From 3afe3e7a2286f110f11a6829f6f458eb5c0d27a7 Mon Sep 17 00:00:00 2001
From: Richard Lindsley <rich.lindsley@gmail.com>
Date: Thu, 16 Feb 2023 17:41:20 -0800
Subject: [PATCH 1/2] Add the shuffle option to the compression method

---
 netcdf/src/variable.rs | 7 +++++--
 netcdf/tests/group.rs  | 2 +-
 netcdf/tests/lib.rs    | 6 +++---
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/netcdf/src/variable.rs b/netcdf/src/variable.rs
index 4a8c1dc..046ac20 100644
--- a/netcdf/src/variable.rs
+++ b/netcdf/src/variable.rs
@@ -170,16 +170,19 @@ impl<'g> VariableMut<'g> {
     /// compression (good for CPU bound tasks), and 9 providing the
     /// highest compression level (good for memory bound tasks)
     ///
+    /// `shuffle` enables a filter to reorder bytes before compressing, which
+    /// can improve compression ratios
+    ///
     /// # Errors
     ///
     /// Not a `netcdf-4` file or `deflate_level` not valid
-    pub fn compression(&mut self, deflate_level: nc_type) -> error::Result<()> {
+    pub fn compression(&mut self, deflate_level: nc_type, shuffle: bool) -> error::Result<()> {
         unsafe {
             error::checked(super::with_lock(|| {
                 nc_def_var_deflate(
                     self.ncid,
                     self.varid,
-                    <_>::from(false),
+                    shuffle.into(),
                     <_>::from(true),
                     deflate_level,
                 )
diff --git a/netcdf/tests/group.rs b/netcdf/tests/group.rs
index ceab0d3..210030d 100644
--- a/netcdf/tests/group.rs
+++ b/netcdf/tests/group.rs
@@ -64,7 +64,7 @@ fn find_variable() {
 
     for mut var in group.variables_mut() {
         if var.dimensions().len() > 0 {
-            var.compression(3).unwrap();
+            var.compression(3, false).unwrap();
         }
         if var.name() == "z" {
             var.chunking(&[1]).unwrap();
diff --git a/netcdf/tests/lib.rs b/netcdf/tests/lib.rs
index 481fabd..eaf3718 100644
--- a/netcdf/tests/lib.rs
+++ b/netcdf/tests/lib.rs
@@ -854,7 +854,7 @@ fn use_compression_chunking() {
     file.add_dimension("x", 10).unwrap();
 
     let var = &mut file.add_variable::<i32>("compressed", &["x"]).unwrap();
-    var.compression(5).unwrap();
+    var.compression(5, false).unwrap();
     var.chunking(&[5]).unwrap();
 
     let v = vec![0i32; 10];
@@ -863,7 +863,7 @@ fn use_compression_chunking() {
     let var = &mut file
         .add_variable::<i32>("compressed2", &["x", "x"])
         .unwrap();
-    var.compression(9).unwrap();
+    var.compression(9, true).unwrap();
     var.chunking(&[5, 5]).unwrap();
     var.put_values(&[1i32, 2, 3, 4, 5, 6, 7, 8, 9, 10], (..10, ..1))
         .unwrap();
@@ -903,7 +903,7 @@ fn set_compression_all_variables_in_a_group() {
         .expect("Could not create variable");
 
     for mut var in file.variables_mut() {
-        var.compression(9).expect("Could not set compression level");
+        var.compression(9, false).expect("Could not set compression level");
     }
 }
 

From f8a14868992e6b4beb6163dc8f935d0500903a8b Mon Sep 17 00:00:00 2001
From: Magnus Ulimoen <magnusu@met.no>
Date: Fri, 17 Feb 2023 15:53:49 +0100
Subject: [PATCH 2/2] Run cargo fmt

---
 netcdf/tests/lib.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/netcdf/tests/lib.rs b/netcdf/tests/lib.rs
index eaf3718..9e57ae6 100644
--- a/netcdf/tests/lib.rs
+++ b/netcdf/tests/lib.rs
@@ -903,7 +903,8 @@ fn set_compression_all_variables_in_a_group() {
         .expect("Could not create variable");
 
     for mut var in file.variables_mut() {
-        var.compression(9, false).expect("Could not set compression level");
+        var.compression(9, false)
+            .expect("Could not set compression level");
     }
 }