flate2/gz/
mod.rs

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1use std::ffi::CString;
2use std::io::prelude::*;
3use std::time;
4
5use crate::bufreader::BufReader;
6use crate::Compression;
7
8pub static FHCRC: u8 = 1 << 1;
9pub static FEXTRA: u8 = 1 << 2;
10pub static FNAME: u8 = 1 << 3;
11pub static FCOMMENT: u8 = 1 << 4;
12
13pub mod bufread;
14pub mod read;
15pub mod write;
16
17/// A structure representing the header of a gzip stream.
18///
19/// The header can contain metadata about the file that was compressed, if
20/// present.
21#[derive(PartialEq, Clone, Debug, Default)]
22pub struct GzHeader {
23    extra: Option<Vec<u8>>,
24    filename: Option<Vec<u8>>,
25    comment: Option<Vec<u8>>,
26    operating_system: u8,
27    mtime: u32,
28}
29
30impl GzHeader {
31    /// Returns the `filename` field of this gzip stream's header, if present.
32    pub fn filename(&self) -> Option<&[u8]> {
33        self.filename.as_ref().map(|s| &s[..])
34    }
35
36    /// Returns the `extra` field of this gzip stream's header, if present.
37    pub fn extra(&self) -> Option<&[u8]> {
38        self.extra.as_ref().map(|s| &s[..])
39    }
40
41    /// Returns the `comment` field of this gzip stream's header, if present.
42    pub fn comment(&self) -> Option<&[u8]> {
43        self.comment.as_ref().map(|s| &s[..])
44    }
45
46    /// Returns the `operating_system` field of this gzip stream's header.
47    ///
48    /// There are predefined values for various operating systems.
49    /// 255 means that the value is unknown.
50    pub fn operating_system(&self) -> u8 {
51        self.operating_system
52    }
53
54    /// This gives the most recent modification time of the original file being compressed.
55    ///
56    /// The time is in Unix format, i.e., seconds since 00:00:00 GMT, Jan. 1, 1970.
57    /// (Note that this may cause problems for MS-DOS and other systems that use local
58    /// rather than Universal time.) If the compressed data did not come from a file,
59    /// `mtime` is set to the time at which compression started.
60    /// `mtime` = 0 means no time stamp is available.
61    ///
62    /// The usage of `mtime` is discouraged because of Year 2038 problem.
63    pub fn mtime(&self) -> u32 {
64        self.mtime
65    }
66
67    /// Returns the most recent modification time represented by a date-time type.
68    /// Returns `None` if the value of the underlying counter is 0,
69    /// indicating no time stamp is available.
70    ///
71    ///
72    /// The time is measured as seconds since 00:00:00 GMT, Jan. 1 1970.
73    /// See [`mtime`](#method.mtime) for more detail.
74    pub fn mtime_as_datetime(&self) -> Option<time::SystemTime> {
75        if self.mtime == 0 {
76            None
77        } else {
78            let duration = time::Duration::new(u64::from(self.mtime), 0);
79            let datetime = time::UNIX_EPOCH + duration;
80            Some(datetime)
81        }
82    }
83}
84
85/// A builder structure to create a new gzip Encoder.
86///
87/// This structure controls header configuration options such as the filename.
88///
89/// # Examples
90///
91/// ```
92/// use std::io::prelude::*;
93/// # use std::io;
94/// use std::fs::File;
95/// use flate2::GzBuilder;
96/// use flate2::Compression;
97///
98/// // GzBuilder opens a file and writes a sample string using GzBuilder pattern
99///
100/// # fn sample_builder() -> Result<(), io::Error> {
101/// let f = File::create("examples/hello_world.gz")?;
102/// let mut gz = GzBuilder::new()
103///                 .filename("hello_world.txt")
104///                 .comment("test file, please delete")
105///                 .write(f, Compression::default());
106/// gz.write_all(b"hello world")?;
107/// gz.finish()?;
108/// # Ok(())
109/// # }
110/// ```
111#[derive(Debug)]
112pub struct GzBuilder {
113    extra: Option<Vec<u8>>,
114    filename: Option<CString>,
115    comment: Option<CString>,
116    operating_system: Option<u8>,
117    mtime: u32,
118}
119
120impl GzBuilder {
121    /// Create a new blank builder with no header by default.
