initial oss-fuzz integration. (rust-lang#267)

fuzz/.gitignore

@@ -0,0 +1,4 @@
+
+target
+corpus
+artifacts

fuzz/Cargo.toml

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+
+[package]
+name = "flate2-fuzz"
+version = "0.0.0"
+authors = ["Automatically generated"]
+publish = false
+edition = "2018"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libfuzzer-sys = "0.4"
+flate2 = { path = ".." }
+
+# Prevent this from interfering with workspaces
+[workspace]
+members = ["."]
+
+[[bin]]
+name = "fuzz_gz_roundtrip"
+path = "fuzz_targets/fuzz_gz_roundtrip.rs"
+test = false
+doc = false

fuzz/fuzz_targets/fuzz_gz_roundtrip.rs

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+#![no_main]
+use libfuzzer_sys::fuzz_target;
+use flate2::write::GzEncoder;
+use flate2::Compression;
+use flate2::read::GzDecoder;
+use std::io::prelude::*;
+
+
+fuzz_target!(|data: &[u8]| {
+    let mut encoder = GzEncoder::new(Vec::new(), Compression::default());
+    encoder.write_all(data).unwrap();
+    let result = encoder.finish().unwrap();
+    let mut r = GzDecoder::new(&result[..]);
+    let mut ret = Vec::new();
+    r.read_to_end(&mut ret).unwrap();
+    assert!(ret == data);
+});