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author | Arseny Kapoulkine <arseny.kapoulkine@gmail.com> | 2017-02-23 00:23:01 +0300 |
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committer | Arseny Kapoulkine <arseny.kapoulkine@gmail.com> | 2017-03-03 07:11:22 -0800 |
commit | 8ce4592e159bc42f7c6136fb5a4627ff2b32efff (patch) | |
tree | bf1e6bf0997bcf8a0dcfbcaa031307e85f76548c | |
parent | 03e4b8de929328eb5cbb031ff535c50396d43bb9 (diff) |
Simplify compact_hash_table implementation
Instead of a separate implementation for find/insert, use just one that
can do both. This reduces the code size and simplifies code coverage;
the resulting code is close to what we had in terms of performance and
since hash table is a fall back should not affect any real workloads.
-rw-r--r-- | src/pugixml.cpp | 83 |
1 files changed, 38 insertions, 45 deletions
diff --git a/src/pugixml.cpp b/src/pugixml.cpp index 7368184..53bb83c 100644 --- a/src/pugixml.cpp +++ b/src/pugixml.cpp @@ -274,61 +274,31 @@ PUGI__NS_BEGIN } } - void** find(const void* key) + void* find(const void* key) { - assert(key); - if (_capacity == 0) return 0; - size_t hashmod = _capacity - 1; - size_t bucket = hash(key) & hashmod; + item_t* item = get_item(key); + assert(item); + assert(item->key == key || (item->key == 0 && item->value == 0)); - for (size_t probe = 0; probe <= hashmod; ++probe) - { - item_t& probe_item = _items[bucket]; - - if (probe_item.key == key) - return &probe_item.value; - - if (probe_item.key == 0) - return 0; - - // hash collision, quadratic probing - bucket = (bucket + probe + 1) & hashmod; - } - - assert(false && "Hash table is full"); - return 0; + return item->value; } - void** insert(const void* key) + void insert(const void* key, void* value) { - assert(key); assert(_capacity != 0 && _count < _capacity - _capacity / 4); - size_t hashmod = _capacity - 1; - size_t bucket = hash(key) & hashmod; + item_t* item = get_item(key); + assert(item); - for (size_t probe = 0; probe <= hashmod; ++probe) + if (item->key == 0) { - item_t& probe_item = _items[bucket]; - - if (probe_item.key == 0) - { - probe_item.key = key; - _count++; - return &probe_item.value; - } - - if (probe_item.key == key) - return &probe_item.value; - - // hash collision, quadratic probing - bucket = (bucket + probe + 1) & hashmod; + _count++; + item->key = key; } - assert(false && "Hash table is full"); - return 0; + item->value = value; } bool reserve() @@ -353,6 +323,29 @@ PUGI__NS_BEGIN bool rehash(); + item_t* get_item(const void* key) + { + assert(key); + assert(_capacity > 0); + + size_t hashmod = _capacity - 1; + size_t bucket = hash(key) & hashmod; + + for (size_t probe = 0; probe <= hashmod; ++probe) + { + item_t& probe_item = _items[bucket]; + + if (probe_item.key == key || probe_item.key == 0) + return &probe_item; + + // hash collision, quadratic probing + bucket = (bucket + probe + 1) & hashmod; + } + + assert(false && "Hash table is full"); + return 0; + } + static unsigned int hash(const void* key) { unsigned int h = static_cast<unsigned int>(reinterpret_cast<uintptr_t>(key)); @@ -381,7 +374,7 @@ PUGI__NS_BEGIN for (size_t i = 0; i < _capacity; ++i) if (_items[i].key) - *rt.insert(_items[i].key) = _items[i].value; + rt.insert(_items[i].key, _items[i].value); if (_items) xml_memory::deallocate(_items); @@ -773,12 +766,12 @@ PUGI__NS_BEGIN template <int header_offset, typename T> PUGI__FN_NO_INLINE T* compact_get_value(const void* object) { - return static_cast<T*>(*compact_get_page(object, header_offset)->allocator->_hash->find(object)); + return static_cast<T*>(compact_get_page(object, header_offset)->allocator->_hash->find(object)); } template <int header_offset, typename T> PUGI__FN_NO_INLINE void compact_set_value(const void* object, T* value) { - *compact_get_page(object, header_offset)->allocator->_hash->insert(object) = value; + compact_get_page(object, header_offset)->allocator->_hash->insert(object, value); } template <typename T, int header_offset, int start = -126> class compact_pointer |