Electroneum
varint.h
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30 // Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
31 
32 #pragma once
33 
34 #include <limits>
35 #include <type_traits>
36 #include <utility>
37 #include <sstream>
38 #include <string>
54 namespace tools {
55 
58  enum {
59  /* \brief Represents the overflow error */
61  /* \brief Represents a non conical represnetation */
63  };
64 
67  template<typename OutputIt, typename T>
68  /* Requires T to be both an integral type and unsigned, should be a compile error if it is not */
70  write_varint(OutputIt &&dest, T i) {
71  /* Make sure that there is one after this */
72  while (i >= 0x80) {
73  *dest = (static_cast<char>(i) & 0x7f) | 0x80;
74  ++dest;
75  i >>= 7; /* I should be in multiples of 7, this should just get the next part */
76  }
77  /* writes the last one to dest */
78  *dest = static_cast<char>(i);
79  dest++; /* Seems kinda pointless... */
80  }
81 
84  template<typename T>
86  {
87  std::stringstream ss;
88  write_varint(std::ostreambuf_iterator<char>(ss), v);
89  return ss.str();
90  }
93  template<int bits, typename InputIt, typename T>
94  typename std::enable_if<std::is_integral<T>::value && std::is_unsigned<T>::value && 0 <= bits && bits <= std::numeric_limits<T>::digits, int>::type
95  read_varint(InputIt &&first, InputIt &&last, T &write) {
96  int read = 0;
97  write = 0;
98  for (int shift = 0;; shift += 7) {
99  if (first == last) {
100  return read;
101  }
102  unsigned char byte = *first;
103  ++first;
104  ++read;
105  if (shift + 7 >= bits && byte >= 1 << (bits - shift)) {
106  return EVARINT_OVERFLOW;
107  }
108  if (byte == 0 && shift != 0) {
109  return EVARINT_REPRESENT;
110  }
111 
112  write |= static_cast<T>(byte & 0x7f) << shift; /* Does the actually placing into write, stripping the first bit */
113 
114  /* If there is no next */
115  if ((byte & 0x80) == 0) {
116  break;
117  }
118  }
119  return read;
120  }
121 
125  template<typename InputIt, typename T>
126  int read_varint(InputIt &&first, InputIt &&last, T &i) {
127  return read_varint<std::numeric_limits<T>::digits>(std::forward<InputIt>(first), std::forward<InputIt>(last), i);
128  }
129 }
const uint32_t T[512]
::std::string string
Definition: gtest-port.h:1097
CXA_THROW_INFO_T void(* dest)(void *))
Definition: stack_trace.cpp:91
Various Tools.
Definition: tools.cpp:31
std::string get_varint_data(const T &v)
Returns the string that represents the varint.
Definition: varint.h:85
const GenericPointer< typename T::ValueType > T2 value
Definition: pointer.h:1225
unsigned int bits[ATOMS]
Definition: rctTypes.h:136
std::enable_if< std::is_integral< T >::value &&std::is_unsigned< T >::value, void >::type write_varint(OutputIt &&dest, T i)
writes a varint to a stream.
Definition: varint.h:70