Struct Buffer

pub struct Buffer { /* private fields */ }

A Buffer is a variable-sized buffer of bytes with read and write methods.

Implementations

impl Buffer

pub fn new() -> Self

Examples found in repository

examples/zlib-writer.rs (line 8)

fn main() {
    let mut b = bytes::Buffer::new();
    let mut w = zlib::Writer::new(&mut b);
    w.write("hello, world\n".as_bytes()).unwrap();
    w.close().unwrap();
    println!("{:?}", b.bytes());
    // Output: [120 156 202 72 205 201 201 215 81 40 207 47 202 73 225 2 4 0 0 255 255 33 231 4 147]
}

examples/bytesbuffer.rs (line 9)

fn main() {
    let mut buf = Buffer::new();
    buf.write_all("hello world".as_bytes()).unwrap();
    println!("{}", buf.string());

    let mut buf = Buffer::new();
    buf.write_byte(33).unwrap();
    buf.write_all("hello world".as_bytes()).unwrap();
    println!("{}", buf.read_byte().unwrap());
    println!("{}", buf.string());
}

examples/flate.rs (line 11)

fn main() {
    let msg = "Hello World! Hello Rust! Hello World! Hello Rust!";
    let mut buffer = bytes::Buffer::new();
    let mut w = flate::Writer::new(&mut buffer, flate::BEST_COMPRESSION).unwrap();
    w.write_all(msg.as_bytes()).unwrap();
    w.close().unwrap();

    let result_str = hex::encode_to_string(buffer.bytes());
    println!(
        "input string    ({:02} bytes): {}",
        msg.as_bytes().len(),
        msg,
    );
    println!(
        "deflated string ({:02} bytes): {}",
        result_str.len() / 2,
        result_str
    );
}

examples/flate-speed.rs (line 16)

fn main() {
    let mut file = File::open("src/testdata/Isaac.Newton-Opticks.txt").unwrap();
    let mut content = Vec::new();
    file.read_to_end(&mut content).unwrap();

    let mut buffer = bytes::Buffer::new();
    let mut w = flate::Writer::new(&mut buffer, flate::BEST_COMPRESSION).unwrap();

    let repeats = 200;
    for _i in 0..repeats {
        w.write_all(&content).unwrap();
    }

    w.close().unwrap();

    let compressed_data = bytes::Buffer::bytes(&buffer);
    let hash = sha256::sum256(compressed_data);
    let hash_str = hex::encode_to_string(&hash);
    println!("compressed data hash:");
    println!("{}", hash_str);
}

examples/flate-dict.rs (line 35)

fn example_dictionary() {
    // The dictionary is a string of bytes. When compressing some input data,
    // the compressor will attempt to substitute substrings with matches found
    // in the dictionary. As such, the dictionary should only contain substrings
    // that are expected to be found in the actual data stream.
    let dict = b"<?xml version=\"1.0\"?><book><data><meta name=\"\" content=\"";

    // The data to compress should (but is not required to) contain frequent
    // substrings that match those in the dictionary.
    let data = r#"<?xml version="1.0"?>
<book>
    <meta name="title" content="The Go Programming Language"/>
    <meta name="authors" content="Alan Donovan and Brian Kernighan"/>
    <meta name="published" content="2015-10-26"/>
    <meta name="isbn" content="978-0134190440"/>
    <data>...</data>
</book>
"#;

    let mut b = bytes::Buffer::new();

    // Compress the data using the specially crafted dictionary.
    {
        let mut zw = flate::Writer::new_dict(&mut b, flate::DEFAULT_COMPRESSION, dict).unwrap();
        let mut data_reader = bytes::new_buffer_string(data);
        std::io::copy(&mut data_reader, &mut zw).unwrap();
        zw.close().unwrap();
    }

    // The decompressor must use the same dictionary as the compressor.
    // Otherwise, the input may appear as corrupted.
    println!("Decompressed output using the dictionary:");
    {
        let mut data_reader = b.bytes();
        let mut zr = flate::Reader::new_dict(&mut data_reader, dict);
        let mut decompressed = bytes::Buffer::new();
        std::io::copy(&mut zr, &mut decompressed).unwrap();
        zr.close().unwrap();
        println!("{}", String::from_utf8_lossy(decompressed.bytes()));
        println!();
    }

    // Substitute all of the bytes in the dictionary with a '#' to visually
    // demonstrate the approximate effectiveness of using a preset dictionary.
    println!("Substrings matched by the dictionary are marked with #:");
    {
        let hash_dict = vec![b'#'; dict.len()];
        let mut zr = flate::Reader::new_dict(&mut b, &hash_dict);
        let mut decompressed = bytes::Buffer::new();
        std::io::copy(&mut zr, &mut decompressed).unwrap();
        zr.close().unwrap();
        println!("{}", String::from_utf8_lossy(decompressed.bytes()));
    }

