BitcoinScirpt may be not able to match Multiple signature script

[zhaojiewen]

In BitcoinScirpt Class,“matchMultisig” method below：

public func matchMultisig() -> ([PublicKey], required: Int)? {
if bytes.count < 1 || bytes.last != OpCode.OP_CHECKMULTISIG {
return nil
}

    var keys = [PublicKey]()

    var it = bytes.startIndex
    guard let (opcode, _) = getScriptOp(index: &it), OpCode.isSmallInteger(opcode) else {
        return nil
    }
    let required = BitcoinScript.decodeNumber(opcode: opcode)
    while case .some(_, let data?) = getScriptOp(index: &it), let key = PublicKey(data: data) {
        keys.append(key)
    }
    if !OpCode.isSmallInteger(opcode) {
        return nil
    }

    let expectedCount = BitcoinScript.decodeNumber(opcode: opcode)
    if keys.count != expectedCount || expectedCount < required {
        return nil
    }
    if it + 1 != bytes.endIndex {
        return nil
    }

    return (keys, required)
}

---

'expectedCount' is equal to 'required', so below code must be entered, and return nil:
if keys.count != expectedCount || expectedCount < required {
return nil
}

[hewigovens]

Hi, could you please submit a PR?