first step towards garbage collected dynamic strings in qc. All strings

external to the progs file are now malloced and then freed at progs reload.
All that needs to be implementd for gc to work is the scanner and deallocator.

include/progs.h

@@ -79,6 +79,7 @@ void PR_Init_Cvars (void);
 
 void PR_ExecuteProgram (progs_t *pr, func_t fnum);
 void PR_LoadProgs (progs_t *pr, char *progsname);
+void PR_LoadStrings (progs_t *pr);
 
 void PR_Profile_f (void);
 
@@ -179,6 +180,13 @@ typedef struct {
 	dfunction_t *f;
 } prstack_t;
 
+typedef struct strref_s {
+	struct strref_s *next;
+	struct strref_s *prev;
+	char *string;
+	int count;
+} strref_t;
+
 struct progs_s {
 	dprograms_t		*progs;
 
@@ -186,6 +194,12 @@ struct progs_s {
 	struct hashtab_s *global_hash;
 	struct hashtab_s *field_hash;
 
+	// garbage collected strings
+	strref_t		*static_strings;
+	strref_t		dynamic_strings[2]; // 0 = head, 1 = tail
+	struct hashtab_s *strref_hash;
+	int				num_strings;
+
 	dfunction_t		*pr_functions;
 	char			*pr_strings;
 	int				pr_stringsize;

libs/gamecode/Makefile.am

@@ -1,6 +1,6 @@
 noinst_LIBRARIES = libqfgamecode.a
 
-libqfgamecode_a_SOURCES = pr_edict.c pr_exec.c
+libqfgamecode_a_SOURCES = pr_edict.c pr_exec.c pr_strings.c
 
 all-local: ../libqfgamecode.a
 

libs/gamecode/pr_edict.c

@@ -1052,6 +1052,9 @@ PR_LoadProgs (progs_t * pr, char *progsname)
 	if ((pr->fields.think = ED_GetFieldIndex (pr, "think")) == -1)
 		PR_Error (pr, "%s: undefined field: think", progsname);
 
+	// initialise the strings managment code
+	PR_LoadStrings (pr);
+
 	// LordHavoc: bounds check anything static
 	for (i = 0, st = pr->pr_statements; i < pr->progs->numstatements; i++, st++) {
 		switch (st->op) {

libs/gamecode/pr_exec.c

@@ -960,35 +960,3 @@ PR_ExecuteProgram (progs_t * pr, func_t fnum)
 		}
 	}
 }
-
-char       *
-PR_GetString (progs_t * pr, int num)
-{
-	if (num < 0) {
-		//Con_DPrintf("GET:%d == %s\n", num, pr->pr_strtbl[-num]);
-		return pr->pr_strtbl[-num];
-	}
-	return pr->pr_strings + num;
-}
-
-int
-PR_SetString (progs_t * pr, char *s)
-{
-	int         i = s - pr->pr_strings;
-
-	if (i < 0 || i > pr->pr_stringsize) {
-		for (i = 1; i <= pr->num_prstr; i++)
-			if (pr->pr_strtbl[i] == s
-				|| strequal (pr->pr_strtbl[i], s))
-				break;
-		if (i < pr->num_prstr)
-			return -i;
-		if (pr->num_prstr == MAX_PRSTR - 1)
-			Sys_Error ("MAX_PRSTR");
-		pr->num_prstr++;
-		pr->pr_strtbl[pr->num_prstr] = s;
-		//Con_DPrintf("SET:%d == %s\n", -pr->num_prstr, s);
-		return -pr->num_prstr;
-	}
-	return (int) (s - pr->pr_strings);
-}

libs/gamecode/pr_strings.c

@@ -0,0 +1,134 @@
+/*
+	pr_strings.c
+
+	progs string managment
+
+	Copyright (C) 1996-1997  Id Software, Inc.
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+	See the GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to:
+
+		Free Software Foundation, Inc.
+		59 Temple Place - Suite 330
+		Boston, MA  02111-1307, USA
+
+	$Id$
+*/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif
+#include <stdlib.h>
+
+#include <stdarg.h>
+
+#include "hash.h"
+#include "progs.h"
+
+static char *
+strref_get_key (void *_sr, void *notused)
+{
+	strref_t *sr = (strref_t*)_sr;
+	return sr->string;
+}
+
+static void
+strref_free (void *_sr, void *_pr)
+{
+	progs_t *pr = (progs_t*)_pr;
+	strref_t *sr = (strref_t*)_sr;
+
+	// free the string and ref only if it's not a static string
+	if (sr < pr->static_strings || sr >= pr->static_strings + pr->num_strings) {
+		free (sr->string);
+
+		sr->next->prev = sr->prev;
+		sr->prev->next = sr->next;
+
+		free (sr);
+	}
+}
+
+void
+PR_LoadStrings (progs_t *pr)
+{
+	int count = 0;
+	char *end = pr->pr_strings + pr->pr_stringsize;
+	char *str = pr->pr_strings;
+
+	while (str < end) {
+		count++;
+		str += strlen (str) + 1;
+	}
+	if (pr->strref_hash) {
+		Hash_FlushTable (pr->strref_hash);
+	} else {
+		pr->strref_hash = Hash_NewTable (1021, strref_get_key, strref_free, pr);
+	}
+
+	pr->dynamic_strings[0].next = &pr->dynamic_strings[1];
+	pr->dynamic_strings[0].prev = 0;
+	pr->dynamic_strings[1].next = 0;
+	pr->dynamic_strings[1].prev = &pr->dynamic_strings[1];
+
+	if (pr->static_strings)
+		free (pr->static_strings);
+	pr->static_strings = calloc (count, sizeof (strref_t));
+	count = 0;
+	str = pr->pr_strings;
+	while (str < end) {
+		pr->static_strings[count].string = str;
+		str += strlen (str) + 1;
+		Hash_Add (pr->strref_hash, &pr->static_strings[count]);
+		count++;
+	}
+	pr->num_strings = count;
+}
+
+char *
+PR_GetString (progs_t *pr, int num)
+{
+	return pr->pr_strings + num;
+}
+
+int
+PR_SetString (progs_t *pr, char *s)
+{
+	strref_t *sr = Hash_Find (pr->strref_hash, s);
+
+	if (sr) {
+		s = sr->string;
+	} else {
+		sr = malloc (sizeof (strref_t));
+		sr->string = strdup(s);
+		sr->count = 0;
+
+		sr->next = pr->dynamic_strings[0].next;
+		sr->prev = pr->dynamic_strings[0].next->prev;
+
+		pr->dynamic_strings[0].next->prev = sr;
+		pr->dynamic_strings[0].next = sr;
+
+		Hash_Add (pr->strref_hash, sr);
+
+		s = sr->string;
+	}
+	return (int) (s - pr->pr_strings);
+}

libs/util/hash.c

@@ -98,7 +98,7 @@ Hash_FlushTable (hashtab_t *tab)
 		while (tab->tab[i]) {
 			hashlink_t *t = tab->tab[i]->next;
 			if (tab->free_ele)
-				tab->free_ele (&tab->tab[i]->data, tab->user_data);
+				tab->free_ele (tab->tab[i]->data, tab->user_data);
 			free (tab->tab[i]);
 			tab->tab[i] = t;
 		}