// Copyright 2024 Gabriel Bjørnager Jensen.
//
// This file is part of bzipper.
//
// bzipper is free software: you can redistribute
// it and/or modify it under the terms of the GNU
// Lesser General Public License as published by
// the Free Software Foundation, either version 3
// of the License, or (at your option) any later
// version.
//
// bzipper is distributed in the hope that it will
// be useful, but WITHOUT ANY WARRANTY; without
// even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Less-
// er General Public License along with bzipper. If
// not, see <https://www.gnu.org/licenses/>.
#[cfg(test)]
mod test;
use crate::{
Deserialise,
DStream,
Error,
FixedStringIter,
Serialise,
SStream,
};
use std::cmp::Ordering;
use std::fmt::{Debug, Display, Formatter, Write};
use std::ops::{Index, IndexMut};
use std::str::FromStr;
/// Owned string with maximum size.
///
/// This is in contrast to [String], which has no size limit is practice, and [str], which is unsized.
#[derive(Clone)]
pub struct FixedString<const N: usize> {
buf: [char; N],
len: usize,
}
impl<const N: usize> FixedString<N> {
/// Constructs a new fixed string.
///
/// The contents of the provided string are copied into the internal buffer.
/// All residual characters are instanced as U+0000 `NULL`.
///
/// # Errors
///
/// If the given string `s` cannot fit into `N` characters, a [`FixedStringTooShort`](Error::FixedStringTooShort) error is returned.
pub fn new(s: &str) -> Result<Self, Error> {
let mut buf = ['\0'; N];
let len = s.chars().count();
for (i, c) in s.chars().enumerate() {
if i >= N { return Err(Error::FixedStringTooShort { len: N, s: s.to_owned() }) }
buf[i] = c;
}
Ok(Self { buf, len })
}
/// Returns the length of the string.
///
/// This does not necessarily equal the value of `N`, as the internal buffer is not required to be used fully.
#[inline(always)]
#[must_use]
pub const fn len(&self) -> usize { self.len }
/// Checks if the string is empty, i.e. `self.len() == 0x0`.
#[inline(always)]
#[must_use]
pub const fn is_empty(&self) -> bool { self.len == 0x0 }
/// Borrows the character at the specified index.
///
/// If no element exists at that position, [`None`] is returned instead.
#[inline]
#[must_use]
pub const fn get(&self, index: usize) -> Option<&char> {
if index >= self.len {
None
} else {
Some(&self.buf[index])
}
}
/// Mutably borrows the character at the specified index.
///
/// If no element exists at that position, [`None`] is returned instead.
#[inline]
#[must_use]
pub fn get_mut(&mut self, index: usize) -> Option<&mut char> {
if index >= self.len {
None
} else {
Some(&mut self.buf[index])
}
}
/// Returns an iterator to the contained characters.
#[inline(always)]
pub fn iter(&self) -> std::slice::Iter<'_, char> { self.buf[0x0..self.len].iter() }
/// Returns a mutable iterator to the contained characters.
