jpeg_decoder/worker/
immediate.rs

Help
1use alloc::vec;
2use alloc::vec::Vec;
3use core::mem;
4use crate::decoder::MAX_COMPONENTS;
5use crate::error::Result;
6use crate::idct::dequantize_and_idct_block;
7use crate::alloc::sync::Arc;
8use crate::parser::Component;
9use super::{RowData, Worker};
10
11pub struct ImmediateWorker {
12    offsets: [usize; MAX_COMPONENTS],
13    results: Vec<Vec<u8>>,
14    components: Vec<Option<Component>>,
15    quantization_tables: Vec<Option<Arc<[u16; 64]>>>,
16}
17
18impl Default for ImmediateWorker {
19    fn default() -> Self {
20        ImmediateWorker {
21            offsets: [0; MAX_COMPONENTS],
22            results: vec![Vec::new(); MAX_COMPONENTS],
23            components: vec![None; MAX_COMPONENTS],
24            quantization_tables: vec![None; MAX_COMPONENTS],
25        }
26    }
27}
28
29impl ImmediateWorker {
30    pub fn start_immediate(&mut self, data: RowData) {
31        assert!(self.results[data.index].is_empty());
32
33        self.offsets[data.index] = 0;
34        self.results[data.index].resize(data.component.block_size.width as usize * data.component.block_size.height as usize * data.component.dct_scale * data.component.dct_scale, 0u8);
35        self.components[data.index] = Some(data.component);
36        self.quantization_tables[data.index] = Some(data.quantization_table);
37    }
38
39    pub fn append_row_immediate(&mut self, (index, data): (usize, Vec<i16>)) {
40        // Convert coefficients from a MCU row to samples.
41
42        let component = self.components[index].as_ref().unwrap();
43        let quantization_table = self.quantization_tables[index].as_ref().unwrap();
44        let block_count = component.block_size.width as usize * component.vertical_sampling_factor as usize;
45        let line_stride = component.block_size.width as usize * component.dct_scale;
46
47        assert_eq!(data.len(), block_count * 64);
48
49        for i in 0..block_count {
50            let x = (i % component.block_size.width as usize) * component.dct_scale;
51            let y = (i / component.block_size.width as usize) * component.dct_scale;
52
53            let coefficients = data[i * 64..(i + 1) * 64].try_into().unwrap();
54            let output = &mut self.results[index][self.offsets[index] + y * line_stride + x..];
55
56            dequantize_and_idct_block(component.dct_scale, coefficients, quantization_table, line_stride, output);
57        }
58
59        self.offsets[index] += block_count * component.dct_scale * component.dct_scale;
60    }
61
62    pub fn get_result_immediate(&mut self, index: usize) -> Vec<u8> {
63        mem::take(&mut self.results[index])
64    }
65}
66
67impl Worker for ImmediateWorker {
68    fn start(&mut self, data: RowData) -> Result<()> {
69        self.start_immediate(data);
70        Ok(())
71    }
72    fn append_row(&mut self, row: (usize, Vec<i16>)) -> Result<()> {
73        self.append_row_immediate(row);
74        Ok(())
75    }
76    fn get_result(&mut self, index: usize) -> Result<Vec<u8>> {
77        Ok(self.get_result_immediate(index))
78    }
79}
jpeg_decoder/worker/immediate.rs

jpeg_decoder/worker/
immediate.rs
