devela/data/collections/stack/methods/convert.rs
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// devela::data::collections::stack::methods::conversion
//
//!
//
use crate::{array_init, Array, Bare, ConstDefault, IndexOutOfBounds, NotEnoughSpace, Own, Stack};
#[cfg(feature = "alloc")]
use crate::{Box, Boxed, Vec};
// helper macro to impl methods for a Stack with custom index size.
//
// $IDX : the index type. E.g. u8, usize
macro_rules! impl_stack {
() => {
#[cfg(feature = "_stack_u8")]
impl_stack![u8:"_stack_u8"
=> u8:"_stack_u8", u16:"_stack_u16", u32:"_stack_u32", usize:"_stack_usize"];
#[cfg(feature = "_stack_u16")]
impl_stack![u16:"_stack_u16"
=> u8:"_stack_u8", u16:"_stack_u16", u32:"_stack_u32", usize:"_stack_usize"];
#[cfg(feature = "_stack_u32")]
impl_stack![u32:"_stack_u32"
=> u8:"_stack_u8", u16:"_stack_u16", u32:"_stack_u32", usize:"_stack_usize"];
#[cfg(feature = "_stack_usize")]
impl_stack![usize:"_stack_usize"
=> u8:"_stack_u8", u16:"_stack_u16", u32:"_stack_u32", usize:"_stack_usize"];
};
($IDX:ty : $cap:literal => $( $NEW_IDX:ty : $new_cap:literal ),+ ) => { crate::paste! {
/* resize */
/// # Stack resize.
// T, S: Bare
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = $cap)))]
impl<T: Default, const CAP: usize> Stack<T, CAP, $IDX, Bare> {
/// Converts the current stack to a different capacity
/// while preserving all existing elements.
///
/// This method creates a new stack with the specified new capacity and moves the
/// current elements into it. The operation ensures that the new stack can accommodate
/// the number of elements currently held in the stack. It is designed to work with
/// both increases and decreases in capacity, as long as the new capacity can fit the
/// current number of elements.
///
/// # Errors
/// Returns [`IndexOutOfBounds(Some(NEW_CAP))`] if `NEW_CAP < self.len()`,
#[doc = "if `CAP > `[`" $IDX "::MAX`]"]
/// or if `CAP > isize::MAX / size_of::<T>()`.
///
/// # Examples
/// ```
#[doc = "# use devela::Stack" $IDX:camel ";"]
#[doc = "let s = Stack" $IDX:camel "::<_, 8>::from([1, 2, 3, 4]);"]
#[doc = "let less_cap: Stack" $IDX:camel "::<_, 4> = s.resize_default().unwrap();"]
/// assert_eq![s.as_slice(), less_cap.as_slice()];
#[doc = "let more_cap: Stack" $IDX:camel "::<_, 12> = s.resize_default().unwrap();"]
/// assert_eq![s.as_slice(), more_cap.as_slice()];
/// assert![s.resize_default::<2>().is_err()]; // too small
/// ```
pub fn resize_default<const NEW_CAP: usize>(self)
-> Result<Stack<T, NEW_CAP, $IDX, Bare>, IndexOutOfBounds> {
if NEW_CAP < (self.len() as usize) ||
NEW_CAP > $IDX::MAX as usize ||
NEW_CAP > isize::MAX as usize / size_of::<T>() {
Err(IndexOutOfBounds(Some(NEW_CAP)))
} else {
let old_arr: [T; CAP] = self.data.into_array();
let mut new_arr =
array_init![default [T; NEW_CAP], "safe_data", "unsafe_array"];
for (i, item) in old_arr.into_iter().enumerate().take(NEW_CAP) {
new_arr[i] = item;
}
Ok(Stack {
data: Array::new(new_arr),
len: self.len,
})
}
}
/// Converts the current stack to a different capacity, dropping elements if needed.
///
/// This method creates a new stack with the specified new capacity and moves the
/// current elements into it. The operation will drop any elements that can't fit
/// in the new capacity, starting with the first ones (from the front of the stack).
