64 lines
2.1 KiB
Go
64 lines
2.1 KiB
Go
// Copyright 2017 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 bloombits
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import (
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"github.com/ethereum/go-ethereum/core/types"
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)
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const BloomLength = 2048
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// BloomBitsCreator takes SectionSize number of header bloom filters and calculates the bloomBits vectors of the section
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type BloomBitsCreator struct {
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blooms [BloomLength][]byte
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sectionSize, bitIndex uint64
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}
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func NewBloomBitsCreator(sectionSize uint64) *BloomBitsCreator {
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b := &BloomBitsCreator{sectionSize: sectionSize}
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for i, _ := range b.blooms {
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b.blooms[i] = make([]byte, sectionSize/8)
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}
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return b
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}
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// AddHeaderBloom takes a single bloom filter and sets the corresponding bit column in memory accordingly
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func (b *BloomBitsCreator) AddHeaderBloom(bloom types.Bloom) {
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if b.bitIndex >= b.sectionSize {
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panic("too many header blooms added")
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}
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byteIdx := b.bitIndex / 8
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bitMask := byte(1) << byte(7-b.bitIndex%8)
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for bloomBitIdx, _ := range b.blooms {
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bloomByteIdx := BloomLength/8 - 1 - bloomBitIdx/8
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bloomBitMask := byte(1) << byte(bloomBitIdx%8)
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if (bloom[bloomByteIdx] & bloomBitMask) != 0 {
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b.blooms[bloomBitIdx][byteIdx] |= bitMask
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}
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}
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b.bitIndex++
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}
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// GetBitVector returns the bit vector belonging to the given bit index after header blooms have been added
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func (b *BloomBitsCreator) GetBitVector(idx uint) []byte {
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if b.bitIndex != b.sectionSize {
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panic("not enough header blooms added")
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}
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return b.blooms[idx][:]
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}
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