mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
92 lines
2.5 KiB
C++
92 lines
2.5 KiB
C++
/*
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This file is part of solidity.
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solidity is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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solidity is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with solidity. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libsolutil/IpfsHash.h>
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#include <libsolutil/Assertions.h>
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#include <libsolutil/Exceptions.h>
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#include <libsolutil/picosha2.h>
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#include <libsolutil/CommonData.h>
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using namespace std;
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using namespace solidity;
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using namespace solidity::util;
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namespace
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{
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bytes varintEncoding(size_t _n)
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{
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bytes encoded;
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while (_n > 0x7f)
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{
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encoded.emplace_back(uint8_t(0x80 | (_n & 0x7f)));
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_n >>= 7;
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}
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encoded.emplace_back(_n);
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return encoded;
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}
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string base58Encode(bytes const& _data)
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{
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static string const alphabet{"123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"};
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bigint data(toHex(_data, HexPrefix::Add));
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string output;
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while (data)
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{
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output += alphabet[size_t(data % alphabet.size())];
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data /= alphabet.size();
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}
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reverse(output.begin(), output.end());
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return output;
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}
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}
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bytes solidity::util::ipfsHash(string _data)
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{
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assertThrow(_data.length() < 1024 * 256, DataTooLong, "IPFS hash for large (chunked) files not yet implemented.");
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bytes lengthAsVarint = varintEncoding(_data.size());
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bytes protobufEncodedData;
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// Type: File
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protobufEncodedData += bytes{0x08, 0x02};
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if (!_data.empty())
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{
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// Data (length delimited bytes)
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protobufEncodedData += bytes{0x12};
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protobufEncodedData += lengthAsVarint;
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protobufEncodedData += asBytes(std::move(_data));
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}
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// filesize: length as varint
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protobufEncodedData += bytes{0x18} + lengthAsVarint;
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// PBDag:
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// Data: (length delimited bytes)
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size_t protobufLength = protobufEncodedData.size();
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bytes blockData = bytes{0x0a} + varintEncoding(protobufLength) + std::move(protobufEncodedData);
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// TODO Handle "large" files with multiple blocks
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// Multihash: sha2-256, 256 bits
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bytes hash = bytes{0x12, 0x20} + picosha2::hash256(std::move(blockData));
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return hash;
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}
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string solidity::util::ipfsHashBase58(string _data)
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{
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return base58Encode(ipfsHash(std::move(_data)));
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}
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