/*
* Copyright(c) 2012 Tim Ruehsen
* Copyright(c) 2015-2016 Free Software Foundation, Inc.
*
* This file is part of libwget.
*
* Libwget 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 3 of the License, or
* (at your option) any later version.
*
* Libwget 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 libwget. If not, see .
*
*
* base64 conversion routines
*
* Changelog
* 21.12.2012 Tim Ruehsen created
*
*/
#include
#include
#include
#include
#include "private.h"
/**
* \file
* \brief Base64 functions
* \defgroup libwget-base64 Base64 functions
* @{
*
* This is a collection base64 encoding/decoding functions used in Wget2.
*/
static const unsigned char base64_2_bin[256] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 0, 0, 0, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0,
0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0,
0, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
static int G_GNUC_WGET_CONST _isbase64(char c)
{
// isalnum(c) does not work for all locales
return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || c == '+' || c == '/';
}
/**
* \param[in] src String to be checked
* \return 1 if \p src is a base64 string, 0 otherwise
*
* Checks whether \p src is a base64 string.
* Returns 0 if \p src is NULL.
*/
int wget_base64_is_string(const char *src)
{
if (src) {
while (_isbase64(*src)) src++;
if (!*src || (*src == '=' && src[1]) || (*src == '=' && src[1] == '=' && src[2]))
return 1;
}
return 0;
}
/**
* \param[out] dst Output buffer
* \param[in] src Base64 string to be decoded
* \param[in] n Length of \p src
* \return Number of bytes written into \p dst
*
* Decodes \p n bytes of the base64 string \p src.
* The decoded bytes are written into \p dst and are 0-terminated.
*
* The size of \p dst has to be at minimum ((\p n + 3) / 4) * 3 + 1 bytes.
*/
size_t wget_base64_decode(char *dst, const char *src, size_t n)
{
const unsigned char *usrc = (const unsigned char *)src;
char *old = dst;
int extra;
// trim '=' at the end
while (n > 0 && !_isbase64(usrc[n - 1]))
n--;
extra = n & 3;
for (n /= 4; n > 0; n--, usrc += 4) {
*dst++ = (char)(base64_2_bin[usrc[0]] << 2 | base64_2_bin[usrc[1]] >> 4);
*dst++ = (char)((base64_2_bin[usrc[1]]&0x0F) << 4 | base64_2_bin[usrc[2]] >> 2);
*dst++ = (char)((base64_2_bin[usrc[2]]&0x03) << 6 | base64_2_bin[usrc[3]]);
}
switch (extra) {
case 1:
// this should not happen
*dst++ = (char) (base64_2_bin[usrc[0]] << 2);
break;
case 2:
*dst++ = (char)(base64_2_bin[usrc[0]] << 2 | base64_2_bin[usrc[1]] >> 4);
*dst = (char)((base64_2_bin[usrc[1]]&0x0F) << 4);
if (*dst) dst++;
break;
case 3:
*dst++ = (char)(base64_2_bin[usrc[0]] << 2 | base64_2_bin[usrc[1]] >> 4);
*dst++ = (char)((base64_2_bin[usrc[1]]&0x0F) << 4 | base64_2_bin[usrc[2]] >> 2);
*dst = (char)((base64_2_bin[usrc[2]]&0x03) << 6);
if (*dst) dst++;
break;
default: // 0: ignore
break;
}
*dst = 0;
return (size_t) (dst - old);
}
/**
* \param[in] src Base64 string to be decoded
* \param[in] n Length of \p src
* \return Decoded bytes, zero terminated
*
* Decodes \p n bytes of the base64 string \p src.
* The decoded bytes are returned in an allocated buffer.
*
* You should free() the returned string when not needed any more.
*/
char *wget_base64_decode_alloc(const char *src, size_t n)
{
char *dst = xmalloc(((n + 3) / 4) * 3 + 1);
wget_base64_decode(dst, src, n);
return dst;
}
/**
* \param[out] dst Base64 output string
* \param[in] src Input buffer
* \param[in] n Number of bytes to be encoded
* \return Length of output string \p dst
*
* Encodes \p n bytes from \p src into a base64 string.
* The encoded string is written into \p dst (0-terminated).
*
* The length of \p dst has to be at minimum ((\p n + 2) / 3) * 4 + 1 bytes.
*/
size_t wget_base64_encode(char *dst, const char *src, size_t n)
{
static const char base64[64] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
const unsigned char *usrc = (const unsigned char *)src;
char *start = dst;
int extra = n % 3;
// convert line by line
for (n /= 3; n > 0; n--, usrc += 3) {
*dst++ = base64[usrc[0] >> 2];
*dst++ = base64[((usrc[0]&3) << 4) | (usrc[1] >> 4)];
*dst++ = base64[((usrc[1]&15) << 2) | (usrc[2] >> 6)];
*dst++ = base64[usrc[2]&0x3f];
}
// special case
if (extra == 1) {
*dst++ = base64[usrc[0] >> 2];
*dst++ = base64[(usrc[0]&3) << 4];
*dst++ = '=';
*dst++ = '=';
} else if (extra == 2) {
*dst++ = base64[usrc[0] >> 2];
*dst++ = base64[((usrc[0]&3) << 4) | (usrc[1] >> 4)];
*dst++ = base64[((usrc[1]&15) << 2)];
*dst++ = '=';
}
*dst = 0;
return (size_t) (dst - start);
}
/**
* \param[in] src Input buffer
* \param[in] n Number of bytes to be encoded
* \return Base64 encoded string
*
* Encodes \p n bytes from input buffer \p src.
* The encoded string is returned in an allocated buffer.
*
* You should free() the returned string when not needed any more.
*/
char *wget_base64_encode_alloc(const char *src, size_t n)
{
char *dst = xmalloc(((n + 2) / 3) * 4 + 1);
wget_base64_encode(dst, src, n);
return dst;
}
/**
* \param[in] fmt Printf-like format string
* \param[in] args Argument list
* \return Base64 encoded string
*
* Encodes the string constructed by \p fmt and \p args.
* The encoded string is returned in an allocated buffer.
*
* You should free() the returned string when not needed any more.
*/
char *wget_base64_encode_vprintf_alloc(const char *fmt, va_list args)
{
char *data = NULL;
size_t n;
n = wget_vasprintf(&data, fmt, args);
if (data) {
char *dst = wget_base64_encode_alloc(data, n);
xfree(data);
return dst;
}
return NULL;
}
/**
* \param[in] fmt Printf-like format string
* \param[in] ... Argument list
* \return Base64 encoded string
*
* Encodes the string constructed by \p fmt and the arguments.
* The encoded string is returned in an allocated buffer.
*
* You should free() the returned string when not needed any more.
*/
char *wget_base64_encode_printf_alloc(const char *fmt, ...)
{
char *dst;
va_list args;
va_start(args, fmt);
dst = wget_base64_encode_vprintf_alloc(fmt, args);
va_end(args);
return dst;
}
/**@}*/