diff options
Diffstat (limited to 'src/lib_json/json_batchallocator.h')
-rw-r--r-- | src/lib_json/json_batchallocator.h | 192 |
1 files changed, 93 insertions, 99 deletions
diff --git a/src/lib_json/json_batchallocator.h b/src/lib_json/json_batchallocator.h index 2a7c024..2fbef7a 100644 --- a/src/lib_json/json_batchallocator.h +++ b/src/lib_json/json_batchallocator.h @@ -4,12 +4,12 @@ // See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE #ifndef JSONCPP_BATCHALLOCATOR_H_INCLUDED -# define JSONCPP_BATCHALLOCATOR_H_INCLUDED +#define JSONCPP_BATCHALLOCATOR_H_INCLUDED -# include <stdlib.h> -# include <assert.h> +#include <stdlib.h> +#include <assert.h> -# ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION +#ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION namespace Json { @@ -18,110 +18,104 @@ namespace Json { * This memory allocator allocates memory for a batch of object (specified by * the page size, the number of object in each page). * - * It does not allow the destruction of a single object. All the allocated objects - * can be destroyed at once. The memory can be either released or reused for future - * allocation. - * - * The in-place new operator must be used to construct the object using the pointer - * returned by allocate. + * It does not allow the destruction of a single object. All the allocated + * objects can be destroyed at once. The memory can be either released or reused + * for future allocation. + * + * The in-place new operator must be used to construct the object using the + * pointer returned by allocate. */ -template<typename AllocatedType - ,const unsigned int objectPerAllocation> -class BatchAllocator -{ +template <typename AllocatedType, const unsigned int objectPerAllocation> +class BatchAllocator { public: - BatchAllocator( unsigned int objectsPerPage = 255 ) - : freeHead_( 0 ) - , objectsPerPage_( objectsPerPage ) - { -// printf( "Size: %d => %s\n", sizeof(AllocatedType), typeid(AllocatedType).name() ); - assert( sizeof(AllocatedType) * objectPerAllocation >= sizeof(AllocatedType *) ); // We must be able to store a slist in the object free space. - assert( objectsPerPage >= 16 ); - batches_ = allocateBatch( 0 ); // allocated a dummy page - currentBatch_ = batches_; - } - - ~BatchAllocator() - { - for ( BatchInfo *batch = batches_; batch; ) + BatchAllocator(unsigned int objectsPerPage = 255) + : freeHead_(0), objectsPerPage_(objectsPerPage) { + // printf( "Size: %d => %s\n", sizeof(AllocatedType), + // typeid(AllocatedType).name() ); + assert(sizeof(AllocatedType) * objectPerAllocation >= + sizeof(AllocatedType*)); // We must be able to store a slist in the + // object free space. + assert(objectsPerPage >= 16); + batches_ = allocateBatch(0); // allocated a dummy page + currentBatch_ = batches_; + } + + ~BatchAllocator() { + for (BatchInfo* batch = batches_; batch;) { + BatchInfo* nextBatch = batch->next_; + free(batch); + batch = nextBatch; + } + } + + /// allocate space for an array of objectPerAllocation object. + /// @warning it is the responsability of the caller to call objects + /// constructors. + AllocatedType* allocate() { + if (freeHead_) // returns node from free list. + { + AllocatedType* object = freeHead_; + freeHead_ = *(AllocatedType**)object; + return object; + } + if (currentBatch_->used_ == currentBatch_->end_) { + currentBatch_ = currentBatch_->next_; + while (currentBatch_ && currentBatch_->used_ == currentBatch_->end_) + currentBatch_ = currentBatch_->next_; + + if (!currentBatch_) // no free batch found, allocate a new one { - BatchInfo *nextBatch = batch->next_; - free( batch ); - batch = nextBatch; + currentBatch_ = allocateBatch(objectsPerPage_); + currentBatch_->next_ = batches_; // insert at the head of the list + batches_ = currentBatch_; } - } - - /// allocate space for an array of objectPerAllocation object. - /// @warning it is the responsability of the caller to call objects constructors. - AllocatedType *allocate() - { - if ( freeHead_ ) // returns node from free list. - { - AllocatedType *object = freeHead_; - freeHead_ = *(AllocatedType **)object; - return object; - } - if ( currentBatch_->used_ == currentBatch_->end_ ) - { - currentBatch_ = currentBatch_->next_; - while ( currentBatch_ && currentBatch_->used_ == currentBatch_->end_ ) - currentBatch_ = currentBatch_->next_; - - if ( !currentBatch_ ) // no free batch found, allocate a new one - { - currentBatch_ = allocateBatch( objectsPerPage_ ); - currentBatch_->next_ = batches_; // insert at the head of the list - batches_ = currentBatch_; - } - } - AllocatedType *allocated = currentBatch_->used_; - currentBatch_->used_ += objectPerAllocation; - return allocated; - } - - /// Release the object. - /// @warning it is the responsability of the caller to actually destruct the object. - void release( AllocatedType *object ) - { - assert( object != 0 ); - *(AllocatedType **)object = freeHead_; - freeHead_ = object; - } + } + AllocatedType* allocated = currentBatch_->used_; + currentBatch_->used_ += objectPerAllocation; + return allocated; + } + + /// Release the object. + /// @warning it is the responsability of the caller to actually destruct the + /// object. + void release(AllocatedType* object) { + assert(object != 0); + *(AllocatedType**)object = freeHead_; + freeHead_ = object; + } private: - struct BatchInfo - { - BatchInfo *next_; - AllocatedType *used_; - AllocatedType *end_; - AllocatedType buffer_[objectPerAllocation]; - }; - - // disabled copy constructor and assignement operator. - BatchAllocator( const BatchAllocator & ); - void operator =( const BatchAllocator &); - - static BatchInfo *allocateBatch( unsigned int objectsPerPage ) - { - const unsigned int mallocSize = sizeof(BatchInfo) - sizeof(AllocatedType)* objectPerAllocation - + sizeof(AllocatedType) * objectPerAllocation * objectsPerPage; - BatchInfo *batch = static_cast<BatchInfo*>( malloc( mallocSize ) ); - batch->next_ = 0; - batch->used_ = batch->buffer_; - batch->end_ = batch->buffer_ + objectsPerPage; - return batch; - } - - BatchInfo *batches_; - BatchInfo *currentBatch_; - /// Head of a single linked list within the allocated space of freeed object - AllocatedType *freeHead_; - unsigned int objectsPerPage_; + struct BatchInfo { + BatchInfo* next_; + AllocatedType* used_; + AllocatedType* end_; + AllocatedType buffer_[objectPerAllocation]; + }; + + // disabled copy constructor and assignement operator. + BatchAllocator(const BatchAllocator&); + void operator=(const BatchAllocator&); + + static BatchInfo* allocateBatch(unsigned int objectsPerPage) { + const unsigned int mallocSize = + sizeof(BatchInfo) - sizeof(AllocatedType) * objectPerAllocation + + sizeof(AllocatedType) * objectPerAllocation * objectsPerPage; + BatchInfo* batch = static_cast<BatchInfo*>(malloc(mallocSize)); + batch->next_ = 0; + batch->used_ = batch->buffer_; + batch->end_ = batch->buffer_ + objectsPerPage; + return batch; + } + + BatchInfo* batches_; + BatchInfo* currentBatch_; + /// Head of a single linked list within the allocated space of freeed object + AllocatedType* freeHead_; + unsigned int objectsPerPage_; }; - } // namespace Json -# endif // ifndef JSONCPP_DOC_INCLUDE_IMPLEMENTATION +#endif // ifndef JSONCPP_DOC_INCLUDE_IMPLEMENTATION #endif // JSONCPP_BATCHALLOCATOR_H_INCLUDED |