import gdb


class KstdVectorPrinter(gdb.ValuePrinter):
    def __init__(self, val):
        self.__val = val
        self.__size = int(val["m_size"])
        self.__capacity = int(val["m_capacity"])

    def to_string(self):
        return f"vector of length {self.__size}, capacity {self.__capacity}"

    def children(self):
        data_pointer = self.__val["m_data"]
        for i in range(self.__size):
            yield (f"[{i}]", (data_pointer + i).dereference())

    def child(self, n):
        if n < self.__size:
            return (f"[{n}]", (self.__val["m_data"] + n).dereference())
        else:
            raise gdb.MemoryError("Index out of range")

    def display_hint(self):
        return "array"

    def num_children(self):
        return self.__size