1package common
 2
 3import (
 4	"encoding/binary"
 5	"fmt"
 6	"math/big"
 7	"time"
 8
 9	ethCommon "github.com/ethereum/go-ethereum/common"
10)
11
12// tokenIDBytesLen defines the length of the TokenID byte array representation
13const tokenIDBytesLen = 4
14
15// Token is a struct that represents an Ethereum token that is supported in Hermez network
16type Token struct {
17	TokenID     TokenID           `meddler:"token_id"`
18	EthBlockNum int64             `meddler:"eth_block_num"` // Ethereum block number in which this token was registered
19	EthAddr     ethCommon.Address `meddler:"eth_addr"`
20	Name        string            `meddler:"name"`
21	Symbol      string            `meddler:"symbol"`
22	Decimals    uint64            `meddler:"decimals"`
23	USD         float64           `meddler:"usd,zeroisnull"`
24	USDUpdate   time.Time         `meddler:"usd_update,utctimez"`
25}
26
27// TokenInfo provides the price of the token in USD
28type TokenInfo struct {
29	TokenID     uint32
30	Value       float64
31	LastUpdated time.Time
32}
33
34// TokenID is the unique identifier of the token, as set in the smart contract
35type TokenID uint32 // current implementation supports up to 2^32 tokens
36
37// Bytes returns a byte array of length 4 representing the TokenID
38func (t TokenID) Bytes() []byte {
39	var tokenIDBytes [4]byte
40	binary.BigEndian.PutUint32(tokenIDBytes[:], uint32(t))
41	return tokenIDBytes[:]
42}
43
44// BigInt returns the *big.Int representation of the TokenID
45func (t TokenID) BigInt() *big.Int {
46	return big.NewInt(int64(t))
47}
48
49// TokenIDFromBytes returns TokenID from a byte array
50func TokenIDFromBytes(b []byte) (TokenID, error) {
51	if len(b) != tokenIDBytesLen {
52		return 0, fmt.Errorf("can not parse TokenID, bytes len %d, expected 4", len(b))
53	}
54	tid := binary.BigEndian.Uint32(b[:4])
55	return TokenID(tid), nil
56}