xcf-rs 0.5.0

use std::fs::File;
use std::io::Write;
use std::path::PathBuf;

use byteorder::{BigEndian, ByteOrder};

extern crate hex_slice;
use hex_slice::AsHex;

use crate::data::color::ColorType;
use crate::data::layer::Layer;
use crate::data::property::Property;
use crate::data::property::PropertyPayload;
use crate::data::xcf::XcfCompression;
use crate::data::tiles::Tiles;
use crate::LayerColorValue;
use crate::PropertyIdentifier;
use crate::RgbaPixel;

pub struct XcfCreator {
    pub version: u16,
    pub data: Vec<u8>,
    pub index: u64,
    pub compression: XcfCompression,
}

//impl Creator for Xcf {
impl XcfCreator {
    fn extend_u32(&mut self, value: u32) {
        let mut width_buf = vec![0; 4];
        BigEndian::write_u32(&mut width_buf, value);
        self.data.extend_from_slice(&width_buf);
        self.index += 4;
    }

    fn extend_u64(&mut self, value: u64) {
        let mut width_buf = vec![0; 8];
        BigEndian::write_u64(&mut width_buf, value);
        self.data.extend_from_slice(&width_buf);
        self.index += 8;
    }

    fn buf_extend_u32(&mut self, data: &mut Vec<u8>, index: &mut u32, value: u32) {
        let size = 4;
        let mut width_buf = vec![0; size];
        BigEndian::write_u32(&mut width_buf, value);
        data.extend_from_slice(&width_buf);
        *index += size as u32;
    }

    fn buf_extend_u64(&mut self, data: &mut Vec<u8>, index: &mut u32, value: u64) {
        let size = 8;
        let mut width_buf = vec![0; size];
        BigEndian::write_u64(&mut width_buf, value);
        data.extend_from_slice(&mut width_buf);
        *index += size as u32;
    }

    fn create_signature(&mut self, gimp_version: u16) {
        let mut signature = format!("gimp xcf v{:03}\0", gimp_version);
        if gimp_version == 1 {
            signature = "gimp xcf file\0".to_string();
        }
        self.data.extend_from_slice(signature.as_bytes());
        self.index += 14;
    }

    fn v10_gimp_string(&mut self, data: &mut Vec<u8>, index: &mut u32, str: &[u8]) {
        let str_count = str.len() as u32;
        self.buf_extend_u32(data, index, str_count + 4);
        data.extend_from_slice(str);
        *index += str_count;
        self.buf_extend_u32(data, index, 0);
    }

    fn gimp_string(&mut self, data: &mut Vec<u8>, index: &mut u32, str: &[u8]) {
        let str_count = str.len() as u32 + 1;
        self.buf_extend_u32(data, index, str_count);
        data.extend_from_slice(str);
        data.extend_from_slice(&[0]);
        *index += str_count;
    }

    fn parasite_prop(&mut self, data: &mut Vec<u8>, index: &mut u32, parasite_title: &str, parasite_data: &str, flags: u32) {
        let title_len = parasite_title.len() + 1;
        self.buf_extend_u32(data, index, title_len as u32);
        data.extend_from_slice(parasite_title.as_bytes());
        data.extend_from_slice(&[0]);
        *index += title_len as u32;
        self.buf_extend_u32(data, index,flags);

        let data_len = parasite_data.len() + 1;
        self.buf_extend_u32(data, index,data_len as u32);
        data.extend_from_slice(parasite_data.as_bytes());
        data.extend_from_slice(&[0]);
        *index += data_len as u32;
    }

    pub fn new(version: u16, width: u32, height: u32, color_type: ColorType) -> Self {
        let data = vec![];
        let index = 0;

        let mut _self = XcfCreator {
            version,
            data,
            index,
            compression: XcfCompression::None,
        };
        _self.create_signature(version);
        _self.extend_u32(width);
        _self.extend_u32(height);
        _self.extend_u32(color_type as u32);

        if version >= 4 {
            _self.extend_u32(150); // 8-bit gamma integer
        }

