迅雷链合约abi编码工具，go语言版本
函数 func JSON(reader io.Reader) (ABI, error) 用于构造ABI对象，参数reader为合约的函数列表。
示例：
const jsondata = `
[
{ "type" : "function", "name" : "balance", "constant" : true },
{ "type" : "function", "name" : "send", "constant" : false, "inputs" : [ { "name" : "amount", "type" : "uint256" } ] }
]`
abi, err := JSON(strings.NewReader(jsondata))
if err != nil {
t.Error(err)
t.FailNow()
}
ABI对象函数func (abi ABI) Pack(name string, args ...interface{}) ([]byte, error)用于生成ABI编码，参数name为调用的合约函数名，可变参数args为可选的合约调用参数。
示例：
if _, err := abi.Pack("balance", 1); err == nil {
t.Error("expected error for balance(1)")
}
ABI对象函数func (abi ABI) Unpack(v interface{}, name string, output []byte) (err error)用于解码合约掉的返回，参数v为合约函数返回的数据结构，name为调用合约函数名，output为合约输出。
示例：
const hexdata = `000000000000000000000000376c47978271565f56deb45495afa69e59c16ab200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000060000000000000000000000000000000000000000000000000000000000000000158`
data, err := hex.DecodeString(hexdata)
type ReceivedEvent struct {
Address common.Address
Amount *big.Int
Memo []byte
}
var ev ReceivedEvent
err = abi.Unpack(&ev, "received", data)
if err != nil {
t.Error(err)
} else {
t.Logf("len(data): %d; received event: %+v", len(data), ev)
}