122    pub fn new() -> GzBuilder {
123        GzBuilder {
124            extra: None,
125            filename: None,
126            comment: None,
127            operating_system: None,
128            mtime: 0,
129        }
130    }
131
132    /// Configure the `mtime` field in the gzip header.
133    pub fn mtime(mut self, mtime: u32) -> GzBuilder {
134        self.mtime = mtime;
135        self
136    }
137
138    /// Configure the `operating_system` field in the gzip header.
139    pub fn operating_system(mut self, os: u8) -> GzBuilder {
140        self.operating_system = Some(os);
141        self
142    }
143
144    /// Configure the `extra` field in the gzip header.
145    pub fn extra<T: Into<Vec<u8>>>(mut self, extra: T) -> GzBuilder {
146        self.extra = Some(extra.into());
147        self
148    }
149
150    /// Configure the `filename` field in the gzip header.
151    ///
152    /// # Panics
153    ///
154    /// Panics if the `filename` slice contains a zero.
155    pub fn filename<T: Into<Vec<u8>>>(mut self, filename: T) -> GzBuilder {
156        self.filename = Some(CString::new(filename.into()).unwrap());
157        self
158    }
159
160    /// Configure the `comment` field in the gzip header.
161    ///
162    /// # Panics
163    ///
164    /// Panics if the `comment` slice contains a zero.
165    pub fn comment<T: Into<Vec<u8>>>(mut self, comment: T) -> GzBuilder {
166        self.comment = Some(CString::new(comment.into()).unwrap());
167        self
168    }
169
170    /// Consume this builder, creating a writer encoder in the process.
171    ///
172    /// The data written to the returned encoder will be compressed and then
173    /// written out to the supplied parameter `w`.
174    pub fn write<W: Write>(self, w: W, lvl: Compression) -> write::GzEncoder<W> {
175        write::gz_encoder(self.into_header(lvl), w, lvl)
176    }
177
178    /// Consume this builder, creating a reader encoder in the process.
179    ///
180    /// Data read from the returned encoder will be the compressed version of
181    /// the data read from the given reader.
182    pub fn read<R: Read>(self, r: R, lvl: Compression) -> read::GzEncoder<R> {
183        read::gz_encoder(self.buf_read(BufReader::new(r), lvl))
184    }
185
186    /// Consume this builder, creating a reader encoder in the process.
187    ///
188    /// Data read from the returned encoder will be the compressed version of
189    /// the data read from the given reader.
190    pub fn buf_read<R>(self, r: R, lvl: Compression) -> bufread::GzEncoder<R>
191    where
192        R: BufRead,
193    {
194        bufread::gz_encoder(self.into_header(lvl), r, lvl)
195    }
196
197    fn into_header(self, lvl: Compression) -> Vec<u8> {
198        let GzBuilder {
199            extra,
200            filename,
201            comment,
202            operating_system,
203            mtime,
204        } = self;
205        let mut flg = 0;
206        let mut header = vec![0u8; 10];
207        match extra {
208            Some(v) => {
209                flg |= FEXTRA;
210                header.push((v.len() >> 0) as u8);
211                header.push((v.len() >> 8) as u8);
212                header.extend(v);
213            }
214            None => {}
215        }
216        match filename {
217            Some(filename) => {
218                flg |= FNAME;
219                header.extend(filename.as_bytes_with_nul().iter().map(|x| *x));
220            }
221            None => {}
222        }
223        match comment {
224            Some(comment) => {
225                flg |= FCOMMENT;
226                header.extend(comment.as_bytes_with_nul().iter().map(|x| *x));
227            }
228            None => {}
229        }
230        header[0] = 0x1f;
231        header[1] = 0x8b;
232        header[2] = 8;
233        header[3] = flg;
234        header[4] = (mtime >> 0) as u8;
235        header[5] = (mtime >> 8) as u8;
236        header[6] = (mtime >> 16) as u8;
237        header[7] = (mtime >> 24) as u8;
238        header[8] = if lvl.0 >= Compression::best().0 {
239            2
240        } else if lvl.0 <= Compression::fast().0 {
241            4
242        } else {
243            0
244        };
245
246        // Typically this byte indicates what OS the gz stream was created on,
247        // but in an effort to have cross-platform reproducible streams just
248        // default this value to 255. I'm not sure that if we "correctly" set
249        // this it'd do anything anyway...