        _self
    }

    fn prop_end(&mut self, data: &mut Vec<u8>, index: &mut u32) {
        self.buf_extend_u32(data, index, 0);
        self.buf_extend_u32(data, index, 0);
        //self.extend_u64(0); // prop : End + size : 0
    }

    pub fn add_properties(&mut self, properties: &Vec<Property>) {
        let mut _has_compression = false;
        for property in properties {
            self.extend_u32(property.kind as u32);
            match &property.payload {
                PropertyPayload::Compression(_value) => {
                    self.extend_u32(property.length as u32); // size

                    self.data.extend_from_slice(&[_value.to_u8()]);
                    self.index += 1;
                    self.compression = _value.clone();
                    _has_compression = true;
                }
                PropertyPayload::ResolutionProperty(_value) => {
                    self.extend_u32(property.length as u32); // size

                    self.extend_u32(_value.xres.to_bits()); // X resolution in DPI
                    self.extend_u32(_value.yres.to_bits()); // Y resolution in DPI
                }
                PropertyPayload::Tatoo(_value) | PropertyPayload::Unit(_value) => {
                    self.extend_u32(property.length as u32); // size

                    self.extend_u32(*_value);
                }
                PropertyPayload::Parasites(_parasites) => {
                    let mut parasite_prop_buf = vec![];
                    let mut parasite_prop_len = 0;
                    for parasite in _parasites {
                        self.parasite_prop(
                            &mut parasite_prop_buf, 
                            &mut parasite_prop_len, 
                            &parasite.name,
                            &parasite.data,
                            parasite.flags
                        );
                    }
                    self.extend_u32(parasite_prop_len); // size
                    self.data.extend_from_slice(&parasite_prop_buf);
                    self.index += parasite_prop_len as u64;
                }
                _ => {
                    self.extend_u32(property.length as u32); // size
                }
            }
        }
        if self.version > 10 && !_has_compression {
            self.extend_u32(PropertyIdentifier::PropCompression as u32);
            self.extend_u32(1); // size
            self.data.extend_from_slice(&[XcfCompression::Rle as u8]);
            self.index += 1;
            self.compression = XcfCompression::Rle;

            // resolution
            self.extend_u32(PropertyIdentifier::PropResolution as u32);
            self.extend_u32(8); // size
            let value: f32 = 300.0;
            self.extend_u32(value.to_bits()); // X resolution in DPI
            self.extend_u32(value.to_bits()); // Y resolution in DPI

            // tatoo
            self.extend_u32(PropertyIdentifier::PropTattoo as u32);
            self.extend_u32(4); // size
            self.extend_u32(2);

            // unit
            self.extend_u32(PropertyIdentifier::PropUnit as u32);
            self.extend_u32(4); // size
            self.extend_u32(1);

            // parasites
            let mut parasite_prop_buf = vec![];
            let mut parasite_prop_len = 0;
            self.parasite_prop(
                &mut parasite_prop_buf, 
                &mut parasite_prop_len, 
                "gimp-comment", 
                //"Created with GIMP",
                "Test Comment",
                1
            );
            self.parasite_prop(
                &mut parasite_prop_buf, 
                &mut parasite_prop_len, 
                "gimp-image-grid", 
                "(style solid)\n(fgcolor (color-rgba 0 0 0 1))\n(bgcolor (color-rgba 1 1 1 1))\n(xspacing 10)\n(yspacing 10)\n(spacing-unit inches)\n(xoffset 0)\n(yoffset 0)\n(offset-unit inches)\n",
                1
            );
            self.extend_u32(PropertyIdentifier::PropParasites as u32);
            self.extend_u32(parasite_prop_len); // size
            self.data.extend_from_slice(&parasite_prop_buf);
            self.index += parasite_prop_len as u64;
        }

