stdlib
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fortran-lang
Support CRC32 hash for reading and writing zip files
Motivation
CRC32 is used as a hashing function to check the data integrity in zip files. To support zip file IO in stdlib natively, we should include a CRC32 hashing function.
Prior Art
! SPDX-License: MIT
!> Implementation of cyclic redundancy check hashing function,
!> used to check the integrity of data in zip files.
module stdlib_hash_crc32
use iso_fortran_env, only : i4 => int32, dp => real64
implicit none
private
public :: crc32_hash
!> Compute crc32 checksum
interface crc32_hash
module procedure crc32_hash_char_r0
module procedure crc32_hash_char_r1
module procedure crc32_hash_i4_r1
module procedure crc32_hash_rdp_r1
end interface crc32_hash
integer(i4), parameter :: crc_table(0:255) = [ &
& int(z'00000000', i4), int(z'77073096', i4), int(z'ee0e612c', i4), int(z'990951ba', i4), &
& int(z'076dc419', i4), int(z'706af48f', i4), int(z'e963a535', i4), int(z'9e6495a3', i4), &
& int(z'0edb8832', i4), int(z'79dcb8a4', i4), int(z'e0d5e91e', i4), int(z'97d2d988', i4), &
& int(z'09b64c2b', i4), int(z'7eb17cbd', i4), int(z'e7b82d07', i4), int(z'90bf1d91', i4), &
& int(z'1db71064', i4), int(z'6ab020f2', i4), int(z'f3b97148', i4), int(z'84be41de', i4), &
& int(z'1adad47d', i4), int(z'6ddde4eb', i4), int(z'f4d4b551', i4), int(z'83d385c7', i4), &
& int(z'136c9856', i4), int(z'646ba8c0', i4), int(z'fd62f97a', i4), int(z'8a65c9ec', i4), &
& int(z'14015c4f', i4), int(z'63066cd9', i4), int(z'fa0f3d63', i4), int(z'8d080df5', i4), &
& int(z'3b6e20c8', i4), int(z'4c69105e', i4), int(z'd56041e4', i4), int(z'a2677172', i4), &
& int(z'3c03e4d1', i4), int(z'4b04d447', i4), int(z'd20d85fd', i4), int(z'a50ab56b', i4), &
& int(z'35b5a8fa', i4), int(z'42b2986c', i4), int(z'dbbbc9d6', i4), int(z'acbcf940', i4), &
& int(z'32d86ce3', i4), int(z'45df5c75', i4), int(z'dcd60dcf', i4), int(z'abd13d59', i4), &
& int(z'26d930ac', i4), int(z'51de003a', i4), int(z'c8d75180', i4), int(z'bfd06116', i4), &
& int(z'21b4f4b5', i4), int(z'56b3c423', i4), int(z'cfba9599', i4), int(z'b8bda50f', i4), &
& int(z'2802b89e', i4), int(z'5f058808', i4), int(z'c60cd9b2', i4), int(z'b10be924', i4), &
& int(z'2f6f7c87', i4), int(z'58684c11', i4), int(z'c1611dab', i4), int(z'b6662d3d', i4), &
& int(z'76dc4190', i4), int(z'01db7106', i4), int(z'98d220bc', i4), int(z'efd5102a', i4), &
& int(z'71b18589', i4), int(z'06b6b51f', i4), int(z'9fbfe4a5', i4), int(z'e8b8d433', i4), &
& int(z'7807c9a2', i4), int(z'0f00f934', i4), int(z'9609a88e', i4), int(z'e10e9818', i4), &
& int(z'7f6a0dbb', i4), int(z'086d3d2d', i4), int(z'91646c97', i4), int(z'e6635c01', i4), &
& int(z'6b6b51f4', i4), int(z'1c6c6162', i4), int(z'856530d8', i4), int(z'f262004e', i4), &
& int(z'6c0695ed', i4), int(z'1b01a57b', i4), int(z'8208f4c1', i4), int(z'f50fc457', i4), &
& int(z'65b0d9c6', i4), int(z'12b7e950', i4), int(z'8bbeb8ea', i4), int(z'fcb9887c', i4), &
& int(z'62dd1ddf', i4), int(z'15da2d49', i4), int(z'8cd37cf3', i4), int(z'fbd44c65', i4), &
& int(z'4db26158', i4), int(z'3ab551ce', i4), int(z'a3bc0074', i4), int(z'd4bb30e2', i4), &
& int(z'4adfa541', i4), int(z'3dd895d7', i4), int(z'a4d1c46d', i4), int(z'd3d6f4fb', i4), &
& int(z'4369e96a', i4), int(z'346ed9fc', i4), int(z'ad678846', i4), int(z'da60b8d0', i4), &
& int(z'44042d73', i4), int(z'33031de5', i4), int(z'aa0a4c5f', i4), int(z'dd0d7cc9', i4), &
& int(z'5005713c', i4), int(z'270241aa', i4), int(z'be0b1010', i4), int(z'c90c2086', i4), &
