forked from ava-labs/coreth
-
Notifications
You must be signed in to change notification settings - Fork 0
/
generator.go
108 lines (99 loc) · 3.89 KB
/
generator.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
// (c) 2019-2020, Ava Labs, Inc.
//
// This file is a derived work, based on the go-ethereum library whose original
// notices appear below.
//
// It is distributed under a license compatible with the licensing terms of the
// original code from which it is derived.
//
// Much love to the original authors for their work.
// **********
// Copyright 2017 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 bloombits
import (
"errors"
"github.com/dim4egster/coreth/core/types"
)
var (
// errSectionOutOfBounds is returned if the user tried to add more bloom filters
// to the batch than available space, or if tries to retrieve above the capacity.
errSectionOutOfBounds = errors.New("section out of bounds")
// errBloomBitOutOfBounds is returned if the user tried to retrieve specified
// bit bloom above the capacity.
errBloomBitOutOfBounds = errors.New("bloom bit out of bounds")
)
// Generator takes a number of bloom filters and generates the rotated bloom bits
// to be used for batched filtering.
type Generator struct {
blooms [types.BloomBitLength][]byte // Rotated blooms for per-bit matching
sections uint // Number of sections to batch together
nextSec uint // Next section to set when adding a bloom
}
// NewGenerator creates a rotated bloom generator that can iteratively fill a
// batched bloom filter's bits.
func NewGenerator(sections uint) (*Generator, error) {
if sections%8 != 0 {
return nil, errors.New("section count not multiple of 8")
}
b := &Generator{sections: sections}
for i := 0; i < types.BloomBitLength; i++ {
b.blooms[i] = make([]byte, sections/8)
}
return b, nil
}
// AddBloom takes a single bloom filter and sets the corresponding bit column
// in memory accordingly.
func (b *Generator) AddBloom(index uint, bloom types.Bloom) error {
// Make sure we're not adding more bloom filters than our capacity
if b.nextSec >= b.sections {
return errSectionOutOfBounds
}
if b.nextSec != index {
return errors.New("bloom filter with unexpected index")
}
// Rotate the bloom and insert into our collection
byteIndex := b.nextSec / 8
bitIndex := byte(7 - b.nextSec%8)
for byt := 0; byt < types.BloomByteLength; byt++ {
bloomByte := bloom[types.BloomByteLength-1-byt]
if bloomByte == 0 {
continue
}
base := 8 * byt
b.blooms[base+7][byteIndex] |= ((bloomByte >> 7) & 1) << bitIndex
b.blooms[base+6][byteIndex] |= ((bloomByte >> 6) & 1) << bitIndex
b.blooms[base+5][byteIndex] |= ((bloomByte >> 5) & 1) << bitIndex
b.blooms[base+4][byteIndex] |= ((bloomByte >> 4) & 1) << bitIndex
b.blooms[base+3][byteIndex] |= ((bloomByte >> 3) & 1) << bitIndex
b.blooms[base+2][byteIndex] |= ((bloomByte >> 2) & 1) << bitIndex
b.blooms[base+1][byteIndex] |= ((bloomByte >> 1) & 1) << bitIndex
b.blooms[base][byteIndex] |= (bloomByte & 1) << bitIndex
}
b.nextSec++
return nil
}
// Bitset returns the bit vector belonging to the given bit index after all
// blooms have been added.
func (b *Generator) Bitset(idx uint) ([]byte, error) {
if b.nextSec != b.sections {
return nil, errors.New("bloom not fully generated yet")
}
if idx >= types.BloomBitLength {
return nil, errBloomBitOutOfBounds
}
return b.blooms[idx], nil
}