        // TODO : replace by : self.propend()
        self.extend_u32(0);
        self.extend_u32(0);
    }

    fn _add_layers_properties(&mut self, data: &mut Vec<u8>, index: &mut u32, layers_properties: &Vec<Property>) {
        for layer_property in layers_properties {
            self.buf_extend_u32(data, index, layer_property.kind as u32);
            self.buf_extend_u32(data, index, layer_property.length as u32); // size
            match &layer_property.payload {
                PropertyPayload::Compression(_value) => {
                    data.extend_from_slice(&[_value.to_u8()]);
                    *index += 1;
                }
                PropertyPayload::OpacityLayer(_value) => {
                    data
                        .extend_from_slice(&[_value.r(), _value.g(), _value.b(), _value.a()]);
                    *index += 4;
                }
                PropertyPayload::FloatOpacityLayer() => {
                    // TODO : à améliorer, ça doit être une valeur en float
                    let float_slice = [63, 128, 0, 0];
                    data.extend_from_slice(&float_slice); // prop float opacity value
                    *index += 4;
                }
                PropertyPayload::VisibleLayer() => {
                    let float_slice = [0, 0, 0, 1];
                    data.extend_from_slice(&float_slice); // prop visible value
                    *index += 4;
                }
                PropertyPayload::OffsetsLayer(_offset_x, _offset_y) => {
                    self.buf_extend_u32(data, index, *_offset_x);
                    self.buf_extend_u32(data, index, *_offset_y);
                }
                PropertyPayload::LinkedLayer(_value)
                | PropertyPayload::ColorTagLayer(_value)
                | PropertyPayload::LockContentLayer(_value)
                | PropertyPayload::LockAlphaLayer(_value)
                | PropertyPayload::LockPositionLayer(_value)
                | PropertyPayload::ApplyMaskLayer(_value)
                | PropertyPayload::EditMaskLayer(_value)
                | PropertyPayload::ShowMaskLayer(_value)
                | PropertyPayload::ModeLayer(_value)
                | PropertyPayload::BlendSpaceLayer(_value)
                | PropertyPayload::CompositeSpaceLayer(_value)
                | PropertyPayload::CompositeModeLayer(_value)
                | PropertyPayload::Tatoo(_value) => {
                    self.buf_extend_u32(data, index, *_value);
                }
                _ => {}
            }
        }
        if self.version > 10 && layers_properties.iter().len() == 0 {
            // active
            self.buf_extend_u32(data, index, PropertyIdentifier::PropActiveLayer as u32);
            self.buf_extend_u32(data, index, 0);
            // opacity
            self.buf_extend_u32(data, index, PropertyIdentifier::PropOpacity as u32);
            self.buf_extend_u32(data, index, 4);
            data.extend_from_slice(&[0, 0, 0, 255]);
            *index += 4;
            // float opacity
            self.buf_extend_u32(data, index, PropertyIdentifier::PropFloatOpacity as u32);
            self.buf_extend_u32(data, index, 4);
            let float_slice = [63, 128, 0, 0];
            data.extend_from_slice(&float_slice); // prop float opacity value
            *index += 4;
            // visible
            self.buf_extend_u32(data, index, PropertyIdentifier::PropVisible as u32);
            self.buf_extend_u32(data, index, 4);
            let float_slice = [0, 0, 0, 1];
            data.extend_from_slice(&float_slice); // prop visible value
            *index += 4;

            // linked
            self.buf_extend_u32(data, index, PropertyIdentifier::PropLinked as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 0);

            // color tag
            self.buf_extend_u32(data, index, PropertyIdentifier::PropColorTag as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 0);

            // lock content
            self.buf_extend_u32(data, index, PropertyIdentifier::PropLockContent as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 0);

            // lock alpha
            self.buf_extend_u32(data, index, PropertyIdentifier::PropLockAlpha as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 0);

            // lock position
            self.buf_extend_u32(data, index, PropertyIdentifier::PropLockPosition as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 0);

            // apply mask
            self.buf_extend_u32(data, index, PropertyIdentifier::PropApplyMask as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 0);

            // edit mask
            self.buf_extend_u32(data, index, PropertyIdentifier::PropEditMask as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 0);

            // show mask
            self.buf_extend_u32(data, index, PropertyIdentifier::PropShowMask as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 0);

            // offsets
            self.buf_extend_u32(data, index, PropertyIdentifier::PropOffsets as u32);
            self.buf_extend_u32(data, index, 8);
            self.buf_extend_u32(data, index, 0);
            self.buf_extend_u32(data, index, 0);

