;===============================================================================
;
; Description:    Reads EXIF info
; Parameter(s):  File name
; Requirement(s):   None
; Return Value(s):  On Success - array with EXIF data:
;                      0 - Date & Time
;                      1 - Camera Vendor
;                      2 - Camera Model
;                      3 - Image Description
;                      4 - Copyright
;                      5 - Orientation
;                      6 - Width
;                      7 - Height
;                      8 - Original Date & Time
;                      9 - Digitized Date & Time
;                     10 - User Comments
;                   On Failure empty string and sets @ERROR:
;                      1 - File is not JPEG file
;                      2 - EXIF info not found
; Author(s):        YDY (Kot) <mpc@nm.ru>
; Version:        1.1.00
; Date:          09.08.2004
; Note(s):        None
;
;===============================================================================

Func _GetEXIFData($file)
Local $pos = 3

If not (_FileReadAtOffsetHEX ($file, 1, 2) = "FFD8") Then
    SetError(1); Not JPEG
    Return("")
Endif

$fs = FileGetSize($file)

While $pos < $fs
    $data = _FileReadAtOffsetHEX ($file, $pos, 4)
    If StringLeft($data, 2) = "FF" then; Valid segment start
        $segtype = StringMid($data, 3, 2)
        if $segtype = "E1" then Return(ParseExif($file,$pos))
        $pos = $pos + Dec(StringRight($data, 4)) + 2
    Else
        Exitloop
    Endif
Wend
SetError(2); Segment not found
Return("")
Endfunc

Func ParseExif($file, $exif_offset)
Local $ByteOrder = 0
Local $ic, $idf_offset, $exif[11]
Local $orient = StringSplit("Normal|Mirrored|180&#9617;|180&#9617; and mirrored|90&#9617; left and mirrored|90&#9617; right|90&#9617; right and mirrored|90&#9617; left", "|")

If _FileReadAtOffsetHEX ($file, $exif_offset+10, 2) = "4D4D" then $ByteOrder = 1

$size = _FileReadAtOffsetHEX ($file, $exif_offset+2, 2)
$exif_offset = $exif_offset + 11 + 9; 9 JFIF header size + 11 - IDF header size, 

For $ic = 0 To 11
    $tag_full = _FileReadAtOffsetHEX($file, $exif_offset + $ic * 12, 12)
    $id = StringLeft($tag_full, 4)
    If $ByteOrder Then $id = StringRight($id, 2) & StringLeft($id, 2)
    Select
        Case $id = "6987"; Exif IDF offset
           $idf_offset = _GetNumValue(StringRight($tag_full, 8), $ByteOrder)
        Case $id = "3201"; DateTime 3201
           $exif[0] = _ReadValue($file, $tag_full, $ByteOrder)
        Case $id = "0F01"; Vendor
           $exif[1] = _ReadValue($file, $tag_full, $ByteOrder)
        Case $id = "1001"; Model
           $exif[2] = _ReadValue($file, $tag_full, $ByteOrder)
        Case $id = "0E01"; ImageDescription
           $exif[3] = _ReadValue($file, $tag_full, $ByteOrder)
        Case $id = "9882"; Copyright
           $exif[4] = _ReadValue($file, $tag_full, $ByteOrder)
        Case $id = "1201"; Orientation
           $value = _GetNumValue(StringRight($tag_full, 8), $ByteOrder)
           If $ByteOrder Then $value = BitShift($value, 16)
           If ($value > 0) and ($value < 9) Then
               $exif[5] = $orient[$value]
           Else
               $exif[5] = "Undefined"
           Endif
    EndSelect
Next

If not ($idf_offset > 0) Then Return($exif)

For $ic = 0 To 23
    $tag_full = _FileReadAtOffsetHEX ($file, $idf_offset + 15 + $ic * 12, 12)
    $id = StringLeft($tag_full, 4)
    If $ByteOrder Then $id = StringRight($id, 2) & StringLeft($id, 2)
    Select
        Case $id = "02A0"; Width
           $exif[6] = _GetNumValue(StringRight($tag_full, 8), $ByteOrder)
        Case $id = "03A0"; Height
           $exif[7] = _GetNumValue(StringRight($tag_full, 8), $ByteOrder)
        Case $id = "0390"; DateTimeOriginal
           $exif[8] = _ReadValue($file, $tag_full, $ByteOrder)
        Case $id = "0490"; DateTimeDigitized
           $exif[9] = _ReadValue($file, $tag_full, $ByteOrder)
        Case $id = "8692"; UserComments
           $exif[10] = _ReadValue($file, $tag_full, $ByteOrder)
    EndSelect
Next
Return($exif)
EndFunc

Func _ReadValue($file, $tag, $ByteOrder)
    Local $count = _GetNumValue(StringMid($tag, 9, 8), $ByteOrder)
    Local $offset = _GetNumValue(StringMid($tag, 17, 8), $ByteOrder)
    Local $tStr = _FileReadAtOffsetHEX ($file, $offset+13, $count)
    Local $oStr = ""
    While StringLen($tStr) > 0
       $oStr = $oStr & Chr(Dec(StringLeft($tStr, 2)))
       $tStr = StringTrimLeft($tStr, 2)
    WEnd
    Return($oStr)
EndFunc

Func _GetNumValue ($input, $ByteOrder)
    Local $tStr = ""
    If $ByteOrder then
        $tStr = $input
    Else
        While StringLen($input) > 0
           $tStr = $tStr & StringRight($input, 2)
           $input = StringTrimRight($input, 2)
        WEnd
    Endif
    Return (Dec($tStr))
EndFunc

Func _FileReadAtOffsetHEX ($file, $offset, $bytes)
    Local $tfile = FileOpen($file, 0)
    Local $tstr = ""
    FileRead($tfile, $offset-1)
    For $i = $offset To $offset + $bytes - 1
        $tstr =  $tstr & Hex(Asc(FileRead($tfile, 1)), 2)
    Next
    FileClose($tfile)
    Return ($tstr)
Endfunc