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// Copyright (c) 2012-2013 The Cryptonote developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#pragma once
#include <limits>
#include <type_traits>
#include <utility>
#include <sstream>
#include <string>
namespace tools {
template<typename OutputIt, typename T>
typename std::enable_if<std::is_integral<T>::value && std::is_unsigned<T>::value, void>::type
write_varint(OutputIt &&dest, T i) {
while (i >= 0x80) {
*dest++ = (static_cast<char>(i) & 0x7f) | 0x80;
i >>= 7;
}
*dest++ = static_cast<char>(i);
}
template<typename t_type>
std::string get_varint_data(const t_type& v)
{
std::stringstream ss;
write_varint(std::ostreambuf_iterator<char>(ss), v);
return ss.str();
}
template<int bits, typename InputIt, typename T>
typename std::enable_if<std::is_integral<T>::value && std::is_unsigned<T>::value && 0 <= bits && bits <= std::numeric_limits<T>::digits, int>::type
read_varint(InputIt &&first, InputIt &&last, T &i) {
int read = 0;
i = 0;
for (int shift = 0;; shift += 7) {
if (first == last) {
return read; // End of input.
}
unsigned char byte = *first++;
++read;
if (shift + 7 >= bits && byte >= 1 << (bits - shift)) {
return -1; // Overflow.
}
if (byte == 0 && shift != 0) {
return -2; // Non-canonical representation.
}
i |= static_cast<T>(byte & 0x7f) << shift;
if ((byte & 0x80) == 0) {
break;
}
}
return read;
}
template<typename InputIt, typename T>
int read_varint(InputIt &&first, InputIt &&last, T &i) {
return read_varint<std::numeric_limits<T>::digits, InputIt, T>(std::move(first), std::move(last), i);
}
}
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