            // if version >= 11, than the layer mode must be the new normal mode (not legacy)
            self.buf_extend_u32(data, index, PropertyIdentifier::PropMode as u32);
            self.buf_extend_u32(data, index, 4); // size
            self.buf_extend_u32(data, index, 28); // mode normal after version 10

            // blend space
            self.buf_extend_u32(data, index, PropertyIdentifier::PropBlendSpace as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 0);

            // composite space
            self.buf_extend_u32(data, index, PropertyIdentifier::PropCompositeSpace as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, u32::MAX);

            // composite mode
            self.buf_extend_u32(data, index, PropertyIdentifier::PropCompositeMode as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, u32::MAX);

            // tatoo
            self.buf_extend_u32(data, index, PropertyIdentifier::PropTattoo as u32);
            self.buf_extend_u32(data, index, 4);
            self.buf_extend_u32(data, index, 2);
        }
        self.prop_end(data, index);
    }

    fn _add_layers_v10(&mut self, _layers: &[Layer]) {
        let mut intermediate_buf = vec![];
        let mut layer_offset_zero_index = 0;

        self.buf_extend_u32(&mut intermediate_buf, &mut layer_offset_zero_index, 0); // layer_offset[n] : 0 = end
        self.buf_extend_u32(&mut intermediate_buf, &mut layer_offset_zero_index, 0); // channel_offset[] = 0 => end

        self.index += layer_offset_zero_index as u64;

        let mut layer_offset_one_buf = vec![];
        let mut layer_offset_one_index = 0;

        self.buf_extend_u32(
            &mut layer_offset_one_buf,
            &mut layer_offset_one_index,
            self.index as u32 + 4,
        ); // layer_offset[0] = le pointer du calque

        layer_offset_one_buf.extend_from_slice(&intermediate_buf);
        self.data.extend_from_slice(&layer_offset_one_buf);
        self.index += layer_offset_one_index as u64;

        self.extend_u32(1); // layer[0] : width=1
        self.extend_u32(1); // layer[0] : height=1
        self.extend_u32(0); // layer[0] : type=RGB

        // layer name :
        let mut layer_name_data = vec!();
        let mut layer_name_len = 0;
        self.v10_gimp_string(&mut layer_name_data, &mut layer_name_len, b"Background");
        self.data.extend_from_slice(&layer_name_data);
        self.index += layer_name_len as u64;

        self.extend_u32(PropertyIdentifier::PropActiveLayer as u32); // prop = 2 : active layer
        self.extend_u32(0);

        self.extend_u32(PropertyIdentifier::PropOpacity as u32); // prop : opacity
        self.extend_u32(4); // prop opacity size
        self.extend_u32(RgbaPixel::new(0, 0, 0, 255).to_u32()); // color of opacity = black

        self.extend_u32(PropertyIdentifier::PropMode as u32); // prop : Mode
        self.extend_u32(4); // prop mode size
        self.extend_u32(0); // prop mode=normal

        // TODO : à améliorer, ça doit être une valeur en float
        self.extend_u32(PropertyIdentifier::PropFloatOpacity as u32); // prop : float opacity
        self.extend_u32(4); // prop float opacity size
        let float_slice = [63, 128, 0, 0];
        self.data.extend_from_slice(&float_slice); // prop float opacity value
        self.index += 4;

        self.extend_u32(PropertyIdentifier::PropVisible as u32); // prop : visible
        self.extend_u32(4); // prop visible size
        let float_slice = [0, 0, 0, 1];
        self.data.extend_from_slice(&float_slice); // prop visible value
        self.index += 4;

        self.extend_u32(PropertyIdentifier::PropLinked as u32); // prop : linked
        self.extend_u32(4); // prop linked size
        self.extend_u32(0); // prop linked value


        // TODO : replace by : self.propend()
        self.extend_u32(0);
        self.extend_u32(0);

        // hierarchy offset
        self.extend_u32(self.index as u32 + 8);
        self.extend_u32(0); // mask offset

