v8::internal::TwoCharHashTableKey Class Reference

Inheritance diagram for v8::internal::TwoCharHashTableKey:

Collaboration diagram for v8::internal::TwoCharHashTableKey:

Public Member Functions
	TwoCharHashTableKey (uint16_t c1, uint16_t c2, uint32_t seed)
bool	IsMatch (Object *o) OVERRIDE
uint32_t	Hash () OVERRIDE
uint32_t	HashForObject (Object *key) OVERRIDE
Handle< Object >	AsHandle (Isolate *isolate) OVERRIDE
Public Member Functions inherited from v8::internal::HashTableKey
virtual	~HashTableKey ()

Private Attributes
uint16_t	c1_
uint16_t	c2_
uint32_t	hash_

Detailed Description

Definition at line 14604 of file objects.cc.

Constructor & Destructor Documentation

TwoCharHashTableKey()

v8::internal::TwoCharHashTableKey::TwoCharHashTableKey ( uint16_t  c1, uint16_t  c2, uint32_t  seed  )

inline

Definition at line 14606 of file objects.cc.

    : c1_(c1), c2_(c2) {
    // Char 1.
    uint32_t hash = seed;
    hash += c1;
    hash += hash << 10;
    hash ^= hash >> 6;
    // Char 2.
    hash += c2;
    hash += hash << 10;
    hash ^= hash >> 6;
    // GetHash.
    hash += hash << 3;
    hash ^= hash >> 11;
    hash += hash << 15;
    if ((hash & String::kHashBitMask) == 0) hash = StringHasher::kZeroHash;
    hash_ = hash;
#ifdef DEBUG
    // If this assert fails then we failed to reproduce the two-character
    // version of the string hashing algorithm above.  One reason could be
    // that we were passed two digits as characters, since the hash
    // algorithm is different in that case.
    uint16_t chars[2] = {c1, c2};
    uint32_t check_hash = StringHasher::HashSequentialString(chars, 2, seed);
    hash = (hash << String::kHashShift) | String::kIsNotArrayIndexMask;
    DCHECK_EQ(static_cast<int32_t>(hash), static_cast<int32_t>(check_hash));
#endif
  }

References DCHECK_EQ, v8::internal::StringHasher::HashSequentialString(), v8::internal::Name::kHashBitMask, v8::internal::Name::kHashShift, v8::internal::Name::kIsNotArrayIndexMask, and v8::internal::StringHasher::kZeroHash.

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Member Function Documentation

AsHandle()

Handle<Object> v8::internal::TwoCharHashTableKey::AsHandle ( Isolate *  isolate )

inlinevirtual

Implements v8::internal::HashTableKey.

Definition at line 14649 of file objects.cc.

                                                     {
    // The TwoCharHashTableKey is only used for looking in the string
    // table, not for adding to it.
    UNREACHABLE();
    return MaybeHandle<Object>().ToHandleChecked();
  }

References UNREACHABLE.

Hash()

uint32_t v8::internal::TwoCharHashTableKey::Hash ( )

inlinevirtual

Implements v8::internal::HashTableKey.

Definition at line 14643 of file objects.cc.

{ return hash_; }

HashForObject()

uint32_t v8::internal::TwoCharHashTableKey::HashForObject ( Object *  key )

inlinevirtual

Implements v8::internal::HashTableKey.

Definition at line 14644 of file objects.cc.

                                               {
    if (!key->IsString()) return 0;
    return String::cast(key)->Hash();
  }

IsMatch()

bool v8::internal::TwoCharHashTableKey::IsMatch ( Object *  o )

inlinevirtual

Implements v8::internal::HashTableKey.

Definition at line 14635 of file objects.cc.

                                   {
    if (!o->IsString()) return false;
    String* other = String::cast(o);
    if (other->length() != 2) return false;
    if (other->Get(0) != c1_) return false;
    return other->Get(1) == c2_;
  }

References v8::internal::String::length().

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Member Data Documentation

c1_

uint16_t v8::internal::TwoCharHashTableKey::c1_

private

Definition at line 14657 of file objects.cc.

c2_

uint16_t v8::internal::TwoCharHashTableKey::c2_

private

Definition at line 14658 of file objects.cc.

hash_

uint32_t v8::internal::TwoCharHashTableKey::hash_

private

Definition at line 14659 of file objects.cc.

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The documentation for this class was generated from the following file:

• /mnt/V8SourceCode/src/objects.cc