// Slightly moulded by Fox to better suit his (poor?) tastes.

/*
The compilation of software known as FreeBSD is distributed under the
following terms:

Copyright (c) 1992-2014 The FreeBSD Project. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
*/

/*
 * Base64 encoding/decoding (RFC1341)
 * Copyright (c) 2005-2011, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "base64.h"

static const unsigned char base64_table[65] =
	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

/**
 * base64_encode - Base64 encode
 * @src: Data to be encoded
 * @len: Length of the data to be encoded
 * @out_len: Pointer to output length variable, or %NULL if not used
 * Returns: Allocated buffer of out_len bytes of encoded data,
 * or %NULL on failure
 *
 * Caller is responsible for freeing the returned buffer. Returned buffer is
 * nul terminated to make it easier to use as a C string. The nul terminator is
 * not included in out_len.
 */

size_t base64_encode_size(size_t len)
{
	size_t olen;
	olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */
	// olen += olen / 72; /* line feeds */
	olen++; /* nul termination */
	Assert(olen >= len);
    return olen;
}

void base64_encode(const unsigned char *src, size_t len,
			       unsigned char *out, size_t *out_len)
{
	unsigned char *pos;
	const unsigned char *end, *in;
	int line_len;

	Assert(out != NULL)

	end = src + len;
	in = src;
	pos = out;
	line_len = 0;
	while (end - in >= 3) {
		*pos++ = base64_table[in[0] >> 2];
		*pos++ = base64_table[((in[0] & 0x03) << 4) | (in[1] >> 4)];
		*pos++ = base64_table[((in[1] & 0x0f) << 2) | (in[2] >> 6)];
		*pos++ = base64_table[in[2] & 0x3f];
		in += 3;
		line_len += 4;
		if (line_len >= 72) {
			// *pos++ = '\n';
			line_len = 0;
		}
	}

	if (end - in) {
		*pos++ = base64_table[in[0] >> 2];
		if (end - in == 1) {
			*pos++ = base64_table[(in[0] & 0x03) << 4];
			*pos++ = '=';
		} else {
			*pos++ = base64_table[((in[0] & 0x03) << 4) |
					      (in[1] >> 4)];
			*pos++ = base64_table[(in[1] & 0x0f) << 2];
		}
		*pos++ = '=';
		line_len += 4;
	}

	if (line_len)
		*pos++ = '\n';

	*pos = '\0';
	if (out_len)
		*out_len = pos - out;
}


/**
 * base64_decode - Base64 decode
 * @src: Data to be decoded
 * @len: Length of the data to be decoded
 * @out_len: Pointer to output length variable
 * Returns: Allocated buffer of out_len bytes of decoded data,
 * or %NULL on failure
 *
 * Caller is responsible for freeing the returned buffer.
 */
unsigned char * base64_decode(const unsigned char *src, size_t len,
			                  unsigned char *out_buffer, size_t *out_len)
{
	unsigned char dtable[256], *out, *pos, block[4], tmp;
	size_t i, count, olen;
	int pad = 0;

    // paranoid
	// os_memset(dtable, 0x80, 256);
    for (i = 0; i < 256; i++) {
        dtable[i] = 0x80;
    }

	for (i = 0; i < sizeof(base64_table) - 1; i++)
		dtable[base64_table[i]] = (unsigned char) i;
	dtable[(int)'='] = 0;

	count = 0;
	for (i = 0; i < len; i++) {
		if (dtable[src[i]] != 0x80)
			count++;
	}

	if (count == 0 || count % 4)
		return NULL;

	olen = count / 4 * 3;
	pos = out = out_buffer;
    Assert(out != NULL)

	count = 0;
	for (i = 0; i < len; i++) {
		tmp = dtable[src[i]];
		if (tmp == 0x80)
			continue;

		if (src[i] == '=')
			pad++;
		block[count] = tmp;
		count++;
		if (count == 4) {
			*pos++ = (block[0] << 2) | (block[1] >> 4);
			*pos++ = (block[1] << 4) | (block[2] >> 2);
			*pos++ = (block[2] << 6) | block[3];
			count = 0;
			if (pad) {
				if (pad == 1)
					pos--;
				else if (pad == 2)
					pos -= 2;
				else {
					/* Invalid padding */
					return NULL;
				}
				break;
			}
		}
	}

	*out_len = pos - out;
	return out;
}