///
/// # Examples
/// ```
#[doc = "# use devela::Stack" $IDX:camel ";"]
#[doc = "let s = Stack" $IDX:camel "::<_, 8>::from([1, 2, 3, 4]);"]
#[doc = "let less_cap: Stack" $IDX:camel "::<_, 4> = s.resize_default_truncate();"]
/// assert_eq![less_cap.as_slice(), s.as_slice()];
#[doc = "let more_cap: Stack" $IDX:camel "::<_, 12> = s.resize_default_truncate();"]
/// assert_eq![more_cap.as_slice(), s.as_slice()];
#[doc = "let drop_cap: Stack" $IDX:camel "::<_, 2> = s.resize_default_truncate();"]
/// assert_eq![drop_cap.as_slice(), &[3, 4]];
/// ```
pub fn resize_default_truncate<const NEW_CAP: usize>(self)
-> Stack<T, NEW_CAP, $IDX, Bare> {
let start_idx = if self.len() as usize > NEW_CAP {
self.len() as usize - NEW_CAP
} else {
0
};
let new_len = core::cmp::min(self.len(), NEW_CAP as $IDX);
let old_arr: [T; CAP] = self.data.into_array();
let mut new_arr = array_init![default [T; NEW_CAP], "safe_data", "unsafe_array"];
for (i, item) in old_arr.into_iter().enumerate().skip(start_idx).take(NEW_CAP) {
new_arr[i - start_idx] = item;
}
Stack {
data: Array::new(new_arr),
len: new_len,
}
}
}
// T, S: Boxed
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = "alloc")))]
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = $cap)))]
impl<T: Default, const CAP: usize> Stack<T, CAP, $IDX, Boxed> {
/// Converts the current stack to a different capacity while preserving all existing
/// elements.
///
/// This method creates a new stack with the specified new capacity and moves the
/// current elements into it. The operation ensures that the new stack can accommodate
/// the number of elements currently held in the stack. It is designed to work with
/// both increases and decreases in capacity, as long as the new capacity can fit the
/// current number of elements.
///
/// # Errors
/// Returns [`IndexOutOfBounds(Some(NEW_CAP))`] if `NEW_CAP < self.len()`,
#[doc = "if `CAP > `[`" $IDX "::MAX`]"]
/// or if `CAP > isize::MAX / size_of::<T>()`.
///
/// # Examples
/// ```
#[doc = "# use devela::{Boxed, Stack" $IDX:camel "};"]
#[doc = "let s = Stack" $IDX:camel "::<_, 8, Boxed>::from([1, 2, 3, 4]);"]
#[doc = "let less_cap: Stack" $IDX:camel
"::<_, 4, Boxed> = s.clone().resize_default().unwrap();"]
/// assert_eq![s.as_slice(), less_cap.as_slice()];
#[doc = "let more_cap: Stack" $IDX:camel
"::<_, 12, Boxed> = s.clone().resize_default().unwrap();"]
/// assert_eq![s.as_slice(), more_cap.as_slice()];
/// assert![s.resize_default::<2>().is_err()]; // too small
/// ```
pub fn resize_default<const NEW_CAP: usize>(self)
-> Result<Stack<T, NEW_CAP, $IDX, Boxed>, IndexOutOfBounds> {
if NEW_CAP < (self.len() as usize) ||
NEW_CAP > $IDX::MAX as usize ||
NEW_CAP > isize::MAX as usize / size_of::<T>() {
Err(IndexOutOfBounds(Some(NEW_CAP)))
} else {
let old_arr = self.data.into_vec();
let mut v = Vec::with_capacity(NEW_CAP);
for item in old_arr.into_iter().take(self.len as usize) {
v.push(item);
}
v.resize_with(NEW_CAP, Default::default);
let new_arr: Box<[T; NEW_CAP]> =
v.into_boxed_slice().try_into().unwrap_or_else(|_| {
panic!("Failed to convert Box<[T]> to Box<[T; NEW_CAP={}]>", NEW_CAP)
});
Ok(Stack {
data: Array::new_boxed(new_arr),
len: self.len,
})
}
}
/// Converts the current stack to a different capacity
/// while preserving all existing elements.
///
/// This method creates a new stack with the specified new capacity and moves the
/// current elements into it. The operation will drop any elements that can't fit
/// in the new capacity, starting with the first ones (from the front of the stack).
///
/// # Examples
/// ```
#[doc = "# use devela::{Boxed, Stack" $IDX:camel "};"]
#[doc = "let s = Stack" $IDX:camel "::<_, 8, Boxed>::from([1, 2, 3, 4]);"]
#[doc = "let less_cap: Stack" $IDX:camel
"::<_, 4, Boxed> = s.clone().resize_default_truncate();"]
/// assert_eq![less_cap.as_slice(), s.as_slice()];
#[doc = "let more_cap: Stack" $IDX:camel
"::<_, 12, Boxed> = s.clone().resize_default_truncate();"]
/// assert_eq![more_cap.as_slice(), s.as_slice()];
#[doc = "let drop_cap: Stack" $IDX:camel
"::<_, 2, Boxed> = s.resize_default_truncate();"]
/// assert_eq![drop_cap.as_slice(), &[3, 4]];
/// ```
pub fn resize_default_truncate<const NEW_CAP: usize>(self)
-> Stack<T, NEW_CAP, $IDX, Boxed> {
let mut old_vec = self.data.into_vec();
// When reducing capacity, truncate elements from the front.
