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//! Creation of stringlets, `new()` and `default()` panic at compile time, unless they make sence.
use crate::*;
impl<Kind: StringletKind, const SIZE: usize> StringletBase<Kind, SIZE>
where
Self: ConfigBase<Kind, SIZE>,
{
/** Create an empty `Self`. Will panic if type can’t be empty, e.g. `Stringlet<1>` or `TrimStringlet<2>` */
#[inline(always)]
#[must_use]
pub const fn new() -> Self {
const {
if Kind::FIXED {
assert!(SIZE == 0, "Stringlet<1> or bigger cannot be empty");
} else if Kind::TRIM {
assert!(SIZE <= 1, "TrimStringlet<2> or bigger cannot be empty");
}
}
// SAFETY always short enough and no bytes that can have a UTF-8 error
unsafe { Self::from_utf8_unchecked(&[]) }
}
pub const fn from_str(str: &str) -> Result<Self> {
match Self::fits(str.len()) {
Ok(()) => {
// SAFETY we checked the length and got UTF-8
Ok(unsafe { Self::from_str_unchecked(str) })
}
Err(e) => Err(e),
}
}
/// # Safety
/// It is the callers responsibility to ensure that the size fits
pub const unsafe fn from_str_unchecked(str: &str) -> Self {
// SAFETY len() is up to the caller
unsafe { Self::from_utf8_unchecked(str.as_bytes()) }
}
/**
```
# use stringlet::Stringlet;
let abcd = unsafe { Stringlet::<4>::from_utf8(b"Abcd") }?;
assert_eq!(abcd, "Abcd");
# Ok::<(), stringlet::error::Error>(())
```
*/
pub const fn from_utf8(str: &[u8]) -> Result<Self> {
// const equivalent of `expr?`
match Self::fits(str.len()) {
Ok(()) => {
match str::from_utf8(str) {
// SAFETY always short enough and no bytes have a UTF-8 error
Ok(str) => Ok(unsafe { Self::from_str_unchecked(str) }),
Err(e) => Err(Utf8Error(e)),
}
}
Err(e) => Err(e),
}
}
/**
```
# use stringlet::Stringlet;
const ABCD: Stringlet<4> =
unsafe { Stringlet::from_utf8_unchecked(b"Abcd") };
assert_eq!(ABCD, "Abcd");
```
# Safety
It is the callers responsibility to ensure that the size fits and the content is UTF-8. */
pub const unsafe fn from_utf8_unchecked(str: &[u8]) -> Self {
let bytes_len = str.len();
/* let mut str_uninit = core::mem::MaybeUninit::uninit();
let str = str_uninit.as_mut_ptr() as *mut u8; */
let mut me_uninit = core::mem::MaybeUninit::<Self>::uninit();
let me = me_uninit.as_mut_ptr() as *mut u8;
// SAFETY we write to whole uninit via pointer methods only before Rust sees the value
unsafe {
core::ptr::copy_nonoverlapping(str.as_ptr(), me, bytes_len);
if Kind::VAR {
me.add(bytes_len).write_bytes(0, SIZE - bytes_len);
me.add(SIZE).write(bytes_len as _);
} else if !Kind::FIXED && SIZE > 0 && SIZE > bytes_len {
me.add(bytes_len).write_bytes(0, SIZE - bytes_len - 1);
let tail = TAG | (SIZE - bytes_len) as u8;
me.add(SIZE - 1).write(tail);
}
me_uninit.assume_init()
}
}
/**
```
# use stringlet::Stringlet;
let abcd = Stringlet::<4>::from_utf8_bytes([b'A', b'b', b'c', b'd'])?;
assert_eq!(abcd, "Abcd");
# Ok::<(), stringlet::error::Error>(())
```
*/
pub const fn from_utf8_bytes(str: [u8; SIZE]) -> Result<Self> {
// const equivalent of `expr?`
match str::from_utf8(&str) {
// SAFETY always short enough and no bytes have a UTF-8 error
Ok(str) => Ok(unsafe { Self::from_str_unchecked(str) }),
Err(e) => Err(Utf8Error(e)),
}
}
/**
```
# use stringlet::Stringlet;
const ABCD: Stringlet<4> =
unsafe { Stringlet::from_utf8_bytes_unchecked([b'A', b'b', b'c', b'd']) };
assert_eq!(ABCD, "Abcd");
```
# Safety
It is the callers responsibility to ensure that the content is UTF-8. */
pub const unsafe fn from_utf8_bytes_unchecked(str: [u8; SIZE]) -> Self {
// SAFETY It is the callers responsibility to ensure that the content is UTF-8.
unsafe { Self::from_utf8_unchecked(&str) }
}
/**
```
# use stringlet::Stringlet;
let abcd = Stringlet::<4>::from_utf8_slice(b"Abcd")?;
assert_eq!(abcd, "Abcd");
# Ok::<(), stringlet::error::Error>(())
```
*/
pub const fn from_utf8_slice(str: &[u8; SIZE]) -> Result<Self> {
// const equivalent of `expr?`
match str::from_utf8(str) {
// SAFETY always short enough and no slice have a UTF-8 error
Ok(str) => Ok(unsafe { Self::from_str_unchecked(str) }),
Err(e) => Err(Utf8Error(e)),
}
}
/**
```
# use stringlet::Stringlet;
const ABCD: Stringlet<4> =
unsafe { Stringlet::from_utf8_slice_unchecked(b"Abcd") };
assert_eq!(ABCD, "Abcd");
```
# Safety
It is the callers responsibility to ensure that the content is UTF-8. */
pub const unsafe fn from_utf8_slice_unchecked(str: &[u8; SIZE]) -> Self {
// SAFETY It is the callers responsibility to ensure that the content is UTF-8.