        // https://testing.developer.gimp.org/core/standards/xcf/#the-hierarchy-structure
        self.extend_u32(1); // width=1
        self.extend_u32(1); // height=1
        self.extend_u32(3); // bpp=3 : RGB color without alpha in 8-bit precision

        self.extend_u32(self.index as u32 + 8); // offset[0]

        self.extend_u32(0); // offset[n] = 0 => end

        self.extend_u32(1); // level[0] width =1
        self.extend_u32(1); // level[0] height =1
        self.extend_u32(self.index as u32 + 8); // offset= le pointer du contenu

        self.extend_u32(0); // data_offset[0] = 0 => end

        //let slice = [00, 158, 00, 36, 00, 222]; // violet r: 158, g: 23, b: 222  with RLE compression
        let slice = [158, 36, 222]; // violet r: 158, g: 36, b: 222  without compression

        // \0\0\2\xa4\0\0\0\0\0\0\0\0\0\x9e
        self.data.extend_from_slice(&slice);
    }

    pub fn add_layers(&mut self, layers: &Vec<Layer>) {
        if self.version < 11 {
            self._add_layers_v10(layers);
            return;
        }
        let nb_layers = layers.iter().len();

        let mut layer_data = vec![];
        let mut layer_index = 0;
        for layer in layers {
            layer_index += 1;
            let mut layer_len = 0;

            let tiles = Tiles::new(layer);

            // Each layers is 8 bits + 8 bits for close layers + 8 bits for close channels
            let layer_offset = self.index + (nb_layers - layer_index + 1) as u64 * 8 + layer_len as u64 + 16;
            /*
            println!(
                "layer[{}] >>>> self.index : {} ---- layer_index {} ---- nb_layers {} layer_len {} ===> {}",
                layer_index - 1,
                self.index,
                layer_index,
                nb_layers,
                layer_len,
                layer_offset
            );
            */
            self.extend_u64(layer_offset); // layer_offset[index -1]
            //self.buf_extend_u64(&mut layer_data, &mut layer_len, pos_layer); // layer_offset[index -1]

            self.buf_extend_u32(&mut layer_data, &mut layer_len, layer.width);
            self.buf_extend_u32(&mut layer_data, &mut layer_len, layer.height);
            self.buf_extend_u32(&mut layer_data, &mut layer_len, layer.kind.kind.clone() as u32);

            // layer name
            self.gimp_string(&mut layer_data, &mut layer_len, layer.name.as_bytes());

            // layer properties
            self._add_layers_properties(&mut layer_data, &mut layer_len, &layer.properties);

            let mut hierarchy_data = vec![];
            let mut hierarchy_len = 0;
            // https://testing.developer.gimp.org/core/standards/xcf/#the-hierarchy-structure
            self.buf_extend_u32(&mut hierarchy_data, &mut hierarchy_len,layer.pixels.width); // width=1
            self.buf_extend_u32(&mut hierarchy_data, &mut hierarchy_len,layer.pixels.height); // height=1

            let layer_has_alpha = LayerColorValue::has_alpha(layer.kind.kind.clone());
            if layer_has_alpha {
                self.buf_extend_u32(&mut hierarchy_data, &mut hierarchy_len, 4); // bpp with alpha
            } else {
                self.buf_extend_u32(&mut hierarchy_data, &mut hierarchy_len, 3); // bpp without alpha
            }

            let mut tiles_headers = vec![];
            let mut tiles_body = vec![];
            let mut tiles_pixels: Vec<Vec<RgbaPixel>> = vec![];
            for _x in 0..tiles.nb {
                tiles_pixels.push(vec![]);
            }

            let mut pixel_index = 0;
            let mut x = 0;
            let mut y = 1;
            for pixel in &layer.pixels.pixels {
                pixel_index += 1;
                x += 1;

                let tile_x = (x as f32 / 64.0).ceil();
                let tile_y = (y as f32 / 64.0).ceil();