if NEW_CAP < self.len as usize {
let excess = self.len as usize - NEW_CAP;
old_vec.drain(0..excess);
}
// Ensure the vector's length matches NEW_CAP before conversion.
old_vec.resize_with(NEW_CAP, Default::default);
let new_arr: Box<[T; NEW_CAP]> =
old_vec.into_boxed_slice().try_into().unwrap_or_else(|_| {
panic!("Failed to convert Box<[T]> to Box<[T; NEW_CAP={}]>", NEW_CAP)
});
Stack {
data: Array::new_boxed(new_arr),
len: core::cmp::min(self.len as usize, NEW_CAP) as $IDX,
}
}
}
// T, S: Bare
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = $cap)))]
impl<T: ConstDefault + Copy, const CAP: usize> Stack<T, CAP, $IDX, Bare> {
/// Converts the current stack to a different capacity
/// while preserving all existing elements.
///
/// This method creates a new stack with the specified new capacity and moves the
/// current elements into it. The operation ensures that the new stack can accommodate
/// the number of elements currently held in the stack. It is designed to work with
/// both increases and decreases in capacity, as long as the new capacity can fit the
/// current number of elements.
///
/// # Errors
/// Returns [`IndexOutOfBounds(Some(NEW_CAP))`] if `NEW_CAP < self.len()`,
#[doc = "if `CAP > `[`" $IDX "::MAX`]"]
/// or if `CAP > isize::MAX / size_of::<T>()`.
///
/// # Examples
/// ```
#[doc = "# use devela::Stack" $IDX:camel ";"]
#[doc = "const S: Stack" $IDX:camel "<i32, 8> = Stack" $IDX:camel "::own_new(0)"]
/// .s_const_unwrap().s.own_push(1).s.own_push(2).s.own_push(3).s;
#[doc = "const T: Stack" $IDX:camel
"<i32, 4> = S.own_resize_default().s_const_unwrap().s;"]
/// assert_eq![S.as_slice(), T.as_slice()];
/// let _ = S.own_resize_default::<2>().s_assert_err(); // too small
/// ```
pub const fn own_resize_default<const NEW_CAP: usize>(self)
-> Own<Result<Stack<T, NEW_CAP, $IDX, Bare>, IndexOutOfBounds>, ()> {
if NEW_CAP < (self.len as usize) ||
NEW_CAP > $IDX::MAX as usize ||
NEW_CAP > isize::MAX as usize / size_of::<T>() {
Own::empty(Err(IndexOutOfBounds(Some(NEW_CAP))))
} else {
let old_arr: [T; CAP] = self.data.into_array_copy();
let mut new_arr = array_init![const_default [T; NEW_CAP]];
let mut i = 0;
while i < self.len as usize {
new_arr[i] = old_arr[i];
i += 1;
}
Own::empty(Ok(Stack {
data: Array::new_bare(new_arr),
len: self.len,
}))
}
}
/// Converts the current stack to a different capacity, dropping elements if needed.
///
/// This method creates a new stack with the specified new capacity and moves the
/// current elements into it. The operation will drop any elements that can't fit
/// in the new capacity, starting with the first ones (from the front of the stack).
///
/// # Examples
/// ```
#[doc = "# use devela::Stack" $IDX:camel ";"]
#[doc = "const S: Stack" $IDX:camel "<i32, 8> = Stack" $IDX:camel "::own_new(0)"]
/// .s_const_unwrap().s.own_push(1).s.own_push(2).s.own_push(3).s;
#[doc = "const T: Stack" $IDX:camel "<i32, 4> = S.own_resize_default_truncate().s;"]
/// assert_eq![S.as_slice(), T.as_slice()];
#[doc = "const U: Stack" $IDX:camel "<i32, 2> = S.own_resize_default_truncate().s;"]
/// assert_eq![U.as_slice(), &[2, 3]];
/// ```
pub const fn own_resize_default_truncate<const NEW_CAP: usize>(self)
-> Own<Stack<T, NEW_CAP, $IDX, Bare>, ()> {
let start_idx = if self.len as usize > NEW_CAP {
self.len as usize - NEW_CAP
} else {
0
};
let new_len = crate::num::Compare(NEW_CAP).min(self.len as usize);
let old_arr: [T; CAP] = self.data.into_array_copy();
let mut new_arr = array_init![const_default [T; NEW_CAP]];
let mut i = 0;
while i < new_len {
new_arr[i] = old_arr[i + start_idx];
i += 1;
}
Own::empty(Stack {
data: Array::new_bare(new_arr),
len: new_len as $IDX,
})
}
}
/* convert */
// T, S: Bare
/// # Stack index-size conversion.
