Write EXIF data to any file

NewExiffile.jl

using Pkg
Pkg.activate(".")
include("./lib/LibExif.jl")
using .LibExif
using Images
using JpegTurbo

function init_tag(exif, ifd, tag)
    exif1 = unsafe_load(exif)
    entry = LibExif.exif_content_get_entry(exif1.ifd[1], tag)
    if entry == C_NULL
        entry =  LibExif.exif_entry_new()
        entry1 = unsafe_load(entry)
        print(entry)
        entry1.tag = tag;
        LibExif.exif_content_add_entry(exif1.ifd[1], entry)
        LibExif.exif_entry_initialize(entry, tag)
        LibExif.exif_entry_unref(entry)
    end
    return entry
end

FILE_BYTE_ORDER = LibExif.EXIF_BYTE_ORDER_INTEL
image_jpg_x = 0x40
image_jpg_y = 0x40
# exif = LibExif.exif_data_new()
# LibExif.exif_data_set_option(exif, LibExif.EXIF_DATA_OPTION_FOLLOW_SPECIFICATION)
# LibExif.exif_data_set_data_type(exif, LibExif.EXIF_DATA_TYPE_COMPRESSED)
# LibExif.exif_data_set_byte_order(exif, LibExif.EXIF_BYTE_ORDER_INTEL)
# LibExif.exif_data_fix(exif)
# entry = init_tag(exif, LibExif.EXIF_IFD_EXIF, LibExif.EXIF_TAG_PIXEL_X_DIMENSION)
# entry1 = unsafe_load(entry)
# LibExif.exif_set_long(entry1.data, FILE_BYTE_ORDER, image_jpg_x)

# entry = init_tag(exif, LibExif.EXIF_IFD_EXIF, LibExif.EXIF_TAG_PIXEL_Y_DIMENSION)
# entry1 = unsafe_load(entry)
# LibExif.exif_set_long(entry1.data, FILE_BYTE_ORDER, image_jpg_y)

# entry = init_tag(exif, LibExif.EXIF_IFD_EXIF, LibExif.EXIF_TAG_COLOR_SPACE)
# entry1 = unsafe_load(entry)
# LibExif.exif_set_short(entry1.data, FILE_BYTE_ORDER, 1)

function test(exif1)
    ifds = 1:5
    numifds(ed) = 5
    read_all = true
    tags::Union{AbstractVector, Tuple} = Vector{LibExif.ExifTag}([])
    ed = unsafe_load(exif1)
    ifds = collect(ifds)
    # ifds = read_all ? collect(1:numifds(ed)) : collect(ifds)
    checkbounds(Bool, collect(1:numifds(ed)), ifds) || throw(BoundsError(collect(1:numifds(ed)), ifds))
    result = Dict{String, Any}()
    tags = read_all ? tags : Set(tags)
    str = Vector{Cuchar}(undef, 1024)

    for i in ifds
        content_ptr = ed.ifd[i] # ques: do we need to unref these too?
        if (content_ptr == C_NULL)
            return error("Unable to read IFD:", i)
        end
        data = unsafe_load(content_ptr)
        if data.count == 0 continue end
        res = unsafe_wrap(Array, data.entries, data.count)
        for i = 1:data.count
            entry = unsafe_load(res[i])
            condition = read_all ? read_all : entry.tag in tags
            if condition
                LibExif.exif_entry_get_value(Ref(entry), str, length(str))
                tag = String(copy(str))[1:max(findfirst(iszero, str)-1, 1)] 
                if string(entry.tag) ∉ keys(result)
                    result[string(entry.tag)] = tag
                end
            end
            if read_all == false
                delete!(tags, entry.tag)
                if tags == Set() break end
            end
        end
    end
    return result
end
exif1 = LibExif.exif_data_new_from_file("test/test_images/canon_makernote_variant_1.jpg")
exif = unsafe_load(exif1)
exif_header = Vector{Cuchar}(
    [0xff, 0xd8, 0xff, 0xe1]
)

# exif_data = Vector{Cuchar}(undef, 1000)

exif_data = Ref{Ptr{Cuchar}}()
# exif_data = ["asdada", "Asdads"]

# ref_exif_data = pointer_from_objref(Ref(exif_data))
# ref_exif_data = pointer(exif_data)
exif_data_len = Cuint(length(exif_data))
ref_exif_data_len = Ref(exif_data_len)

img = Gray.(zeros(4, 3))
data =  jpeg_encode(img)
# println(exif_data_len)
# println(ref_exif_data)
# println(ref_exif_data_len)
LibExif.exif_data_save_data(exif1, exif_data, ref_exif_data_len)
# println(test(exif1)) # this works
groups_vec = unsafe_wrap(Array, exif_data[], 5000)
len = findfirst([0xff,0xd8, 0xff, 0xd9], groups_vec)[4]
groups_vec = groups_vec[1:max(len, 1)]
open("sherlock-holmes2.jpg","w") do file
    write(file, exif_header) # done
    write(file, UInt8((len+2) >> 8))
    write(file, UInt8((len+2) & 0xff))
    write(file, groups_vec)
    write(file, data[3:end])
end
@info "Tags read from written file" read_tags("sherlock-holmes2.jpg")
println("Decoded data")
@info "Data Decoded from written file" jpeg_decode("sherlock-holmes2.jpg")