/*
 * Base64.c
 * Copyright (c) 2006 Ryan Martell. (rdm4@martellventures.com)
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

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

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>


unsigned char map2[] =
{
    0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
    0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x01,
    0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
    0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
    0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
    0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
    0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
    0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33
};

int b64_decode(lua_State *L)
{
    int i, v;
	unsigned char out[512];
	unsigned char *dst = out;
	char *in;
	if(lua_gettop(L) != 1)
	{
		lua_pushstring(L, "invalid arg list");
		lua_error(L);
		return 0;
	}
	in = (char *)lua_tostring (L, 1);
    v = 0;
    for (i = 0; in[i] && in[i] != '='; i++) {
        unsigned int index= in[i]-43;
        if (index>=(sizeof(map2)/sizeof(map2[0])) || map2[index] == 0xff)
            return -1;
        v = (v << 6) + map2[index];
        if (i & 3) {
            if (dst - out < 512) {
                *dst++ = v >> (6 - 2 * (i & 3));
            }
        }
    }
	if(!(dst - out))
		return 0;
	 lua_pushlstring(L, (char*)out, dst - out);
    return 1;
}

/*****************************************************************************
* b64_encode: stolen from VLC's http.c
* simplified by michael
* fixed edge cases and made it work from data (vs. strings) by ryan.
*****************************************************************************/

int b64_encode(lua_State *L)
{
    static const char b64[] =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    char *ret, *dst, *src, tmp[1024];
    unsigned i_bits = 0;
    int i_shift = 0;
    int bytes_remaining, len;
	if(lua_gettop(L) != 1)
	{
		lua_pushstring(L, "invalid arg list");
		lua_error(L);
		return 0;
	}
	src = (char *)lua_tostring (L, 1);
    bytes_remaining = len = strlen(src);
	if (len < 512) {
        ret = dst = tmp;
    } else
        return 0;

    if (len) {                  // special edge case, what should we really do here?
        while (bytes_remaining) {
            i_bits = (i_bits << 8) + *src++;
            bytes_remaining--;
            i_shift += 8;

            do {
                *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];
                i_shift -= 6;
            } while (i_shift > 6 || (bytes_remaining == 0 && i_shift > 0));
        }
        while ((dst - ret) & 3)
            *dst++ = '=';
    }
    *dst = '\0';
	lua_pushstring(L, tmp);
    return 1;
}