1package common
 2
 3import (
 4	"encoding/binary"
 5	"fmt"
 6	"math/big"
 7
 8	ethCommon "github.com/ethereum/go-ethereum/common"
 9)
10
11const batchNumBytesLen = 4
12
13// Batch is a struct that represents Hermez network batch
14type Batch struct {
15	BatchNum      BatchNum             `meddler:"batch_num"`
16	EthBlockNum   int64                `meddler:"eth_block_num"` // Ethereum block in which the batch is forged
17	ForgerAddr    ethCommon.Address    `meddler:"forger_addr"`   // TODO: Should this be retrieved via slot reference?
18	CollectedFees map[TokenID]*big.Int `meddler:"fees_collected,json"`
19	StateRoot     Hash                 `meddler:"state_root"`
20	NumAccounts   int                  `meddler:"num_accounts"`
21	ExitRoot      Hash                 `meddler:"exit_root"`
22	ForgeL1TxsNum int64                `meddler:"forge_l1_txs_num"` // optional, Only when the batch forges L1 txs. Identifier that corresponds to the group of L1 txs forged in the current batch.
23	SlotNum       SlotNum              `meddler:"slot_num"`         // Slot in which the batch is forged
24}
25
26// BatchNum identifies a batch
27type BatchNum uint32
28
29// Bytes returns a byte array of length 4 representing the BatchNum
30func (bn BatchNum) Bytes() []byte {
31	var batchNumBytes [4]byte
32	binary.LittleEndian.PutUint32(batchNumBytes[:], uint32(bn))
33	return batchNumBytes[:]
34}
35
36// BatchNumFromBytes returns BatchNum from a []byte
37func BatchNumFromBytes(b []byte) (BatchNum, error) {
38	if len(b) != batchNumBytesLen {
39		return 0, fmt.Errorf("can not parse BatchNumFromBytes, bytes len %d, expected 4", len(b))
40	}
41	batchNum := binary.LittleEndian.Uint32(b[:4])
42	return BatchNum(batchNum), nil
43}