Created convenience function for opening a sub-board or mail base

"the right way", this will be used to replace a lot of copy/pasta over time.

src/sbbs3/scfglib.h

@@ -87,6 +87,7 @@ char*	ltoaf(long l, char *str);     /* Converts long to flag string */
 uchar	attrstr(char *str);		/* Convert ATTR string into attribute int */
 
 int		smb_storage_mode(scfg_t*, smb_t*);
+int		smb_open_sub(scfg_t*, smb_t*, unsigned int subnum);
 
 #ifdef __cplusplus
 }

src/sbbs3/scfglib1.c

@@ -860,3 +860,30 @@ int smb_storage_mode(scfg_t* cfg, smb_t* smb)
 		return SMB_FASTALLOC;
 	return SMB_SELFPACK;
 }
+
+int smb_open_sub(scfg_t* cfg, smb_t* smb, unsigned int subnum)
+{
+	int retval;
+
+	if(subnum != INVALID_SUB && subnum >= cfg->total_subs)
+		return SMB_FAILURE;
+	memset(smb, 0, sizeof(smb_t));
+	if(subnum == INVALID_SUB) {
+		SAFEPRINTF(smb->file, "%smail", cfg->data_dir);
+		smb->status.max_crcs	= cfg->mail_maxcrcs;
+		smb->status.max_msgs	= 0;
+		smb->status.max_age		= cfg->mail_maxage;
+		smb->status.attr		= SMB_EMAIL;
+	} else {
+		SAFEPRINTF2(smb->file, "%s%s", cfg->sub[subnum]->data_dir, cfg->sub[subnum]->code);
+		smb->status.max_crcs	= cfg->sub[subnum]->maxcrcs;
+		smb->status.max_msgs	= cfg->sub[subnum]->maxmsgs;
+		smb->status.max_age		= cfg->sub[subnum]->maxage;
+		smb->status.attr		= cfg->sub[subnum]->misc&SUB_HYPER ? SMB_HYPERALLOC :0;
+	}
+	smb->retry_time = cfg->smb_retry_time;
+	if((retval = smb_open(smb)) == SMB_SUCCESS)
+		smb->subnum = subnum;
+	return retval;
+}
+