NS-3 based Named Data Networking (NDN) simulator
ndnSIM 2.5: NDN, CCN, CCNx, content centric networks
API Documentation
base64-decode.cpp
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5  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
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21 
24 
25 namespace ndn {
26 namespace security {
27 namespace transform {
28 
34 {
35 public:
36  Impl()
37  : m_base64(BIO_new(BIO_f_base64()))
38  , m_source(BIO_new(BIO_s_mem()))
39  {
40  // Input may not be written in a single time.
41  // Do not return EOF when source is empty unless explicitly requested
42  BIO_set_mem_eof_return(m_source, -1);
43 
44  // connect base64 transform to the data source.
45  BIO_push(m_base64, m_source);
46  }
47 
49  {
50  BIO_free_all(m_base64);
51  }
52 
53 public:
54  BIO* m_base64;
55  BIO* m_source; // BIO_f_base64 alone does not work without a source
56 };
57 
58 static const size_t BUFFER_LENGTH = 1024;
59 
60 Base64Decode::Base64Decode(bool expectNewlineEvery64Bytes)
61  : m_impl(make_unique<Impl>())
62 {
63  if (!expectNewlineEvery64Bytes)
64  BIO_set_flags(m_impl->m_base64, BIO_FLAGS_BASE64_NO_NL);
65 }
66 
67 Base64Decode::~Base64Decode() = default;
68 
69 void
70 Base64Decode::preTransform()
71 {
72  while (isOutputBufferEmpty()) {
73  fillOutputBuffer();
74  if (isOutputBufferEmpty()) // nothing to read from BIO, return
75  return;
76 
78  }
79 }
80 
81 size_t
82 Base64Decode::convert(const uint8_t* buf, size_t size)
83 {
84  int wLen = BIO_write(m_impl->m_source, buf, size);
85 
86  if (wLen <= 0) { // fail to write data
87  if (!BIO_should_retry(m_impl->m_source)) {
88  // we haven't written everything but some error happens, and we cannot retry
89  BOOST_THROW_EXCEPTION(Error(getIndex(), "Failed to accept more input"));
90  }
91  return 0;
92  }
93  else { // update number of bytes written
94  return wLen;
95  }
96 }
97 
98 void
99 Base64Decode::finalize()
100 {
101  BIO_set_mem_eof_return(m_impl->m_source, 0);
102 
103  fillOutputBuffer();
104 
105  while (!isOutputBufferEmpty()) {
107  if (isOutputBufferEmpty())
108  fillOutputBuffer();
109  }
110 }
111 
112 void
113 Base64Decode::fillOutputBuffer()
114 {
115  // OpenSSL base64 BIO cannot give us the number bytes of partial decoded result,
116  // so we just try to read a chunk.
117  auto buffer = make_unique<OBuffer>(BUFFER_LENGTH);
118  int rLen = BIO_read(m_impl->m_base64, buffer->data(), buffer->size());
119  if (rLen <= 0)
120  return;
121 
122  if (static_cast<size_t>(rLen) < buffer->size())
123  buffer->erase(buffer->begin() + rLen, buffer->end());
124 
125  setOutputBuffer(std::move(buffer));
126 }
127 
128 unique_ptr<Transform>
129 base64Decode(bool expectNewlineEvery64Bytes)
130 {
131  return make_unique<Base64Decode>(expectNewlineEvery64Bytes);
132 }
133 
134 } // namespace transform
135 } // namespace security
136 } // namespace ndn
Copyright (c) 2011-2015 Regents of the University of California.
size_t getIndex() const
Get the module index.
unique_ptr< Transform > base64Decode(bool expectNewlineEvery64Bytes)
bool isOutputBufferEmpty() const
Check if output buffer is empty.
static const size_t BUFFER_LENGTH
The implementation class which contains the internal state of the filter which includes openssl speci...
void setOutputBuffer(unique_ptr< OBuffer > buffer)
Set output buffer to buffer.
Base64Decode(bool expectNewlineEvery64Bytes=true)
Create a base64 decoding module.
void flushOutputBuffer()
Read the content from output buffer and write it into next module.