1 // Copyright 2018 The Android Open Source Project 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 #pragma once 15 16 #include <unordered_set> 17 18 #include <inttypes.h> 19 #include <stddef.h> 20 #include <string.h> 21 22 namespace android { 23 namespace base { 24 25 // Class to make it easier to set up memory regions where it is fast 26 // to allocate/deallocate buffers that have size within 27 // the specified range. 28 class Pool { 29 public: 30 // minSize/maxSize: the target range of sizes for which we want to 31 // make allocations fast. the greater the range, the more space 32 // traded off. 33 // chunksPerSize: the target maximum number of live objects of 34 // each size that are expected. the higher it is, the more space 35 // traded off. 36 // 37 // Rough space cost formula: 38 // O(chunksPerSize * log2(maxSize / minSize) * maxSize) 39 Pool(size_t minSize = 8, 40 size_t maxSize = 4096, 41 size_t chunksPerSize = 256); 42 43 // All memory allocated by this pool 44 // is automatically deleted when the pool 45 // is deconstructed. 46 ~Pool(); 47 48 void* alloc(size_t wantedSize); 49 void free(void* ptr); 50 51 // Convenience function to free everything currently allocated. 52 void freeAll(); 53 54 // Convenience function to allocate an array 55 // of objects of type T. 56 template <class T> 57 T* allocArray(size_t count) { 58 size_t bytes = sizeof(T) * count; 59 void* res = alloc(bytes); 60 return (T*) res; 61 } 62 63 char* strDup(const char* toCopy) { 64 size_t bytes = strlen(toCopy) + 1; 65 void* res = alloc(bytes); 66 memset(res, 0x0, bytes); 67 memcpy(res, toCopy, bytes); 68 return (char*)res; 69 } 70 71 char** strDupArray(const char* const* arrayToCopy, size_t count) { 72 char** res = allocArray<char*>(count); 73 74 for (size_t i = 0; i < count; i++) { 75 res[i] = strDup(arrayToCopy[i]); 76 } 77 78 return res; 79 } 80 81 void* dupArray(const void* buf, size_t bytes) { 82 void* res = alloc(bytes); 83 memcpy(res, buf, bytes); 84 return res; 85 } 86 87 private: 88 class Impl; 89 Impl* mImpl = nullptr; 90 91 std::unordered_set<void*> mFallbackPtrs; 92 }; 93 94 } // namespace base 95 } // namespace android 96
