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// Copyright (c) 2017-2019, The Monero Project
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "hex.h"
#include <iterator>
#include <limits>
#include <ostream>
#include <stdexcept>
namespace epee
{
namespace
{
template<typename T>
void write_hex(T&& out, const span<const std::uint8_t> src)
{
static constexpr const char hex[] = u8"0123456789abcdef";
static_assert(sizeof(hex) == 17, "bad string size");
for (const std::uint8_t byte : src)
{
*out = hex[byte >> 4];
++out;
*out = hex[byte & 0x0F];
++out;
}
}
}
template<typename T>
T to_hex::convert(const span<const std::uint8_t> src)
{
if (std::numeric_limits<std::size_t>::max() / 2 < src.size())
throw std::range_error("hex_view::to_string exceeded maximum size");
T out{};
out.resize(src.size() * 2);
to_hex::buffer_unchecked((char*)out.data(), src); // can't see the non const version in wipeable_string??
return out;
}
std::string to_hex::string(const span<const std::uint8_t> src) { return convert<std::string>(src); }
epee::wipeable_string to_hex::wipeable_string(const span<const std::uint8_t> src) { return convert<epee::wipeable_string>(src); }
void to_hex::buffer(std::ostream& out, const span<const std::uint8_t> src)
{
write_hex(std::ostreambuf_iterator<char>{out}, src);
}
void to_hex::formatted(std::ostream& out, const span<const std::uint8_t> src)
{
out.put('<');
buffer(out, src);
out.put('>');
}
void to_hex::buffer_unchecked(char* out, const span<const std::uint8_t> src) noexcept
{
return write_hex(out, src);
}
std::vector<uint8_t> from_hex::vector(const boost::string_ref src)
{
// should we include a specific character
auto include = [](char input) {
// we ignore spaces and colons
return !std::isspace(input) && input != ':';
};
// the number of relevant characters to decode
auto count = std::count_if(src.begin(), src.end(), include);
// this must be a multiple of two, otherwise we have a truncated input
if (count % 2) {
throw std::length_error{ "Invalid hexadecimal input length" };
}
std::vector<uint8_t> result;
result.reserve(count / 2);
// the data to work with (std::string is always null-terminated)
auto data = src.begin();
// convert a single hex character to an unsigned integer
auto char_to_int = [](const char *input) {
switch (std::tolower(*input)) {
case '0': return 0;
case '1': return 1;
case '2': return 2;
case '3': return 3;
case '4': return 4;
case '5': return 5;
case '6': return 6;
case '7': return 7;
case '8': return 8;
case '9': return 9;
case 'a': return 10;
case 'b': return 11;
case 'c': return 12;
case 'd': return 13;
case 'e': return 14;
case 'f': return 15;
default: throw std::range_error{ "Invalid hexadecimal input" };
}
};
// keep going until we reach the end
while (data != src.end()) {
// skip unwanted characters
if (!include(*data)) {
++data;
continue;
}
// convert two matching characters to int
auto high = char_to_int(data++);
auto low = char_to_int(data++);
result.push_back(high << 4 | low);
}
return result;
}
}
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