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Diffstat (limited to 'core/bloombits/utils.go')
-rw-r--r-- | core/bloombits/utils.go | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/core/bloombits/utils.go b/core/bloombits/utils.go new file mode 100644 index 000000000..d0755cb65 --- /dev/null +++ b/core/bloombits/utils.go @@ -0,0 +1,63 @@ +// 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 ( + "github.com/ethereum/go-ethereum/core/types" +) + +const BloomLength = 2048 + +// BloomBitsCreator takes SectionSize number of header bloom filters and calculates the bloomBits vectors of the section +type BloomBitsCreator struct { + blooms [BloomLength][]byte + sectionSize, bitIndex uint64 +} + +func NewBloomBitsCreator(sectionSize uint64) *BloomBitsCreator { + b := &BloomBitsCreator{sectionSize: sectionSize} + for i, _ := range b.blooms { + b.blooms[i] = make([]byte, sectionSize/8) + } + return b +} + +// AddHeaderBloom takes a single bloom filter and sets the corresponding bit column in memory accordingly +func (b *BloomBitsCreator) AddHeaderBloom(bloom types.Bloom) { + if b.bitIndex >= b.sectionSize { + panic("too many header blooms added") + } + + byteIdx := b.bitIndex / 8 + bitMask := byte(1) << byte(7-b.bitIndex%8) + for bloomBitIdx, _ := range b.blooms { + bloomByteIdx := BloomLength/8 - 1 - bloomBitIdx/8 + bloomBitMask := byte(1) << byte(bloomBitIdx%8) + if (bloom[bloomByteIdx] & bloomBitMask) != 0 { + b.blooms[bloomBitIdx][byteIdx] |= bitMask + } + } + b.bitIndex++ +} + +// GetBitVector returns the bit vector belonging to the given bit index after header blooms have been added +func (b *BloomBitsCreator) GetBitVector(idx uint) []byte { + if b.bitIndex != b.sectionSize { + panic("not enough header blooms added") + } + + return b.blooms[idx][:] +} |