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/* ISC license. */
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <skalibs/gensetdyn.h>
#include <skalibs/avltree.h>
#include "dynstorage.h"
/*
This is probably way overengineered, we could strdup the instance parameters
into the instances themselves; there would be a little param duplication, but
likely not much, and chances are we would save memory.
However, a fundamental principle of C memory management is: separate structure
from storage. Failing to abide by it leads to spaghettification of storage
paths, and ultimately memory leaks.
So, we store all our dynamic strings (i.e. user-provided strings that only
appear in transient storage like buffers but that need a longer lifetime) here,
and nowhere else. Duplication is prevented via refcounting.
*/
typedef struct cell_s cell_t, *cell_t_ref ;
struct cell_s
{
char *s ;
uint32_t refcount ;
} ;
#define CELL_ZERO { .s = 0, .refcount = 0 } ;
static gensetdyn cells = GENSETDYN_INIT(cell_t, 3, 3, 8) ;
static void *dynstorage_dtok (uint32_t d, void *data)
{
return GENSETDYN_P(cell_t, (gensetdyn *)data, d)->s ;
}
static int dynstorage_cmp (void const *a, void const *b, void *data)
{
(void)data ;
return strcmp((char const *)a, (char const *)b) ;
}
static avltree dynstorage = AVLTREE_INIT(3, 3, 8, &dynstorage_dtok, &dynstorage_cmp, &cells) ;
char const *dynstorage_add (char const *s)
{
cell_t *p ;
uint32_t d ;
if (avltree_search(&dynstorage, s, &d))
{
p = GENSETDYN_P(cell_t, &cells, d) ;
p->refcount++ ;
return p->s ;
}
if (!gensetdyn_new(&cells, &d)) return 0 ;
p = GENSETDYN_P(cell_t, &cells, d) ;
p->s = strdup(s) ;
if (!p->s) goto err0 ;
p->refcount = 1 ;
if (!avltree_insert(&dynstorage, d)) goto err1 ;
return p->s ;
err1:
free(p->s) ;
err0:
gensetdyn_delete(&cells, d) ;
return 0 ;
}
void dynstorage_remove (char const *s)
{
uint32_t d ;
if (avltree_search(&dynstorage, s, &d)
{
cell_t *p = GENSETDYN_P(cell_t, &cells, d) ;
if (!--p->refcount)
{
avltree_delete(&dynstorage, s) ;
free(p->s) ;
gensetdyn_delete(&cells, d) ;
}
}
}
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