Parsing arguments with Docopt

Cargo.lock

@@ -3,17 +3,26 @@ name = "zvault"
 version = "0.1.0"
 dependencies = [
  "blake2-rfc 0.2.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "docopt 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "mmap 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "murmurhash3 0.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "quick-error 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rmp-serde 0.12.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.9.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_utils 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_yaml 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "squash-sys 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "aho-corasick"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "memchr 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bitflags"
 version = "0.7.0"
@@ -38,9 +47,15 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
-name = "gcc"
+name = "docopt"
-version = "0.3.43"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "lazy_static 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "strsim 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 
 [[package]]
 name = "kernel32-sys"
@@ -51,6 +66,11 @@ dependencies = [
  "winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "libc"
 version = "0.1.12"
@@ -66,6 +86,14 @@ name = "linked-hash-map"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "memchr"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "mmap"
 version = "0.1.1"
@@ -104,8 +132,20 @@ dependencies = [
 ]
 
 [[package]]
-name = "redox_syscall"
+name = "regex"
-version = "0.1.16"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "aho-corasick 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "thread_local 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "utf8-ranges 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -127,18 +167,6 @@ dependencies = [
  "serde 0.9.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "rust-crypto"
-version = "0.2.36"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
- "time 0.1.36 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "rustc-serialize"
 version = "0.3.22"
@@ -177,6 +205,11 @@ dependencies = [
  "pkg-config 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "strsim"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "tempdir"
 version = "0.3.5"
@@ -186,16 +219,41 @@ dependencies = [
 ]
 
 [[package]]
-name = "time"
+name = "thread-id"
-version = "0.1.36"
+version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
- "redox_syscall 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "thread_local"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "thread-id 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "unreachable"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "utf8-ranges"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "void"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "winapi"
 version = "0.2.8"
@@ -215,32 +273,40 @@ dependencies = [
 ]
 
