/**
 * @file bstring.h
 * @author Ambroz Bizjak <ambrop7@gmail.com>
 * 
 * @section LICENSE
 * 
 * This file is part of BadVPN.
 * 
 * BadVPN is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 * 
 * BadVPN 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 the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef BADVPN_BSTRING_H
#define BADVPN_BSTRING_H

#include <misc/debug.h>

#include <stdlib.h>
#include <string.h>

#define BSTRING_TYPE_STATIC 5
#define BSTRING_TYPE_DYNAMIC 7
#define BSTRING_TYPE_EXTERNAL 11

#define BSTRING_STATIC_SIZE 23
#define BSTRING_STATIC_MAX (BSTRING_STATIC_SIZE - 1)

typedef struct {
    union {
        struct {
            char type;
            char static_string[BSTRING_STATIC_SIZE];
        } us;
        struct {
            char type;
            char *dynamic_string;
        } ud;
        struct {
            char type;
            const char *external_string;
        } ue;
    } u;
} BString;

static void BString__assert (BString *o)
{
    switch (o->u.us.type) {
        case BSTRING_TYPE_STATIC:
        case BSTRING_TYPE_DYNAMIC:
        case BSTRING_TYPE_EXTERNAL:
            return;
    }
    
    ASSERT(0);
}

static int BString_Init (BString *o, const char *str)
{
    if (strlen(str) <= BSTRING_STATIC_MAX) {
        strcpy(o->u.us.static_string, str);
        o->u.us.type = BSTRING_TYPE_STATIC;
    } else {
        if (!(o->u.ud.dynamic_string = malloc(strlen(str) + 1))) {
            return 0;
        }
        strcpy(o->u.ud.dynamic_string, str);
        o->u.ud.type = BSTRING_TYPE_DYNAMIC;
    }
    
    BString__assert(o);
    return 1;
}

static void BString_InitStatic (BString *o, const char *str)
{
    ASSERT(strlen(str) <= BSTRING_STATIC_MAX)
    
    strcpy(o->u.us.static_string, str);
    o->u.us.type = BSTRING_TYPE_STATIC;
    
    BString__assert(o);
}

static void BString_InitExternal (BString *o, const char *str)
{
    o->u.ue.external_string = str;
    o->u.ue.type = BSTRING_TYPE_EXTERNAL;
    
    BString__assert(o);
}

static void BString_InitAllocated (BString *o, char *str)
{
    o->u.ud.dynamic_string = str;
    o->u.ud.type = BSTRING_TYPE_DYNAMIC;
    
    BString__assert(o);
}

static void BString_Free (BString *o)
{
    BString__assert(o);
    
    if (o->u.ud.type == BSTRING_TYPE_DYNAMIC) {
        free(o->u.ud.dynamic_string);
    }
}

static const char * BString_Get (BString *o)
{
    BString__assert(o);
    
    switch (o->u.us.type) {
        case BSTRING_TYPE_STATIC: return o->u.us.static_string;
        case BSTRING_TYPE_DYNAMIC: return o->u.ud.dynamic_string;
        case BSTRING_TYPE_EXTERNAL: return o->u.ue.external_string;
    }
    
    ASSERT(0);
    return NULL;
}

#endif