path: root/core/types/bloom9.go

// 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 types

import (
    "fmt"
    "math/big"

    "github.com/dexon-foundation/dexon/common/hexutil"
    "github.com/dexon-foundation/dexon/crypto"
)

type bytesBacked interface {
    Bytes() []byte
}

const (
    // BloomByteLength represents the number of bytes used in a header log bloom.
    BloomByteLength = 256

    // BloomBitLength represents the number of bits used in a header log bloom.
    BloomBitLength = 8 * BloomByteLength
)

// Bloom represents a 2048 bit bloom filter.
type Bloom [BloomByteLength]byte

// BytesToBloom converts a byte slice to a bloom filter.
// It panics if b is not of suitable size.
func BytesToBloom(b []byte) Bloom {
    var bloom Bloom
    bloom.SetBytes(b)
    return bloom
}

// SetBytes sets the content of b to the given bytes.
// It panics if d is not of suitable size.
func (b *Bloom) SetBytes(d []byte) {
    if len(b) < len(d) {
        panic(fmt.Sprintf("bloom bytes too big %d %d", len(b), len(d)))
    }
    copy(b[BloomByteLength-len(d):], d)
}

// Add adds d to the filter. Future calls of Test(d) will return true.
func (b *Bloom) Add(d *big.Int) {
    bin := new(big.Int).SetBytes(b[:])
    bin.Or(bin, bloom9(d.Bytes()))
    b.SetBytes(bin.Bytes())
}

// Big converts b to a big integer.
func (b Bloom) Big() *big.Int {
    return new(big.Int).SetBytes(b[:])
}

func (b Bloom) Bytes() []byte {
    return b[:]
}

func (b Bloom) Test(test *big.Int) bool {
    return BloomLookup(b, test)
}

func (b Bloom) TestBytes(test []byte) bool {
    return b.Test(new(big.Int).SetBytes(test))

}

// MarshalText encodes b as a hex string with 0x prefix.
func (b Bloom) MarshalText() ([]byte, error) {
    return hexutil.Bytes(b[:]).MarshalText()
}

// UnmarshalText b as a hex string with 0x prefix.
func (b *Bloom) UnmarshalText(input []byte) error {
    return hexutil.UnmarshalFixedText("Bloom", input, b[:])
}

func CreateBloom(receipts Receipts) Bloom {
    bin := new(big.Int)
    for _, receipt := range receipts {
        bin.Or(bin, LogsBloom(receipt.Logs))
    }

    return BytesToBloom(bin.Bytes())
}

func LogsBloom(logs []*Log) *big.Int {
    bin := new(big.Int)
    for _, log := range logs {
        bin.Or(bin, bloom9(log.Address.Bytes()))
        for _, b := range log.Topics {
            bin.Or(bin, bloom9(b[:]))
        }
    }

    return bin
}

func bloom9(b []byte) *big.Int {
    b = crypto.Keccak256(b)

    r := new(big.Int)

    for i := 0; i < 6; i += 2 {
        t := big.NewInt(1)
        b := (uint(b[i+1]) + (uint(b[i]) << 8)) & 2047
        r.Or(r, t.Lsh(t, b))
    }

    return r
}

var Bloom9 = bloom9

func BloomLookup(bin Bloom, topic bytesBacked) bool {
    bloom := bin.Big()
    cmp := bloom9(topic.Bytes())

    return bloom.And(bloom, cmp).Cmp(cmp) == 0
}