base64-decode.cpp
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21 
23 
24 #include <openssl/bio.h>
25 #include <openssl/evp.h>
26 
27 namespace ndn::security::transform {
28 
29 class Base64Decode::Impl : boost::noncopyable
30 {
31 public:
32  Impl()
33  : m_base64(BIO_new(BIO_f_base64()))
34  , m_source(BIO_new(BIO_s_mem()))
35  {
36  // Input may not be written in a single time.
37  // Do not return EOF when source is empty unless explicitly requested
38  BIO_set_mem_eof_return(m_source, -1);
39 
40  // connect base64 transform to the data source.
41  BIO_push(m_base64, m_source);
42  }
43 
44  ~Impl()
45  {
46  BIO_free_all(m_base64);
47  }
48 
49 public:
50  BIO* m_base64;
51  BIO* m_source; // BIO_f_base64 alone does not work without a source
52 };
53 
54 
55 Base64Decode::Base64Decode(bool expectNewlineEvery64Bytes)
56  : m_impl(make_unique<Impl>())
57 {
58  if (!expectNewlineEvery64Bytes)
59  BIO_set_flags(m_impl->m_base64, BIO_FLAGS_BASE64_NO_NL);
60 }
61 
62 Base64Decode::~Base64Decode() = default;
63 
64 void
65 Base64Decode::preTransform()
66 {
67  while (isOutputBufferEmpty()) {
68  fillOutputBuffer();
69  if (isOutputBufferEmpty()) // nothing to read from BIO, return
70  return;
71 
73  }
74 }
75 
76 size_t
77 Base64Decode::convert(span<const uint8_t> buf)
78 {
79  int wLen = BIO_write(m_impl->m_source, buf.data(), buf.size());
80 
81  if (wLen <= 0) { // fail to write data
82  if (!BIO_should_retry(m_impl->m_source)) {
83  // we haven't written everything but some error happens, and we cannot retry
84  NDN_THROW(Error(getIndex(), "Failed to accept more input"));
85  }
86  return 0;
87  }
88  else { // update number of bytes written
89  return wLen;
90  }
91 }
92 
93 void
94 Base64Decode::finalize()
95 {
96  BIO_set_mem_eof_return(m_impl->m_source, 0);
97 
98  fillOutputBuffer();
99 
100  while (!isOutputBufferEmpty()) {
102  if (isOutputBufferEmpty())
103  fillOutputBuffer();
104  }
105 }
106 
107 void
108 Base64Decode::fillOutputBuffer()
109 {
110  // OpenSSL base64 BIO cannot give us the number bytes of partial decoded result,
111  // so we just try to read a chunk.
112  auto buffer = make_unique<OBuffer>(1024);
113  int rLen = BIO_read(m_impl->m_base64, buffer->data(), buffer->size());
114  if (rLen <= 0)
115  return;
116 
117  if (static_cast<size_t>(rLen) < buffer->size())
118  buffer->erase(buffer->begin() + rLen, buffer->end());
119 
120  setOutputBuffer(std::move(buffer));
121 }
122 
123 unique_ptr<Transform>
124 base64Decode(bool expectNewlineEvery64Bytes)
125 {
126  return make_unique<Base64Decode>(expectNewlineEvery64Bytes);
127 }
128 
129 } // namespace ndn::security::transform
Base64Decode(bool expectNewlineEvery64Bytes=true)
Create a base64 decoding module.
size_t getIndex() const
Get the module index.
void setOutputBuffer(unique_ptr< OBuffer > buffer)
Set output buffer to buffer.
bool isOutputBufferEmpty() const
Check if output buffer is empty.
void flushOutputBuffer()
Read the content from output buffer and write it into next module.
#define NDN_THROW(e)
Definition: exception.hpp:56
unique_ptr< Transform > base64Decode(bool expectNewlineEvery64Bytes)