FreeRDP/libfreerdp/crypto/base64.c
2013-09-05 12:14:32 +02:00

149 lines
2.7 KiB
C

/**
* FreeRDP: A Remote Desktop Protocol Implementation
* Base64 Encoding & Decoding
*
* Copyright 2011-2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <winpr/crt.h>
#include <freerdp/crypto/crypto.h>
static const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
char* crypto_base64_encode(BYTE* data, int length)
{
int c;
BYTE* q;
char* p;
char* str;
int i = 0;
q = data;
p = str = (char*) malloc((length + 3) * 4 / 3 + 1);
while (i < length)
{
c = q[i++];
c <<= 8;
if (i < length)
c += q[i];
i++;
c <<= 8;
if (i < length)
c += q[i];
i++;
*p++ = base64[(c & 0x00FC0000) >> 18];
*p++ = base64[(c & 0x0003F000) >> 12];
if (i > length + 1)
*p++ = '=';
else
*p++ = base64[(c & 0x00000FC0) >> 6];
if (i > length)
*p++ = '=';
else
*p++ = base64[c & 0x0000003F];
}
*p = 0;
return str;
}
static int base64_decode_char(char c)
{
if (c >= 'A' && c <= 'Z')
return c - 'A';
if (c >= 'a' && c <= 'z')
return c - 'a' + 26;
if (c >= '0' && c <= '9')
return c - '0' + 52;
if (c == '+')
return 62;
if (c == '/')
return 63;
if (c == '=')
return -1;
return -1;
}
static void* base64_decode(BYTE* s, int length, int* data_len)
{
char* p;
int n[4];
BYTE* q;
BYTE* data;
if (length % 4)
return NULL;
n[0] = n[1] = n[2] = n[3] = 0;
q = data = (BYTE*) malloc(length / 4 * 3);
for (p = (char*) s; *p; )
{
n[0] = base64_decode_char(*p++);
n[1] = base64_decode_char(*p++);
n[2] = base64_decode_char(*p++);
n[3] = base64_decode_char(*p++);
if ((n[0] == -1) || (n[1] == -1))
{
free(data);
return NULL;
}
if ((n[2] == -1) && (n[3] != -1))
{
free(data);
return NULL;
}
q[0] = (n[0] << 2) + (n[1] >> 4);
if (n[2] != -1)
q[1] = ((n[1] & 15) << 4) + (n[2] >> 2);
if (n[3] != -1)
q[2] = ((n[2] & 3) << 6) + n[3];
q += 3;
}
*data_len = q - data - (n[2] == -1) - (n[3] == -1);
return data;
}
void crypto_base64_decode(BYTE* enc_data, int length, BYTE** dec_data, int* res_length)
{
*dec_data = base64_decode(enc_data, length, res_length);
}