compression/rle: delete RLE compression

RLE compression was used briefly but removed before the Frontier
release. The algorithm was never documented anywhere, the implementation
was inefficient and buggy. It's time to remove this package.

compression/rle/read_write.go

@@ -1,101 +0,0 @@
-// Copyright 2014 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-// Package rle implements the run-length encoding used for Ethereum data.
-package rle
-
-import (
-	"bytes"
-	"errors"
-
-	"github.com/ethereum/go-ethereum/crypto"
-)
-
-const (
-	token             byte = 0xfe
-	emptyShaToken          = 0xfd
-	emptyListShaToken      = 0xfe
-	tokenToken             = 0xff
-)
-
-var empty = crypto.Keccak256([]byte(""))
-var emptyList = crypto.Keccak256([]byte{0x80})
-
-func Decompress(dat []byte) ([]byte, error) {
-	buf := new(bytes.Buffer)
-
-	for i := 0; i < len(dat); i++ {
-		if dat[i] == token {
-			if i+1 < len(dat) {
-				switch dat[i+1] {
-				case emptyShaToken:
-					buf.Write(empty)
-				case emptyListShaToken:
-					buf.Write(emptyList)
-				case tokenToken:
-					buf.WriteByte(token)
-				default:
-					buf.Write(make([]byte, int(dat[i+1]-2)))
-				}
-				i++
-			} else {
-				return nil, errors.New("error reading bytes. token encountered without proceeding bytes")
-			}
-		} else {
-			buf.WriteByte(dat[i])
-		}
-	}
-
-	return buf.Bytes(), nil
-}
-
-func compressChunk(dat []byte) (ret []byte, n int) {
-	switch {
-	case dat[0] == token:
-		return []byte{token, tokenToken}, 1
-	case len(dat) > 1 && dat[0] == 0x0 && dat[1] == 0x0:
-		j := 0
-		for j <= 254 && j < len(dat) {
-			if dat[j] != 0 {
-				break
-			}
-			j++
-		}
-		return []byte{token, byte(j + 2)}, j
-	case len(dat) >= 32:
-		if dat[0] == empty[0] && bytes.Equal(dat[:32], empty) {
-			return []byte{token, emptyShaToken}, 32
-		} else if dat[0] == emptyList[0] && bytes.Equal(dat[:32], emptyList) {
-			return []byte{token, emptyListShaToken}, 32
-		}
-		fallthrough
-	default:
-		return dat[:1], 1
-	}
-}
-
-func Compress(dat []byte) []byte {
-	buf := new(bytes.Buffer)
-
-	i := 0
-	for i < len(dat) {
-		b, n := compressChunk(dat[i:])
-		buf.Write(b)
-		i += n
-	}
-
-	return buf.Bytes()
-}

compression/rle/read_write_test.go

@@ -1,50 +0,0 @@
-// Copyright 2014 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-package rle
-
-import (
-	"testing"
-
-	checker "gopkg.in/check.v1"
-)
-
-func Test(t *testing.T) { checker.TestingT(t) }
-
-type CompressionRleSuite struct{}
-
-var _ = checker.Suite(&CompressionRleSuite{})
-
-func (s *CompressionRleSuite) TestDecompressSimple(c *checker.C) {
-	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}
-	res, err := Decompress([]byte{token, 0xfd})
-	c.Assert(err, checker.IsNil)
-	c.Assert(res, checker.DeepEquals, exp)
-
-	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}
-	res, err = Decompress([]byte{token, 0xfe})
-	c.Assert(err, checker.IsNil)
-	c.Assert(res, checker.DeepEquals, exp)
-
-	res, err = Decompress([]byte{token, 0xff})
-	c.Assert(err, checker.IsNil)
-	c.Assert(res, checker.DeepEquals, []byte{token})
-
-	res, err = Decompress([]byte{token, 12})
-	c.Assert(err, checker.IsNil)
-	c.Assert(res, checker.DeepEquals, make([]byte, 10))
-
-}

ethdb/database.go

@@ -91,9 +91,6 @@ func (db *LDBDatabase) Path() string {
 
 // Put puts the given key / value to the queue
 func (db *LDBDatabase) Put(key []byte, value []byte) error {
-	// Generate the data to write to disk, update the meter and write
-	//value = rle.Compress(value)
-
 	return db.db.Put(key, value, nil)
 }
 
@@ -103,18 +100,15 @@ func (db *LDBDatabase) Has(key []byte) (bool, error) {
 
 // Get returns the given key if it's present.
 func (db *LDBDatabase) Get(key []byte) ([]byte, error) {
-	// Retrieve the key and increment the miss counter if not found
 	dat, err := db.db.Get(key, nil)
 	if err != nil {
 		return nil, err
 	}
 	return dat, nil
-	//return rle.Decompress(dat)
 }
 
 // Delete deletes the key from the queue and database
 func (db *LDBDatabase) Delete(key []byte) error {
-	// Execute the actual operation
 	return db.db.Delete(key, nil)
 }
 

swarm/storage/database.go

@@ -22,7 +22,6 @@ package storage
 import (
 	"fmt"
 
-	"github.com/ethereum/go-ethereum/compression/rle"
 	"github.com/syndtr/goleveldb/leveldb"
 	"github.com/syndtr/goleveldb/leveldb/iterator"
 	"github.com/syndtr/goleveldb/leveldb/opt"
@@ -32,7 +31,6 @@ const openFileLimit = 128
 
 type LDBDatabase struct {
 	db *leveldb.DB
-	comp bool
 }
 
 func NewLDBDatabase(file string) (*LDBDatabase, error) {
@@ -42,16 +40,12 @@ func NewLDBDatabase(file string) (*LDBDatabase, error) {
 		return nil, err
 	}
 
-	database := &LDBDatabase{db: db, comp: false}
+	database := &LDBDatabase{db: db}
 
 	return database, nil
 }
 
 func (self *LDBDatabase) Put(key []byte, value []byte) {
-	if self.comp {
-		value = rle.Compress(value)
-	}
-
 	err := self.db.Put(key, value, nil)
 	if err != nil {
 		fmt.Println("Error put", err)
@@ -63,11 +57,6 @@ func (self *LDBDatabase) Get(key []byte) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-
-	if self.comp {
-		return rle.Decompress(dat)
-	}
-
 	return dat, nil
 }