DAMASK_EICMD/src/base64.f90

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Fortran
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!--------------------------------------------------------------------------------------------------
!> @author Martin Diehl, Max-Planck-Institut für Eisenforschung GmbH
!> @brief Decode Base64 strings
!--------------------------------------------------------------------------------------------------
module base64
use prec
use IO
implicit none
private
public :: &
base64_init, &
base64_to_bytes, &
base64_nBase64, &
base64_nByte
contains
!--------------------------------------------------------------------------------------------------
!> @brief do self test
!--------------------------------------------------------------------------------------------------
subroutine base64_init
write(6,'(/,a)') ' <<<+- base64 init -+>>>'; flush(6)
call selfTest
end subroutine base64_init
!--------------------------------------------------------------------------------------------------
!> @brief calculate number of Base64 characters required for storage of N bytes
!--------------------------------------------------------------------------------------------------
pure function base64_nBase64(nByte)
integer(pLongInt), intent(in) :: nByte
integer(pLongInt) :: base64_nBase64
base64_nBase64 = 4_pLongInt * (nByte/3_pLongInt + merge(1_pLongInt,0_pLongInt,mod(nByte,3_pLongInt) /= 0_pLongInt))
end function base64_nBase64
!--------------------------------------------------------------------------------------------------
!> @brief calculate number of bytes required for storage of N Base64 characters
!--------------------------------------------------------------------------------------------------
pure function base64_nByte(nBase64)
integer(pLongInt), intent(in) :: nBase64
integer(pLongInt) :: base64_nByte
base64_nByte = 3_pLongInt * (nBase64/4_pLongInt)
end function base64_nByte
!--------------------------------------------------------------------------------------------------
!> @brief return byte-wise binary representation of a (part of a) Base64 ASCII string
!--------------------------------------------------------------------------------------------------
pure function base64_to_bytes(base64_str,s,e) result(bytes)
character(len=*), intent(in) :: base64_str !< Base64 string representation
integer(pLongInt), intent(in), optional :: &
s, & !< start (in bytes)
e !< end (in bytes)
integer(pLongInt) :: s_, e_
integer(C_SIGNED_CHAR), dimension(:), allocatable :: bytes, bytes_raw
allocate(bytes_raw(base64_nByte(len_trim(base64_str,pLongInt))))
if(present(s)) then
s_ = s
else
s_ = 1
endif
if(present(e)) then
e_ = e
else
e_ = size(bytes_raw,kind=pLongInt)
endif
! ToDo: inefficient for s_>>1 or e_<<size(bytes_raw)
call decode_base64(bytes_raw,base64_str)
bytes = bytes_raw(s_:e_)
end function base64_to_bytes
!--------------------------------------------------------------------------------------------------
!> @brief convert a Base64 ASCII string into its byte-wise binary representation
!> @details https://en.wikipedia.org/wiki/Base64
!--------------------------------------------------------------------------------------------------
pure subroutine decode_base64(bytes,base64_str)
integer(C_SIGNED_CHAR), intent(out),dimension(:) :: bytes !< byte-wise representation
character(len=*), intent(in) :: base64_str !< Base64 string representation
integer(C_SIGNED_CHAR), dimension(0:3) :: charPos
integer(pLongInt) :: c, b, bytesLen,base64Len, p
character(len=*), parameter :: encoding='ABCDEFGHIJKLMNOPQRSTUVWXYZ&
&abcdefghijklmnopqrstuvwxyz0123456789+/'
bytes = 0_C_SIGNED_CHAR
bytesLen = size(bytes,kind=pLongInt)
base64Len = len_trim(base64_str,kind=pLongInt)
c = 1_pLongInt
b = 1_pLongInt
2020-09-08 09:26:01 +05:30
do while(b <= bytesLen+3_pLongInt .and. c <= base64Len+4_pLongInt)
do p=0_pLongInt,3_pLongInt
if(c+p<=len(base64_str,kind=pLongInt)) then
charPos(p) = int(merge(index(encoding,base64_str(c+p:c+p))-1, 0, base64_str(c+p:c+p) /= '='),C_SIGNED_CHAR)
else
charPos(p) = 0_C_SIGNED_CHAR
endif
enddo
if (b+0<=bytesLen) then
call mvbits(charPos(0),0,6,bytes(b+0),2)
call mvbits(charPos(1),4,2,bytes(b+0),0)
endif
if (b+1<=bytesLen) then
call mvbits(charPos(1),0,4,bytes(b+1),4)
call mvbits(charPos(2),2,4,bytes(b+1),0)
endif
if (b+2<=bytesLen) then
call mvbits(charPos(2),0,2,bytes(b+2),6)
call mvbits(charPos(3),0,6,bytes(b+2),0)
endif
b = b+3_pLongInt
c = c+4_pLongInt
enddo
end subroutine decode_base64
!--------------------------------------------------------------------------------------------------
!> @brief check correctness of base64 functions
!--------------------------------------------------------------------------------------------------
subroutine selfTest
integer(C_SIGNED_CHAR), dimension(:), allocatable :: bytes
character(len=*), parameter :: zero_to_three = 'AAECAw=='
allocate(bytes(7), source = -1_C_SIGNED_CHAR)
call decode_base64(bytes,zero_to_three)
if(any(bytes /= int([0,1,2,3,0,0,0],C_SIGNED_CHAR)) .or. size(bytes) /= 7) call IO_error(0,ext_msg='base64_decode')
bytes = base64_to_bytes(zero_to_three)
if(any(bytes /= int([0,1,2,3,0,0],C_SIGNED_CHAR)) .or. size(bytes) /= 6) call IO_error(0,ext_msg='base64_to_bytes')
bytes = base64_to_bytes(zero_to_three,s=2_pLongInt)
if(any(bytes /= int([1,2,3,0,0],C_SIGNED_CHAR)) .or. size(bytes) /= 5) call IO_error(0,ext_msg='base64_to_bytes/s')
bytes = base64_to_bytes(zero_to_three,s=2_pLongInt,e=3_pLongInt)
if(any(bytes /= int([1,2],C_SIGNED_CHAR)) .or. size(bytes) /= 2) call IO_error(0,ext_msg='base64_to_bytes/s/e')
bytes = base64_to_bytes(zero_to_three,e=2_pLongInt)
if(any(bytes /= int([0,1],C_SIGNED_CHAR)) .or. size(bytes) /= 2) call IO_error(0,ext_msg='base64_to_bytes/e')
! https://en.wikipedia.org/wiki/Base64#Output_padding
if(base64_nBase64(20_pLongInt) /= 28_pLongInt) call IO_error(0,ext_msg='base64_nBase64/20/28')
if(base64_nBase64(19_pLongInt) /= 28_pLongInt) call IO_error(0,ext_msg='base64_nBase64/19/28')
if(base64_nBase64(18_pLongInt) /= 24_pLongInt) call IO_error(0,ext_msg='base64_nBase64/18/24')
if(base64_nBase64(17_pLongInt) /= 24_pLongInt) call IO_error(0,ext_msg='base64_nBase64/17/24')
if(base64_nBase64(16_pLongInt) /= 24_pLongInt) call IO_error(0,ext_msg='base64_nBase64/16/24')
if(base64_nByte(4_pLongInt) /= 3_pLongInt) call IO_error(0,ext_msg='base64_nByte/4/3')
if(base64_nByte(8_pLongInt) /= 6_pLongInt) call IO_error(0,ext_msg='base64_nByte/8/6')
end subroutine selfTest
end module base64