95a7cfe0ea
BUG=v8:6325,v8:5402 Change-Id: If0c975fe377c0178c488fc1bedd02f9c8289ebbc Reviewed-on: https://chromium-review.googlesource.com/490086 Reviewed-by: Michael Starzinger <mstarzinger@chromium.org> Commit-Queue: Marja Hölttä <marja@chromium.org> Cr-Commit-Position: refs/heads/master@{#44979}
91 lines
3.0 KiB
C++
91 lines
3.0 KiB
C++
// Copyright 2017 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef V8_STRING_HASHER_H_
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#define V8_STRING_HASHER_H_
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#include "src/globals.h"
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namespace v8 {
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namespace internal {
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class ConsString;
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class String;
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template <typename T>
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class Vector;
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class V8_EXPORT_PRIVATE StringHasher {
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public:
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explicit inline StringHasher(int length, uint32_t seed);
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template <typename schar>
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static inline uint32_t HashSequentialString(const schar* chars, int length,
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uint32_t seed);
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// Reads all the data, even for long strings and computes the utf16 length.
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static uint32_t ComputeUtf8Hash(Vector<const char> chars, uint32_t seed,
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int* utf16_length_out);
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// Calculated hash value for a string consisting of 1 to
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// String::kMaxArrayIndexSize digits with no leading zeros (except "0").
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// value is represented decimal value.
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static uint32_t MakeArrayIndexHash(uint32_t value, int length);
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// No string is allowed to have a hash of zero. That value is reserved
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// for internal properties. If the hash calculation yields zero then we
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// use 27 instead.
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static const int kZeroHash = 27;
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// Reusable parts of the hashing algorithm.
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INLINE(static uint32_t AddCharacterCore(uint32_t running_hash, uint16_t c));
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INLINE(static uint32_t GetHashCore(uint32_t running_hash));
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INLINE(static uint32_t ComputeRunningHash(uint32_t running_hash,
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const uc16* chars, int length));
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INLINE(static uint32_t ComputeRunningHashOneByte(uint32_t running_hash,
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const char* chars,
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int length));
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protected:
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// Returns the value to store in the hash field of a string with
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// the given length and contents.
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uint32_t GetHashField();
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// Returns true if the hash of this string can be computed without
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// looking at the contents.
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inline bool has_trivial_hash();
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// Adds a block of characters to the hash.
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template <typename Char>
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inline void AddCharacters(const Char* chars, int len);
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private:
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// Add a character to the hash.
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inline void AddCharacter(uint16_t c);
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// Update index. Returns true if string is still an index.
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inline bool UpdateIndex(uint16_t c);
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int length_;
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uint32_t raw_running_hash_;
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uint32_t array_index_;
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bool is_array_index_;
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bool is_first_char_;
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DISALLOW_COPY_AND_ASSIGN(StringHasher);
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};
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class IteratingStringHasher : public StringHasher {
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public:
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static inline uint32_t Hash(String* string, uint32_t seed);
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inline void VisitOneByteString(const uint8_t* chars, int length);
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inline void VisitTwoByteString(const uint16_t* chars, int length);
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private:
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inline IteratingStringHasher(int len, uint32_t seed);
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void VisitConsString(ConsString* cons_string);
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DISALLOW_COPY_AND_ASSIGN(IteratingStringHasher);
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};
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} // namespace internal
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} // namespace v8
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#endif // V8_STRING_HASHER_H_
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