53 lines
1.7 KiB
C
53 lines
1.7 KiB
C
#ifndef DATA_POOL_H
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#define DATA_POOL_H
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#include "maxminddb.h"
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#include <stdbool.h>
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#include <stddef.h>
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// This should be large enough that we never need to grow the array of pointers
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// to blocks. 32 is enough. Even starting out of with size 1 (1 struct), the
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// 32nd element alone will provide 2**32 structs as we exponentially increase
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// the number in each block. Being confident that we do not have to grow the
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// array lets us avoid writing code to do that. That code would be risky as it
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// would rarely be hit and likely not be well tested.
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#define DATA_POOL_NUM_BLOCKS 32
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// A pool of memory for MMDB_entry_data_list_s structs. This is so we can
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// allocate multiple up front rather than one at a time for performance
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// reasons.
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//
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// The order you add elements to it (by calling data_pool_alloc()) ends up as
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// the order of the list.
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//
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// The memory only grows. There is no support for releasing an element you take
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// back to the pool.
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typedef struct MMDB_data_pool_s {
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// Index of the current block we're allocating out of.
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size_t index;
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// The size of the current block, counting by structs.
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size_t size;
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// How many used in the current block, counting by structs.
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size_t used;
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// The current block we're allocating out of.
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MMDB_entry_data_list_s *block;
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// The size of each block.
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size_t sizes[DATA_POOL_NUM_BLOCKS];
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// An array of pointers to blocks of memory holding space for list
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// elements.
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MMDB_entry_data_list_s *blocks[DATA_POOL_NUM_BLOCKS];
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} MMDB_data_pool_s;
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MMDB_data_pool_s *data_pool_new(size_t const);
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void data_pool_destroy(MMDB_data_pool_s *const);
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MMDB_entry_data_list_s *data_pool_alloc(MMDB_data_pool_s *const);
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MMDB_entry_data_list_s *data_pool_to_list(MMDB_data_pool_s *const);
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#endif
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