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/**
* @file
* @ingroup cgraph_core
*/
/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-v10.html
*
* Contributors: Details at https://graphviz.org
*************************************************************************/
#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <cgraph/cghdr.h>
#include <inttypes.h>
#include <stdint.h>
#include <stdlib.h>
#include <util/alloc.h>
/* a default ID allocator that works off the shared string lib */
/// information the ID allocator needs to do its job
typedef struct {
IDTYPE counter; ///< base to derive next identifier from
Agraph_t *g; ///< graph in use
} state_t;
static void *idopen(Agraph_t * g, Agdisc_t* disc)
{
(void)disc;
state_t *s = gv_alloc(sizeof(state_t));
*s = (state_t){.g = g};
return s;
}
static long idmap(void *state, int objtype, char *str, IDTYPE *id,
int createflag)
{
char *s;
state_t *st = state;
(void)objtype;
if (str) {
if (createflag)
s = agstrdup(st->g, str);
else
s = agstrbind(st->g, str);
// The scheme of using pointers as the IDs of named objects and odd
// numbers as the IDs of unnamed objects relies on heap pointers being
// even, to avoid collisions. So the low bit had better be unset.
assert((uintptr_t)s % 2 == 0 &&
"heap pointer with low bit set will collide with anonymous IDs");
*id = (IDTYPE)(uintptr_t)s;
} else {
*id = st->counter * 2 + 1;
++st->counter;
}
return 1;
}
static void idfree(void *state, int objtype, IDTYPE id)
{
(void)objtype;
state_t *st = state;
if (id % 2 == 0)
agstrfree(st->g, (char *)(uintptr_t)id, false);
}
static char *idprint(void *state, int objtype, IDTYPE id)
{
(void)state;
(void)objtype;
if (id % 2 == 0)
return (char *)(uintptr_t)id;
else
return NULL;
}
static void idregister(void *state, int objtype, void *obj)
{
(void)state;
(void)objtype;
(void)obj;
}
Agiddisc_t AgIdDisc = {
idopen,
idmap,
idfree,
idprint,
free,
idregister
};
/* aux functions incl. support for disciplines with anonymous IDs */
int agmapnametoid(Agraph_t * g, int objtype, char *str,
IDTYPE *result, bool createflag) {
int rv;
if (str && str[0] != LOCALNAMEPREFIX) {
rv = (int) AGDISC(g, id)->map(AGCLOS(g, id), objtype, str, result,
createflag);
if (rv)
return rv;
}
/* either an internal ID, or disc. can't map strings */
if (str) {
rv = aginternalmaplookup(g, objtype, str, result);
if (rv)
return rv;
} else
rv = 0;
if (createflag) {
/* get a new anonymous ID, and store in the internal map */
rv = (int) AGDISC(g, id)->map(AGCLOS(g, id), objtype, NULL, result,
createflag);
if (rv && str)
aginternalmapinsert(g, objtype, str, *result);
}
return rv;
}
void agfreeid(Agraph_t * g, int objtype, IDTYPE id)
{
(void) aginternalmapdelete(g, objtype, id);
(AGDISC(g, id)->free) (AGCLOS(g, id), objtype, id);
}
/**
* Return string representation of object.
* In general, returns the name of node or graph,
* and the key of an edge. If edge is anonymous, returns NULL.
* Uses static buffer for anonymous graphs.
*/
char *agnameof(void *obj)
{
Agraph_t *g;
char *rv;
/* perform internal lookup first */
g = agraphof(obj);
rv = aginternalmapprint(g, AGTYPE(obj), AGID(obj));
if (rv != NULL)
return rv;
if (AGDISC(g, id)->print) {
rv = AGDISC(g, id)->print(AGCLOS(g, id), AGTYPE(obj), AGID(obj));
if (rv != NULL)
return rv;
}
if (AGTYPE(obj) != AGEDGE) {
static char buf[32];
snprintf(buf, sizeof(buf), "%c%" PRIu64, LOCALNAMEPREFIX, AGID(obj));
rv = buf;
}
else
rv = 0;
return rv;
}
/* register a graph object in an external namespace */
void agregister(Agraph_t * g, int objtype, void *obj)
{
AGDISC(g, id)->idregister(AGCLOS(g, id), objtype, obj);
}
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