93 lines
2.9 KiB
C++
93 lines
2.9 KiB
C++
/*
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* Chromaprint -- Audio fingerprinting toolkit
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* Copyright (C) 2010 Lukas Lalinsky <lalinsky@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
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* USA
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*/
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#include <algorithm>
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#include <assert.h>
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#include "base64.h"
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#include "bit_string_writer.h"
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#include "debug.h"
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using namespace std;
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using namespace Chromaprint;
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static const char kBase64Chars[65] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
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static const char kBase64CharsReversed[128] = {
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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,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 0, 0, 52,
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53, 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5,
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6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
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25, 0, 0, 0, 0, 63, 0, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
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38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 0, 0, 0, 0, 0
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};
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string Chromaprint::Base64Encode(const string &orig)
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{
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int size = orig.size();
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int encoded_size = (size * 4 + 2) / 3;
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string encoded(encoded_size, '\x00');
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const unsigned char *src = (unsigned char *)orig.data();
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string::iterator dest = encoded.begin();
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while (size > 0) {
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*dest++ = kBase64Chars[(src[0] >> 2)];
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*dest++ = kBase64Chars[((src[0] << 4) | (--size ? (src[1] >> 4) : 0)) & 63];
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if (size) {
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*dest++ = kBase64Chars[((src[1] << 2) | (--size ? (src[2] >> 6) : 0)) & 63];
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if (size) {
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*dest++ = kBase64Chars[src[2] & 63];
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--size;
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}
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}
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src += 3;
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}
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return encoded;
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}
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string Chromaprint::Base64Decode(const string &encoded)
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{
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string str((3 * encoded.size()) / 4, '\x00');
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const unsigned char *src = (const unsigned char *)encoded.data();
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int size = encoded.size();
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string::iterator dest = str.begin();
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while (size > 0) {
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int b0 = kBase64CharsReversed[*src++];
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if (--size) {
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int b1 = kBase64CharsReversed[*src++];
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int r = (b0 << 2) | (b1 >> 4);
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assert(dest != str.end());
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*dest++ = r;
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if (--size) {
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int b2 = kBase64CharsReversed[*src++];
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r = ((b1 << 4) & 255) | (b2 >> 2);
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assert(dest != str.end());
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*dest++ = r;
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if (--size) {
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int b3 = kBase64CharsReversed[*src++];
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r = ((b2 << 6) & 255) | b3;
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assert(dest != str.end());
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*dest++ = r;
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--size;
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}
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}
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}
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}
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return str;
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}
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