    // Output:
    // Decompressed output using the dictionary:
    // <?xml version="1.0"?>
    // <book>
    // 	<meta name="title" content="The Go Programming Language"/>
    // 	<meta name="authors" content="Alan Donovan and Brian Kernighan"/>
    // 	<meta name="published" content="2015-10-26"/>
    // 	<meta name="isbn" content="978-0134190440"/>
    // 	<data>...</data>
    // </book>
    //
    // Substrings matched by the dictionary are marked with #:
    // #####################
    // ######
    // 	############title###########The Go Programming Language"/#
    // 	############authors###########Alan Donovan and Brian Kernighan"/#
    // 	############published###########2015-10-26"/#
    // 	############isbn###########978-0134190440"/#
    // 	######...</#####
    // </#####
}

pub fn bytes(&self) -> &[u8]

bytes returns a slice of length b.len() holding the unread portion of the buffer. The slice is valid for use only until the next buffer modification (that is, only until the next call to a method like Read, Write, Reset, or Truncate). The slice aliases the buffer content at least until the next buffer modification, so immediate changes to the slice will affect the result of future reads.

Examples found in repository

examples/zlib-writer.rs (line 12)

fn main() {
    let mut b = bytes::Buffer::new();
    let mut w = zlib::Writer::new(&mut b);
    w.write("hello, world\n".as_bytes()).unwrap();
    w.close().unwrap();
    println!("{:?}", b.bytes());
    // Output: [120 156 202 72 205 201 201 215 81 40 207 47 202 73 225 2 4 0 0 255 255 33 231 4 147]
}

examples/flate.rs (line 16)

fn main() {
    let msg = "Hello World! Hello Rust! Hello World! Hello Rust!";
    let mut buffer = bytes::Buffer::new();
    let mut w = flate::Writer::new(&mut buffer, flate::BEST_COMPRESSION).unwrap();
    w.write_all(msg.as_bytes()).unwrap();
    w.close().unwrap();

    let result_str = hex::encode_to_string(buffer.bytes());
    println!(
        "input string    ({:02} bytes): {}",
        msg.as_bytes().len(),
        msg,
    );
    println!(
        "deflated string ({:02} bytes): {}",
        result_str.len() / 2,
        result_str
    );
}

examples/flate-speed.rs (line 26)

fn main() {
    let mut file = File::open("src/testdata/Isaac.Newton-Opticks.txt").unwrap();
    let mut content = Vec::new();
    file.read_to_end(&mut content).unwrap();

    let mut buffer = bytes::Buffer::new();
    let mut w = flate::Writer::new(&mut buffer, flate::BEST_COMPRESSION).unwrap();

    let repeats = 200;
    for _i in 0..repeats {
        w.write_all(&content).unwrap();
    }

    w.close().unwrap();

    let compressed_data = bytes::Buffer::bytes(&buffer);
    let hash = sha256::sum256(compressed_data);
    let hash_str = hex::encode_to_string(&hash);
    println!("compressed data hash:");
    println!("{}", hash_str);
}

examples/flate-dict.rs (line 49)

fn example_dictionary() {
    // The dictionary is a string of bytes. When compressing some input data,
    // the compressor will attempt to substitute substrings with matches found
    // in the dictionary. As such, the dictionary should only contain substrings
    // that are expected to be found in the actual data stream.
    let dict = b"<?xml version=\"1.0\"?><book><data><meta name=\"\" content=\"";

    // The data to compress should (but is not required to) contain frequent
    // substrings that match those in the dictionary.
    let data = r#"<?xml version="1.0"?>
<book>
    <meta name="title" content="The Go Programming Language"/>
    <meta name="authors" content="Alan Donovan and Brian Kernighan"/>
    <meta name="published" content="2015-10-26"/>
    <meta name="isbn" content="978-0134190440"/>
    <data>...</data>
</book>
"#;

    let mut b = bytes::Buffer::new();

    // Compress the data using the specially crafted dictionary.
    {
        let mut zw = flate::Writer::new_dict(&mut b, flate::DEFAULT_COMPRESSION, dict).unwrap();
        let mut data_reader = bytes::new_buffer_string(data);
        std::io::copy(&mut data_reader, &mut zw).unwrap();
        zw.close().unwrap();
    }

    // The decompressor must use the same dictionary as the compressor.
    // Otherwise, the input may appear as corrupted.
    println!("Decompressed output using the dictionary:");
    {
        let mut data_reader = b.bytes();
        let mut zr = flate::Reader::new_dict(&mut data_reader, dict);
        let mut decompressed = bytes::Buffer::new();
        std::io::copy(&mut zr, &mut decompressed).unwrap();
        zr.close().unwrap();
        println!("{}", String::from_utf8_lossy(decompressed.bytes()));
        println!();
    }

    // Substitute all of the bytes in the dictionary with a '#' to visually
    // demonstrate the approximate effectiveness of using a preset dictionary.
    println!("Substrings matched by the dictionary are marked with #:");
    {
        let hash_dict = vec![b'#'; dict.len()];
        let mut zr = flate::Reader::new_dict(&mut b, &hash_dict);
        let mut decompressed = bytes::Buffer::new();
        std::io::copy(&mut zr, &mut decompressed).unwrap();
        zr.close().unwrap();
        println!("{}", String::from_utf8_lossy(decompressed.bytes()));
    }

