Expand description
Library for strings of fixed maximum lengths that can be copied and stack-allocated using const generics.
The structures provided by this crate are fstr, zstr and tstr. However, tstr is not exported and can only be used through the type aliases str8, str16, str32, through str256.
The size of (std::mem::size_of) types str8 and zstr<8> are 8 bytes, compared to 16 bytes for &str, providing more efficient ways of representing very small strings.
Version 0.2.x adds unicode support and a module for zero_terminated strings in the structure zstr. These strings are more memory efficient than fstr but less efficient in terms of run time.
For version 0.2.2, the str8 through str256 type aliases where
changed to refer to another, internal type distinct from fstr and
zstr. This type represents strings of up to 255 bytes with a
[u8;N] underneath where it’s assumed that N<=256. The first
byte of the array holds the length of the string in bytes. This structure
represents the best combination of fstr and zstr in terms of speed
and memory efficiency. However, because Rust does not currently provide
a why to specify conditions on const generics at compile time, such as
where N<=256, the internal “tiny string” type tstr is not exported and can
only be used through the aliases. These strings implement that same
functions and traits as fstr and zstr so the documentation for
these structures also apply to the hidden type.
For version 0.2.2 the fsiter construct and direct iterator implmentation for fstr has been removed. Use the fstr::chars function instead.
Examples
let a:fstr<8> = fstr::from("abcdefg"); //creates fstr from &str
let a1:fstr<8> = a; // copied, not moved
let a2:&str = a.to_str();
let a3:String = a.to_string();
assert_eq!(a.nth_ascii(2), 'c');
let ab = a.substr(1,5); // copies substring to new fstr
assert_eq!(ab,"bcde"); // can compare with &str
assert!(a<ab); // implements Ord trait (and Hash, Debug, Display)
let mut u:fstr<8> = fstr::from("aλb"); //unicode support
for x in u.nth(1) {assert_eq!(x,'λ');} // nth returns Option<char>
assert!(u.set(1,'μ')); // changes a character of the same character class
assert!(!u.set(1,'c')); // .set returns false on failure
assert!(u.set(2,'c'));
assert_eq!(u, "aμc");
assert_eq!(u.len(),4); // length in bytes
assert_eq!(u.charlen(),3); // length in chars
let mut ac:fstr<16> = a.resize(); // copies to larger capacity string
let remainder:&str = ac.push("hijklmnopqrst"); //appends string, returns left over
assert_eq!(ac.len(),16);
assert_eq!(remainder, "qrst");
ac.truncate(10); // shortens string in place
assert_eq!(&ac,"abcdefghij");zstr and the type aliases str8…str256 implement the same capabilities as fstr.
Re-exports
pub use zero_terminated::*;Modules
Structs
main type: string of size up to const N:
Type Definitions
Each type strN is represented underneath by a [u8;N] with N<=256.
The first byte of the array always holds the length of the string.
Each such type can hold a string of up to N-1 bytes, with max size=255.
These types represent the best compromise between fstr and zstr in
terms of speed and memory efficiency.