& int(z'5768b525', i4), int(z'206f85b3', i4), int(z'b966d409', i4), int(z'ce61e49f', i4), &
& int(z'5edef90e', i4), int(z'29d9c998', i4), int(z'b0d09822', i4), int(z'c7d7a8b4', i4), &
& int(z'59b33d17', i4), int(z'2eb40d81', i4), int(z'b7bd5c3b', i4), int(z'c0ba6cad', i4), &
& int(z'edb88320', i4), int(z'9abfb3b6', i4), int(z'03b6e20c', i4), int(z'74b1d29a', i4), &
& int(z'ead54739', i4), int(z'9dd277af', i4), int(z'04db2615', i4), int(z'73dc1683', i4), &
& int(z'e3630b12', i4), int(z'94643b84', i4), int(z'0d6d6a3e', i4), int(z'7a6a5aa8', i4), &
& int(z'e40ecf0b', i4), int(z'9309ff9d', i4), int(z'0a00ae27', i4), int(z'7d079eb1', i4), &
& int(z'f00f9344', i4), int(z'8708a3d2', i4), int(z'1e01f268', i4), int(z'6906c2fe', i4), &
& int(z'f762575d', i4), int(z'806567cb', i4), int(z'196c3671', i4), int(z'6e6b06e7', i4), &
& int(z'fed41b76', i4), int(z'89d32be0', i4), int(z'10da7a5a', i4), int(z'67dd4acc', i4), &
& int(z'f9b9df6f', i4), int(z'8ebeeff9', i4), int(z'17b7be43', i4), int(z'60b08ed5', i4), &
& int(z'd6d6a3e8', i4), int(z'a1d1937e', i4), int(z'38d8c2c4', i4), int(z'4fdff252', i4), &
& int(z'd1bb67f1', i4), int(z'a6bc5767', i4), int(z'3fb506dd', i4), int(z'48b2364b', i4), &
& int(z'd80d2bda', i4), int(z'af0a1b4c', i4), int(z'36034af6', i4), int(z'41047a60', i4), &
& int(z'df60efc3', i4), int(z'a867df55', i4), int(z'316e8eef', i4), int(z'4669be79', i4), &
& int(z'cb61b38c', i4), int(z'bc66831a', i4), int(z'256fd2a0', i4), int(z'5268e236', i4), &
& int(z'cc0c7795', i4), int(z'bb0b4703', i4), int(z'220216b9', i4), int(z'5505262f', i4), &
& int(z'c5ba3bbe', i4), int(z'b2bd0b28', i4), int(z'2bb45a92', i4), int(z'5cb36a04', i4), &
& int(z'c2d7ffa7', i4), int(z'b5d0cf31', i4), int(z'2cd99e8b', i4), int(z'5bdeae1d', i4), &
& int(z'9b64c2b0', i4), int(z'ec63f226', i4), int(z'756aa39c', i4), int(z'026d930a', i4), &
& int(z'9c0906a9', i4), int(z'eb0e363f', i4), int(z'72076785', i4), int(z'05005713', i4), &
& int(z'95bf4a82', i4), int(z'e2b87a14', i4), int(z'7bb12bae', i4), int(z'0cb61b38', i4), &
& int(z'92d28e9b', i4), int(z'e5d5be0d', i4), int(z'7cdcefb7', i4), int(z'0bdbdf21', i4), &
& int(z'86d3d2d4', i4), int(z'f1d4e242', i4), int(z'68ddb3f8', i4), int(z'1fda836e', i4), &
& int(z'81be16cd', i4), int(z'f6b9265b', i4), int(z'6fb077e1', i4), int(z'18b74777', i4), &
& int(z'88085ae6', i4), int(z'ff0f6a70', i4), int(z'66063bca', i4), int(z'11010b5c', i4), &
& int(z'8f659eff', i4), int(z'f862ae69', i4), int(z'616bffd3', i4), int(z'166ccf45', i4), &
& int(z'a00ae278', i4), int(z'd70dd2ee', i4), int(z'4e048354', i4), int(z'3903b3c2', i4), &
& int(z'a7672661', i4), int(z'd06016f7', i4), int(z'4969474d', i4), int(z'3e6e77db', i4), &
& int(z'aed16a4a', i4), int(z'd9d65adc', i4), int(z'40df0b66', i4), int(z'37d83bf0', i4), &
& int(z'a9bcae53', i4), int(z'debb9ec5', i4), int(z'47b2cf7f', i4), int(z'30b5ffe9', i4), &
& int(z'bdbdf21c', i4), int(z'cabac28a', i4), int(z'53b39330', i4), int(z'24b4a3a6', i4), &
& int(z'bad03605', i4), int(z'cdd70693', i4), int(z'54de5729', i4), int(z'23d967bf', i4), &
& int(z'b3667a2e', i4), int(z'c4614ab8', i4), int(z'5d681b02', i4), int(z'2a6f2b94', i4), &
& int(z'b40bbe37', i4), int(z'c30c8ea1', i4), int(z'5a05df1b', i4), int(z'2d02ef8d', i4)]
contains
!> Compute crc32 checksum for a character string
pure function crc32_hash_char_r0(val, crc_in) result(crc)
!> Previous crc32 checksum to continue from
integer(i4), intent(in), optional :: crc_in
!> Value to hash
character(len=*), intent(in) :: val
!> Resulting crc32 checksum
integer(i4) :: crc
integer :: ii
if (present(crc_in)) then
