary)
// to the string that ToString(ToNumber(literal)) would generate.
// and then adding that string with AddOneByteSymbol.
// This string is the actual value used as key in an object literal,
// and the one that must be different from the other keys.
int AddNumber(Vector<const uint8_t> key, int value);
private:
int AddSymbol(Vector<const uint8_t> key, bool is_one_byte, int value);
// Backs up the key and its length in the backing store.
// The backup is stored with a base 127 encoding of the
// length (plus a bit saying whether the string is one byte),
// followed by the bytes of the key.
uint8_t* BackupKey(Vector<const uint8_t> key, bool is_one_byte);
// Compare two encoded keys (both pointing into the backing store)
// for having the same base-127 encoded lengths and representation.
// and then having the same 'length' bytes following.
static bool Match(void* first, void* second);
// Creates a hash from a sequence of bytes.
static uint32_t Hash(Vector<const uint8_t> key, bool is_one_byte);
// Checks whether a string containing a JS number is its canonical
// form.
static bool IsNumberCanonical(Vector<const uint8_t> key);
// Size of buffer. Sufficient for using it to call DoubleToCString in
// from conversions.h.
static const int kBufferSize = 100;
UnicodeCache* unicode_constants_;
// Backing store used to store strings used as hashmap keys.
SequenceCollector<unsigned char> backing_store_;
base::CustomMatcherHashMap map_;
// Buffer used for string->number->canonical string conversions.
char number_buffer_[kBufferSize];
};
} // namespace internal
} // namespace v8
#endif // V8_PARSING_DUPLICATE_FINDER_H_
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