Function decode_integer 

pub fn decode_integer(
    data: &mut PerCodecData,
    lb: Option<i128>,
    ub: Option<i128>,
    is_extensible: bool,
) -> Result<(i128, bool), PerCodecError>

Decode an Integer

Given an Integer Specification with PER Visible Constraints, decode an Integer Value to obtain the integer value which will always be returned as an i128 value.

Note: The maximum (and minimum) value to be decoded is limited to an i128 value. For the protocols that are currently supported this limit is acceptable.

lb and ub are upper and lower bounds as determined by the PER Constraints (and hence can be None if no Constraints are not speicifed. is_extensible specifies whether the defined type is extensible (as per PER Constraints). Returned value is the value of the Integer (i128) and whether the value is outside the extension root (bool: true if value is outside the extension root.).