NS-3 based Named Data Networking (NDN) simulator
ndnSIM 2.5: NDN, CCN, CCNx, content centric networks
API Documentation
string-helper.cpp
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1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2013-2019 Regents of the University of California.
4  *
5  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
6  *
7  * ndn-cxx library is free software: you can redistribute it and/or modify it under the
8  * terms of the GNU Lesser General Public License as published by the Free Software
9  * Foundation, either version 3 of the License, or (at your option) any later version.
10  *
11  * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
12  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
13  * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
14  *
15  * You should have received copies of the GNU General Public License and GNU Lesser
16  * General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
17  * <http://www.gnu.org/licenses/>.
18  *
19  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
20  */
21 
29 
30 #include <sstream>
31 
32 namespace ndn {
33 
34 std::ostream&
35 operator<<(std::ostream& os, const AsHex& hex)
36 {
37  printHex(os, hex.m_value, os.flags() & std::ostream::uppercase);
38  return os;
39 }
40 
41 void
42 printHex(std::ostream& os, uint64_t num, bool wantUpperCase)
43 {
44  auto osFlags = os.flags();
45  // std::showbase doesn't work with number 0
46  os << "0x" << std::noshowbase << std::noshowpos
47  << (wantUpperCase ? std::uppercase : std::nouppercase)
48  << std::hex << num;
49  os.flags(osFlags);
50 }
51 
52 void
53 printHex(std::ostream& os, const uint8_t* buffer, size_t length, bool wantUpperCase)
54 {
55  namespace tr = security::transform;
56  BOOST_ASSERT(buffer != nullptr || length == 0);
57  tr::bufferSource(buffer, length) >> tr::hexEncode(wantUpperCase) >> tr::streamSink(os);
58 }
59 
60 void
61 printHex(std::ostream& os, const Buffer& buffer, bool wantUpperCase)
62 {
63  return printHex(os, buffer.data(), buffer.size(), wantUpperCase);
64 }
65 
66 std::string
67 toHex(const uint8_t* buffer, size_t length, bool wantUpperCase)
68 {
69  std::ostringstream result;
70  printHex(result, buffer, length, wantUpperCase);
71  return result.str();
72 }
73 
74 std::string
75 toHex(const Buffer& buffer, bool wantUpperCase)
76 {
77  return toHex(buffer.data(), buffer.size(), wantUpperCase);
78 }
79 
80 shared_ptr<Buffer>
81 fromHex(const std::string& hexString)
82 {
83  namespace tr = security::transform;
84 
85  OBufferStream os;
86  try {
87  tr::bufferSource(hexString) >> tr::hexDecode() >> tr::streamSink(os);
88  }
89  catch (const tr::Error& e) {
90  NDN_THROW_NESTED(StringHelperError("Conversion from hex failed: "s + e.what()));
91  }
92 
93  return os.buf();
94 }
95 
96 std::string
97 escape(const std::string& str)
98 {
99  std::ostringstream os;
100  escape(os, str.data(), str.size());
101  return os.str();
102 }
103 
104 void
105 escape(std::ostream& os, const char* str, size_t len)
106 {
107  for (size_t i = 0; i < len; ++i) {
108  auto c = str[i];
109  // Unreserved characters don't need to be escaped.
110  if ((c >= 'a' && c <= 'z') ||
111  (c >= 'A' && c <= 'Z') ||
112  (c >= '0' && c <= '9') ||
113  c == '-' || c == '.' ||
114  c == '_' || c == '~') {
115  os << c;
116  }
117  else {
118  os << '%';
119  os << toHexChar((c & 0xf0) >> 4);
120  os << toHexChar(c & 0xf);
121  }
122  }
123 }
124 
125 std::string
126 unescape(const std::string& str)
127 {
128  std::ostringstream os;
129  unescape(os, str.data(), str.size());
130  return os.str();
131 }
132 
133 void
134 unescape(std::ostream& os, const char* str, size_t len)
135 {
136  for (size_t i = 0; i < len; ++i) {
137  if (str[i] == '%' && i + 2 < len) {
138  int hi = fromHexChar(str[i + 1]);
139  int lo = fromHexChar(str[i + 2]);
140 
141  if (hi < 0 || lo < 0)
142  // Invalid hex characters, so just keep the escaped string.
143  os << str[i] << str[i + 1] << str[i + 2];
144  else
145  os << static_cast<char>((hi << 4) | lo);
146 
147  // Skip ahead past the escaped value.
148  i += 2;
149  }
150  else {
151  // Just copy through.
152  os << str[i];
153  }
154  }
155 }
156 
157 } // namespace ndn
ndn::fromHex
shared_ptr< Buffer > fromHex(const std::string &hexString)
Convert the hex string to buffer.
Definition: string-helper.cpp:81
string-helper.hpp
buffer-source.hpp
ndn::AsHex
Helper class to convert a number to hexadecimal format, for use with stream insertion operators.
Definition: string-helper.hpp:49
ndn::Buffer
General-purpose automatically managed/resized buffer.
Definition: buffer.hpp:41
ndn::toHexChar
constexpr NDN_CXX_NODISCARD char toHexChar(unsigned int n, bool wantUpperCase=true) noexcept
Convert (the least significant nibble of) n to the corresponding hex character.
Definition: string-helper.hpp:153
ndn::security::transform::bufferSource
BufferSource bufferSource
Definition: buffer-source.hpp:73
hex-encode.hpp
NDN_THROW_NESTED
#define NDN_THROW_NESTED(e)
Definition: exception.hpp:71
ndn::security::transform::hexEncode
unique_ptr< Transform > hexEncode(bool useUpperCase)
Definition: hex-encode.cpp:70
hex-decode.hpp
ndn::printHex
void printHex(std::ostream &os, uint64_t num, bool wantUpperCase)
Output the hex representation of num to the output stream os.
Definition: string-helper.cpp:42
ndn::unescape
std::string unescape(const std::string &str)
Decode a percent-encoded string.
Definition: string-helper.cpp:126
stream-sink.hpp
ndn::security::transform::hexDecode
unique_ptr< Transform > hexDecode()
Definition: hex-decode.cpp:114
ndn::OBufferStream
implements an output stream that constructs ndn::Buffer
Definition: buffer-stream.hpp:71
ndn::toHex
std::string toHex(const uint8_t *buffer, size_t length, bool wantUpperCase)
Return a string containing the hex representation of the bytes in buffer.
Definition: string-helper.cpp:67
ndn::StringHelperError
Definition: string-helper.hpp:32
ndn::security::transform::streamSink
unique_ptr< Sink > streamSink(std::ostream &os)
Definition: stream-sink.cpp:53
ndn::operator<<
std::ostream & operator<<(std::ostream &os, const Data &data)
Definition: data.cpp:322
ndn::escape
std::string escape(const std::string &str)
Percent-encode a string.
Definition: string-helper.cpp:97
buffer.hpp
buffer-stream.hpp
ndn::OBufferStream::buf
shared_ptr< Buffer > buf()
Flush written data to the stream and return shared pointer to the underlying buffer.
Definition: buffer-stream.cpp:54
ndn
Copyright (c) 2011-2015 Regents of the University of California.
Definition: ndn-strategy-choice-helper.hpp:34
ndn::fromHexChar
constexpr NDN_CXX_NODISCARD int fromHexChar(char c) noexcept
Convert the hex character c to an integer in [0, 15], or -1 if it's not a hex character.
Definition: string-helper.hpp:164