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#![cfg_attr(feature = "cargo-clippy", allow(clippy::useless_attribute))]
use std::{io, usize};
use crate::errors::HeaderErr;
use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
use num_traits::{FromPrimitive, ToPrimitive};
mod builder;
#[cfg(test)]
mod test;
pub use self::builder::HeaderBuilder;
pub const QUALITY_MAX: u16 = 1024;
pub const BLOCK_DEFAULT: u8 = 7;
pub const BLOCK_MAX: u8 = 30;
const MAGIC: u32 = 'G' as u32 | (('F' as u32) << 8) | (('W' as u32) << 16) | (('X' as u32) << 24);
#[derive(Clone, Copy, Debug, PartialEq, ToPrimitive, FromPrimitive)]
pub enum Filter {
Linear = 0,
Cubic = 1,
}
#[derive(Clone, Copy, Debug, PartialEq, ToPrimitive, FromPrimitive)]
pub enum Quantization {
Scalar = 0,
}
#[derive(Clone, Copy, Debug, PartialEq, ToPrimitive, FromPrimitive)]
pub enum Encoder {
Turbo = 0,
Fast = 1,
Contextual = 2,
}
#[derive(Clone, Copy, Debug, PartialEq, ToPrimitive, FromPrimitive)]
pub enum Intent {
Generic = 0,
RGB = 7,
RGBA = 8,
BGR = 10,
BGRA = 11,
YUV444 = 12,
}
#[derive(Debug, PartialEq)]
pub struct Header {
pub version: u32,
pub width: u32,
pub height: u32,
pub layers: u16,
pub channels: u16,
pub bit_depth: u8,
pub is_signed: bool,
pub quality: u16,
pub chroma_scale: u8,
pub block_size: u8,
pub filter: Filter,
pub quantization: Quantization,
pub encoder: Encoder,
pub intent: Intent,
pub metadata_size: u32,
pub(crate) channel_size: usize,
pub(crate) image_size: usize,
}
impl Header {
pub fn decode(encoded: &mut impl io::Read) -> Result<Header, HeaderErr> {
if encoded.read_u32::<LittleEndian>()? != MAGIC {
return Err(HeaderErr::WrongMagic);
}
let version = encoded.read_u32::<LittleEndian>()?;
let width = encoded.read_u32::<LittleEndian>()?;
let height = encoded.read_u32::<LittleEndian>()?;
let channels = encoded
.read_u16::<LittleEndian>()?
.checked_add(1)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong channels value")))?;
let layers = encoded
.read_u16::<LittleEndian>()?
.checked_add(1)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong layers value")))?;
let tmp = encoded.read_u24::<LittleEndian>()?;
let block_size = ((tmp & 0b11111) as u8)
.checked_add(2)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong block_size value")))?;
let chroma_scale = (((tmp >> 5) & 0xff) as u8)
.checked_add(1)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong chroma_scale value")))?;
let quality = (((tmp >> 13) & 0b11_1111_1111) as u16)
.checked_add(1)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong quality value")))?;
let is_signed = (tmp >> 23) == 1;
let bit_depth = encoded
.read_u8()?
.checked_add(1)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong bit_depth value")))?;
let intent = Intent::from_u8(encoded.read_u8()?)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong intent value")))?;
let encoder = Encoder::from_u8(encoded.read_u8()?)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong encoder value")))?;
let quantization = Quantization::from_u8(encoded.read_u8()?)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong quantization value")))?;
let filter = Filter::from_u8(encoded.read_u8()?)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong filter value")))?;
let metadata_size = encoded
.read_u32::<LittleEndian>()?
.checked_mul(4)
.ok_or_else(|| HeaderErr::WrongValue(String::from("Wrong metadata_size value")))?;
if is_signed || bit_depth > 8 {
return Err(HeaderErr::WrongValue(String::from(
"Unsupported bit_depth and is_signed values",
)));
}
let builder = HeaderBuilder {
width,
height,
layers,
channels,
quality,
chroma_scale,
block_size,
filter,
encoder,
intent,
metadata_size,
};
let mut header = builder.build()?;
header.version = version;
header.bit_depth = bit_depth;
header.is_signed = is_signed;
header.quantization = quantization;
Ok(header)
}
pub fn encode(&self, buff: &mut impl io::Write) -> io::Result<()> {
buff.write_u32::<LittleEndian>(MAGIC)?;
buff.write_u32::<LittleEndian>(self.version)?;
buff.write_u32::<LittleEndian>(self.width)?;
buff.write_u32::<LittleEndian>(self.height)?;
buff.write_u16::<LittleEndian>(self.channels - 1)?;
buff.write_u16::<LittleEndian>(self.layers - 1)?;
let tmp = u32::from(self.block_size - 2)
| (u32::from(self.chroma_scale - 1) << 5)
| (u32::from(self.quality - 1) << 13)
| ((if self.is_signed { 1 } else { 0 }) << 23);
buff.write_u24::<LittleEndian>(tmp)?;
buff.write_u8(self.bit_depth - 1)?;
buff.write_u8(self.intent.to_u8().unwrap())?;
buff.write_u8(self.encoder.to_u8().unwrap())?;
buff.write_u8(self.quantization.to_u8().unwrap())?;
buff.write_u8(self.filter.to_u8().unwrap())?;
buff.write_u32::<LittleEndian>(self.metadata_size / 4)?;
Ok(())
}
pub fn get_decompress_buffer_size(&self, downsampling: usize) -> usize {
self.get_downsampled_image_size(downsampling) * ((self.bit_depth + 7) / 8) as usize
}
pub fn get_boost(&self) -> i16 {
if self.quality == QUALITY_MAX {
1
} else {
8
}
}
pub fn get_downsampled_width(&self, downsampling: usize) -> usize {
(self.width as usize + (1 << downsampling) - 1) >> downsampling
}
pub fn get_downsampled_height(&self, downsampling: usize) -> usize {
(self.height as usize + (1 << downsampling) - 1) >> downsampling
}
pub fn get_downsampled_channel_size(&self, downsampling: usize) -> usize {
self.get_downsampled_width(downsampling) * self.get_downsampled_height(downsampling)
}
pub fn get_channel_size(&self) -> usize {
self.channel_size
}
pub fn get_chroma_quality(&self) -> i32 {
1.max(
(i32::from(self.quality) + i32::from(self.chroma_scale) / 2)
/ i32::from(self.chroma_scale),
)
}
pub fn get_image_size(&self) -> usize {
self.image_size
}
pub fn get_downsampled_image_size(&self, downsampling: usize) -> usize {
self.get_downsampled_channel_size(downsampling)
* self.layers as usize
* self.channels as usize
}
}