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arangodb/arangod/VocBase/headers.c

257 lines
9.0 KiB
C

////////////////////////////////////////////////////////////////////////////////
/// @brief datafiles
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2004-2013 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is triAGENS GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
/// @author Copyright 2011-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "headers.h"
#include "VocBase/primary-collection.h"
// -----------------------------------------------------------------------------
// --SECTION-- private defines
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup VocBase
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief minium number of headers per block
////////////////////////////////////////////////////////////////////////////////
#define BLOCK_SIZE_UNIT (128)
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- private types
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief headers
////////////////////////////////////////////////////////////////////////////////
typedef struct simple_headers_s {
TRI_headers_t base;
TRI_doc_mptr_t const* _freelist;
TRI_vector_pointer_t _blocks;
size_t _headerSize;
}
simple_headers_t;
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief get the size (number of entries) for a block, based on a function
///
/// this adaptively increases the number of entries per block until a certain
/// threshold. the benefit of this is that small collections (with few
/// documents) only use little memory whereas bigger collections allocate new
/// blocks in bigger chunks.
/// the lowest value for the number of entries in a block is BLOCK_SIZE_UNIT,
/// the highest value is BLOCK_SIZE_UNIT << 8.
////////////////////////////////////////////////////////////////////////////////
static size_t GetBlockSize (const size_t blockNumber) {
if (blockNumber < 8) {
return (size_t) (BLOCK_SIZE_UNIT << blockNumber);
}
return (size_t) (BLOCK_SIZE_UNIT << 8);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief clears an header
////////////////////////////////////////////////////////////////////////////////
static void ClearSimpleHeaders (TRI_doc_mptr_t* header, size_t headerSize) {
TRI_ASSERT_DEBUG(header);
memset(header, 0, headerSize);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief requests a header
////////////////////////////////////////////////////////////////////////////////
static TRI_doc_mptr_t* RequestSimpleHeaders (TRI_headers_t* h) {
simple_headers_t* headers = (simple_headers_t*) h;
char const* header;
TRI_doc_mptr_t* result;
if (headers->_freelist == NULL) {
char* begin;
char* ptr;
size_t blockSize;
blockSize = GetBlockSize(headers->_blocks._length);
TRI_ASSERT_DEBUG(blockSize > 0);
begin = TRI_Allocate(TRI_UNKNOWN_MEM_ZONE, blockSize * headers->_headerSize, true);
// out of memory
if (begin == NULL) {
TRI_set_errno(TRI_ERROR_OUT_OF_MEMORY);
return NULL;
}
ptr = begin + headers->_headerSize * (blockSize - 1);
header = NULL;
for (; begin <= ptr; ptr -= headers->_headerSize) {
((TRI_doc_mptr_t*) ptr)->_data = header;
header = ptr;
}
TRI_ASSERT_DEBUG(headers != NULL);
headers->_freelist = (TRI_doc_mptr_t*) header;
TRI_PushBackVectorPointer(&headers->_blocks, begin);
}
TRI_ASSERT_DEBUG(headers->_freelist != NULL);
result = CONST_CAST(headers->_freelist);
headers->_freelist = result->_data;
result->_data = NULL;
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief releases a header, putting it back onto the freelist
////////////////////////////////////////////////////////////////////////////////
static void ReleaseSimpleHeaders (TRI_headers_t* h, TRI_doc_mptr_t* header) {
simple_headers_t* headers = (simple_headers_t*) h;
ClearSimpleHeaders(header, headers->_headerSize);
header->_data = headers->_freelist;
headers->_freelist = header;
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- public functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup VocBase
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a new simple headers structures
////////////////////////////////////////////////////////////////////////////////
TRI_headers_t* TRI_CreateSimpleHeaders (size_t headerSize) {
simple_headers_t* headers = TRI_Allocate(TRI_UNKNOWN_MEM_ZONE, sizeof(simple_headers_t), false);
if (headers == NULL) {
TRI_set_errno(TRI_ERROR_OUT_OF_MEMORY);
return NULL;
}
headers->base.request = RequestSimpleHeaders;
headers->base.release = ReleaseSimpleHeaders;
headers->_freelist = NULL;
headers->_headerSize = headerSize;
TRI_InitVectorPointer(&headers->_blocks, TRI_UNKNOWN_MEM_ZONE);
return &headers->base;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroys a simple headers structures, but does not free the pointer
////////////////////////////////////////////////////////////////////////////////
void TRI_DestroySimpleHeaders (TRI_headers_t* h) {
simple_headers_t* headers = (simple_headers_t*) h;
size_t i;
for (i = 0; i < headers->_blocks._length; ++i) {
TRI_Free(TRI_UNKNOWN_MEM_ZONE, headers->_blocks._buffer[i]);
}
TRI_DestroyVectorPointer(&headers->_blocks);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroys a simple headers structures, but does not free the pointer
////////////////////////////////////////////////////////////////////////////////
void TRI_FreeSimpleHeaders (TRI_headers_t* headers) {
TRI_DestroySimpleHeaders(headers);
TRI_Free(TRI_UNKNOWN_MEM_ZONE, headers);
}
// -----------------------------------------------------------------------------
// --SECTION-- protected functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief iterates over all headers
////////////////////////////////////////////////////////////////////////////////
void TRI_IterateSimpleHeaders (TRI_headers_t* headers,
void (*iterator)(TRI_doc_mptr_t const*, void*),
void* data) {
simple_headers_t* h = (simple_headers_t*) headers;
size_t i;
for (i = 0; i < h->_blocks._length; ++i) {
size_t blockSize = GetBlockSize(i);
TRI_doc_mptr_t* begin = h->_blocks._buffer[i];
TRI_doc_mptr_t* end = begin + blockSize;
for (; begin < end; ++begin) {
iterator(begin, data);
}
}
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// Local Variables:
// mode: outline-minor
// outline-regexp: "/// @brief\\|/// {@inheritDoc}\\|/// @addtogroup\\|/// @page\\|// --SECTION--\\|/// @\\}"
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