MFEM  v4.5.1
Finite element discretization library
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binaryio.cpp
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1 // Copyright (c) 2010-2022, Lawrence Livermore National Security, LLC. Produced
2 // at the Lawrence Livermore National Laboratory. All Rights reserved. See files
3 // LICENSE and NOTICE for details. LLNL-CODE-806117.
4 //
5 // This file is part of the MFEM library. For more information and source code
6 // availability visit https://mfem.org.
7 //
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10 // CONTRIBUTING.md for details.
11 
12 #include "binaryio.hpp"
13 #include "error.hpp"
14 
15 namespace mfem
16 {
17 namespace bin_io
18 {
19 
20 static const char b64str[]
21  = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
22  "abcdefghijklmnopqrstuvwxyz"
23  "0123456789+/";
24 
25 void WriteBase64(std::ostream &out, const void *bytes, size_t nbytes)
26 {
27  const unsigned char *in = static_cast<const unsigned char *>(bytes);
28  const unsigned char *end = in + nbytes;
29  while (end - in >= 3)
30  {
31  out << b64str[in[0] >> 2];
32  out << b64str[((in[0] & 0x03) << 4) | (in[1] >> 4)];
33  out << b64str[((in[1] & 0x0f) << 2) | (in[2] >> 6)];
34  out << b64str[in[2] & 0x3f];
35  in += 3;
36  }
37  if (end - in > 0) // Padding
38  {
39  out << b64str[in[0] >> 2];
40  if (end - in == 1)
41  {
42  out << b64str[(in[0] & 0x03) << 4];
43  out << '=';
44  }
45  else // end - in == 2
46  {
47  out << b64str[((in[0] & 0x03) << 4) | (in[1] >> 4)];
48  out << b64str[(in[1] & 0x0f) << 2];
49  }
50  out << '=';
51  }
52 }
53 
54 static const unsigned char b64table[] =
55 {
56  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
57  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
58  255,255,255,255,255,255,255,255,255,255,255,62, 255,62, 255,63,
59  52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255,255,255,0, 255,255,
60  255,0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
61  15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255,255,255,255,63,
62  255,26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
63  41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 255,255,255,255,255,
64  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
65  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
66  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
67  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
68  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
69  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
70  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
71  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255
72 };
73 
74 void DecodeBase64(const char *src, size_t len, std::vector<char> &buf)
75 {
76  const unsigned char *in = (const unsigned char *)src;
77  buf.clear();
78  size_t count = 0;
79  for (size_t i=0; i<len; ++i) { if (b64table[in[i]] != 255) { ++count; } }
80  if (count % 4 != 0) { return; }
81  buf.resize(3*len/4);
82  unsigned char *out = (unsigned char *)buf.data();
83  count = 0;
84  int pad = 0;
85  unsigned char c[4];
86  for (size_t i=0; i<len; ++i)
87  {
88  unsigned char t = b64table[in[i]];
89  if (t == 255) { continue; }
90  if (in[i] == '=') { ++pad; }
91  c[count++] = t;
92  if (count == 4)
93  {
94  *out++ = (c[0] << 2) | (c[1] >> 4);
95  if (pad <= 1) { *out++ = (c[1] << 4) | (c[2] >> 2); }
96  if (pad == 0) { *out++ = (c[2] << 6) | c[3]; }
97  count = pad = 0;
98  }
99  }
100  buf.resize(out - (unsigned char *)buf.data());
101 }
102 
103 size_t NumBase64Chars(size_t nbytes) { return ((4*nbytes/3) + 3) & ~3; }
104 
105 } // namespace mfem::bin_io
106 } // namespace mfem
void DecodeBase64(const char *src, size_t len, std::vector< char > &buf)
Decode len base-64 encoded characters in the buffer src, and store the resulting decoded data in buf...
Definition: binaryio.cpp:74
void WriteBase64(std::ostream &out, const void *bytes, size_t nbytes)
Given a buffer bytes of length nbytes, encode the data in base-64 format, and write the encoded data ...
Definition: binaryio.cpp:25
size_t NumBase64Chars(size_t nbytes)
Return the number of characters needed to encode nbytes in base-64.
Definition: binaryio.cpp:103
RefCoord t[3]
OutStream out(std::cout)
Global stream used by the library for standard output. Initially it uses the same std::streambuf as s...
Definition: globals.hpp:66