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#include "buffer_manager.h"
#include "buffer_entry.h"
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
struct __buffer_manager_t
{
cmph_uint32 memory_avail; // memory available
buffer_entry_t ** buffer_entries; // buffer entries to be managed
cmph_uint32 nentries; // number of entries to be managed
cmph_uint32 *memory_avail_list; // memory available list
int pos_avail_list; // current position in memory available list
};
buffer_manager_t * buffer_manager_new(cmph_uint32 memory_avail, cmph_uint32 nentries)
{
cmph_uint32 memory_avail_entry, i;
buffer_manager_t *buff_manager = (buffer_manager_t *)malloc(sizeof(buffer_manager_t));
assert(buff_manager);
buff_manager->memory_avail = memory_avail;
buff_manager->buffer_entries = (buffer_entry_t **)calloc((size_t)nentries, sizeof(buffer_entry_t *));
buff_manager->memory_avail_list = (cmph_uint32 *)calloc((size_t)nentries, sizeof(cmph_uint32));
buff_manager->pos_avail_list = -1;
buff_manager->nentries = nentries;
memory_avail_entry = buff_manager->memory_avail/buff_manager->nentries + 1;
for(i = 0; i < buff_manager->nentries; i++)
{
buff_manager->buffer_entries[i] = buffer_entry_new(memory_avail_entry);
}
return buff_manager;
}
void buffer_manager_open(buffer_manager_t * buffer_manager, cmph_uint32 index, char * filename)
{
buffer_entry_open(buffer_manager->buffer_entries[index], filename);
}
cmph_uint8 * buffer_manager_read_key(buffer_manager_t * buffer_manager, cmph_uint32 index, cmph_uint32 * keylen)
{
cmph_uint8 * key = NULL;
if (buffer_manager->pos_avail_list >= 0 ) // recovering memory
{
cmph_uint32 new_capacity = buffer_entry_get_capacity(buffer_manager->buffer_entries[index]) + buffer_manager->memory_avail_list[(buffer_manager->pos_avail_list)--];
buffer_entry_set_capacity(buffer_manager->buffer_entries[index], new_capacity);
}
key = buffer_entry_read_key(buffer_manager->buffer_entries[index], keylen);
if (key == NULL) // storing memory to be recovered
{
buffer_manager->memory_avail_list[++(buffer_manager->pos_avail_list)] = buffer_entry_get_capacity(buffer_manager->buffer_entries[index]);
}
return key;
}
void buffer_manager_destroy(buffer_manager_t * buffer_manager)
{
cmph_uint32 i;
for(i = 0; i < buffer_manager->nentries; i++)
{
buffer_entry_destroy(buffer_manager->buffer_entries[i]);
}
free(buffer_manager->memory_avail_list);
free(buffer_manager->buffer_entries);
free(buffer_manager);
}
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