binary_from_base64.hpp 3.8 KB

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  1. #ifndef BOOST_ARCHIVE_ITERATORS_BINARY_FROM_BASE64_HPP
  2. #define BOOST_ARCHIVE_ITERATORS_BINARY_FROM_BASE64_HPP
  3. // MS compatible compilers support #pragma once
  4. #if defined(_MSC_VER)
  5. # pragma once
  6. #endif
  7. /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
  8. // binary_from_base64.hpp
  9. // (C) Copyright 2002 Robert Ramey - http://www.rrsd.com .
  10. // Use, modification and distribution is subject to the Boost Software
  11. // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  12. // http://www.boost.org/LICENSE_1_0.txt)
  13. // See http://www.boost.org for updates, documentation, and revision history.
  14. #include <boost/assert.hpp>
  15. #include <boost/serialization/throw_exception.hpp>
  16. #include <boost/static_assert.hpp>
  17. #include <boost/iterator/transform_iterator.hpp>
  18. #include <boost/archive/iterators/dataflow_exception.hpp>
  19. namespace boost {
  20. namespace archive {
  21. namespace iterators {
  22. /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
  23. // convert base64 characters to binary data
  24. namespace detail {
  25. template<class CharType>
  26. struct to_6_bit {
  27. typedef CharType result_type;
  28. CharType operator()(CharType t) const{
  29. static const signed char lookup_table[] = {
  30. -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  31. -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  32. -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,
  33. 52,53,54,55,56,57,58,59,60,61,-1,-1,-1, 0,-1,-1, // render '=' as 0
  34. -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,
  35. 15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
  36. -1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
  37. 41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1
  38. };
  39. // metrowerks trips this assertion - how come?
  40. #if ! defined(__MWERKS__)
  41. BOOST_STATIC_ASSERT(128 == sizeof(lookup_table));
  42. #endif
  43. signed char value = -1;
  44. if((unsigned)t <= 127)
  45. value = lookup_table[(unsigned)t];
  46. if(-1 == value)
  47. boost::serialization::throw_exception(
  48. dataflow_exception(dataflow_exception::invalid_base64_character)
  49. );
  50. return value;
  51. }
  52. };
  53. } // namespace detail
  54. // note: what we would like to do is
  55. // template<class Base, class CharType = typename Base::value_type>
  56. // typedef transform_iterator<
  57. // from_6_bit<CharType>,
  58. // transform_width<Base, 6, sizeof(Base::value_type) * 8, CharType>
  59. // > base64_from_binary;
  60. // but C++ won't accept this. Rather than using a "type generator" and
  61. // using a different syntax, make a derivation which should be equivalent.
  62. //
  63. // Another issue addressed here is that the transform_iterator doesn't have
  64. // a templated constructor. This makes it incompatible with the dataflow
  65. // ideal. This is also addressed here.
  66. template<
  67. class Base,
  68. class CharType = typename boost::iterator_value<Base>::type
  69. >
  70. class binary_from_base64 : public
  71. transform_iterator<
  72. detail::to_6_bit<CharType>,
  73. Base
  74. >
  75. {
  76. friend class boost::iterator_core_access;
  77. typedef transform_iterator<
  78. detail::to_6_bit<CharType>,
  79. Base
  80. > super_t;
  81. public:
  82. // make composible buy using templated constructor
  83. template<class T>
  84. binary_from_base64(T start) :
  85. super_t(
  86. Base(static_cast< T >(start)),
  87. detail::to_6_bit<CharType>()
  88. )
  89. {}
  90. // intel 7.1 doesn't like default copy constructor
  91. binary_from_base64(const binary_from_base64 & rhs) :
  92. super_t(
  93. Base(rhs.base_reference()),
  94. detail::to_6_bit<CharType>()
  95. )
  96. {}
  97. // binary_from_base64(){};
  98. };
  99. } // namespace iterators
  100. } // namespace archive
  101. } // namespace boost
  102. #endif // BOOST_ARCHIVE_ITERATORS_BINARY_FROM_BASE64_HPP