Module bitstream_io::write[−][src]

Expand description

Traits and implementations for writing bits to a stream.

Example

Writing the initial STREAMINFO block to a FLAC file, as documented in its specification.

use std::io::Write;
use bitstream_io::{BigEndian, BitWriter, BitWrite};

let mut flac: Vec<u8> = Vec::new();
{
    let mut writer = BitWriter::endian(&mut flac, BigEndian);

    // stream marker
    writer.write_bytes(b"fLaC").unwrap();

    // metadata block header
    let last_block: bool = false;
    let block_type: u8 = 0;
    let block_size: u32 = 34;
    writer.write_bit(last_block).unwrap();
    writer.write(7, block_type).unwrap();
    writer.write(24, block_size).unwrap();

    // STREAMINFO block
    let minimum_block_size: u16 = 4096;
    let maximum_block_size: u16 = 4096;
    let minimum_frame_size: u32 = 1542;
    let maximum_frame_size: u32 = 8546;
    let sample_rate: u32 = 44100;
    let channels: u8 = 2;
    let bits_per_sample: u8 = 16;
    let total_samples: u64 = 304844;
    writer.write(16, minimum_block_size).unwrap();
    writer.write(16, maximum_block_size).unwrap();
    writer.write(24, minimum_frame_size).unwrap();
    writer.write(24, maximum_frame_size).unwrap();
    writer.write(20, sample_rate).unwrap();
    writer.write(3, channels - 1).unwrap();
    writer.write(5, bits_per_sample - 1).unwrap();
    writer.write(36, total_samples).unwrap();
}

// STREAMINFO's MD5 sum

// Note that the wrapped writer can be used once bitstream writing
// is finished at exactly the position one would expect.

flac.write_all(
    b"\xFA\xF2\x69\x2F\xFD\xEC\x2D\x5B\x30\x01\x76\xB4\x62\x88\x7D\x92")
    .unwrap();

assert_eq!(flac, vec![0x66,0x4C,0x61,0x43,0x00,0x00,0x00,0x22,
                      0x10,0x00,0x10,0x00,0x00,0x06,0x06,0x00,
                      0x21,0x62,0x0A,0xC4,0x42,0xF0,0x00,0x04,
                      0xA6,0xCC,0xFA,0xF2,0x69,0x2F,0xFD,0xEC,
                      0x2D,0x5B,0x30,0x01,0x76,0xB4,0x62,0x88,
                      0x7D,0x92]);