#[inline(always)]
pub fn iter_mut(&mut self) -> std::slice::IterMut<'_, char> { self.buf[0x0..self.len].iter_mut() }
}
impl<const N: usize> Debug for FixedString<N> {
fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
f.write_char('"')?;
for c in self { write!(f, "{}", c.escape_debug())? }
f.write_char('"')?;
Ok(())
}
}
impl<const N: usize> Deserialise for FixedString<N> {
type Error = Error;
fn deserialise(stream: &mut DStream) -> Result<Self, Self::Error> {
let len = usize::try_from(u64::deserialise(stream)?).unwrap();
let data = stream.take(len)?;
let s = std::str::from_utf8(data)
.map_err(|e| Error::InvalidUtf8 { source: e })?;
let len = s.chars().count();
if len > N {
return Err(Error::FixedStringTooShort { len, s: s.to_owned() });
}
let mut buf = ['\0'; N];
for (i, c) in s.chars().enumerate() {
buf[i] = c;
}
Ok(Self { buf, len })
}
}
impl<const N: usize> Default for FixedString<N> {
#[inline(always)]
fn default() -> Self { Self {
buf: ['\0'; N],
len: 0x0,
} }
}
impl<const N: usize> Display for FixedString<N> {
fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
for c in self { write!(f, "{c}")? }
Ok(())
}
}
impl<const N: usize> Eq for FixedString<N> { }
impl<const N: usize> From<[char; N]> for FixedString<N> {
fn from(value: [char; N]) -> Self { Self {
buf: value,
len: N,
} }
}
impl<const N: usize> FromStr for FixedString<N> {
type Err = Error;
fn from_str(s: &str) -> Result<Self, Error> { Self::new(s) }
}
impl<const N: usize> Index<usize> for FixedString<N> {
type Output = char;
fn index(&self, index: usize) -> &Self::Output { self.get(index).unwrap() }
}
impl<const N: usize> IndexMut<usize> for FixedString<N> {
fn index_mut(&mut self, index: usize) -> &mut Self::Output { self.get_mut(index).unwrap() }
}
impl<const N: usize> IntoIterator for FixedString<N> {
type Item = char;
type IntoIter = FixedStringIter<N>;
fn into_iter(self) -> Self::IntoIter {
FixedStringIter {
buf: self.buf,
len: self.len,
pos: Some(0x0),
}
}
}
impl<'a, const N: usize> IntoIterator for &'a FixedString<N> {
type Item = &'a char;
type IntoIter = std::slice::Iter<'a, char>;
fn into_iter(self) -> Self::IntoIter { self.iter() }
}
impl<'a, const N: usize> IntoIterator for &'a mut FixedString<N> {
type Item = &'a mut char;
type IntoIter = std::slice::IterMut<'a, char>;
fn into_iter(self) -> Self::IntoIter { self.iter_mut() }
}
impl<const N: usize> Ord for FixedString<N> {
fn cmp(&self, other: &Self) -> Ordering { self.partial_cmp(other).unwrap() }
}
impl<const N: usize, const M: usize> PartialEq<FixedString<M>> for FixedString<N> {
fn eq(&self, other: &FixedString<M>) -> bool {
if self.len() != other.len() { return false };
for i in 0x0..self.len() {
if self.buf[i] != other.buf[i] { return false };
}
true
}
}
impl<const N: usize> PartialEq<&str> for FixedString<N> {
fn eq(&self, other: &&str) -> bool {
for (i, c) in other.chars().enumerate() {
if self.buf.get(i) != Some(&c) { return false };
}
true
}
}
impl<const N: usize, const M: usize> PartialOrd<FixedString<M>> for FixedString<N> {
fn partial_cmp(&self, other: &FixedString<M>) -> Option<Ordering> {
let len = self.len().max(other.len());
for i in 0x0..len {
let lc = self.get(i);
let rc = other.get(i);
match (lc, rc) {
(None, None) => return Some(Ordering::Equal),
(Some(_), None) => return Some(Ordering::Greater),
(None, Some(_)) => return Some(Ordering::Less),
(Some(lc), Some(rc)) => {
let ordering = lc.cmp(rc);
if ordering != Ordering::Equal { return Some(ordering) };
}
}
}
Some(Ordering::Equal)
}
}
impl<const N: usize> Serialise for FixedString<N> {
fn serialise(&self, stream: &mut SStream) {
let s: String = self.iter().collect();
let len = u64::try_from(s.len()).unwrap();
stream.append(&len.to_be_bytes());
stream.append(&s.into_bytes());
}
}
impl<const N: usize> TryFrom<&str> for FixedString<N> {
type Error = Error;
#[inline(always)]
fn try_from(value: &str) -> Result<Self, Self::Error> { Self::new(value) }
}