crc = crc_in
else
crc = 0_i4
end if
crc = not(crc)
do ii = 1, len(val)
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(val(ii:ii))), 255)))
enddo
crc = not(crc)
end function crc32_hash_char_r0
!> Compute crc32 checksum for a character array
pure function crc32_hash_char_r1(val, crc_in) result(crc)
!> Previous crc32 checksum to continue from
integer(i4), intent(in), optional :: crc_in
!> Value to hash
character(len=1), intent(in) :: val(:)
!> Resulting crc32 checksum
integer(i4) :: crc
integer :: ii
if (present(crc_in)) then
crc = crc_in
else
crc = 0_i4
end if
crc = not(crc)
do ii = 1, size(val)
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(val(ii))), 255)))
enddo
crc = not(crc)
end function crc32_hash_char_r1
!> Compute crc32 checksum for a 4-byte integer array
pure function crc32_hash_i4_r1(val, crc_in) result(crc)
!> Previous crc32 checksum to continue from
integer(i4), intent(in), optional :: crc_in
!> Value to hash
integer(i4), intent(in) :: val(:)
!> Resulting crc32 checksum
integer(i4) :: crc
integer :: ii
character(len=1) :: chunk(4)
if (present(crc_in)) then
crc = crc_in
else
crc = 0_i4
end if
crc = not(crc)
do ii = 1, size(val)
chunk = transfer(val(ii), chunk)
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(1))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(2))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(3))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(4))), 255)))
enddo
crc = not(crc)
end function crc32_hash_i4_r1
!> Compute crc32 checksum for a real array
pure function crc32_hash_rdp_r1(val, crc_in) result(crc)
!> Previous crc32 checksum to continue from
integer(i4), intent(in), optional :: crc_in
!> Value to hash
real(dp), intent(in) :: val(:)
!> Resulting crc32 checksum
integer(i4) :: crc
integer :: ii
character(len=1) :: chunk(8)
if (present(crc_in)) then
crc = crc_in
else
crc = 0_i4
end if
crc = not(crc)
do ii = 1, size(val)
chunk = transfer(val(ii), chunk)
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(1))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(2))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(3))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(4))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(5))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(6))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(7))), 255)))
crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(chunk(8))), 255)))
enddo
crc = not(crc)
end function crc32_hash_rdp_r1
end module stdlib_hash_crc32
Additional Information
No response
This is a great idea, @awvwgk! I'm just wondering—should both of your recently opened issues be handled in a single PR, given that they both deal with IO on zip files? Or do you see a reason to track them separately?
CRC32 hashes can be an internal utility for zip file IO or generally available for stdlib users. By itself CRC32 is not such a good hashing function compared to the ones already in stdlib, there might be no added benefit for exposing it as part of the hash module.
I opened this issue to discuss whether there is a preference for either way
I would say to make it visible as a public functionality of a module dedicated to zip file io. No reason to hide it, even if as of now the only usecase would be this one.
Would it make sense to template out the functions with fypp? looking as your proposal implementation I would say it is feasable.
I think it's a great idea @awvwgk - I will ping @wassup05 that may want to (or you may want to) open a PR about it.