                //println!("tiles_len : {}, tile_width_nb: {}, y: {}, tile_y: {}, tile_x: {}, i: {}",
                //    tiles.len(),
                //    tile_width_nb,
                //    y,
                //    tile_y,
                //    tile_x,
                //    tile_width_nb as usize * (tile_y as usize - 1) + tile_x as usize - 1
                //);
                tiles_pixels[tiles.nb_width as usize * (tile_y as usize - 1) + tile_x as usize - 1].push(*pixel);

                if pixel_index % layer.width == 0 {
                    y += 1;
                    x = 0;
                }
            }

            /*
            let mut inc = 0;
            for _t in &tiles {
                inc +=1;
                println!("tile[{}] = length {}", inc, _t.len());
                if inc == 1 {
                    println!("tile : \n\n {:?}", tiles[0]);
                }
            }
            */

            if self.compression == XcfCompression::Rle {
                /*
                let pixels_index = self.index + layer_index as u64 * 8 + nb_layers as u64 * 8 + layer_len as u64;
                println!(
                    "pixels_index : {} = {}",
                    layer_offset,
                    pixels_index
                );
                */
                let nb_of_pixels = layer.pixels.pixels.iter().len() as u32;
                let nb_pixels_of_layers = layer.pixels.width * layer.pixels.height;
                if nb_pixels_of_layers != nb_of_pixels {
                    panic!(
                        "Number of pixels on the layers {} and pixels {} aren't equals",
                        nb_pixels_of_layers, nb_of_pixels
                    );
                }

                //let tile_pointer_size = 8 * nb_of_tiles + 4;

                let mut offset_data = vec![];
                let mut offset_len = 0;
                //let hierarchy_ofs = self.index + layer_index as u64 * 8 + nb_layers as u64 * 8 + 8 + layer_len as u64 + 8;
                let hierarchy_ofs =  layer_offset + layer_len as u64 + 16;
                //println!(
                //    "hierarchy_ofs : {} + {} = {}",
                //    layer_offset,
                //    layer_len,
                //    hierarchy_ofs
                //);
                self.buf_extend_u32(&mut offset_data, &mut offset_len,layer.pixels.width); // level[0] width
                self.buf_extend_u32(&mut offset_data, &mut offset_len,layer.pixels.height); // level[0] height
                self.buf_extend_u32(&mut offset_data, &mut offset_len,0); // ptr : Pointer to tile data
    
                let offset_index = hierarchy_ofs + offset_len as u64 + tiles.nb as u64 * 8 + 8;
                //println!(
                //    "offset_index : {} + {} + {} + 8 = offset_index = {}",
                //    hierarchy_ofs,
                //    offset_len,
                //    tiles.nb,
                //    offset_index
                //);
                for _tile in &tiles_pixels {
                    self.buf_extend_u64(&mut hierarchy_data, &mut hierarchy_len, offset_index); // offset[n]
                }
                self.buf_extend_u64(&mut hierarchy_data, &mut hierarchy_len, 0); // offset[2]

                let mut tiles_headers_len = 0;
                for tile in &tiles_pixels {
                    let tile_index = offset_index as u32 + 16 + tiles.nb * 8 + tiles_body.len() as u32;
                    //println!("tile_index : {}, offset_index: {}, nb_of_tiles : {}, tiles_len : {}", tile_index, offset_index, nb_of_tiles, tiles_body.len());
                    self.buf_extend_u32(&mut tiles_headers, &mut tiles_headers_len, tile_index);
                    self.buf_extend_u32(&mut tiles_headers, &mut tiles_headers_len, 0);
                    tiles_headers_len = 0;

                    let mut buffer_r = vec![];
                    let mut buffer_g = vec![];
                    let mut buffer_b = vec![];
                    let mut buffer_a = vec![];
                    for pixel in tile {
                        buffer_r.push(pixel.r());
                        buffer_g.push(pixel.g());
                        buffer_b.push(pixel.b());
                        if layer_has_alpha {
                            buffer_a.push(pixel.a());
                        }
                    }

                    let rle_r = rle_compress(&buffer_r);
                    //println!("buffer r : {:?}", buffer_r);
                    //println!("rle r : {:?}\n\n", rle_r);
                    tiles_body.extend(rle_r);

                    let rle_g = rle_compress(&buffer_g);
                    //println!("buffer g : {:?}", buffer_g);
                    //println!("rle g : {:?}\n\n", rle_g);
                    tiles_body.extend(rle_g);

