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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include "buffer_type.h"
namespace vespalib::datastore {
/**
* Concrete class used to manage allocation and de-allocation of
* elements of type ElemType in data store buffers.
*
* Layout of each entry is:
*
* elements[array_size] - array of elements in entry
* padding - to align entries
* dynamic_array_size - number of array elements that should
* be visible to reader.
*/
template <typename ElemT>
class DynamicArrayBufferType : public BufferTypeBase
{
public:
using ElemType = ElemT;
protected:
static const ElemType& empty_entry() noexcept;
ElemType* get_entry(void *buffer, size_t offset) noexcept { return get_entry(buffer, offset, entry_size()); }
const ElemType* get_entry(const void *buffer, size_t offset) const noexcept { return get_entry(buffer, offset, entry_size()); }
public:
DynamicArrayBufferType(const DynamicArrayBufferType &rhs) = delete;
DynamicArrayBufferType & operator=(const DynamicArrayBufferType &rhs) = delete;
DynamicArrayBufferType(DynamicArrayBufferType && rhs) noexcept = default;
DynamicArrayBufferType & operator=(DynamicArrayBufferType && rhs) noexcept = default;
DynamicArrayBufferType(uint32_t array_size, uint32_t min_entries, uint32_t max_entries,
uint32_t num_entries_for_new_buffer, float allocGrowFactor) noexcept;
~DynamicArrayBufferType() override;
void destroy_entries(void* buffer, EntryCount num_entries) override;
void fallback_copy(void* new_buffer, const void* old_buffer, EntryCount num_entries) override;
void initialize_reserved_entries(void* buffer, EntryCount reserved_entries) override;
void clean_hold(void* buffer, size_t offset, EntryCount num_entries, CleanContext cleanCxt) override;
static uint32_t calc_entry_size(uint32_t array_size) noexcept;
static ElemType* get_entry(void* buffer, size_t offset, uint32_t entry_size) noexcept { return reinterpret_cast<ElemType*>(static_cast<char*>(buffer) + offset * entry_size); }
static const ElemType* get_entry(const void* buffer, size_t offset, uint32_t entry_size) noexcept { return reinterpret_cast<const ElemType*>(static_cast<const char*>(buffer) + offset * entry_size); }
static uint32_t get_dynamic_array_size(const void *buffer, uint32_t entry_size) noexcept { return *reinterpret_cast<const uint32_t*>(static_cast<const char*>(buffer) + entry_size - sizeof(uint32_t)); }
static void set_dynamic_array_size(void *buffer, uint32_t entry_size, uint32_t array_size) noexcept { *reinterpret_cast<uint32_t*>(static_cast<char*>(buffer) + entry_size - sizeof(uint32_t)) = array_size; }
};
extern template class DynamicArrayBufferType<char>;
extern template class DynamicArrayBufferType<int8_t>;
extern template class DynamicArrayBufferType<int16_t>;
extern template class DynamicArrayBufferType<int32_t>;
extern template class DynamicArrayBufferType<int64_t>;
extern template class DynamicArrayBufferType<float>;
extern template class DynamicArrayBufferType<double>;
extern template class DynamicArrayBufferType<AtomicEntryRef>;
}
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