feat: Add zstd support (#56)

.vscode/settings.json

@@ -1,3 +1,3 @@
 {
-	"rust-analyzer.cargo.features": ["default", "lzma", "deflate64", "bzip2"]
+	"rust-analyzer.cargo.features": ["default", "lzma", "deflate64", "bzip2", "zstd"]
 }

Cargo.toml

@@ -38,6 +38,7 @@ cfg-if = "1.0.0"
 lzma-rs = { version = "0.3.0", features = ["stream"], optional = true }
 deflate64 = { version = "0.1.7", optional = true }
 bzip2 = { version = "0.4.4", optional = true }
+zstd = { version = "0.13.0", optional = true }
 
 [features]
 default = ["sync", "file", "deflate"]
@@ -47,6 +48,7 @@ deflate = ["dep:flate2"]
 deflate64 = ["dep:deflate64"]
 lzma = ["dep:lzma-rs"]
 bzip2 = ["dep:bzip2"]
+zstd = ["dep:zstd"]
 
 [dev-dependencies]
 clap = { version = "4.4.18", features = ["derive"] }

src/reader/sync/entry_reader/mod.rs

@@ -19,6 +19,9 @@ mod deflate64_dec;
 #[cfg(feature = "bzip2")]
 mod bzip2_dec;
 
+#[cfg(feature = "zstd")]
+mod zstd_dec;
+
 use cfg_if::cfg_if;
 use oval::Buffer;
 use std::io;
@@ -309,6 +312,15 @@ where
                     }
                 }
             }
+            Method::Zstd => {
+                cfg_if! {
+                    if #[cfg(feature = "zstd")] {
+                        Box::new(zstd_dec::mk_decoder(limited_reader)?)
+                    } else {
+                        return Err(Error::method_not_enabled(self.method));
+                    }
+                }
+            }
             method => {
                 return Err(Error::method_not_supported(method));
             }

src/reader/sync/entry_reader/zstd_dec.rs

@@ -0,0 +1,23 @@
+use std::io::{BufReader, Read};
+
+use zstd::stream::Decoder as ZstdDecoder;
+
+use crate::reader::sync::{Decoder, LimitedReader};
+
+impl<R> Decoder<R> for ZstdDecoder<'static, BufReader<R>>
+where
+    R: Read,
+{
+    fn into_inner(self: Box<Self>) -> R {
+        Self::finish(*self).into_inner()
+    }
+
+    fn get_mut(&mut self) -> &mut R {
+        Self::get_mut(self).get_mut()
+    }
+}
+
+pub(crate) fn mk_decoder(r: LimitedReader) -> std::io::Result<impl Decoder<LimitedReader>> {
+    // TODO: have LimitedReader (and Buffer) implement BufRead, cf. https://github.com/fasterthanlime/rc-zip/issues/55
+    ZstdDecoder::with_buffer(BufReader::new(r))
+}

tests/integration_tests.rs

@@ -308,6 +308,19 @@ fn test_cases() -> Vec<ZipTest> {
             }],
             ..Default::default()
         },
+        // same with zstd
+        #[cfg(feature = "zstd")]
+        ZipTest {
+            source: ZipSource::File("found-me-zstd.zip"),
+            expected_encoding: Some(Encoding::Utf8),
+            files: vec![ZipTestFile {
+                name: "found-me.txt",
+                content: FileContent::Bytes("Oh no, you found me\n".repeat(5000).into()),
+                modified: Some(date((2024, 1, 31), (6, 10, 25), 800491400, time_zone(0)).unwrap()),
+                ..Default::default()
+            }],
+            ..Default::default()
+        },
     ]
 }