mirror of https://github.com/aria2/aria2
186 lines
6.3 KiB
C++
186 lines
6.3 KiB
C++
/* <!-- copyright */
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/*
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* aria2 - The high speed download utility
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*
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* Copyright (C) 2011 Tatsuhiro Tsujikawa
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* In addition, as a special exception, the copyright holders give
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* permission to link the code of portions of this program with the
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* OpenSSL library under certain conditions as described in each
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* individual source file, and distribute linked combinations
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* including the two.
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* You must obey the GNU General Public License in all respects
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* for all of the code used other than OpenSSL. If you modify
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* file(s) with this exception, you may extend this exception to your
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* version of the file(s), but you are not obligated to do so. If you
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* do not wish to do so, delete this exception statement from your
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* version. If you delete this exception statement from all source
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* files in the program, then also delete it here.
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*/
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/* copyright --> */
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#ifndef D_BASE64_H
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#define D_BASE64_H
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#include <string>
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namespace aria2 {
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namespace base64 {
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template <typename InputIterator>
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std::string encode(InputIterator first, InputIterator last)
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{
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static const char CHAR_TABLE[] = {
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
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'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
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'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
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'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
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'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/',
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};
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std::string res;
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size_t len = last - first;
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if (len == 0) {
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return res;
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}
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size_t r = len % 3;
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InputIterator j = last - r;
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char temp[4];
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while (first != j) {
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int n = static_cast<unsigned char>(*first++) << 16;
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n += static_cast<unsigned char>(*first++) << 8;
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n += static_cast<unsigned char>(*first++);
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temp[0] = CHAR_TABLE[n >> 18];
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temp[1] = CHAR_TABLE[(n >> 12) & 0x3fu];
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temp[2] = CHAR_TABLE[(n >> 6) & 0x3fu];
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temp[3] = CHAR_TABLE[n & 0x3fu];
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res.append(temp, sizeof(temp));
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}
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if (r == 2) {
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int n = static_cast<unsigned char>(*first++) << 16;
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n += static_cast<unsigned char>(*first++) << 8;
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temp[0] = CHAR_TABLE[n >> 18];
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temp[1] = CHAR_TABLE[(n >> 12) & 0x3fu];
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temp[2] = CHAR_TABLE[(n >> 6) & 0x3fu];
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temp[3] = '=';
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res.append(temp, sizeof(temp));
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}
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else if (r == 1) {
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int n = static_cast<unsigned char>(*first++) << 16;
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temp[0] = CHAR_TABLE[n >> 18];
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temp[1] = CHAR_TABLE[(n >> 12) & 0x3fu];
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temp[2] = '=';
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temp[3] = '=';
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res.append(temp, sizeof(temp));
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}
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return res;
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}
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template <typename InputIterator>
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InputIterator getNext(InputIterator first, InputIterator last, const int* tbl)
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{
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for (; first != last; ++first) {
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if (tbl[static_cast<size_t>(*first)] != -1 || *first == '=') {
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break;
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}
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}
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return first;
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}
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template <typename InputIterator>
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std::string decode(InputIterator first, InputIterator last)
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{
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static const int INDEX_TABLE[] = {
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57,
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58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6,
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7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
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25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
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37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1};
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std::string res;
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InputIterator k[4];
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int eq = 0;
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for (; first != last;) {
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for (int i = 1; i <= 4; ++i) {
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k[i - 1] = getNext(first, last, INDEX_TABLE);
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if (k[i - 1] == last) {
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// If i == 1, input may look like this: "TWFu\n" (i.e.,
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// garbage at the end)
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if (i != 1) {
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res.clear();
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}
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return res;
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}
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else if (*k[i - 1] == '=' && eq == 0) {
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eq = i;
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}
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first = k[i - 1] + 1;
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}
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if (eq) {
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break;
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}
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int n = (INDEX_TABLE[static_cast<unsigned char>(*k[0])] << 18) +
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(INDEX_TABLE[static_cast<unsigned char>(*k[1])] << 12) +
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(INDEX_TABLE[static_cast<unsigned char>(*k[2])] << 6) +
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INDEX_TABLE[static_cast<unsigned char>(*k[3])];
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res += n >> 16;
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res += n >> 8 & 0xffu;
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res += n & 0xffu;
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}
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if (eq) {
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if (eq <= 2) {
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res.clear();
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return res;
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}
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else {
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for (int i = eq; i <= 4; ++i) {
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if (*k[i - 1] != '=') {
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res.clear();
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return res;
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}
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}
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if (eq == 3) {
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int n = (INDEX_TABLE[static_cast<unsigned char>(*k[0])] << 18) +
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(INDEX_TABLE[static_cast<unsigned char>(*k[1])] << 12);
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res += n >> 16;
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}
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else if (eq == 4) {
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int n = (INDEX_TABLE[static_cast<unsigned char>(*k[0])] << 18) +
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(INDEX_TABLE[static_cast<unsigned char>(*k[1])] << 12) +
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(INDEX_TABLE[static_cast<unsigned char>(*k[2])] << 6);
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res += n >> 16;
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res += n >> 8 & 0xffu;
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}
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}
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}
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return res;
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}
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} // namespace base64
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} // namespace aria2
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#endif // D_BASE64_H
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