is_first_byte_of_character Function

public pure function is_first_byte_of_character(chara) result(res)

Uses

This function determines if a given character is the first byte of a UTF-8 multibyte character. It takes a 1-byte character as input and returns a logical value indicating if it is the first byte of an UTF-8 binary string.

Arguments

Type IntentOptional Attributes Name
character(len=1), intent(in) :: chara

Return Value logical


Source Code

   pure function is_first_byte_of_character(chara) result(res)
      use, intrinsic :: iso_fortran_env
      implicit none
      character(1), intent(in) :: chara   ! Input single byte character

      logical       :: res             ! Result indicating if it is the first byte of a multibyte character.
      integer(int8) :: byte, shift_6   ! Integer representation of the character and shifted value.

      ! Convert the character to its integer representation
      byte = int(ichar(chara), kind(byte))

      ! Initialize the result to `.true.` (assume it is the first byte).
      res = .true.

      ! Shift the byte 6 bits to the right.
      shift_6 = ishft(byte, -6)

      ! If the shifted value equals 2 (10_2), it is a continuation byte, not the first byte.
      if (shift_6 == 2) res = .false.

   end function is_first_byte_of_character