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authorDaniel Wilhelm <shieldwed@outlook.com>2019-02-13 21:05:15 +0000
committerDaniel Wilhelm <shieldwed@outlook.com>2019-02-13 21:05:15 +0000
commit2e618740c10a6dc7f5a8ee031a196b4ac95b1294 (patch)
tree475a67b0b138f2b1cd5f02eaab8e413f7eee62c6 /zen/base64.h
parentMerge branch '10.8' into 'master' (diff)
parent10.9 (diff)
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Merge branch '10.9' into 'master'10.9
10.9 See merge request opensource-tracking/FreeFileSync!6
Diffstat (limited to 'zen/base64.h')
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+// *****************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0 *
+// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
+// *****************************************************************************
+
+#ifndef BASE64_H_08473021856321840873021487213453214
+#define BASE64_H_08473021856321840873021487213453214
+
+#include <iterator>
+#include "type_traits.h"
+
+
+namespace zen
+{
+//http://en.wikipedia.org/wiki/Base64
+/*
+Usage:
+ const std::string input = "Sample text";
+ std::string output;
+ zen::encodeBase64(input.begin(), input.end(), std::back_inserter(output));
+ //output contains "U2FtcGxlIHRleHQ="
+*/
+template <class InputIterator, class OutputIterator>
+OutputIterator encodeBase64(InputIterator first, InputIterator last, OutputIterator result); //nothrow!
+
+template <class InputIterator, class OutputIterator>
+OutputIterator decodeBase64(InputIterator first, InputIterator last, OutputIterator result); //nothrow!
+
+std::string stringEncodeBase64(const std::string& str);
+std::string stringDecodeBase64(const std::string& str);
+
+
+
+
+
+
+
+
+
+
+//------------------------- implementation -------------------------------
+namespace impl
+{
+//64 chars for base64 encoding + padding char
+constexpr char ENCODING_MIME[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
+constexpr signed char DECODING_MIME[] =
+{
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
+ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, 64, -1, -1,
+ -1, 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, -1, -1, -1, -1, -1,
+ -1, 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, -1, -1, -1, -1, -1
+ };
+const unsigned char INDEX_PAD = 64; //"="
+}
+
+
+template <class InputIterator, class OutputIterator> inline
+OutputIterator encodeBase64(InputIterator first, InputIterator last, OutputIterator result)
+{
+ using namespace impl;
+ static_assert(sizeof(typename std::iterator_traits<InputIterator>::value_type) == 1);
+ static_assert(arraySize(ENCODING_MIME) == 64 + 1 + 1);
+ static_assert(arrayAccumulate<int>(ENCODING_MIME) + INDEX_PAD == 5602);
+
+ while (first != last)
+ {
+ const unsigned char a = static_cast<unsigned char>(*first++);
+ *result++ = ENCODING_MIME[a >> 2];
+
+ if (first == last)
+ {
+ *result++ = ENCODING_MIME[((a & 0x3) << 4)];
+ *result++ = ENCODING_MIME[INDEX_PAD];
+ *result++ = ENCODING_MIME[INDEX_PAD];
+ break;
+ }
+ const unsigned char b = static_cast<unsigned char>(*first++);
+ *result++ = ENCODING_MIME[((a & 0x3) << 4) | (b >> 4)];
+
+ if (first == last)
+ {
+ *result++ = ENCODING_MIME[((b & 0xf) << 2)];
+ *result++ = ENCODING_MIME[INDEX_PAD];
+ break;
+ }
+ const unsigned char c = static_cast<unsigned char>(*first++);
+ *result++ = ENCODING_MIME[((b & 0xf) << 2) | (c >> 6)];
+ *result++ = ENCODING_MIME[c & 0x3f];
+ }
+ return result;
+}
+
+
+template <class InputIterator, class OutputIterator> inline
+OutputIterator decodeBase64(InputIterator first, InputIterator last, OutputIterator result)
+{
+ using namespace impl;
+ static_assert(sizeof(typename std::iterator_traits<InputIterator>::value_type) == 1);
+ static_assert(arraySize(DECODING_MIME) == 128);
+ static_assert(arrayAccumulate<int>(DECODING_MIME) + INDEX_PAD == 2081);
+
+ const unsigned char INDEX_END = INDEX_PAD + 1;
+
+ auto readIndex = [&]() -> unsigned char //return index within [0, 64] or INDEX_END if end of input
+ {
+ for (;;)
+ {
+ if (first == last)
+ return INDEX_END;
+
+ const unsigned char ch = static_cast<unsigned char>(*first++);
+ if (ch < 128) //we're in lower ASCII table half
+ {
+ const int index = DECODING_MIME[ch];
+ if (0 <= index && index <= static_cast<int>(INDEX_PAD)) //skip all unknown characters (including carriage return, line-break, tab)
+ return static_cast<unsigned char>(index);
+ }
+ }
+ };
+
+ for (;;)
+ {
+ const unsigned char index1 = readIndex();
+ const unsigned char index2 = readIndex();
+ if (index1 >= INDEX_PAD || index2 >= INDEX_PAD)
+ {
+ assert(index1 == INDEX_END && index2 == INDEX_END);
+ break;
+ }
+ *result++ = static_cast<char>((index1 << 2) | (index2 >> 4));
+
+ const unsigned char index3 = readIndex();
+ if (index3 >= INDEX_PAD) //padding
+ {
+ assert(index3 == INDEX_PAD);
+ break;
+ }
+ *result++ = static_cast<char>(((index2 & 0xf) << 4) | (index3 >> 2));
+
+ const unsigned char index4 = readIndex();
+ if (index4 >= INDEX_PAD) //padding
+ {
+ assert(index4 == INDEX_PAD);
+ break;
+ }
+ *result++ = static_cast<char>(((index3 & 0x3) << 6) | index4);
+ }
+ return result;
+}
+
+
+inline
+std::string stringEncodeBase64(const std::string& str)
+{
+ std::string out;
+ encodeBase64(str.begin(), str.end(), std::back_inserter(out));
+ return out;
+}
+
+
+inline
+std::string stringDecodeBase64(const std::string& str)
+{
+ std::string out;
+ decodeBase64(str.begin(), str.end(), std::back_inserter(out));
+ return out;
+}
+}
+
+#endif //BASE64_H_08473021856321840873021487213453214
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