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path: root/ethchain/bloom9.go
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package ethchain

import (
    "math/big"

    "github.com/ethereum/go-ethereum/ethstate"
    "github.com/ethereum/go-ethereum/ethutil"
)

func CreateBloom(block *Block) []byte {
    bin := new(big.Int)
    bin.Or(bin, bloom9(block.Coinbase))
    for _, receipt := range block.Receipts() {
        bin.Or(bin, LogsBloom(receipt.logs))
    }

    return bin.Bytes()
}

func LogsBloom(logs ethstate.Logs) *big.Int {
    bin := new(big.Int)
    for _, log := range logs {
        data := [][]byte{log.Address}
        for _, topic := range log.Topics {
            data = append(data, topic)
        }

        if log.Data != nil {
            data = append(data, log.Data)
        }

        for _, b := range data {
            bin.Or(bin, bloom9(b))
        }
    }

    return bin
}

func bloom9(b []byte) *big.Int {
    r := new(big.Int)
    for _, i := range []int{0, 2, 4} {
        t := big.NewInt(1)
        r.Or(r, t.Lsh(t, uint(b[i+1])+256*(uint(b[i])&1)))
    }

    return r
}

func BloomLookup(bin, topic []byte) bool {
    bloom := ethutil.BigD(bin)
    cmp := bloom9(topic)

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