MODULE ModMain

!   This module contains routines to illustrate internal compiler errors.

    IMPLICIT NONE       ! Enforce explicit typing of all variables

    PUBLIC :: Proc_Main_I
    PUBLIC :: Proc_Main_II

    PRIVATE

    ABSTRACT INTERFACE
        !----------------------------------------------------------------------
        FUNCTION Proc_CB_ABST(ByteArr, Offset) RESULT(Res)
            !^ an abstract procedure for callback routines.
            IMPORT
            INTEGER(KIND=1), INTENT(IN) :: ByteArr(0:)
            INTEGER,         INTENT(IN) :: Offset
            INTEGER(KIND=8)             :: Res
        END FUNCTION Proc_CB_ABST
        !----------------------------------------------------------------------
    END INTERFACE
    INTERFACE
        !----------------------------------------------------------------------
        MODULE FUNCTION Proc_Main_I(Input, Algo) RESULT(Output)
            !^ main procedure I.
            INTEGER(KIND=1), INTENT(IN) :: Input(:)
            INTEGER,         INTENT(IN) :: Algo
            INTEGER(KIND=8)             :: Output
        END FUNCTION
        !----------------------------------------------------------------------
        MODULE FUNCTION Proc_Main_II(Input, Algo) RESULT(Output)
            !^ main procedure I.
            INTEGER(KIND=1), INTENT(IN) :: Input(:)
            INTEGER,         INTENT(IN) :: Algo
            INTEGER(KIND=8)             :: Output
        END FUNCTION
        !----------------------------------------------------------------------
    END INTERFACE

    CONTAINS

    !**************************************************************************
    FUNCTION MaskI64(ByteVal) RESULT(LongVal)
        ! arguments
        INTEGER(KIND=1), INTENT(IN) :: ByteVal
        INTEGER(KIND=8)             :: LongVal
        ! execution
        LongVal = IAND(INT(ByteVal, KIND=8), Z'00000000000000FF')
        RETURN
    END FUNCTION MaskI64
    !**************************************************************************
    FUNCTION Proc_CB_I(ByteArr, Offset) RESULT(Res)
        !^ callback routine - implementation#1.
        ! arguments
        INTEGER(KIND=1), INTENT(IN) :: ByteArr(0:)
        INTEGER,         INTENT(IN) :: Offset
        INTEGER(KIND=8)             :: Res
        ! execution
        Res = 0
        CALL MVBITS(MaskI64(ByteArr(Offset)),   0, 8, Res,  0)
        CALL MVBITS(MaskI64(ByteArr(Offset+1)), 0, 8, Res,  8)
        CALL MVBITS(MaskI64(ByteArr(Offset+2)), 0, 8, Res, 16)
        CALL MVBITS(MaskI64(ByteArr(Offset+3)), 0, 8, Res, 24)
        CALL MVBITS(MaskI64(ByteArr(Offset+4)), 0, 8, Res, 32)
        CALL MVBITS(MaskI64(ByteArr(Offset+5)), 0, 8, Res, 40)
        CALL MVBITS(MaskI64(ByteArr(Offset+6)), 0, 8, Res, 48)
        CALL MVBITS(MaskI64(ByteArr(Offset+7)), 0, 8, Res, 56)
        RETURN
    END FUNCTION Proc_CB_I
    !**************************************************************************
    FUNCTION Proc_CB_II(ByteArr, Offset) RESULT(Res)
        !^ callback routine - implementation#2.
        ! arguments
        INTEGER(KIND=1), INTENT(IN) :: ByteArr(0:)
        INTEGER,         INTENT(IN) :: Offset
        INTEGER(KIND=8)             :: Res
        ! execution
        Res =        MaskI64(ByteArr(Offset))        + &
              SHIFTL(MaskI64(ByteArr(Offset+1)),  8) + &
              SHIFTL(MaskI64(ByteArr(Offset+2)), 16) + &
              SHIFTL(MaskI64(ByteArr(Offset+3)), 24) + &
              SHIFTL(MaskI64(ByteArr(Offset+4)), 32) + &
              SHIFTL(MaskI64(ByteArr(Offset+5)), 40) + &
              SHIFTL(MaskI64(ByteArr(Offset+6)), 48) + &
              SHIFTL(MaskI64(ByteArr(Offset+7)), 56)
        RETURN
    END FUNCTION Proc_CB_II
    !**************************************************************************
    FUNCTION Proc_CB_III(ByteArr, Offset) RESULT(Res)
        !^ callback routine - implementation#3.
        ! arguments
        INTEGER(KIND=1), INTENT(IN) :: ByteArr(0:)
        INTEGER,         INTENT(IN) :: Offset
        INTEGER(KIND=8)             :: Res
        Res = TRANSFER([ByteArr(Offset),   ByteArr(Offset+1), ByteArr(Offset+2), &
                        ByteArr(Offset+3), ByteArr(Offset+4), ByteArr(Offset+5), &
                        ByteArr(Offset+6), ByteArr(Offset+7)], 0_8)
        RETURN
    END FUNCTION Proc_CB_III
    !**************************************************************************

END MODULE ModMain