250        header[9] = operating_system.unwrap_or(255);
251        return header;
252    }
253}
254
255#[cfg(test)]
256mod tests {
257    use std::io::prelude::*;
258
259    use super::{read, write, GzBuilder};
260    use crate::Compression;
261    use rand::{thread_rng, Rng};
262
263    #[test]
264    fn roundtrip() {
265        let mut e = write::GzEncoder::new(Vec::new(), Compression::default());
266        e.write_all(b"foo bar baz").unwrap();
267        let inner = e.finish().unwrap();
268        let mut d = read::GzDecoder::new(&inner[..]);
269        let mut s = String::new();
270        d.read_to_string(&mut s).unwrap();
271        assert_eq!(s, "foo bar baz");
272    }
273
274    #[test]
275    fn roundtrip_zero() {
276        let e = write::GzEncoder::new(Vec::new(), Compression::default());
277        let inner = e.finish().unwrap();
278        let mut d = read::GzDecoder::new(&inner[..]);
279        let mut s = String::new();
280        d.read_to_string(&mut s).unwrap();
281        assert_eq!(s, "");
282    }
283
284    #[test]
285    fn roundtrip_big() {
286        let mut real = Vec::new();
287        let mut w = write::GzEncoder::new(Vec::new(), Compression::default());
288        let v = crate::random_bytes().take(1024).collect::<Vec<_>>();
289        for _ in 0..200 {
290            let to_write = &v[..thread_rng().gen_range(0, v.len())];
291            real.extend(to_write.iter().map(|x| *x));
292            w.write_all(to_write).unwrap();
293        }
294        let result = w.finish().unwrap();
295        let mut r = read::GzDecoder::new(&result[..]);
296        let mut v = Vec::new();
297        r.read_to_end(&mut v).unwrap();
298        assert!(v == real);
299    }
300
301    #[test]
302    fn roundtrip_big2() {
303        let v = crate::random_bytes().take(1024 * 1024).collect::<Vec<_>>();
304        let mut r = read::GzDecoder::new(read::GzEncoder::new(&v[..], Compression::default()));
305        let mut res = Vec::new();
306        r.read_to_end(&mut res).unwrap();
307        assert!(res == v);
308    }
309
310    #[test]
311    fn fields() {
312        let r = vec![0, 2, 4, 6];
313        let e = GzBuilder::new()
314            .filename("foo.rs")
315            .comment("bar")
316            .extra(vec![0, 1, 2, 3])
317            .read(&r[..], Compression::default());
318        let mut d = read::GzDecoder::new(e);
319        assert_eq!(d.header().unwrap().filename(), Some(&b"foo.rs"[..]));
320        assert_eq!(d.header().unwrap().comment(), Some(&b"bar"[..]));
321        assert_eq!(d.header().unwrap().extra(), Some(&b"\x00\x01\x02\x03"[..]));
322        let mut res = Vec::new();
323        d.read_to_end(&mut res).unwrap();
324        assert_eq!(res, vec![0, 2, 4, 6]);
325    }
326
327    #[test]
328    fn keep_reading_after_end() {
329        let mut e = write::GzEncoder::new(Vec::new(), Compression::default());
330        e.write_all(b"foo bar baz").unwrap();
331        let inner = e.finish().unwrap();
332        let mut d = read::GzDecoder::new(&inner[..]);
333        let mut s = String::new();
334        d.read_to_string(&mut s).unwrap();
335        assert_eq!(s, "foo bar baz");
336        d.read_to_string(&mut s).unwrap();
337        assert_eq!(s, "foo bar baz");
338    }
339
340    #[test]
341    fn qc_reader() {
342        ::quickcheck::quickcheck(test as fn(_) -> _);
343
344        fn test(v: Vec<u8>) -> bool {
345            let r = read::GzEncoder::new(&v[..], Compression::default());
346            let mut r = read::GzDecoder::new(r);
347            let mut v2 = Vec::new();
348            r.read_to_end(&mut v2).unwrap();
349            v == v2
350        }
351    }
352
353    #[test]
354    fn flush_after_write() {
355        let mut f = write::GzEncoder::new(Vec::new(), Compression::default());
356        write!(f, "Hello world").unwrap();
357        f.flush().unwrap();
358    }
359}
flate2/gz/mod.rs

flate2/gz/
mod.rs
