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/*
This software may only be used by you under license from AT&T Corp.
("AT&T"). A copy of AT&T's Source Code Agreement is available at
AT&T's Internet website having the URL:
<http://www.research.att.com/sw/tools/graphviz/license/source.html>
If you received this software without first entering into a license
with AT&T, you have an infringing copy of this software and cannot use
it without violating AT&T's intellectual property rights.
*/
#pragma prototyped
#include "libgraph.h"
#ifdef DMALLOC
#include "dmalloc.h"
#endif
typedef struct refstr_t {
Dtlink_t link;
unsigned int refcnt;
char s[1];
} refstr_t;
static Dtdisc_t Refstrdisc = {
offsetof(refstr_t,s[0]),
0,
0,
((Dtmake_f)0),
((Dtfree_f)0),
((Dtcompar_f)0), /* use strcmp */
((Dthash_f)0),
((Dtmemory_f)0),
((Dtevent_f)0)
};
static Dict_t* StringDict;
#ifdef DEBUG
static int refstrprint(refstr_t* r)
{
fprintf(stderr,"%s\n",r->s); return 0;
}
agrefstrdump(void)
{
dtwalk(StringDict,refstrprint);
}
#endif
static void initialize_strings(void)
{
StringDict = dtopen(&Refstrdisc,Dttree);
}
char *agstrdup(char* s)
{
refstr_t *key,*r;
if (StringDict == NULL) initialize_strings();
if (s == NULL) return s;
key = (refstr_t*)(s - offsetof(refstr_t,s[0]));
r = (refstr_t*) dtsearch(StringDict,key);
if (r) r->refcnt++;
else {
r = (refstr_t*) malloc(sizeof(refstr_t)+strlen(s));
r->refcnt = 1;
strcpy(r->s,s);
dtinsert(StringDict,r);
}
return r->s;
}
void agstrfree(char* s)
{
refstr_t *key,*r;
if ((StringDict == NULL) || (s == NULL)) return;
key = (refstr_t*)(s - offsetof(refstr_t,s[0]));
r = (refstr_t*) dtsearch(StringDict,key);
if (r) {
r->refcnt--;
if (r->refcnt <= 0) {
dtdelete(StringDict,r);
free(r);
}
}
else fprintf(stderr,"agstrfree lost %s\n",s);
}
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