Source file exifanalyze.ml
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(** Exif data analyzer
Due to its updated-on-demand and lots-of-tags nature,
This module is implemented in a separate file from exif.ml
and its interface file is auto created.
*)
open Exifutil
open Exif
open Exif.Numbers
open Exif.Entry.Pack
let analyze_datetime s =
match DateTime.of_string s with
| (`Ok _ as r) -> r
| `Error s ->
match DateTime.of_string_packed_unix_time s with
| `Ok v -> `EncodedInUnixTime v
| (`Error _ as e) -> e
let analyze_ifd (tag, pack) = match tag, pack with
| 0x10f, Asciis s -> `Make s
| 0x110, Asciis s -> `Model s
| 0x112, Shorts [| 1 |] -> `Orientation `TopLeft
| 0x112, Shorts [| 2 |] -> `Orientation `TopRight
| 0x112, Shorts [| 3 |] -> `Orientation `BottomRight
| 0x112, Shorts [| 4 |] -> `Orientation `BottomLeft
| 0x112, Shorts [| 5 |] -> `Orientation `LeftTop
| 0x112, Shorts [| 6 |] -> `Orientation `RightTop
| 0x112, Shorts [| 7 |] -> `Orientation `RightBottom
| 0x112, Shorts [| 8 |] -> `Orientation `LeftBottom
| 0x11a, Rationals [| r |] -> `XResolution r
| 0x11b, Rationals [| r |] -> `YResolution r
| 0x128, Shorts [| 2 |] -> `ResolutionUnit `Inches
| 0x128, Shorts [| 3 |] -> `ResolutionUnit `Centimeters
| 0x131, s -> `Software s
| 0x132, Asciis s -> `DateTime (analyze_datetime s)
| _ -> `Unknown (tag, pack)
let analyze_exif (tag, pack) = match tag, pack with
| 0x9000, Undefined s -> `ExifVersion s
| 0x927c, Undefined s -> `MakerNote s
| 0x9286, Undefined s -> `UserComment s
| 0x9003, Asciis s -> `DateTimeOriginal (analyze_datetime s)
| 0x9004, Asciis s -> `DateTimeDigitized (analyze_datetime s)
| 0x9290, Asciis s -> `SubsecTime s
| 0x9291, Asciis s -> `SubsecTimeOriginal s
| 0x9292, Asciis s -> `SubsecTimeDigitized s
| _ -> `Unknown (tag, pack)
module GPS = struct
type latitude = [ `North | `South ] * rational
type longitude = [ `East | `West ] * rational
type altitude = [ `AboveSeaLevel | `BelowSeaLevel ] * rational
type time_stamp_utc = {
hour : rational;
min : rational;
sec : rational;
}
type direction = [ `True | `Magnetic ] * rational
type map_datum = string
type t = {
version : (int * int * int * int) option;
latitude : latitude option;
longitude : longitude option;
altitude : altitude option;
time_stamp_utc : time_stamp_utc option;
direction : direction option;
map_datum : map_datum option
}
end
let analyze_gps (tag, v) = match tag, v with
| 00, Bytes [|x;y;z;w|] -> `GPSVersion (x,y,z,w)
| 01, Asciis "N" -> `NorthLatitude
| 01, Asciis "S" -> `SouthLatitude
| 02, Rationals [|r|] -> `Latitude r
| 03, Asciis "E" -> `EastLongitude
| 03, Asciis "W" -> `WestLongitude
| 04, Rationals [|r|] -> `Longitude r
| 05, Bytes [|0|] -> `AboveSeaLevel
| 05, Bytes [|1|] -> `BelowSeaLevel
| 06, Rationals [|r|] -> `Altitude r
| 07, Rationals [|h;m;s|] ->
`TimeStampUTC (float_of_rational h,
float_of_rational m,
float_of_rational s)
| 07, SRationals [|h;m;s|] ->
`TimeStampUTCinSRationals (float_of_srational h,
float_of_srational m,
float_of_srational s)
| 16, Asciis "T" -> `ImgDirectionTrue
| 16, Asciis "M" -> `ImgDirectionMagnetic
| 17, Rationals [|r|] -> `ImgDirection r
| 18, Asciis s -> `GPSMapDatum s
| 29, Asciis s -> `GPSDate (Date.of_string s)
| _ -> `Unknown (tag, v)
let exif_datetime t = match Data.unpack_exif t with
| Some entries ->
List.find_map_opt (function
| `DateTimeOriginal t -> Some t
| _ -> None)
(List.map analyze_exif entries)
| None -> None
let ifd_0_datetime t = match Data.unpack_ifd_0 t with
| Some entries ->
List.find_map_opt (function
| `DateTime t -> Some t
| _ -> None)
(List.map analyze_ifd entries)
| None -> None
let datetime t = match exif_datetime t with
| (Some _ as res) -> res
| None -> ifd_0_datetime t
