mirror of https://github.com/ethereum/go-ethereum
compression/rle: delete RLE compression (#16468)
Felix Lange
7 years ago
committed by
GitHub
parent
315b9b18df
commit
0fac705ed0
@ -1,101 +0,0 @@ |
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// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser 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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//
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// The go-ethereum library 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 Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package rle implements the run-length encoding used for Ethereum data.
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package rle |
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import ( |
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"bytes" |
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"errors" |
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"github.com/ethereum/go-ethereum/crypto" |
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) |
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const ( |
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token byte = 0xfe |
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emptyShaToken = 0xfd |
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emptyListShaToken = 0xfe |
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tokenToken = 0xff |
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) |
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var empty = crypto.Keccak256([]byte("")) |
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var emptyList = crypto.Keccak256([]byte{0x80}) |
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func Decompress(dat []byte) ([]byte, error) { |
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buf := new(bytes.Buffer) |
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for i := 0; i < len(dat); i++ { |
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if dat[i] == token { |
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if i+1 < len(dat) { |
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switch dat[i+1] { |
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case emptyShaToken: |
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buf.Write(empty) |
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case emptyListShaToken: |
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buf.Write(emptyList) |
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case tokenToken: |
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buf.WriteByte(token) |
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default: |
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buf.Write(make([]byte, int(dat[i+1]-2))) |
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} |
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i++ |
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} else { |
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return nil, errors.New("error reading bytes. token encountered without proceeding bytes") |
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} |
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} else { |
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buf.WriteByte(dat[i]) |
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} |
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} |
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return buf.Bytes(), nil |
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} |
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func compressChunk(dat []byte) (ret []byte, n int) { |
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switch { |
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case dat[0] == token: |
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return []byte{token, tokenToken}, 1 |
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case len(dat) > 1 && dat[0] == 0x0 && dat[1] == 0x0: |
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j := 0 |
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for j <= 254 && j < len(dat) { |
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if dat[j] != 0 { |
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break |
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} |
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j++ |
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} |
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return []byte{token, byte(j + 2)}, j |
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case len(dat) >= 32: |
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if dat[0] == empty[0] && bytes.Equal(dat[:32], empty) { |
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return []byte{token, emptyShaToken}, 32 |
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} else if dat[0] == emptyList[0] && bytes.Equal(dat[:32], emptyList) { |
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return []byte{token, emptyListShaToken}, 32 |
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} |
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fallthrough |
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default: |
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return dat[:1], 1 |
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} |
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} |
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func Compress(dat []byte) []byte { |
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buf := new(bytes.Buffer) |
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i := 0 |
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for i < len(dat) { |
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b, n := compressChunk(dat[i:]) |
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buf.Write(b) |
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i += n |
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} |
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return buf.Bytes() |
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} |
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@ -1,50 +0,0 @@ |
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// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
|
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// it under the terms of the GNU Lesser 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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//
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// The go-ethereum library 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 Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package rle |
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import ( |
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"testing" |
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checker "gopkg.in/check.v1" |
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) |
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func Test(t *testing.T) { checker.TestingT(t) } |
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type CompressionRleSuite struct{} |
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var _ = checker.Suite(&CompressionRleSuite{}) |
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func (s *CompressionRleSuite) TestDecompressSimple(c *checker.C) { |
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exp := []byte{0xc5, 0xd2, 0x46, 0x1, 0x86, 0xf7, 0x23, 0x3c, 0x92, 0x7e, 0x7d, 0xb2, 0xdc, 0xc7, 0x3, 0xc0, 0xe5, 0x0, 0xb6, 0x53, 0xca, 0x82, 0x27, 0x3b, 0x7b, 0xfa, 0xd8, 0x4, 0x5d, 0x85, 0xa4, 0x70} |
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res, err := Decompress([]byte{token, 0xfd}) |
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c.Assert(err, checker.IsNil) |
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c.Assert(res, checker.DeepEquals, exp) |
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exp = []byte{0x56, 0xe8, 0x1f, 0x17, 0x1b, 0xcc, 0x55, 0xa6, 0xff, 0x83, 0x45, 0xe6, 0x92, 0xc0, 0xf8, 0x6e, 0x5b, 0x48, 0xe0, 0x1b, 0x99, 0x6c, 0xad, 0xc0, 0x1, 0x62, 0x2f, 0xb5, 0xe3, 0x63, 0xb4, 0x21} |
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res, err = Decompress([]byte{token, 0xfe}) |
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c.Assert(err, checker.IsNil) |
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c.Assert(res, checker.DeepEquals, exp) |
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res, err = Decompress([]byte{token, 0xff}) |
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c.Assert(err, checker.IsNil) |
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c.Assert(res, checker.DeepEquals, []byte{token}) |
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res, err = Decompress([]byte{token, 12}) |
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c.Assert(err, checker.IsNil) |
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c.Assert(res, checker.DeepEquals, make([]byte, 10)) |
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} |
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