                    let  rle_b = rle_compress(&buffer_b);
                    //println!("buffer b : {:?}", buffer_b);
                    //println!("rle b : {:?}\n\n", rle_b);
                    tiles_body.extend(rle_b);

                    if layer_has_alpha {
                        let rle_a = rle_compress(&buffer_a);
                        //println!("buffer a : {:?}", buffer_a);
                        //println!("rle a : {:?}\n\n", rle_a);
                        tiles_body.extend(rle_a);
                    }
                }

                hierarchy_data.extend_from_slice(&offset_data);
                hierarchy_len += offset_len;

                // hierarchy offset
                self.buf_extend_u64(&mut layer_data, &mut layer_len, hierarchy_ofs); // hierarchy_ofs=
                self.buf_extend_u64(&mut layer_data, &mut layer_len,0); // layer mask offset

                layer_data.extend_from_slice(&hierarchy_data);
                layer_len += hierarchy_len;
                tiles_headers.extend_from_slice(&[0, 0, 0, 0]);

                layer_data.extend_from_slice(&tiles_headers);
                layer_data.extend_from_slice(&tiles_body);
                layer_len += tiles_headers.len() as u32 + tiles_body.len() as u32;
                self.index += layer_len as u64;
            } else {
                panic!("not implemented");
            }
        }
        self.extend_u64(0); // layer_offset[1] = 0
        self.extend_u64(0); // channel_offset[0] = 0
        self.data.extend_from_slice(&layer_data);
    }

    pub fn save(&mut self, path: &PathBuf) -> Result<File, crate::Error> {
        let mut new_file = File::create(&path)?;
        new_file.write_all(self.data.as_slice())?;
        Ok(new_file)
    }
}

pub fn short_run_identical(verbatim: &[u8]) -> Vec<u8> {
    println!("short run identical");
    if verbatim.len() < 1 {
        panic!("Wrong verbatim lengh : {}", verbatim.len());
    }
    vec![(verbatim.len() - 1) as u8, verbatim[0]]
}

pub fn long_run_identical(verbatim: &[u8]) -> Vec<u8> {
    println!("long run identical");
    if verbatim.len() < 127 {
        panic!("Wrong verbatim lengh : {}", verbatim.len());
    }
    // verbatim_len = p*256+q
    let p = verbatim.len() / 256;
    let q = verbatim.len() % 256;
    vec![127, p as u8, q as u8, verbatim[0]]
}

pub fn run_identical(verbatim: &[u8]) -> Vec<u8> {
    if verbatim.len() > 126 {
        return long_run_identical(&verbatim);
    }
    short_run_identical(&verbatim)
}

pub fn short_run_diff(verbatim: &[u8]) -> Vec<u8> {
    println!("short run diff");
    if verbatim.len() < 1 {
        panic!("Wrong verbatim lengh : {}", verbatim.len());
    }
    let mut r = vec![(256 - verbatim.len()) as u8];
    r.extend_from_slice(verbatim);
    r
}

pub fn long_run_diff(verbatim: &[u8]) -> Vec<u8> {
    println!("long run diff");
    if verbatim.len() < 127 {
        panic!("Wrong verbatim lengh : {}", verbatim.len());
    }
    // verbatim_len = p*256+q
    let p = verbatim.len() / 256;
    let q = verbatim.len() % 256;
    let mut r = vec![128, p as u8, q as u8];
    r.extend_from_slice(verbatim);
    r
}

pub fn run_diff(verbatim: &[u8]) -> Vec<u8> {
    if verbatim.len() > 126 {
        return long_run_diff(&verbatim);
    }
    short_run_diff(&verbatim)
}

pub fn is_identiqual(values: &[u8]) -> bool {
    if values.len() < 2 {
        panic!("Wrong values lengh : {}", values.len());
    }
    let value = values[0];
    for v in &values[1..values.len()] {
        if value != *v {
            return false;
        }
    }
    return true;
}

