beyond-blockchain/bbclib-go

/*
Copyright (c) 2018 Zettant Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package bbclib

import (
    "bytes"
    "fmt"
)

/*
BBcCrossRef definition

CrossRef stands for CrossReference, which holds information in other domain for inter-domain collaboration of transaction authenticity.

"IDLength" is not included in a packed data. It is for internal use only.

"DomainID" is the identifier of a domain and the length of the ID must be 256 bits (=32 bytes).
"TransactionID" is that of transaction object in other domain (specified by the DomainID).
*/
type (
    BBcCrossRef struct {
        IdLengthConf  *BBcIdConfig
        Version          uint32
        DomainID      []byte
        TransactionID []byte
    }
)

// The length of DomainID must be 256-bit in any domain.
const (
    DomainIDLength = 32
)

// Stringer outputs the content of the object
func (p *BBcCrossRef) Stringer() string {
    ret := "Cross_Ref:\n"
    ret += fmt.Sprintf("  domain_id: %x\n", p.DomainID)
    ret += fmt.Sprintf("  transaction_id: %x\n", p.TransactionID)
    return ret
}

// Set ID length configuration
func (p *BBcCrossRef) SetIdLengthConf(conf * BBcIdConfig) {
    p.IdLengthConf = conf
}

// Add sets essential information to the BBcCrossRef object
func (p *BBcCrossRef) Add(domainID *[]byte, txid *[]byte) {
    if domainID != nil {
        p.DomainID = make([]byte, DomainIDLength)
        copy(p.DomainID, *domainID)
    }
    if txid != nil {
        p.TransactionID = make([]byte, p.IdLengthConf.TransactionIdLength)
        copy(p.TransactionID, (*txid)[:p.IdLengthConf.TransactionIdLength])
    }
}

// Pack returns binary data from the BBcCrossRef object
func (p *BBcCrossRef) Pack() ([]byte, error) {
    buf := new(bytes.Buffer)

    PutBigInt(buf, &p.DomainID, DomainIDLength)
    PutBigInt(buf, &p.TransactionID, p.IdLengthConf.TransactionIdLength)

    return buf.Bytes(), nil
}

// Unpack the binary data to the BBcCrossRef object
func (p *BBcCrossRef) Unpack(dat *[]byte) error {
    var err error
    buf := bytes.NewBuffer(*dat)

    p.DomainID, _, err = GetBigInt(buf)
    if err != nil {
        return err
    }

    p.TransactionID, _, err = GetBigInt(buf)
    if err != nil {
        return err
    }

    return nil
}