    // Output:
    // Decompressed output using the dictionary:
    // <?xml version="1.0"?>
    // <book>
    // 	<meta name="title" content="The Go Programming Language"/>
    // 	<meta name="authors" content="Alan Donovan and Brian Kernighan"/>
    // 	<meta name="published" content="2015-10-26"/>
    // 	<meta name="isbn" content="978-0134190440"/>
    // 	<data>...</data>
    // </book>
    //
    // Substrings matched by the dictionary are marked with #:
    // #####################
    // ######
    // 	############title###########The Go Programming Language"/#
    // 	############authors###########Alan Donovan and Brian Kernighan"/#
    // 	############published###########2015-10-26"/#
    // 	############isbn###########978-0134190440"/#
    // 	######...</#####
    // </#####
}

pub fn string(&self) -> String

string returns the contents of the unread portion of the buffer as a string.

Examples found in repository

examples/bytesbuffer.rs (line 11)

fn main() {
    let mut buf = Buffer::new();
    buf.write_all("hello world".as_bytes()).unwrap();
    println!("{}", buf.string());

    let mut buf = Buffer::new();
    buf.write_byte(33).unwrap();
    buf.write_all("hello world".as_bytes()).unwrap();
    println!("{}", buf.read_byte().unwrap());
    println!("{}", buf.string());
}

pub fn len(&self) -> usize

len returns the number of bytes of the unread portion of the buffer; b.Len() == len(b.bytes()).

pub fn is_empty(&self) -> bool

pub fn cap(&self) -> usize

cap returns the capacity of the buffer’s underlying byte slice, that is, the total space allocated for the buffer’s data.

pub fn truncate(&mut self, n: usize)

pub fn reset(&mut self)

reset resets the buffer to be empty, but it retains the underlying storage for use by future writes. Reset is the same as Truncate(0).

pub fn grow(&mut self, n: usize)

grow grows the buffer’s capacity, if necessary, to guarantee space for another n bytes. After Grow(n), at least n bytes can be written to the buffer without another allocation.

impl Buffer

pub fn write_string(&mut self, s: &str) -> Result<usize>

write_string appends the contents of s to the buffer, growing the buffer as needed. The return value n is the length of s.

pub fn write_byte(&mut self, c: u8) -> Result<()>

write_byte appends the byte c to the buffer, growing the buffer as needed.

Examples found in repository

examples/bytesbuffer.rs (line 14)

fn main() {
    let mut buf = Buffer::new();
    buf.write_all("hello world".as_bytes()).unwrap();
    println!("{}", buf.string());

    let mut buf = Buffer::new();
    buf.write_byte(33).unwrap();
    buf.write_all("hello world".as_bytes()).unwrap();
    println!("{}", buf.read_byte().unwrap());
    println!("{}", buf.string());
}

pub fn read_byte(&mut self) -> Option<u8>

read_byte reads and returns the next byte from the buffer. If no byte is available, it returns None.

Examples found in repository

examples/bytesbuffer.rs (line 16)

fn main() {
    let mut buf = Buffer::new();
    buf.write_all("hello world".as_bytes()).unwrap();
    println!("{}", buf.string());

    let mut buf = Buffer::new();
    buf.write_byte(33).unwrap();
    buf.write_all("hello world".as_bytes()).unwrap();
    println!("{}", buf.read_byte().unwrap());
    println!("{}", buf.string());
}

Trait Implementations

impl BufRead for Buffer

fn fill_buf(&mut self) -> Result<&[u8]>

Returns the contents of the internal buffer, filling it with more data, via Read methods, if empty.

fn consume(&mut self, amt: usize)

Marks the given amount of additional bytes from the internal buffer as having been read. Subsequent calls to read only return bytes that have not been marked as read.

fn has_data_left(&mut self) -> Result<bool, Error>

🔬This is a nightly-only experimental API. (buf_read_has_data_left)

Checks if there is any data left to be read.

fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes into buf until the delimiter byte or EOF is reached.

fn skip_until(&mut self, byte: u8) -> Result<usize, Error>

Skips all bytes until the delimiter byte or EOF is reached.

fn read_line(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until a newline (the 0xA byte) is reached, and append them to the provided String buffer.

fn split(self, byte: u8) -> Split<Self>

where Self: Sized,

Returns an iterator over the contents of this reader split on the byte byte.

fn lines(self) -> Lines<Self>

where Self: Sized,

Returns an iterator over the lines of this reader.

impl Default for Buffer

fn default() -> Self

Returns the “default value” for a type.

impl Read for Buffer

fn read(&mut self, p: &mut [u8]) -> Result<usize>

Read reads the next p.len() bytes from the buffer or until the buffer is drained. The return value n is the number of bytes read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl Write for Buffer

fn write(&mut self, p: &[u8]) -> Result<usize>

write appends the contents of p to the buffer, growing the buffer as needed. The return value n is the length of p.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.