boinc/lib/base64.cpp

209 lines
6.1 KiB
C++

// This file is part of BOINC.
// http://boinc.berkeley.edu
// Copyright (C) 2008 University of California
//
// BOINC 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.
//
// BOINC 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 BOINC. If not, see <http://www.gnu.org/licenses/>.
#ifdef _WIN32
#include "boinc_win.h"
#endif
#ifndef _WIN32
#include "config.h"
#endif
#include "base64.h"
#ifdef _USING_FCGI_
#include "boinc_fcgi.h"
#endif
using std::string;
// Table of characters coding the 64 values.
static char base64_value_to_char[64] =
{
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', // 0- 9
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', // 10-19
'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', // 20-29
'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', // 30-39
'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', // 40-49
'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', // 50-59
'8', '9', '+', '/' // 60-63
};
// Table of base64 values for first 128 characters.
static short base64_char_to_value[128] =
{
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0- 9
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10- 19
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 20- 29
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 30- 39
-1, -1, -1, 62, -1, -1, -1, 63, 52, 53, // 40- 49
54, 55, 56, 57, 58, 59, 60, 61, -1, -1, // 50- 59
-1, -1, -1, -1, -1, 0, 1, 2, 3, 4, // 60- 69
5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 70- 79
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 80- 89
25, -1, -1, -1, -1, -1, -1, 26, 27, 28, // 90- 99
29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // 100-109
39, 40, 41, 42, 43, 44, 45, 46, 47, 48, // 110-119
49, 50, 51, -1, -1, -1, -1, -1 // 120-127
};
/* The following diagram shows the logical steps by which three octets
get transformed into four base64 characters.
.--------. .--------. .--------.
|aaaaaabb| |bbbbcccc| |ccdddddd|
`--------' `--------' `--------'
6 2 4 4 2 6
.--------+--------+--------+--------.
|00aaaaaa|00bbbbbb|00cccccc|00dddddd|
`--------+--------+--------+--------'
.--------+--------+--------+--------.
|AAAAAAAA|BBBBBBBB|CCCCCCCC|DDDDDDDD|
`--------+--------+--------+--------'
The octets are divided into 6 bit chunks, which are then encoded into
base64 characters. */
string r_base64_encode (const char* from, size_t length)
{
string result;
result.reserve(length + length/3 + 1);
size_t i = 0;
int c;
unsigned int value;
while (i < length)
{
c = from[i++];
// Process first byte of a triplet.
result += base64_value_to_char[0x3f & c >> 2];
value = (0x03 & c) << 4;
// Process second byte of a triplet.
if (i == length)
{
result += base64_value_to_char[value];
result += '=';
result += '=';
break;
}
c = from[i++];
result += base64_value_to_char[value | (0x0f & c >> 4)];
value = (0x0f & c) << 2;
// Process third byte of a triplet.
if (i == length)
{
result += base64_value_to_char[value];
result += '=';
break;
}
c = from[i++];
result += base64_value_to_char[value | (0x03 & c >> 6)];
result += base64_value_to_char[0x3f & c];
}
return result;
}
#define IS_ASCII(Character) \
((Character) < 128)
#define IS_BASE64(Character) \
(IS_ASCII (Character) && base64_char_to_value[Character] >= 0)
#define IS_BASE64_IGNORABLE(Character) \
((Character) == ' ' || (Character) == '\t' || (Character) == '\n' \
|| (Character) == '\f' || (Character) == '\r')
#define READ_QUADRUPLET_BYTE() \
do { \
if (i == length) return result; \
c = from[i++]; \
} \
while (IS_BASE64_IGNORABLE (c))
string r_base64_decode (const char* from, size_t length)
{
size_t i = 0;
string result;
unsigned char c;
unsigned long value;
while (true)
{
// Process first byte of a quadruplet.
READ_QUADRUPLET_BYTE();
if (!IS_BASE64 (c))
throw InvalidBase64Exception();
value = base64_char_to_value[c] << 18;
// Process second byte of a quadruplet.
READ_QUADRUPLET_BYTE();
if (!IS_BASE64 (c))
throw InvalidBase64Exception();
value |= base64_char_to_value[c] << 12;
c = (unsigned char) (value >> 16);
result += c;
// Process third byte of a quadruplet.
READ_QUADRUPLET_BYTE();
if (c == '=')
{
READ_QUADRUPLET_BYTE();
if (c != '=')
throw InvalidBase64Exception();
continue;
}
if (!IS_BASE64 (c))
throw InvalidBase64Exception();
value |= base64_char_to_value[c] << 6;
c = (unsigned char) (0xff & value >> 8);
result += c;
// Process fourth byte of a quadruplet.
READ_QUADRUPLET_BYTE();
if (c == '=')
continue;
if (!IS_BASE64 (c))
throw InvalidBase64Exception();
value |= base64_char_to_value[c];
c = (unsigned char) (0xff & value);
result += c;
}
}
const char *BOINC_RCSID_2b47467419 = "$Id$";