Huanyu

code/Base64/Base64.cpp

@@ -0,0 +1,282 @@
+/*
+   base64.cpp and base64.h
+
+   base64 encoding and decoding with C++.
+   More information at
+     https://renenyffenegger.ch/notes/development/Base64/Encoding-and-decoding-base-64-with-cpp
+
+   Version: 2.rc.09 (release candidate)
+
+   Copyright (C) 2004-2017, 2020-2022 René Nyffenegger
+
+   This source code is provided 'as-is', without any express or implied
+   warranty. In no event will the author be held liable for any damages
+   arising from the use of this software.
+
+   Permission is granted to anyone to use this software for any purpose,
+   including commercial applications, and to alter it and redistribute it
+   freely, subject to the following restrictions:
+
+   1. The origin of this source code must not be misrepresented; you must not
+      claim that you wrote the original source code. If you use this source code
+      in a product, an acknowledgment in the product documentation would be
+      appreciated but is not required.
+
+   2. Altered source versions must be plainly marked as such, and must not be
+      misrepresented as being the original source code.
+
+   3. This notice may not be removed or altered from any source distribution.
+
+   René Nyffenegger rene.nyffenegger@adp-gmbh.ch
+
+*/
+
+#include "base64.h"
+
+#include <algorithm>
+#include <stdexcept>
+
+ //
+ // Depending on the url parameter in base64_chars, one of
+ // two sets of base64 characters needs to be chosen.
+ // They differ in their last two characters.
+ //
+static const char* base64_chars[2] = {
+             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+             "abcdefghijklmnopqrstuvwxyz"
+             "0123456789"
+             "+/",
+
+             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+             "abcdefghijklmnopqrstuvwxyz"
+             "0123456789"
+             "-_"};
+
+static unsigned int pos_of_char(const unsigned char chr) {
+ //
+ // Return the position of chr within base64_encode()
+ //
+
+    if      (chr >= 'A' && chr <= 'Z') return chr - 'A';
+    else if (chr >= 'a' && chr <= 'z') return chr - 'a' + ('Z' - 'A')               + 1;
+    else if (chr >= '0' && chr <= '9') return chr - '0' + ('Z' - 'A') + ('z' - 'a') + 2;
+    else if (chr == '+' || chr == '-') return 62; // Be liberal with input and accept both url ('-') and non-url ('+') base 64 characters (
+    else if (chr == '/' || chr == '_') return 63; // Ditto for '/' and '_'
+    else
+ //
+ // 2020-10-23: Throw std::exception rather than const char*
+ //(Pablo Martin-Gomez, https://github.com/Bouska)
+ //
+    throw std::runtime_error("Input is not valid base64-encoded data.");
+}
+
+static std::string insert_linebreaks(std::string str, size_t distance) {
+ //
+ // Provided by https://github.com/JomaCorpFX, adapted by me.
+ //
+    if (!str.length()) {
+        return "";
+    }
+
+    size_t pos = distance;
+
+    while (pos < str.size()) {
+        str.insert(pos, "\n");
+        pos += distance + 1;
+    }
+
+    return str;
+}
+
+template <typename String, unsigned int line_length>
+static std::string encode_with_line_breaks(String s) {
+  return insert_linebreaks(base64_encode(s, false), line_length);
+}
+
+template <typename String>
+static std::string encode_pem(String s) {
+  return encode_with_line_breaks<String, 64>(s);
+}
+
+template <typename String>
+static std::string encode_mime(String s) {
+  return encode_with_line_breaks<String, 76>(s);
+}
+
+template <typename String>
+static std::string encode(String s, bool url) {
+  return base64_encode(reinterpret_cast<const unsigned char*>(s.data()), s.length(), url);
+}
+
+std::string base64_encode(unsigned char const* bytes_to_encode, size_t in_len, bool url) {
+
+    size_t len_encoded = (in_len +2) / 3 * 4;
+
+    unsigned char trailing_char = url ? '.' : '=';
+
+ //
+ // Choose set of base64 characters. They differ
+ // for the last two positions, depending on the url
+ // parameter.
+ // A bool (as is the parameter url) is guaranteed
+ // to evaluate to either 0 or 1 in C++ therefore,
+ // the correct character set is chosen by subscripting
+ // base64_chars with url.
+ //
+    const char* base64_chars_ = base64_chars[url];
+
+    std::string ret;
+    ret.reserve(len_encoded);
+
+    unsigned int pos = 0;
+
+    while (pos < in_len) {
+        ret.push_back(base64_chars_[(bytes_to_encode[pos + 0] & 0xfc) >> 2]);
+
+        if (pos+1 < in_len) {
+           ret.push_back(base64_chars_[((bytes_to_encode[pos + 0] & 0x03) << 4) + ((bytes_to_encode[pos + 1] & 0xf0) >> 4)]);
+
+           if (pos+2 < in_len) {
+              ret.push_back(base64_chars_[((bytes_to_encode[pos + 1] & 0x0f) << 2) + ((bytes_to_encode[pos + 2] & 0xc0) >> 6)]);
+              ret.push_back(base64_chars_[  bytes_to_encode[pos + 2] & 0x3f]);
+           }
+           else {
+              ret.push_back(base64_chars_[(bytes_to_encode[pos + 1] & 0x0f) << 2]);
+              ret.push_back(trailing_char);
+           }
+        }
+        else {
+
+            ret.push_back(base64_chars_[(bytes_to_encode[pos + 0] & 0x03) << 4]);
+            ret.push_back(trailing_char);
+            ret.push_back(trailing_char);
+        }
+
+        pos += 3;
+    }
+
+
+    return ret;
+}
+
+template <typename String>
+static std::string decode(String const& encoded_string, bool remove_linebreaks) {
+ //
+ // decode(…) is templated so that it can be used with String = const std::string&
+ // or std::string_view (requires at least C++17)
+ //
+
+    if (encoded_string.empty()) return std::string();
+
+    if (remove_linebreaks) {
+
+       std::string copy(encoded_string);
+
+       copy.erase(std::remove(copy.begin(), copy.end(), '\n'), copy.end());
+
+       return base64_decode(copy, false);
+    }
+
+    size_t length_of_string = encoded_string.length();
+    size_t pos = 0;
+
+ //
+ // The approximate length (bytes) of the decoded string might be one or
+ // two bytes smaller, depending on the amount of trailing equal signs
+ // in the encoded string. This approximation is needed to reserve
+ // enough space in the string to be returned.
+ //
+    size_t approx_length_of_decoded_string = length_of_string / 4 * 3;
+    std::string ret;
+    ret.reserve(approx_length_of_decoded_string);
+
+    while (pos < length_of_string) {
+    //
+    // Iterate over encoded input string in chunks. The size of all
+    // chunks except the last one is 4 bytes.
+    //
+    // The last chunk might be padded with equal signs or dots
+    // in order to make it 4 bytes in size as well, but this
+    // is not required as per RFC 2045.
+    //
+    // All chunks except the last one produce three output bytes.
+    //
+    // The last chunk produces at least one and up to three bytes.
+    //
+
+       size_t pos_of_char_1 = pos_of_char(encoded_string.at(pos+1) );
+
+    //
+    // Emit the first output byte that is produced in each chunk:
+    //
+       ret.push_back(static_cast<std::string::value_type>( ( (pos_of_char(encoded_string.at(pos+0)) ) << 2 ) + ( (pos_of_char_1 & 0x30 ) >> 4)));
+
+       if ( ( pos + 2 < length_of_string  )       &&  // Check for data that is not padded with equal signs (which is allowed by RFC 2045)
+              encoded_string.at(pos+2) != '='     &&
+              encoded_string.at(pos+2) != '.'         // accept URL-safe base 64 strings, too, so check for '.' also.
+          )
+       {
+       //
+       // Emit a chunk's second byte (which might not be produced in the last chunk).
+       //
+          unsigned int pos_of_char_2 = pos_of_char(encoded_string.at(pos+2) );
+          ret.push_back(static_cast<std::string::value_type>( (( pos_of_char_1 & 0x0f) << 4) + (( pos_of_char_2 & 0x3c) >> 2)));
+
+          if ( ( pos + 3 < length_of_string )     &&
+                 encoded_string.at(pos+3) != '='  &&
+                 encoded_string.at(pos+3) != '.'
+             )
+          {
+          //
+          // Emit a chunk's third byte (which might not be produced in the last chunk).
+          //
+             ret.push_back(static_cast<std::string::value_type>( ( (pos_of_char_2 & 0x03 ) << 6 ) + pos_of_char(encoded_string.at(pos+3))   ));
+          }
+       }
+
+       pos += 4;
+    }
+
+    return ret;
+}
+
+std::string base64_decode(std::string const& s, bool remove_linebreaks) {
+   return decode(s, remove_linebreaks);
+}
+
+std::string base64_encode(std::string const& s, bool url) {
+   return encode(s, url);
+}
+
+std::string base64_encode_pem (std::string const& s) {
+   return encode_pem(s);
+}
+
+std::string base64_encode_mime(std::string const& s) {
+   return encode_mime(s);
+}
+
+#if __cplusplus >= 201703L
+//
+// Interface with std::string_view rather than const std::string&
+// Requires C++17
+// Provided by Yannic Bonenberger (https://github.com/Yannic)
+//
+
+std::string base64_encode(std::string_view s, bool url) {
+   return encode(s, url);
+}
+
+std::string base64_encode_pem(std::string_view s) {
+   return encode_pem(s);
+}
+
+std::string base64_encode_mime(std::string_view s) {
+   return encode_mime(s);
+}
+
+std::string base64_decode(std::string_view s, bool remove_linebreaks) {
+   return decode(s, remove_linebreaks);
+}
+
+#endif  // __cplusplus >= 201703L

