[−][src]Crate bitlab

Objective:

To extract a range of bits from a binary data source or to insert a range of bits into a binary data structure

Status

passively-maintained

Documentation

This crate is published at crates.io. The detailed documentation is available at docs.rs/bitlab

Version

1.0.0

Example 1:

Start at bit offset 1, extract 3 bits and interpret the result as u8

use bitlab::*;
let a: i8 = -33; // = 0b1101_1111;
let b = a.get_u8(1, 3).unwrap();  // 1 --> 101 <-- 1111
//                                         = 5
assert_eq!(b, 5);

Example 2:

use bitlab::*;
let a: u8 = 0b0000_0101;
 
// Get the most significant bit. It has the bit offset 0
assert_eq!(a.get_bit(0).unwrap(), false);
 
// Set the most significant bit. Expect 0b1000_0101
assert_eq!(a.set_bit(0).unwrap(), 133);
 
// Clear the most significant bit. Expect 0b0000_0101
assert_eq!(a.clear_bit(0).unwrap(), 5);

Example 3:

The data source is a vector of u8 types. We want to go to byte offset 1, bit offset 7 and starting from there extract 3 bits as an u16

use bitlab::*;
let v: Vec<u8> = vec!{ 0x48, 0x61, 0x6C, 0x6C, 0x6F }; // = "Hallo"
let bar = v.get_u16(1, 7, 3); // relevant bytes = 0x616C = 0b0110_000  --> 1_01 <-- 10_1100
//                                                                         = 5
assert_eq!(bar.unwrap(), 5);

Example 4:

Insert a 2 bit unsigned integer value (b = 3) into a variable starting at the bit offset 1, where the offset = zero is the most significant bit.

use bitlab::*;
let a : u8 = 0;
let b : u8 = 3;
let c = a.set(1, 2, b).unwrap();
assert_eq!(c, 0b0110_0000);

Example 5:

Insert the value 3 (only 2 bits = 0b11) from a u8 into a vector at byte offset = 1 and bit offset = 15

use bitlab::*;
let a : u8 = 3; // = 0b0000_0011
let mut v: Vec<u8> = vec!{ 0x48, 0x61, 0x6C, 0x6C, 0x6F };
// relevant bytes = 0x6C_6C = 0b0110_110 --> 0_0 <-- 110_1100
let bar = v.set(1, 15, 2, a);
assert_eq!(v[2], 0b0110_1101);
assert_eq!(v[3], 0b1110_1100);

Example 6:

There is a very simple application in the examples directory, which extracts the color resolution from a real gif file. To run it enter the following in the command line

cargo run --release --example gif

MIT Licence

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.

Traits

ExtractBitsFromIntegralTypes	Defines a number of functions, which extract a range of bits from primitive numeric types (u8, u16, u32 and u64, i8, i16, i32 and i64) and return the result as one of the following types (u8, u16, u32 and u64, i8, i16, i32 and i64) E.g. the a.get_u8(5,3) function extracts the bits 5,6 and 7 of the variable a and returns the result as a u8 variable
ExtractBitsFromVecU8	Defines a number of functions, which extract a range of bits from a Vec There is one function for each variable type to be returned Important: the contents of the vector are assumed to be big endian (network order)
InsertBitsIntoVecU8	Defines a functions, which inserts a range of bits into a Vec Important: the contents of the vector are assumed to be big endian (network order)
InsertIntoSizedIntegerTypes	Provides a single function to insert a sized integer into an other sized integer type
SignedInfo	A trait to find out if a varibale type is signed or unsigned for integer types.
SingleBits	Defines a set of functions to get, set and clear single bits
TypeInfo	A trait to get the data type as a string for a integer and floating point types.

Functions

n_required_bits_for_a_signed_int	How many bits does it take to write a signed integer?
n_required_bits_for_an_unsigned_int	How many bits does it take to write an unsigned integer?