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = $cap)))]
impl<T, const CAP: usize> Stack<T, CAP, $IDX, Bare> {
$(
/// Converts the current stack index size `IDX` to a `NEW_IDX`.
///
/// # Errors
#[doc = "Returns [`NotEnoughSpace`] if `CAP > `[`" $NEW_IDX "::MAX`]."]
///
/// # Examples
/// ```
#[doc = "# use devela::data::*;"]
#[doc = "let s = Stack" $IDX:camel "::<_, 6>::from([1, 2, 3, 4]);"]
#[doc = "let t: Stack" $NEW_IDX:camel "::<_, 6> = s.to_idx_" $NEW_IDX "().unwrap();"]
/// assert_eq![s.as_slice(), t.as_slice()];
/// ```
#[cfg(feature = $new_cap)]
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = $new_cap)))]
pub fn [<to_idx_ $NEW_IDX>](self)
-> Result<Stack<T, CAP, $NEW_IDX, Bare>, NotEnoughSpace> {
if CAP > $NEW_IDX::MAX as usize {
Err(NotEnoughSpace(Some($NEW_IDX::MAX as usize - CAP)))
} else {
Ok(Stack { data: self.data, len: self.len as $NEW_IDX })
}
}
)+
}
// T, S: Boxed
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = "alloc")))]
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = $cap)))]
impl<T, const CAP: usize> Stack<T, CAP, $IDX, Boxed> {
$(
/// Converts the current stack index size `IDX` to a `NEW_IDX`.
///
/// # Errors
#[doc = "Returns [`NotEnoughSpace`] if `CAP > `[`" $NEW_IDX "::MAX`]."]
///
/// # Examples
/// ```
#[doc = "# use devela::*;"]
#[doc = "let s = Stack" $IDX:camel "::<_, 6, Boxed>::from([1, 2, 3]);"]
#[doc = "let t: Stack" $NEW_IDX:camel "::<_, 6, Boxed> = s.to_idx_"
$NEW_IDX "().unwrap();"]
/// assert_eq![t.as_slice(), &[1, 2, 3]];
/// ```
#[cfg(feature = $new_cap)]
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = $new_cap)))]
pub fn [<to_idx_ $NEW_IDX>](self)
-> Result<Stack<T, CAP, $NEW_IDX, Boxed>, NotEnoughSpace> {
if CAP > $NEW_IDX::MAX as usize {
Err(NotEnoughSpace(Some($NEW_IDX::MAX as usize - CAP)))
} else {
Ok(Stack { data: self.data, len: self.len as $NEW_IDX })
}
}
)+
}
// T: Copy, S: Bare
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = $cap)))]
impl<T: Copy, const CAP: usize> Stack<T, CAP, $IDX, Bare> {
$(
/// Converts the current stack index size `IDX` to a `NEW_IDX`.
///
/// # Errors
#[doc = "Returns [`NotEnoughSpace`] if `CAP > `[`" $NEW_IDX "::MAX`]."]
///
/// # Examples
/// ```
#[doc = "# use devela::data::*;"]
#[doc = "const S: Stack" $IDX:camel "<i32, 6> = Stack" $IDX:camel "::own_new(0)"]
/// .s_const_unwrap().s.own_push(1).s.own_push(2).s.own_push(3).s;
#[doc = "const T: Stack" $NEW_IDX:camel "<i32, 6> = S.own_to_idx_"
$NEW_IDX "().s_const_unwrap().s;"]
/// assert_eq![S.as_slice(), T.as_slice()];
/// ```
#[cfg(feature = $new_cap)]
#[cfg_attr(feature = "nightly_doc", doc(cfg(feature = $new_cap)))]
pub const fn [<own_to_idx_ $NEW_IDX>](self)
-> Own<Result<Stack<T, CAP, $NEW_IDX, Bare>, NotEnoughSpace>, ()> {
if CAP > $NEW_IDX::MAX as usize {
Own::empty(Err(NotEnoughSpace(Some($NEW_IDX::MAX as usize - CAP))))
} else {
Own::empty(Ok(Stack { data: self.data, len: self.len as $NEW_IDX }))
}
}
)+
}
}};
}
impl_stack!();