// https://testing.developer.gimp.org/core/standards/xcf/#rle-compressed-tile-data
pub fn rle_compress(data: &Vec<u8>) -> Vec<u8> {
    let mut compress_data = vec![];
    let mut verbatim: Vec<u8> = vec![];
    let mut i = 0;
    for byte in data {
        i += 1;
        verbatim.push(*byte);

        if i >= data.len() - 1 {
            break;
        }
        let val = *byte;
        let mut val_last_1 = val;
        let mut val_last_2 = val;
        if i > 1 {
            val_last_1 = data[i - 2];
        }
        if i > 2 {
            val_last_2 = data[i - 3];
        }
        let val_1 = data[i];
        let val_2 = data[i + 1];
        let mut val_3 = val_2;
        if i < data.len() - 2 {
            val_3 = data[i + 2];
        }

        //println!(
        //    "i: {}, val-2: {}, val-1: {}, val: {}, val+1: {}, val+2: {}, val+3: {}, v_len: {}",
        //    i,
        //    val_last_2,
        //    val_last_1,
        //    val,
        //    val_1,
        //    val_2,
        //    val_3,
        //    verbatim.len()
        //);
        if i == 2
        && val_last_1 == val
        && val != val_1 {
            let buffer = short_run_identical(&verbatim);
            compress_data.extend_from_slice(&buffer);
            verbatim = vec![];
            continue;
        }
        if i == 1
        && val != val_1
        && val_1 == val_2
        && val_2 == val_3 {
            let buffer = run_diff(&verbatim);
            compress_data.extend_from_slice(&buffer);
            verbatim = vec![];
            continue;
        }
        if i > 2
        && val_last_2 == val_last_1
        && val_last_1 == val
        && val != val_1 {
            println!("f 2: {:?}", verbatim);
            let buffer = run_identical(&verbatim);
            compress_data.extend_from_slice(&buffer);
            verbatim = vec![];
            continue;
        }

        if i > 4  && i < data.len() - 2
           && is_identiqual(&vec![data[i - 3], data[i - 4], data[i - 5]])
           && val_last_1 == val
           && val != val_1
        {
            println!("f 3: {:?}", verbatim);
            let buffer = run_identical(&verbatim);
            compress_data.extend_from_slice(&buffer);
            verbatim = vec![];
            continue;
        }

        if i < data.len() - 2
        && val != val_1
        && val_1 == val_2
        && val_2 == val_3 {
            println!("f 4");
            let buffer = run_diff(&verbatim);
            compress_data.extend_from_slice(&buffer);
            verbatim = vec![];
            continue;
        }
    }
    verbatim.push(data[data.len() - 1]);
    let val = verbatim[verbatim.len() - 1];
    let mut val_last_1 = val;
    let mut val_last_2 = val;
    let mut val_last_3 = val;
    if verbatim.len() > 1 {
        val_last_1 = verbatim[verbatim.len() - 2];
    }
    if verbatim.len() > 2 {
        val_last_2 = verbatim[verbatim.len() - 3];
    }
    if verbatim.len() > 3 {
        val_last_3 = verbatim[verbatim.len() - 4];
    }
    let mut buffer;

    if verbatim.len() >= 2 && val == val_last_1 && val_last_1 == val_last_2 {
        println!("1.");
        if data.len() == 1 {
            buffer = vec![0, verbatim[0]];
        } else {
            buffer = run_identical(&verbatim);
        }
    } else if verbatim.len() >= 2 && val != val_last_1 && val_last_1 == val_last_2 && val_last_2 == val_last_3 {
        println!("1.1");
        buffer = run_identical(&verbatim[..verbatim.len() - 1]);
        buffer.push(0);
        buffer.push(val);
    } else if verbatim.len() >= 2 && val == val_last_1 {
        println!("2.");
        //println!("2. c: {:?}, v: {:?}", compress_data, verbatim);
        buffer = run_diff(&verbatim[..verbatim.len() - 2]);
        buffer.push(1);
        buffer.push(verbatim[verbatim.len() - 1]);
    } else {
        println!("3.");
        buffer = run_diff(&verbatim);
    }

    compress_data.extend_from_slice(&buffer);
    compress_data
}