text: /*
   * Base64 encoding/decoding (RFC1341)
   * Copyright (c) 2005, Jouni Malinen <j@w1.fi>
   *
   * This program 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.
   *
   * Alternatively, this software may be distributed under the terms of BSD
   * license.
   *
   * See README and COPYING for more details.
   */
  
  #include "includes.h"
  
  #include "os.h"
  #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.
   */
  unsigned char * base64_encode(const unsigned char *src, size_t len,
  			      size_t *out_len)
  {
  	unsigned char *out, *pos;
  	const unsigned char *end, *in;
  	size_t olen;
  #ifdef MULTI_LINE
  	int line_len;
  #endif
  
  	olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */
  #ifdef MULTI_LINE
  	olen += olen / 72; /* line feeds */
  #endif
  	olen++; /* nul termination */
  	out = os_malloc(olen);
  	if (out == NULL)
  		return NULL;
  
  	end = src + len;
  	in = src;
  	pos = out;
  #ifdef MULTI_LINE
  	line_len = 0;
  #endif
  	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;
  #ifdef MULTI_LINE
  		line_len += 4;
  		if (line_len >= 72) {
  			*pos++ = '\n';
  			line_len = 0;
  		}
  #endif
  	}
  
  	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++ = '=';
  #ifdef MULTI_LINE
  		line_len += 4;
  #endif
  	}
  #ifdef MULTI_LINE
  	if (line_len)
  		*pos++ = '\n';
  #endif
  
  	*pos = '\0';
  	if (out_len)
  		*out_len = pos - out;
  	return 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,
  			      size_t *out_len)
  {
  	unsigned char dtable[256], *out, *pos, in[4], block[4], tmp;
  	size_t i, count, olen;
  
  	os_memset(dtable, 0x80, 256);
  	for (i = 0; i < sizeof(base64_table) - 1; i++)
  		dtable[base64_table[i]] = (unsigned char) i;
  	dtable['='] = 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 = os_malloc(olen);
  	if (out == NULL)
  		return NULL;
  
  	count = 0;
  	for (i = 0; i < len; i++) {
  		tmp = dtable[src[i]];
  		if (tmp == 0x80)
  			continue;
  
  		in[count] = src[i];
  		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 (pos > out) {
  		if (in[2] == '=')
  			pos -= 2;
  		else if (in[3] == '=')
  			pos--;
  	}
  
  	*out_len = pos - out;
  	return out;
  }
  
  
  #ifdef TEST_MAIN
  #include <stdio.h>
  
  int main(int argc, char *argv[])
  {
  	FILE *f;
  	size_t len, elen;
  	unsigned char *buf, *e;
  
  	if (argc != 4) {
  		printf("Usage: base64 <encode|decode> <in file> <out file>\n");
  		return -1;
  	}
  
  	buf = os_readfile(argv[2], &len);
  	if (buf == NULL)
  		return -1;
  
  	if (strcmp(argv[1], "encode") == 0)
  		e = base64_encode(buf, len, &elen);
  	else
  		e = base64_decode(buf, len, &elen);
  	if (e == NULL)
  		return -2;
  	f = fopen(argv[3], "w");
  	if (f == NULL)
  		return -3;
  	fwrite(e, 1, elen, f);
  	fclose(f);
  	free(e);
  
  	return 0;
  }
  #endif /* TEST_MAIN */
  