mirror of
https://github.com/matrix-construct/construct
synced 2024-10-31 19:08:59 +01:00
163 lines
3.6 KiB
C++
163 lines
3.6 KiB
C++
// The Construct
|
|
//
|
|
// Copyright (C) The Construct Developers, Authors & Contributors
|
|
// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
|
|
//
|
|
// 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 is present in all copies. The
|
|
// full license for this software is available in the LICENSE file.
|
|
|
|
namespace ircd::b58
|
|
{
|
|
[[gnu::visibility("internal")]]
|
|
extern const string_view dict;
|
|
|
|
static thread_local char conv_tmp_buf[64_KiB];
|
|
}
|
|
|
|
decltype(ircd::b58::dict)
|
|
ircd::b58::dict
|
|
{
|
|
"123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"_sv
|
|
};
|
|
|
|
//
|
|
// Conversion convenience suite
|
|
//
|
|
|
|
ircd::string_view
|
|
ircd::b58::fromb64(const mutable_buffer &out,
|
|
const string_view &in)
|
|
{
|
|
if(unlikely(b64::decode_size(in) > size(conv_tmp_buf)))
|
|
throw error
|
|
{
|
|
"String too large for conversion at this time."
|
|
};
|
|
|
|
return b58::encode(out, b64::decode(conv_tmp_buf, in));
|
|
}
|
|
|
|
ircd::string_view
|
|
ircd::b58::tob64_unpadded(const mutable_buffer &out,
|
|
const string_view &in)
|
|
{
|
|
if(unlikely(b58::decode_size(in) > size(conv_tmp_buf)))
|
|
throw error
|
|
{
|
|
"String too large for conversion at this time."
|
|
};
|
|
|
|
return b64::encode_unpadded(out, b58::decode(conv_tmp_buf, in));
|
|
}
|
|
|
|
ircd::string_view
|
|
ircd::b58::tob64(const mutable_buffer &out,
|
|
const string_view &in)
|
|
{
|
|
if(unlikely(b58::decode_size(in) > size(conv_tmp_buf)))
|
|
throw error
|
|
{
|
|
"String too large for conversion at this time."
|
|
};
|
|
|
|
return b64::encode(out, b58::decode(conv_tmp_buf, in));
|
|
}
|
|
|
|
//
|
|
// Base58 decode
|
|
//
|
|
|
|
ircd::const_buffer
|
|
ircd::b58::decode(const mutable_buffer &buf,
|
|
const string_view &in)
|
|
{
|
|
auto p(begin(in));
|
|
size_t zeroes(0);
|
|
for(; p != end(in) && *p == '1'; ++p)
|
|
++zeroes;
|
|
|
|
const mutable_buffer out
|
|
{
|
|
data(buf) + zeroes, std::min(b58::decode_size(in), size(buf) - zeroes)
|
|
};
|
|
|
|
assert(size(out) + zeroes <= size(buf));
|
|
memset(data(out), 0, size(out));
|
|
|
|
size_t length(0);
|
|
for(size_t i(0); p != end(in); ++p, length = i, i = 0)
|
|
{
|
|
auto carry(dict.find(*p));
|
|
if(unlikely(carry == std::string::npos))
|
|
throw std::out_of_range
|
|
{
|
|
"Invalid base58 character"
|
|
};
|
|
|
|
for(auto it(rbegin(out)); (carry || i < length) && it != rend(out); ++it, i++)
|
|
{
|
|
carry += 58 * (*it);
|
|
*it = carry % 256;
|
|
carry /= 256;
|
|
}
|
|
}
|
|
|
|
auto it(begin(buf));
|
|
assert(it + zeroes + length <= end(buf));
|
|
for(; it != end(buf) && zeroes; *it++ = 0, --zeroes);
|
|
memmove(it, data(out) + (size(out) - length), length);
|
|
return const_buffer
|
|
{
|
|
begin(buf), it + length
|
|
};
|
|
}
|
|
|
|
//
|
|
// Base58 encode
|
|
//
|
|
|
|
ircd::string_view
|
|
ircd::b58::encode(const mutable_buffer &buf,
|
|
const const_buffer &in)
|
|
noexcept
|
|
{
|
|
auto p(begin(in));
|
|
size_t zeroes(0);
|
|
for(; p != end(in) && *p == 0; ++p)
|
|
++zeroes;
|
|
|
|
const mutable_buffer out
|
|
{
|
|
data(buf) + zeroes, std::min(b58::encode_size(in), size(buf) - zeroes)
|
|
};
|
|
|
|
assert(size(out) + zeroes <= size(buf));
|
|
memset(data(out), 0, size(out));
|
|
|
|
size_t length(0);
|
|
for(size_t i(0); p != end(in); ++p, length = i, i = 0)
|
|
{
|
|
size_t carry(*p);
|
|
for(auto it(rbegin(out)); (carry || i < length) && it != rend(out); ++it, i++)
|
|
{
|
|
carry += 256 * (*it);
|
|
*it = carry % 58;
|
|
carry /= 58;
|
|
}
|
|
}
|
|
|
|
auto it(begin(buf));
|
|
assert(it + zeroes + length <= end(buf));
|
|
for(; it != end(buf) && zeroes; *it++ = '1', --zeroes);
|
|
memmove(it, data(out) + (size(out) - length), length);
|
|
return string_view
|
|
{
|
|
begin(buf), std::transform(it, it + length, it, []
|
|
(const uint8_t &in)
|
|
{
|
|
return dict.at(in);
|
|
})
|
|
};
|
|
}
|