 [metadata]
+"checksum aho-corasick 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0638fd549427caa90c499814196d1b9e3725eb4d15d7339d6de073a680ed0ca2"
 "checksum bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "aad18937a628ec6abcd26d1489012cc0e18c21798210f491af69ded9b881106d"
 "checksum blake2-rfc 0.2.17 (registry+https://github.com/rust-lang/crates.io-index)" = "0c6a476f32fef3402f1161f89d0d39822809627754a126f8441ff2a9d45e2d59"
 "checksum byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c40977b0ee6b9885c9013cd41d9feffdd22deb3bb4dc3a71d901cc7a77de18c8"
 "checksum constant_time_eq 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "07dcb7959f0f6f1cf662f9a7ff389bcb919924d99ac41cf31f10d611d8721323"
-"checksum gcc 0.3.43 (registry+https://github.com/rust-lang/crates.io-index)" = "c07c758b972368e703a562686adb39125707cc1ef3399da8c019fc6c2498a75d"
+"checksum docopt 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ab32ea6e284d87987066f21a9e809a73c14720571ef34516f0890b3d355ccfd8"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
+"checksum lazy_static 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "7291b1dd97d331f752620b02dfdbc231df7fc01bf282a00769e1cdb963c460dc"
 "checksum libc 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "e32a70cf75e5846d53a673923498228bbec6a8624708a9ea5645f075d6276122"
 "checksum libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)" = "88ee81885f9f04bff991e306fea7c1c60a5f0f9e409e99f6b40e3311a3363135"
 "checksum linked-hash-map 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6d262045c5b87c0861b3f004610afd0e2c851e2908d08b6c870cbb9d5f494ecd"
+"checksum memchr 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1dbccc0e46f1ea47b9f17e6d67c5a96bd27030519c519c9c91327e31275a47b4"
 "checksum mmap 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0bc85448a6006dd2ba26a385a564a8a0f1f2c7e78c70f1a70b2e0f4af286b823"
 "checksum murmurhash3 0.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "a2983372caf4480544083767bf2d27defafe32af49ab4df3a0b7fc90793a3664"
 "checksum num-traits 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)" = "e1cbfa3781f3fe73dc05321bed52a06d2d491eaa764c52335cf4399f046ece99"
 "checksum pkg-config 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "3a8b4c6b8165cd1a1cd4b9b120978131389f64bdaf456435caa41e630edba903"
 "checksum quick-error 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0aad603e8d7fb67da22dbdf1f4b826ce8829e406124109e73cf1b2454b93a71c"
 "checksum rand 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "022e0636ec2519ddae48154b028864bdce4eaf7d35226ab8e65c611be97b189d"
-"checksum redox_syscall 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "8dd35cc9a8bdec562c757e3d43c1526b5c6d2653e23e2315065bc25556550753"
+"checksum regex 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4278c17d0f6d62dfef0ab00028feb45bd7d2102843f80763474eeb1be8a10c01"
+"checksum regex-syntax 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2f9191b1f57603095f105d317e375d19b1c9c5c3185ea9633a99a6dcbed04457"
 "checksum rmp 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)" = "e59917c01f49718a59c644a621a4848aafc6577c4a47d66270d78951a807541a"
 "checksum rmp-serde 0.12.2 (registry+https://github.com/rust-lang/crates.io-index)" = "06ec4d0cdea2645de5d0e649f90c3e654205d913e14adefa452257314a24e76e"
-"checksum rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)" = "f76d05d3993fd5f4af9434e8e436db163a12a9d40e1a58a726f27a01dfd12a2a"
 "checksum rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)" = "237546c689f20bb44980270c73c3b9edd0891c1be49cc1274406134a66d3957b"
 "checksum serde 0.9.11 (registry+https://github.com/rust-lang/crates.io-index)" = "a702319c807c016e51f672e5c77d6f0b46afddd744b5e437d6b8436b888b458f"
 "checksum serde_utils 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b34a52969c7fc0254e214b82518c9a95dc88c84fc84cd847add314996a031be6"
 "checksum serde_yaml 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f8bd3f24ad8c7bcd34a6d70ba676dc11302b96f4f166aa5f947762e01098844d"
 "checksum squash-sys 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "db1f9dde91d819b7746e153bc32489fa19e6a106c3d7f2b92187a4efbdc88b40"
+"checksum strsim 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b4d15c810519a91cf877e7e36e63fe068815c678181439f2f29e2562147c3694"
 "checksum tempdir 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "87974a6f5c1dfb344d733055601650059a3363de2a6104819293baff662132d6"
-"checksum time 0.1.36 (registry+https://github.com/rust-lang/crates.io-index)" = "211b63c112206356ef1ff9b19355f43740fc3f85960c598a93d3a3d3ba7beade"
+"checksum thread-id 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4437c97558c70d129e40629a5b385b3fb1ffac301e63941335e4d354081ec14a"
+"checksum thread_local 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "c85048c6260d17cf486ceae3282d9fb6b90be220bf5b28c400f5485ffc29f0c7"
+"checksum unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1f2ae5ddb18e1c92664717616dd9549dde73f539f01bd7b77c2edb2446bdff91"
+"checksum utf8-ranges 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "662fab6525a98beff2921d7f61a39e7d59e0b425ebc7d0d9e66d316e55124122"
+"checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
 "checksum yaml-rust 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e66366e18dc58b46801afbf2ca7661a9f59cc8c5962c29892b6039b4f86fa992"

Cargo.toml

@@ -13,3 +13,5 @@ mmap = "*"
 quick-error = "1.1"
 blake2-rfc = "*"
 murmurhash3 = "*"
+docopt = "0.7"
+rustc-serialize = "0.3"

src/main.rs

@@ -7,6 +7,8 @@ extern crate blake2_rfc as blake2;
 extern crate murmurhash3;
 extern crate serde_yaml;
 #[macro_use] extern crate quick_error;
+extern crate docopt;
+extern crate rustc_serialize;
 
 mod errors;
 mod util;
@@ -20,59 +22,110 @@ use chunker::ChunkerType;
 use repository::{Repository, Config, Mode};
 use util::{ChecksumType, Compression, HashMethod};
 
-use std::path::Path;
 use std::fs::File;
-use std::env;
 use std::io::Read;
 use std::time;
 
+use docopt::Docopt;
+
+
+static USAGE: &'static str = "
+Usage:
+    zvault init <repo>
+    zvault algotest <path>
+    zvault check [--full] <repo>
+    zvault test <repo> <path>
+
+Options:
+    --full                     Whether to verify the repository by loading all bundles
+    --bundle-size SIZE         The target size of a full bundle in MiB [default: 25]
+    --chunker METHOD           The chunking algorithm to use [default: fastcdc]
+    --chunk-size SIZE          The target average chunk size in KiB [default: 8]
+    --compression COMPRESSION  The compression to use [default: brotli/3]
+";
+
+
+#[derive(RustcDecodable, Debug)]
+struct Args {
+    cmd_init: bool,
+    cmd_algotest: bool,
+    cmd_test: bool,
+    cmd_check: bool,
+    arg_repo: Option<String>,
+    arg_path: Option<String>,
+    flag_full: bool,
+    flag_bundle_size: usize,
+    flag_chunker: String,
+    flag_chunk_size: usize,
+    flag_compression: String
+}
+
 
