From 4dd30523a9fba5bb7bcc6f490250e49647d480a9 Mon Sep 17 00:00:00 2001
From: divverent <divverent@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Sun, 2 May 2010 12:32:18 +0000
Subject: [PATCH] unset command

From: Blub <blub@donotreply>

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@10114 d7cf8633-e32d-0410-b094-e92efae38249
---
 cmd.c  |  1 +
 cvar.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 cvar.h |  1 +
 3 files changed, 86 insertions(+)

diff --git a/cmd.c b/cmd.c
index 47e40a4f..f8baf912 100644
--- a/cmd.c
+++ b/cmd.c
@@ -1185,6 +1185,7 @@ void Cmd_Init_Commands (void)
 	Cmd_AddCommand ("wait", Cmd_Wait_f, "make script execution wait for next rendered frame");
 	Cmd_AddCommand ("set", Cvar_Set_f, "create or change the value of a console variable");
 	Cmd_AddCommand ("seta", Cvar_SetA_f, "create or change the value of a console variable that will be saved to config.cfg");
+	Cmd_AddCommand ("unset", Cvar_Del_f, "delete a cvar (does not work for static ones like _cl_name, or read-only ones)");
 #ifdef FILLALLCVARSWITHRUBBISH
 	Cmd_AddCommand ("fillallcvarswithrubbish", Cvar_FillAll_f, "fill all cvars with a specified number of characters to provoke buffer overruns");
 #endif /* FILLALLCVARSWITHRUBBISH */
diff --git a/cvar.c b/cvar.c
index 8f3abc39..bf6df5ad 100644
--- a/cvar.c
+++ b/cvar.c
@@ -70,6 +70,36 @@ cvar_t *Cvar_FindVarAfter (const char *prev_var_name, int neededflags)
 	return var;
 }
 
+cvar_t *Cvar_FindVarLink (const char *var_name, cvar_t **parent, cvar_t ***link, cvar_t **prev_alpha)
+{
+	int hashindex;
+	cvar_t *var;
+
+	// use hash lookup to minimize search time
+	hashindex = CRC_Block((const unsigned char *)var_name, strlen(var_name));
+	if(parent) *parent = NULL;
+	if(prev_alpha) *prev_alpha = NULL;
+	if(link) *link = &cvar_hashtable[hashindex];
+	for (var = cvar_hashtable[hashindex];var;var = var->nextonhashchain)
+	{
+		if (!strcmp (var_name, var->name))
+		{
+			if(!prev_alpha || var == cvar_vars)
+				return var;
+
+			*prev_alpha = cvar_vars;
+			// if prev_alpha happens to become NULL then there has been some inconsistency elsewhere
+			// already - should I still insert '*prev_alpha &&' in the loop?
+			while((*prev_alpha)->next != var)
+				*prev_alpha = (*prev_alpha)->next;
+			return var;
+		}
+		if(parent) *parent = var;
+	}
+
+	return NULL;
+}
+
 /*
 ============
 Cvar_VariableValue
@@ -820,6 +850,60 @@ void Cvar_SetA_f (void)
 	Cvar_Get(Cmd_Argv(1), Cmd_Argv(2), CVAR_SAVE, Cmd_Argc() > 3 ? Cmd_Argv(3) : NULL);
 }
 
+void Cvar_Del_f (void)
+{
+	int i;
+	cvar_t *cvar, *parent, **link, *prev;
+
+	if(Cmd_Argc() < 2)
+	{
+		Con_Printf("Del: wrong number of parameters, useage: unset <variablename1> [<variablename2> ...]\n");
+		return;
+	}
+	for(i = 1; i < Cmd_Argc(); ++i)
+	{
+		cvar = Cvar_FindVarLink(Cmd_Argv(i), &parent, &link, &prev);
+		if(!cvar)
+		{
+			Con_Printf("Del: %s is not defined\n", Cmd_Argv(i));
+			continue;
+		}
+		if(cvar->flags & CVAR_READONLY)
+		{
+			Con_Printf("Del: %s is read-only\n", cvar->name);
+			continue;
+		}
+		if(!(cvar->flags & CVAR_ALLOCATED))
+		{
+			Con_Printf("Del: %s is static and cannot be deleted\n", cvar->name);
+			continue;
+		}
+		if(cvar == cvar_vars)
+		{
+			cvar_vars = cvar->next;
+		}
+		else
+		{
+			// in this case, prev must be set, otherwise there has been some inconsistensy
+			// elsewhere already... should I still check for prev != NULL?
+			prev->next = cvar->next;
+		}
+
+		if(parent)
+			parent->nextonhashchain = cvar->nextonhashchain;
+		else if(link)
+			*link = cvar->nextonhashchain;
+
+		if(cvar->description != cvar_dummy_description)
+			Z_Free(cvar->description);
+
+		Z_Free(cvar->name);
+		Z_Free(cvar->string);
+		Z_Free(cvar->defstring);
+		Z_Free(cvar);
+	}
+}
+
 #ifdef FILLALLCVARSWITHRUBBISH
 void Cvar_FillAll_f()
 {
diff --git a/cvar.h b/cvar.h
index 636ca40b..1c04d86e 100644
--- a/cvar.h
+++ b/cvar.h
@@ -205,6 +205,7 @@ void Cvar_List_f (void);
 
 void Cvar_Set_f (void);
 void Cvar_SetA_f (void);
+void Cvar_Del_f (void);
 // commands to create new cvars (or set existing ones)
 // seta creates an archived cvar (saved to config)
 
-- 
2.39.2