BitcoinScript may not get script size

[zhaojiewen]

In BitcoinScript Extention,function "func getScriptOp(index: inout Int) -> (opcode: UInt8, operand: Data?)? " below:
func getScriptOp(index: inout Int) -> (opcode: UInt8, operand: Data?)? {
// Read instruction
if index >= bytes.endIndex {
return nil
}

    let opcode = bytes[index]
    index += 1

    if opcode > OpCode.OP_PUSHDATA4 {
        return (opcode: opcode, operand: nil)
    }

    // Immediate operand
    var size = 0
    if opcode < OpCode.OP_PUSHDATA1 {
        size = Int(opcode)
    } else if opcode == OpCode.OP_PUSHDATA1 {
        if bytes.endIndex - index < 1 {
            return nil
        }
        size = index
        index += 1
    } else if opcode == OpCode.OP_PUSHDATA2 {
        if bytes.endIndex - index < 2 {
            return nil
        }
        size = Int(readLE16(at: index))
        index += 2
    } else if opcode == OpCode.OP_PUSHDATA4 {
        if bytes.endIndex - index < 4 {
            return nil
        }
        size = Int(readLE32(at: index))
        index += 4
    }
    if bytes.endIndex - index < size {
        return nil
    }
    let operand = data[index ..< index + size]
    index += size

    return (opcode: opcode, operand: operand)
}

---

when opcode == OpCode.OP_PUSHDATA1, that 'size = index' should be replaced by 'size = Int(bytes[index])'

[hewigovens]

Hi, could you please submit a PR?