82 lines
2.9 KiB
C++
82 lines
2.9 KiB
C++
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/* Copyright (c) 2017 Pieter Wuille
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <sidechain/bitcoin/segwit_addr.hpp>
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#include <sidechain/bitcoin/bech32.hpp>
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namespace
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{
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typedef std::vector<uint8_t> data;
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/** Convert from one power-of-2 number base to another. */
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template<int frombits, int tobits, bool pad>
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bool convertbits(data& out, const data& in) {
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int acc = 0;
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int bits = 0;
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const int maxv = (1 << tobits) - 1;
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const int max_acc = (1 << (frombits + tobits - 1)) - 1;
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for (size_t i = 0; i < in.size(); ++i) {
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int value = in[i];
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acc = ((acc << frombits) | value) & max_acc;
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bits += frombits;
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while (bits >= tobits) {
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bits -= tobits;
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out.push_back((acc >> bits) & maxv);
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}
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}
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if (pad) {
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if (bits) out.push_back((acc << (tobits - bits)) & maxv);
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} else if (bits >= frombits || ((acc << (tobits - bits)) & maxv)) {
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return false;
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}
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return true;
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}
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}
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namespace sidechain { namespace segwit_addr {
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/** Decode a SegWit address. */
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std::pair<int, data> decode(const std::string& hrp, const std::string& addr) {
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std::pair<std::string, data> dec = sidechain::bech32::Decode(addr);
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if (dec.first != hrp || dec.second.size() < 1) return std::make_pair(-1, data());
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data conv;
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if (!convertbits<5, 8, false>(conv, data(dec.second.begin() + 1, dec.second.end())) ||
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conv.size() < 2 || conv.size() > 40 || dec.second[0] > 16 || (dec.second[0] == 0 &&
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conv.size() != 20 && conv.size() != 32)) {
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return std::make_pair(-1, data());
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}
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return std::make_pair(dec.second[0], conv);
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}
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/** Encode a SegWit address. */
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std::string encode(const std::string& hrp, int witver, const data& witprog) {
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data enc;
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enc.push_back(witver);
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convertbits<8, 5, true>(enc, witprog);
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std::string ret = sidechain::bech32::Encode(hrp, enc);
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if (decode(hrp, ret).first == -1) return "";
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return ret;
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}
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} }
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