1 files changed, 80 insertions, 0 deletions
diff --git a/vendor/jpeg-decoder/src/worker/immediate.rs b/vendor/jpeg-decoder/src/worker/immediate.rs
new file mode 100644
index 0000000..8c6e7db
--- /dev/null
+++ b/vendor/jpeg-decoder/src/worker/immediate.rs
@@ -0,0 +1,80 @@
+use alloc::vec;
+use alloc::vec::Vec;
+use core::mem;
+use core::convert::TryInto;
+use crate::decoder::MAX_COMPONENTS;
+use crate::error::Result;
+use crate::idct::dequantize_and_idct_block;
+use crate::alloc::sync::Arc;
+use crate::parser::Component;
+use super::{RowData, Worker};
+
+pub struct ImmediateWorker {
+    offsets: [usize; MAX_COMPONENTS],
+    results: Vec<Vec<u8>>,
+    components: Vec<Option<Component>>,
+    quantization_tables: Vec<Option<Arc<[u16; 64]>>>,
+}
+
+impl Default for ImmediateWorker {
+    fn default() -> Self {
+        ImmediateWorker {
+            offsets: [0; MAX_COMPONENTS],
+            results: vec![Vec::new(); MAX_COMPONENTS],
+            components: vec![None; MAX_COMPONENTS],
+            quantization_tables: vec![None; MAX_COMPONENTS],
+        }
+    }
+}
+
+impl ImmediateWorker {
+    pub fn start_immediate(&mut self, data: RowData) {
+        assert!(self.results[data.index].is_empty());
+
+        self.offsets[data.index] = 0;
+        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);
+        self.components[data.index] = Some(data.component);
+        self.quantization_tables[data.index] = Some(data.quantization_table);
+    }
+
+    pub fn append_row_immediate(&mut self, (index, data): (usize, Vec<i16>)) {
+        // Convert coefficients from a MCU row to samples.
+
+        let component = self.components[index].as_ref().unwrap();
+        let quantization_table = self.quantization_tables[index].as_ref().unwrap();
+        let block_count = component.block_size.width as usize * component.vertical_sampling_factor as usize;
+        let line_stride = component.block_size.width as usize * component.dct_scale;
+
+        assert_eq!(data.len(), block_count * 64);
+
+        for i in 0..block_count {
+            let x = (i % component.block_size.width as usize) * component.dct_scale;
+            let y = (i / component.block_size.width as usize) * component.dct_scale;
+
+            let coefficients = data[i * 64..(i + 1) * 64].try_into().unwrap();
+            let output = &mut self.results[index][self.offsets[index] + y * line_stride + x..];
+
+            dequantize_and_idct_block(component.dct_scale, coefficients, quantization_table, line_stride, output);
+        }
+
+        self.offsets[index] += block_count * component.dct_scale * component.dct_scale;
+    }
+
+    pub fn get_result_immediate(&mut self, index: usize) -> Vec<u8> {
+        mem::take(&mut self.results[index])
+    }
+}
+
+impl Worker for ImmediateWorker {
+    fn start(&mut self, data: RowData) -> Result<()> {
+        self.start_immediate(data);
+        Ok(())
+    }
+    fn append_row(&mut self, row: (usize, Vec<i16>)) -> Result<()> {
+        self.append_row_immediate(row);
+        Ok(())
+    }
+    fn get_result(&mut self, index: usize) -> Result<Vec<u8>> {
+        Ok(self.get_result_immediate(index))
+    }
+}