 fn main() {
-    let path: &Path = "test_data".as_ref();
+    let args: Args = Docopt::new(USAGE).and_then(|d| d.decode()).unwrap_or_else(|e| e.exit());
-    let mut repo = if path.exists() {
+    println!("{:?}", args);
-        Repository::open(path).unwrap()
+
-    } else {
+    if args.cmd_algotest {
-        Repository::create(path, Config {
+        algotest::run(&args.arg_path.unwrap());
-            bundle_size: 25*1024*1024,
+        return
+    }
+
+    if args.cmd_init {
+        let chunker = ChunkerType::from(&args.flag_chunker, args.flag_chunk_size, 0).expect("No such chunk algorithm");
+        let compression = if args.flag_compression == "none" {
+            None
+        } else {
+            Some(Compression::from_string(&args.flag_compression).expect("Failed to parse compression"))
+        };
+        Repository::create(&args.arg_repo.unwrap(), Config {
+            bundle_size: args.flag_bundle_size*1024*1024,
             checksum: ChecksumType::Blake2_256,
-            chunker: ChunkerType::FastCdc((8*1024, 0)),
+            chunker: chunker,
-            compression: Some(Compression::Brotli(1)),
+            compression: compression,
             hash: HashMethod::Blake2
-        }).unwrap()
+        }).unwrap();
-    };
+        return
-    print!("Integrity check before...");
+    }
-    repo.check(true).unwrap();
-    println!(" done.");
 
-    let file_path = env::args().nth(1).expect("Need file as argument");
+    let mut repo = Repository::open(&args.arg_repo.unwrap()).unwrap();
-    print!("Reading file {}...", file_path);
-    let mut data = Vec::new();
-    let mut file = File::open(file_path).unwrap();
-    file.read_to_end(&mut data).unwrap();
-    println!(" done. {} bytes", data.len());
 
-    print!("Adding data to repository...");
+    if args.cmd_check {
-    let start = time::Instant::now();
+        repo.check(args.flag_full).unwrap();
-    let chunks = repo.put_data(Mode::Content, &data).unwrap();
+        return
-    repo.flush().unwrap();
+    }
-    let elapsed = start.elapsed();
-    let duration = elapsed.as_secs() as f64 * 1.0 + elapsed.subsec_nanos() as f64 / 1_000_000_000.0;
-    let write_speed = data.len() as f64 / duration;
-    println!(" done. {} chunks, {:.1} MB/s", chunks.len(), write_speed / 1_000_000.0);
 
-    println!("Integrity check after...");
+    if args.cmd_test {
-    repo.check(true).unwrap();
+        print!("Integrity check before...");
-    println!(" done.");
+        repo.check(true).unwrap();
+        println!(" done.");
 
-    print!("Reading data from repository...");
+        let file_path = args.arg_path.unwrap();
-    let start = time::Instant::now();
+        print!("Reading file {}...", file_path);
-    let data2 = repo.get_data(&chunks).unwrap();
+        let mut data = Vec::new();
-    let elapsed = start.elapsed();
+        let mut file = File::open(file_path).unwrap();
-    let duration = elapsed.as_secs() as f64 * 1.0 + elapsed.subsec_nanos() as f64 / 1_000_000_000.0;
+        file.read_to_end(&mut data).unwrap();
-    let read_speed = data.len() as f64 / duration;
+        println!(" done. {} bytes", data.len());
-    assert_eq!(data.len(), data2.len());
-    println!(" done. {:.1} MB/s", read_speed / 1_000_000.0);
 
-    //algotest::run("test.tar");
+        print!("Adding data to repository...");
+        let start = time::Instant::now();
+        let chunks = repo.put_data(Mode::Content, &data).unwrap();
+        repo.flush().unwrap();
+        let elapsed = start.elapsed();
+        let duration = elapsed.as_secs() as f64 * 1.0 + elapsed.subsec_nanos() as f64 / 1_000_000_000.0;
+        let write_speed = data.len() as f64 / duration;
+        println!(" done. {} chunks, {:.1} MB/s", chunks.len(), write_speed / 1_000_000.0);
 
