sigar/src/sigar_cache.c

88 lines
1.9 KiB
C

#include "sigar.h"
#include "sigar_private.h"
#include "sigar_util.h"
/*
* hash table to cache values where key is a unique number
* such as:
* pid -> some process data
* uid -> user name
* gid -> group name
*/
#define ENTRIES_SIZE(n) \
(sizeof(sigar_cache_entry_t *) * (n))
/* wrap free() for use w/ dmalloc */
static void free_value(void *ptr)
{
free(ptr);
}
sigar_cache_t *sigar_cache_new(int size)
{
sigar_cache_t *table = malloc(sizeof(*table));
table->count = 0;
table->size = size;
table->entries = malloc(ENTRIES_SIZE(size));
memset(table->entries, '\0', ENTRIES_SIZE(size));
table->free_value = free_value;
return table;
}
sigar_cache_entry_t *sigar_cache_get(sigar_cache_t *table,
sigar_uint64_t key)
{
sigar_cache_entry_t *entry, **ptr;
for (ptr = table->entries + (key % table->size), entry = *ptr;
entry; ptr = &entry->next, entry = *ptr)
{
if (entry->id == key) {
return entry;
}
}
if (table->count++ > table->size) {
unsigned int new_size = table->size * 2;
table->entries =
realloc(table->entries, ENTRIES_SIZE(new_size));
memset(table->entries + table->size, '\0',
ENTRIES_SIZE(new_size - table->size));
table->size = new_size;
}
*ptr = entry = malloc(sizeof(*entry));
entry->id = key;
entry->value = NULL;
entry->next = NULL;
return entry;
}
void sigar_cache_destroy(sigar_cache_t *table)
{
int i;
sigar_cache_entry_t **entries = table->entries;
for (i=0; i<table->size; i++) {
sigar_cache_entry_t *entry, *ptr;
entry = *entries++;
while (entry) {
if (entry->value) {
table->free_value(entry->value);
}
ptr = entry->next;
free(entry);
entry = ptr;
}
}
free(table->entries);
free(table);
}