; writing ZIP format for fasmg by Grom PE
; allows to output multiple files in a single zip file (uncompressed)

ZIP::
; todo: calculate crc32 only once instead of on every pass (is that possible?)
; todo: sandbox the contents in add2zip..endadd2zip so it's possible to use org inside and other complex formats

virtual at 0
  crc32table::
  repeat 256
    r = %-1
    repeat 8
      r = r shr 1 xor (0xEDB88320 * r and 1)
    end repeat
    dd r
  end repeat
end virtual

namespace ZIP
  VersionToExtract := 20
  VersionMadeBy := 63
  FILE_INDEX = 0
  HAS_FILES = 0
  FILE_OFFSET = $%
end namespace

macro endadd2zip
  namespace ZIP
    FILE_SIZE = $% - FILE_OFFSET

    if HAS_FILES
      match e,entry
        c = 0xffffffff
        repeat FILE_SIZE, a:0
          ; fixme: fragile, breaks if "org" is used inside the region
          load b:byte from e.Data:a
          load t dword from crc32table:(b xor (c and 0xFF))*4
          c = c shr 8 xor t
        end repeat
        e.Crc32 = c xor 0xffffffff
        e.CompressedSize = FILE_SIZE
        e.UncompressedSize = FILE_SIZE
      end match
      FILE_INDEX = FILE_INDEX + 1
    end if
  end namespace
end macro

macro add2zip name*
  namespace ZIP
    local e
    endadd2zip
    e.GeneralPurpose = 0
    e.CompressionMethod = 0
    e.FileTime = 0
    e.FileDate = 0
    e.FileNameLength = lengthof name
    e.FileAttributes = 0
    e.FileAttributesExt = 0
    e.LocalHeaderOffset = $%%
    e.FileName = name
    entry equ e

    db 'PK',3,4
    dw VersionToExtract
    dw e.GeneralPurpose
    dw e.CompressionMethod
    dw e.FileTime
    dw e.FileDate
    dd e.Crc32
    dd e.CompressedSize
    dd e.UncompressedSize
    dw e.FileNameLength
    dw 0 ; ExtraFieldLength
    db e.FileName
    ;db '' ; ExtraField
    org 0
    e.Data::

    FILE_OFFSET = $%
    HAS_FILES = 1
  end namespace
end macro

postpone
  purge add2zip
  endadd2zip
  namespace ZIP
  org $%%
central:
  irpv e,entry
    db 'PK',1,2
    dw VersionMadeBy
    dw VersionToExtract
    dw e.GeneralPurpose
    dw e.CompressionMethod
    dw e.FileTime
    dw e.FileDate
    dd e.Crc32
    dd e.CompressedSize
    dd e.UncompressedSize
    dw e.FileNameLength
    dw 0 ; ExtraFieldLength
    dw 0 ; CommentLength
    dw 0 ; DiskNumber
    dw e.FileAttributes
    dd e.FileAttributesExt
    dd e.LocalHeaderOffset

    db e.FileName
    ;db '' ; ExtraField
    ;db '' ; Comment
  end irpv
tail:
  db 'PK',5,6
  dw 0 ; Number of this disk
  dw 0 ; Number of the disk with the start of the central repository
  dw NUMBER_OF_FILES
  dw NUMBER_OF_FILES
  dd tail - central
  dd central
  dw 0 ; Comment length
  ;db '' ; Comment

  NUMBER_OF_FILES := FILE_INDEX
  end namespace
end postpone
    

include 'zipwrite.inc'

db 'Some non-zip data that goes in the beginning',10

add2zip 'hello.txt'
db 'Hello world!',10

add2zip 'greetings.txt'
db 'Greetings to all the flat assembler fans!',10
    

todo: calculate crc32 only once instead of on every pass (is that possible?)