code/Base64/Base64.h

@@ -0,0 +1,35 @@
+//
+//  base64 encoding and decoding with C++.
+//  Version: 2.rc.09 (release candidate)
+//
+
+#ifndef BASE64_H_C0CE2A47_D10E_42C9_A27C_C883944E704A
+#define BASE64_H_C0CE2A47_D10E_42C9_A27C_C883944E704A
+
+#include <string>
+
+#if __cplusplus >= 201703L
+#include <string_view>
+#endif  // __cplusplus >= 201703L
+
+std::string base64_encode     (std::string const& s, bool url = false);
+std::string base64_encode_pem (std::string const& s);
+std::string base64_encode_mime(std::string const& s);
+
+std::string base64_decode(std::string const& s, bool remove_linebreaks = false);
+std::string base64_encode(unsigned char const*, size_t len, bool url = false);
+
+#if __cplusplus >= 201703L
+//
+// Interface with std::string_view rather than const std::string&
+// Requires C++17
+// Provided by Yannic Bonenberger (https://github.com/Yannic)
+//
+std::string base64_encode     (std::string_view s, bool url = false);
+std::string base64_encode_pem (std::string_view s);
+std::string base64_encode_mime(std::string_view s);
+
+std::string base64_decode(std::string_view s, bool remove_linebreaks = false);
+#endif  // __cplusplus >= 201703L
+
+#endif /* BASE64_H_C0CE2A47_D10E_42C9_A27C_C883944E704A */