Make libdeflater and zopfli optional (#319)

* Make `libdeflater` and `zopfli` optional

Cargo.toml

@@ -33,11 +33,11 @@ bit-vec = "^0.6.2"
 byteorder = "^1.0.0"
 crc = "^1.2.0"
 itertools = "^0.9.0"
-zopfli = "^0.4.0"
+zopfli = { version = "^0.4.0", optional = true }
 miniz_oxide = "0.4"
 rgb = "0.8.25"
 indexmap = { version = "1.6.0", features = ["rayon"] }
-libdeflater = "0.5.0"
+libdeflater = { version = "0.5.0", optional = true }
 log = "0.4.11"
 stderrlog = { version = "0.5.0", optional = true }
 
@@ -71,7 +71,7 @@ binary = [
     "wild",
     "stderrlog",
 ]
-default = ["binary", "parallel"]
+default = ["binary", "parallel", "libdeflater", "zopfli"]
 parallel = ["rayon"]
 
 [lib]

src/deflate/mod.rs

@@ -3,12 +3,13 @@ use crate::error::PngError;
 use crate::Deadline;
 use crate::PngResult;
 use indexmap::IndexSet;
-use std::cmp::max;
 
 #[doc(hidden)]
 pub mod miniz_stream;
 
+#[cfg(feature = "libdeflater")]
 mod deflater;
+#[cfg(feature = "libdeflater")]
 pub use deflater::deflate as libdeflater_deflate;
 
 #[cfg(any(target_arch = "x86_64", target_arch = "aarch64"))]
@@ -47,7 +48,10 @@ pub fn deflate(
     miniz_stream::compress_to_vec_oxipng(data, zc, zw.into(), zs.into(), max_size, deadline)
 }
 
+#[cfg(feature = "zopfli")]
 pub fn zopfli_deflate(data: &[u8]) -> PngResult<Vec<u8>> {
+    use std::cmp::max;
+
     let mut output = Vec::with_capacity(max(1024, data.len() / 20));
     let options = zopfli::Options::default();
     match zopfli::compress(&options, &zopfli::Format::Zlib, data, &mut output) {
@@ -79,8 +83,10 @@ pub enum Deflaters {
         /// Default: `15`
         window: u8,
     },
+    #[cfg(feature = "zopfli")]
     /// Use the better but slower Zopfli implementation
     Zopfli,
+    #[cfg(feature = "libdeflater")]
     /// Use libdeflater.
     Libdeflater,
 }

src/lib.rs

@@ -12,6 +12,11 @@
 #![warn(clippy::path_buf_push_overwrite)]
 #![warn(clippy::range_plus_one)]
 #![allow(clippy::cognitive_complexity)]
+#![cfg_attr(
+    not(any(feature = "libdeflater", feature = "zopfli")),
+    allow(irrefutable_let_patterns),
+    allow(unreachable_patterns)
+)]
 
 #[cfg(feature = "parallel")]
 extern crate rayon;
@@ -569,7 +574,9 @@ fn optimize_png(
                     &best_size,
                     &deadline,
                 ),
+                #[cfg(feature = "zopfli")]
                 Deflaters::Zopfli => deflate::zopfli_deflate(filtered),
+                #[cfg(feature = "libdeflater")]
                 Deflaters::Libdeflater => deflate::libdeflater_deflate(filtered, &best_size),
             };