unsafe { Self::from_utf8_unchecked(str) }
}
#[doc(hidden)]
#[inline]
pub const fn _from_macro(str: &str) -> Self {
match Self::fits(str.len()) {
// SAFETY we checked the length and got UTF-8
Ok(()) => unsafe { Self::from_str_unchecked(str) },
Err(TooLong) => panic!("stringlet!(...): parameter too long for its type."),
Err(TooShort) => panic!("stringlet!(...): parameter too short for its type."),
Err(Utf8Error(_)) => unreachable!(),
}
}
pub(crate) const fn fits(len: usize) -> Result<()> {
if len > SIZE {
Err(TooLong)
} else if (Kind::FIXED && len == SIZE)
|| Kind::VAR
|| Kind::SLIM
|| (Kind::TRIM && len >= const { SIZE.saturating_sub(1) })
{
Ok(())
} else {
Err(TooShort)
}
}
}
impl_for! {
Default:
fn default() -> Self {
Self::new()
}
}
#[cfg(doctest)]
mod doctests {
/**
```compile_fail
_ = stringlet::Stringlet::<1>::new();
```
*/
fn test_stringlet_1_new_compile_fail() {}
/**
```compile_fail
let _x: stringlet::Stringlet<1> = Default::default();
```
*/
fn test_stringlet_1_default_compile_fail() {}
/**
```compile_fail
_ = stringlet::TrimStringlet::<2>::new();
```
*/
fn test_trim_stringlet_2_new_compile_fail() {}
/**
```compile_fail
let _x: stringlet::TrimStringlet<2> = Default::default();
```
*/
fn test_trim_stringlet_2_default_compile_fail() {}
/**
```compile_fail
_ = stringlet::VarStringlet::<256>::new();
```
*/
fn test_var_stringlet_256_new_compile_fail() {}
/**
```compile_fail
let _x: stringlet::VarStringlet<256> = Default::default();
```
*/
fn test_var_stringlet_256_default_compile_fail() {}
/**
```compile_fail
_ = stringlet::SlimStringlet::<65>::new();
```
*/
fn test_slim_stringlet_65_new_compile_fail() {}
/**
```compile_fail
let _x: stringlet::SlimStringlet<65> = Default::default();
```
*/
fn test_slim_stringlet_65_default_compile_fail() {}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_fits() {
assert!(Stringlet::<0>::fits(0).is_ok());
assert!(Stringlet::<0>::fits(1).is_err());
assert!(Stringlet::<1>::fits(1).is_ok());
assert!(Stringlet::<1>::fits(0).is_err());
assert!(Stringlet::<256>::fits(256).is_ok());
assert!(VarStringlet::<0>::fits(0).is_ok());
assert!(!VarStringlet::<0>::fits(1).is_ok());
assert!(VarStringlet::<1>::fits(1).is_ok());
assert!(VarStringlet::<1>::fits(0).is_ok());
assert!(VarStringlet::<2>::fits(0).is_ok());
assert!(VarStringlet::<255>::fits(0).is_ok());
assert!(VarStringlet::<255>::fits(255).is_ok());
assert!(TrimStringlet::<0>::fits(0).is_ok());
assert!(!TrimStringlet::<0>::fits(1).is_ok());
assert!(TrimStringlet::<1>::fits(0).is_ok());
assert!(TrimStringlet::<1>::fits(1).is_ok());
assert!(!TrimStringlet::<2>::fits(0).is_ok());
assert!(TrimStringlet::<256>::fits(255).is_ok());
assert!(TrimStringlet::<256>::fits(256).is_ok());
assert!(SlimStringlet::<0>::fits(0).is_ok());
assert!(!SlimStringlet::<0>::fits(1).is_ok());
assert!(SlimStringlet::<1>::fits(1).is_ok());
assert!(SlimStringlet::<1>::fits(0).is_ok());
assert!(SlimStringlet::<2>::fits(0).is_ok());
assert!(SlimStringlet::<64>::fits(0).is_ok());
assert!(SlimStringlet::<64>::fits(64).is_ok());
}
#[test]
fn test_new() {
let s = Stringlet::<0>::new();
assert!(s.is_empty());
let s = TrimStringlet::<0>::new();
assert!(s.is_empty());
let s = TrimStringlet::<1>::new();
assert!(s.is_empty());
let s = VarStringlet::<8>::new();
assert!(s.is_empty());
let s = SlimStringlet::<8>::new();
assert!(s.is_empty());
}
#[test]
fn test_default() {
let s: Stringlet<0> = Default::default();
assert!(s.is_empty());
let s: TrimStringlet<0> = Default::default();
assert!(s.is_empty());
let s: TrimStringlet<1> = Default::default();
assert!(s.is_empty());
let s: VarStringlet = Default::default();
assert!(s.is_empty());
let s: SlimStringlet = Default::default();
assert!(s.is_empty());
}
}