Merge pull request #1857 from bash/remove-scoped_threadpool

Remove multithreading in HDR decoding

Cargo.toml

@@ -37,7 +37,6 @@ num-traits = "0.2.0"
 gif = { version = "0.12", optional = true }
 jpeg = { package = "jpeg-decoder", version = "0.3.0", default-features = false, optional = true }
 png = { version = "0.17.6", optional = true }
-scoped_threadpool = { version = "0.1", optional = true }
 tiff = { version = "0.8.0", optional = true }
 ravif = { version = "0.11.0", optional = true }
 rgb = { version = "0.8.25", optional = true }
@@ -67,7 +66,7 @@ ico = ["bmp", "png"]
 pnm = []
 tga = []
 bmp = []
-hdr = ["scoped_threadpool"]
+hdr = []
 dxt = []
 dds = ["dxt"]
 farbfeld = []

Cargo.toml.public-private-dependencies

@@ -37,7 +37,6 @@ num-traits = { version = "0.2.0", public = true }
 gif = { version = "0.11.1", optional = true }
 jpeg = { package = "jpeg-decoder", version = "0.2.1", default-features = false, optional = true }
 png = { version = "0.17.0", optional = true }
-scoped_threadpool = { version = "0.1", optional = true }
 tiff = { version = "0.7.1", optional = true }
 ravif = { version = "0.8.0", optional = true }
 rgb = { version = "0.8.25", optional = true }
@@ -63,7 +62,7 @@ pnm = []
 tga = []
 webp = []
 bmp = []
-hdr = ["scoped_threadpool"]
+hdr = []
 dxt = []
 dds = ["dxt"]
 farbfeld = []

src/codecs/hdr/decoder.rs

@@ -1,6 +1,5 @@
 use crate::Primitive;
 use num_traits::identities::Zero;
-use scoped_threadpool::Pool;
 #[cfg(test)]
 use std::borrow::Cow;
 use std::convert::TryFrom;
@@ -460,21 +459,16 @@ impl<R: BufRead> HdrDecoder<R> {
         }
 
         let chunks_iter = output_slice.chunks_mut(self.width as usize);
-        let mut pool = Pool::new(8); //
-
-        (pool.scoped(|scope| {
-            for chunk in chunks_iter {
-                let mut buf = vec![Default::default(); self.width as usize];
-                read_scanline(&mut self.r, &mut buf[..])?;
-                let f = &f;
-                scope.execute(move || {
-                    for (dst, &pix) in chunk.iter_mut().zip(buf.iter()) {
-                        *dst = f(pix);
-                    }
-                });
+
+        let mut buf = vec![Default::default(); self.width as usize];
+        for chunk in chunks_iter {
+            // read_scanline overwrites the entire buffer or returns an Err,
+            // so not resetting the buffer here is ok.
+            read_scanline(&mut self.r, &mut buf[..])?;
+            for (dst, &pix) in chunk.iter_mut().zip(buf.iter()) {
+                *dst = f(pix);
             }
-            Ok(())
-        }) as Result<(), ImageError>)?;
+        }
         Ok(())
     }