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Side by Side Diff: src/gpu/GrTHashTable.h

Issue 421253003: Finish removing GrTHashTable (Closed) Base URL: https://skia.googlesource.com/skia.git@master
Patch Set: Created 6 years, 4 months ago
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1
2 /*
3 * Copyright 2010 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10
11 #ifndef GrTHashTable_DEFINED
12 #define GrTHashTable_DEFINED
13
14 #include "GrTypes.h"
15 #include "SkTDArray.h"
16
17 /**
18 * Key needs
19 * static bool Equals(const Entry&, const Key&);
20 * static bool LessThan(const Entry&, const Key&);
21 * static bool Equals(const Entry&, const Entry&); for SK_DEBUG if GrTHashT able::validate() is called
22 * static bool LessThan(const Entry&, const Entry&); for SK_DEBUG if GrTHas hTable::validate() is called
23 * uint32_t getHash() const;
24 *
25 * Allows duplicate key entries but on find you may get
26 * any of the duplicate entries returned.
27 */
28 template <typename T, typename Key, size_t kHashBits> class GrTHashTable {
29 public:
30 GrTHashTable() { this->clearHash(); }
31 ~GrTHashTable() {}
32
33 int count() const { return fSorted.count(); }
34
35 struct Any {
36 // Return the first resource that matches the key.
37 bool operator()(const T*) const { return true; }
38 };
39
40 T* find(const Key& key) const { return this->find(key, Any()); }
41 template <typename Filter> T* find(const Key&, Filter filter) const;
42
43 // return true if key was unique when inserted.
44 bool insert(const Key&, T*);
45 void remove(const Key&, const T*);
46
47 void deleteAll();
48
49 #ifdef SK_DEBUG
50 void validate() const;
51 bool contains(T*) const;
52 #endif
53
54 // testing
55 const SkTDArray<T*>& getArray() const { return fSorted; }
56 SkTDArray<T*>& getArray() { return fSorted; }
57 private:
58 void clearHash() { sk_bzero(fHash, sizeof(fHash)); }
59
60 enum {
61 kHashCount = 1 << kHashBits,
62 kHashMask = kHashCount - 1
63 };
64 static unsigned hash2Index(intptr_t hash) {
65 #if 0
66 if (sizeof(hash) == 8) {
67 hash ^= hash >> 32;
68 }
69 #endif
70 hash ^= hash >> 16;
71 if (kHashBits <= 8) {
72 hash ^= hash >> 8;
73 }
74 return hash & kHashMask;
75 }
76
77 mutable T* fHash[kHashCount];
78 SkTDArray<T*> fSorted;
79
80 // search fSorted, and return the found index, or ~index of where it
81 // should be inserted
82 int searchArray(const Key&) const;
83 };
84
85 ///////////////////////////////////////////////////////////////////////////////
86
87 template <typename T, typename Key, size_t kHashBits>
88 int GrTHashTable<T, Key, kHashBits>::searchArray(const Key& key) const {
89 int count = fSorted.count();
90 if (0 == count) {
91 // we should insert it at 0
92 return ~0;
93 }
94
95 const T* const* array = fSorted.begin();
96 int high = count - 1;
97 int low = 0;
98 while (high > low) {
99 int index = (low + high) >> 1;
100 if (Key::LessThan(*array[index], key)) {
101 low = index + 1;
102 } else {
103 high = index;
104 }
105 }
106
107 // check if we found it
108 if (Key::Equals(*array[high], key)) {
109 // above search should have found the first occurrence if there
110 // are multiple.
111 SkASSERT(0 == high || Key::LessThan(*array[high - 1], key));
112 return high;
113 }
114
115 // now return the ~ of where we should insert it
116 if (Key::LessThan(*array[high], key)) {
117 high += 1;
118 }
119 return ~high;
120 }
121
122 template <typename T, typename Key, size_t kHashBits>
123 template <typename Filter>
124 T* GrTHashTable<T, Key, kHashBits>::find(const Key& key, Filter filter) const {
125
126 int hashIndex = hash2Index(key.getHash());
127 T* elem = fHash[hashIndex];
128
129 if (NULL != elem && Key::Equals(*elem, key) && filter(elem)) {
130 return elem;
131 }
132
133 // bsearch for the key in our sorted array
134 int index = this->searchArray(key);
135 if (index < 0) {
136 return NULL;
137 }
138
139 const T* const* array = fSorted.begin();
140
141 // above search should have found the first occurrence if there
142 // are multiple.
143 SkASSERT(0 == index || Key::LessThan(*array[index - 1], key));
144
145 for ( ; index < count() && Key::Equals(*array[index], key); ++index) {
146 if (filter(fSorted[index])) {
147 // update the hash
148 fHash[hashIndex] = fSorted[index];
149 return fSorted[index];
150 }
151 }
152
153 return NULL;
154 }
155
156 template <typename T, typename Key, size_t kHashBits>
157 bool GrTHashTable<T, Key, kHashBits>::insert(const Key& key, T* elem) {
158 int index = this->searchArray(key);
159 bool first = index < 0;
160 if (first) {
161 // turn it into the actual index
162 index = ~index;
163 }
164 // add it to our array
165 *fSorted.insert(index) = elem;
166 // update our hash table (overwrites any dupe's position in the hash)
167 fHash[hash2Index(key.getHash())] = elem;
168 return first;
169 }
170
171 template <typename T, typename Key, size_t kHashBits>
172 void GrTHashTable<T, Key, kHashBits>::remove(const Key& key, const T* elem) {
173 int index = hash2Index(key.getHash());
174 if (fHash[index] == elem) {
175 fHash[index] = NULL;
176 }
177
178 // remove from our sorted array
179 index = this->searchArray(key);
180 SkASSERT(index >= 0);
181 // if there are multiple matches searchArray will give us the first match
182 // march forward until we find elem.
183 while (elem != fSorted[index]) {
184 ++index;
185 SkASSERT(index < fSorted.count());
186 }
187 SkASSERT(elem == fSorted[index]);
188 fSorted.remove(index);
189 }
190
191 template <typename T, typename Key, size_t kHashBits>
192 void GrTHashTable<T, Key, kHashBits>::deleteAll() {
193 fSorted.deleteAll();
194 this->clearHash();
195 }
196
197 #ifdef SK_DEBUG
198 template <typename T, typename Key, size_t kHashBits>
199 void GrTHashTable<T, Key, kHashBits>::validate() const {
200 int count = fSorted.count();
201 for (int i = 1; i < count; i++) {
202 SkASSERT(Key::LessThan(*fSorted[i - 1], *fSorted[i]) ||
203 Key::Equals(*fSorted[i - 1], *fSorted[i]));
204 }
205 }
206
207 template <typename T, typename Key, size_t kHashBits>
208 bool GrTHashTable<T, Key, kHashBits>::contains(T* elem) const {
209 int index = fSorted.find(elem);
210 return index >= 0;
211 }
212
213 #endif
214
215 #endif
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