+        println!("Integrity check after...");
+        repo.check(true).unwrap();
+        println!(" done.");
+
+        print!("Reading data from repository...");
+        let start = time::Instant::now();
+        let data2 = repo.get_data(&chunks).unwrap();
+        let elapsed = start.elapsed();
+        let duration = elapsed.as_secs() as f64 * 1.0 + elapsed.subsec_nanos() as f64 / 1_000_000_000.0;
+        let read_speed = data.len() as f64 / duration;
+        assert_eq!(data.len(), data2.len());
+        println!(" done. {:.1} MB/s", read_speed / 1_000_000.0);
+    }
 }

src/repository/config.rs

@@ -67,47 +67,22 @@ impl ChunkerType {
 
 
 
-struct CompressionYaml {
-    codec: String,
-    level: Option<u8>
-}
-impl Default for CompressionYaml {
-    fn default() -> Self {
-        CompressionYaml {
-            codec: "brotli".to_string(),
-            level: None
-        }
-    }
-}
-serde_impl!(CompressionYaml(String) {
-    codec: String => "codec",
-    level: Option<u8> => "level"
-});
-
 impl Compression {
-    fn from_yaml(yaml: CompressionYaml) -> Result<Self, &'static str> {
+    #[inline]
-        match &yaml.codec as &str {
+    fn from_yaml(yaml: String) -> Result<Self, &'static str> {
-            "snappy" => Ok(Compression::Snappy(())),
+        Compression::from_string(&yaml)
-            "zstd" => Ok(Compression::ZStd(yaml.level.unwrap_or(5))),
-            "deflate" | "zlib" | "gzip" => Ok(Compression::Deflate(yaml.level.unwrap_or(5))),
-            "brotli" => Ok(Compression::Brotli(yaml.level.unwrap_or(5))),
-            "lzma2" => Ok(Compression::Lzma2(yaml.level.unwrap_or(5))),
-            _ => Err("Unsupported codec")
-        }
     }
 
-    fn to_yaml(&self) -> CompressionYaml {
+    #[inline]
-        CompressionYaml {
+    fn to_yaml(&self) -> String {
-            codec: self.name().to_string(),
+        self.to_string()
-            level: self.level()
-        }
     }
 }
 
 
 
 struct ConfigYaml {
-    compression: Option<CompressionYaml>,
+    compression: Option<String>,
     bundle_size: usize,
     chunker: ChunkerYaml,
     checksum: String,
@@ -116,7 +91,7 @@ struct ConfigYaml {
 impl Default for ConfigYaml {
     fn default() -> Self {
         ConfigYaml {
-            compression: Some(CompressionYaml { codec: "brotli".to_string(), level: Some(5) }),
+            compression: Some("brotli/5".to_string()),
             bundle_size: 25*1024*1024,
             chunker: ChunkerYaml::default(),
             checksum: "blake2_256".to_string(),
@@ -125,7 +100,7 @@ impl Default for ConfigYaml {
     }
 }
 serde_impl!(ConfigYaml(String) {
-    compression: Option<CompressionYaml> => "compression",
+    compression: Option<String> => "compression",
     bundle_size: usize => "bundle_size",
     chunker: ChunkerYaml => "chunker",
     checksum: String => "checksum",

src/util/compression.rs

@@ -1,6 +1,7 @@
 use std::ptr;
 use std::ffi::{CStr, CString};
 use std::io::Write;
+use std::str::FromStr;
 
 use squash::*;
 
@@ -23,6 +24,34 @@ serde_impl!(Compression(u64) {
 
 
 impl Compression {
+    #[inline]
+    pub fn to_string(&self) -> String {
+        if let Some(level) = self.level() {
+            format!("{}/{}", self.name(), level)
+        } else {
+            self.name().to_string()
+        }
+    }
+
+    #[inline]
+    pub fn from_string(name: &str) -> Result<Self, &'static str> {
+        let (name, level) = if let Some(pos) = name.find("/") {
+            let level = try!(u8::from_str(&name[pos+1..]).map_err(|_| "Level must be a number"));
+            let name = &name[..pos];
+            (name, level)
+        } else {
+            (name, 5)
+        };
+        match name {
+            "snappy" => Ok(Compression::Snappy(())),
+            "zstd" => Ok(Compression::ZStd(level)),
+            "deflate" | "zlib" | "gzip" => Ok(Compression::Deflate(level)),
+            "brotli" => Ok(Compression::Brotli(level)),
+            "lzma2" => Ok(Compression::Lzma2(level)),
+            _ => Err("Unsupported codec")
+        }
+    }
+
     #[inline]
     pub fn name(&self) -> &'static str {
         match *self {