BitSparrow in Rust

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Encoding

use bitsparrow::Encoder;

let buffer = Encoder::new()
             .uint8(100)
             .string("Foo")
             .end();

assert_eq!(buffer, &[0x64,0x03,0x46,0x6f,0x6f])

Each method on the Encoder will consume the instance of the struct. If you need to break the monad chain, store the intermediate state of the encoder, e.g.:

use bitsparrow::Encoder;

let encoder = Encoder::new();
encoder.uint8(100);

/* ... */

let buffer = encoder.string("Foo").end();

assert_eq!(buffer, &[0x64,0x03,0x46,0x6f,0x6f]);

Decoding

use bitsparrow::Decoder;

let buffer = &[0x64,0x03,0x46,0x6f,0x6f];
let mut decoder = Decoder::new(buffer);

assert_eq!(100u8, decoder.uint8().unwrap());
assert_eq!("Foo", decoder.string().unwrap());
assert_eq!(true, decoder.end());

Decoder allows you to retrieve the values in order they were encoded. Calling the end method is optional - it will return true if you have read the entire buffer, ensuring the entire buffer has been read.

Performance

All primitive number types are encoded and decoded using straight low level memory copying and type transmutations. Even on little-endian hardware (the encoded data is always big-endian) the cost of encoding/decoding is virtually none:

test allocate_8 ... bench:          26 ns/iter (+/- 4)
test decode_f64 ... bench:           0 ns/iter (+/- 0)
test decode_u64 ... bench:           0 ns/iter (+/- 0)
test encode_f64 ... bench:          26 ns/iter (+/- 6)
test encode_u64 ... bench:          26 ns/iter (+/- 3)

Encoding benchmark includes allocating 8 bytes on the heap, the allocate_8 just creates Vec::with_capacity(8) to demonstrate that the actual encoding process is very, very cheap.

The MIT License (MIT)

Copyright (c) 2016 BitSparrow

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.