I added CRC natively into fasmarm for this reason. Doing a native CRC is much faster than with a macro. And makes doing it on every pass is almost inconsequential in terms of the extra time needed. If the defining parameters are made flexible enough then it can accommodate all the common bit lengths and polynomials.

macro tar_number? value*,length:8
        local d
        repeat length-1
                d = value shr ((length-1-%)*3)
                if d > 0
                        db '0' + d and 111b
                else
                        db 20h
                end if
        end repeat
        db 20h
end macro

macro tar_record? name

        local data,size,checksum_field,checksum,byte

        org 0

        db string name,(100 - lengthof string name) dup 0
        tar_number 10077o       ; file mode
        tar_number 0            ; owner id
        tar_number 0            ; group id
        tar_number size,12      ; file size
        tar_number %t,12        ; last modification time
        checksum_field db 8 dup 20h
        db '0',100 dup 0        ; normal file

        checksum = 0
        repeat $
                load byte : 1 from $-%
                checksum = checksum + byte
        end repeat
        repeat 6
                byte = checksum shr ((6-%)*3)
                store '0' + byte and 111b : 1 at checksum_field + % - 1
        end repeat
        store 0:1 at checksum_field + 7

        db 512-$ dup 0

        org 0
        data = $%
        define $% ($%-data)
        define $%% ($%%-data)

        macro end?.tar_record?
                size = $%
                db (512 - size and 511) dup 0
                restore $%,$%%
                purge end?.tar_record?
        end macro

end macro    

tar_record 'hello.txt'

        db 'Hello world!',10

end tar_record

tar_record 'greetings.txt'

        db 'Greetings to all the flat assembler fans!',10

end tar_record

db 2*512 dup 0  ; two null records to mark the end of tarball    

macro tar_number? value*,length:8
        local d
        repeat length-1
                d = value shr ((length-1-%)*3)
                if d > 0
                        db '0' + d and 111b
                else
                        db 20h
                end if
        end repeat
        db 20h
end macro

macro tar_record? name

        local postponed,data,size,checksum_field,checksum,byte

        org 0

        db string name,(100 - lengthof string name) dup 0
        tar_number 10077o       ; file mode
        tar_number 0            ; owner id
        tar_number 0            ; group id
        tar_number size,12      ; file size
        tar_number %t,12        ; last modification time
        checksum_field db 8 dup 20h
        db '0',100 dup 0        ; normal file

        checksum = 0
        repeat $
                load byte : 1 from $-%
                checksum = checksum + byte
        end repeat
        repeat 6
                byte = checksum shr ((6-%)*3)
                store '0' + byte and 111b : 1 at checksum_field + % - 1
        end repeat
        store 0:1 at checksum_field + 7

        db 512-$ dup 0

        org 0
        data = $%
        define $% ($%-data)
        define $%% ($%%-data)

        macro postponed
        end macro

        macro postpone?!
            esc macro postponed 
        end macro  

        macro end?.postpone?!  
                postponed 
            esc end macro  
        end macro

        macro end?.tar_record?
                postponed
                size = $%
                db (512 - size and 511) dup 0
                restore $%,$%%
                purge postpone?,end?.postpone?,end?.tar_record?
        end macro

end macro    

tar_record 'hello.txt'

        db 'Hello world!',10

end tar_record

tar_record 'win32.exe'

        include 'win32.asm'     ; example from fasmg package

end tar_record

db 2*512 dup 0  ; two null records to mark the end of tarball    

Grom PE wrote:

todo: calculate crc32 only once instead of on every pass (is that possible?)

While I tried to avoid exposing details of the resolving process to the constructions of language, the calculation of checksums is an example of place where it is tempting to introduce a way to compute them only in the final pass. Or, to be more precise: to make it possible to mark some code in such a way that it would get assembled only when everything that came before is already correctly resolved. It is easy to add something like that to fasmg, in form of a built-in variable that could be checked with "if", but I'm still considering the consequences of such move on the overall design of the language.

postpone ?
    ; ...
end postpone    

Can I create folder?

format binary as 'tar'

include 'tar.inc'


tar_record 'texts/hello.txt'

        db 'Hello world!',10

end tar_record

tar_record 'bytes.bin'

        repeat 256, c:0
                db c
        end repeat

end tar_record

db 2*512 dup 0  ; two null records to mark the end of tarball