/
utils.h
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/
utils.h
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//------------------------------------------------------------------------------
/*
This file is part of rippled: https://github.com/ripple/rippled
Copyright (c) 2016 Ripple Labs Inc.
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#ifndef RIPPLE_CONDITIONS_UTILS_H
#define RIPPLE_CONDITIONS_UTILS_H
#include <ripple/basics/Buffer.h>
#include <ripple/basics/Slice.h>
#include <ripple/basics/strHex.h>
#include <ripple/conditions/impl/error.h>
#include <boost/dynamic_bitset.hpp>
#include <iomanip>
#include <limits>
#include <sstream>
#include <stdexcept>
#include <string>
#include <utility>
#include <vector>
namespace ripple {
namespace cryptoconditions {
// A collection of functions to decode binary blobs
// encoded with X.690 Distinguished Encoding Rules.
//
// This is a very trivial decoder and only implements
// the bare minimum needed to support PreimageSha256.
namespace der {
// The preamble encapsulates the DER identifier and
// length octets:
struct Preamble
{
explicit Preamble() = default;
std::uint8_t type = 0;
std::size_t tag = 0;
std::size_t length = 0;
};
inline bool
isPrimitive(Preamble const& p)
{
return (p.type & 0x20) == 0;
}
inline bool
isConstructed(Preamble const& p)
{
return !isPrimitive(p);
}
inline bool
isUniversal(Preamble const& p)
{
return (p.type & 0xC0) == 0;
}
inline bool
isApplication(Preamble const& p)
{
return (p.type & 0xC0) == 0x40;
}
inline bool
isContextSpecific(Preamble const& p)
{
return (p.type & 0xC0) == 0x80;
}
inline bool
isPrivate(Preamble const& p)
{
return (p.type & 0xC0) == 0xC0;
}
inline Preamble
parsePreamble(Slice& s, std::error_code& ec)
{
Preamble p;
if (s.size() < 2)
{
ec = error::short_preamble;
return p;
}
p.type = s[0] & 0xE0;
p.tag = s[0] & 0x1F;
s += 1;
if (p.tag == 0x1F)
{ // Long tag form, which we do not support:
ec = error::long_tag;
return p;
}
p.length = s[0];
s += 1;
if (p.length & 0x80)
{ // Long form length:
std::size_t const cnt = p.length & 0x7F;
if (cnt == 0)
{
ec = error::malformed_encoding;
return p;
}
if (cnt > sizeof(std::size_t))
{
ec = error::large_size;
return p;
}
if (cnt > s.size())
{
ec = error::short_preamble;
return p;
}
p.length = 0;
for (std::size_t i = 0; i != cnt; ++i)
p.length = (p.length << 8) + s[i];
s += cnt;
if (p.length == 0)
{
ec = error::malformed_encoding;
return p;
}
}
return p;
}
inline Buffer
parseOctetString(Slice& s, std::uint32_t count, std::error_code& ec)
{
if (count > s.size())
{
ec = error::buffer_underfull;
return {};
}
if (count > 65535)
{
ec = error::large_size;
return {};
}
Buffer b(s.data(), count);
s += count;
return b;
}
template <class Integer>
Integer
parseInteger(Slice& s, std::size_t count, std::error_code& ec)
{
Integer v{0};
if (s.empty())
{
// can never have zero sized integers
ec = error::malformed_encoding;
return v;
}
if (count > s.size())
{
ec = error::buffer_underfull;
return v;
}
const bool isSigned = std::numeric_limits<Integer>::is_signed;
// unsigned types may have a leading zero octet
const size_t maxLength = isSigned ? sizeof(Integer) : sizeof(Integer) + 1;
if (count > maxLength)
{
ec = error::large_size;
return v;
}
if (!isSigned && (s[0] & (1 << 7)))
{
// trying to decode a negative number into a positive value
ec = error::malformed_encoding;
return v;
}
if (!isSigned && count == sizeof(Integer) + 1 && s[0])
{
// since integers are coded as two's complement, the first byte may
// be zero for unsigned reps
ec = error::malformed_encoding;
return v;
}
v = 0;
for (size_t i = 0; i < count; ++i)
v = (v << 8) | (s[i] & 0xff);
if (isSigned && (s[0] & (1 << 7)))
{
for (int i = count; i < sizeof(Integer); ++i)
v |= (Integer(0xff) << (8 * i));
}
s += count;
return v;
}
} // namespace der
} // namespace cryptoconditions
} // namespace ripple
#endif