dd3c6d1303After some discussion with PVH I realise that the repo structure in the last reorg was very rust-centric. In an attempt to put each language on a level footing move the rust code and project files into ./rust
340 lines
10 KiB
Rust
340 lines
10 KiB
Rust
use std::ffi::c_void;
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use std::mem::size_of;
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use crate::doc::map::item::AMmapItem;
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#[repr(C)]
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struct Detail {
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len: usize,
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offset: isize,
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ptr: *const c_void,
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}
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/// \note cbindgen won't propagate the value of a `std::mem::size_of<T>()` call
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/// (https://github.com/eqrion/cbindgen/issues/252) but it will
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/// propagate the name of a constant initialized from it so if the
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/// constant's name is a symbolic representation of the value it can be
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/// converted into a number by post-processing the header it generated.
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pub const USIZE_USIZE_USIZE_: usize = size_of::<Detail>();
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impl Detail {
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fn new(map_items: &[AMmapItem], offset: isize) -> Self {
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Self {
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len: map_items.len(),
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offset,
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ptr: map_items.as_ptr() as *const c_void,
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}
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}
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pub fn advance(&mut self, n: isize) {
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if n == 0 {
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return;
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}
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let len = self.len as isize;
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self.offset = if self.offset < 0 {
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// It's reversed.
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let unclipped = self.offset.checked_sub(n).unwrap_or(isize::MIN);
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if unclipped >= 0 {
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// Clip it to the forward stop.
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len
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} else {
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std::cmp::min(std::cmp::max(-(len + 1), unclipped), -1)
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}
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} else {
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let unclipped = self.offset.checked_add(n).unwrap_or(isize::MAX);
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if unclipped < 0 {
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// Clip it to the reverse stop.
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-(len + 1)
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} else {
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std::cmp::max(0, std::cmp::min(unclipped, len))
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}
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}
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}
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pub fn get_index(&self) -> usize {
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(self.offset
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+ if self.offset < 0 {
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self.len as isize
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} else {
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0
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}) as usize
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}
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pub fn next(&mut self, n: isize) -> Option<&AMmapItem> {
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if self.is_stopped() {
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return None;
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}
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let slice: &[AMmapItem] =
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unsafe { std::slice::from_raw_parts(self.ptr as *const AMmapItem, self.len) };
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let value = &slice[self.get_index()];
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self.advance(n);
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Some(value)
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}
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pub fn is_stopped(&self) -> bool {
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let len = self.len as isize;
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self.offset < -len || self.offset == len
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}
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pub fn prev(&mut self, n: isize) -> Option<&AMmapItem> {
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self.advance(-n);
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if self.is_stopped() {
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return None;
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}
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let slice: &[AMmapItem] =
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unsafe { std::slice::from_raw_parts(self.ptr as *const AMmapItem, self.len) };
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Some(&slice[self.get_index()])
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}
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pub fn reversed(&self) -> Self {
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Self {
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len: self.len,
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offset: -(self.offset + 1),
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ptr: self.ptr,
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}
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}
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pub fn rewound(&self) -> Self {
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Self {
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len: self.len,
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offset: if self.offset < 0 { -1 } else { 0 },
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ptr: self.ptr,
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}
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}
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}
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impl From<Detail> for [u8; USIZE_USIZE_USIZE_] {
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fn from(detail: Detail) -> Self {
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unsafe {
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std::slice::from_raw_parts((&detail as *const Detail) as *const u8, USIZE_USIZE_USIZE_)
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.try_into()
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.unwrap()
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}
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}
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}
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/// \struct AMmapItems
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/// \installed_headerfile
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/// \brief A random-access iterator over a sequence of map object items.
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#[repr(C)]
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#[derive(Eq, PartialEq)]
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pub struct AMmapItems {
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/// An implementation detail that is intentionally opaque.
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/// \warning Modifying \p detail will cause undefined behavior.
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/// \note The actual size of \p detail will vary by platform, this is just
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/// the one for the platform this documentation was built on.
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detail: [u8; USIZE_USIZE_USIZE_],
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}
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impl AMmapItems {
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pub fn new(map_items: &[AMmapItem]) -> Self {
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Self {
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detail: Detail::new(map_items, 0).into(),
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}
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}
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pub fn advance(&mut self, n: isize) {
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let detail = unsafe { &mut *(self.detail.as_mut_ptr() as *mut Detail) };
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detail.advance(n);
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}
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pub fn len(&self) -> usize {
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let detail = unsafe { &*(self.detail.as_ptr() as *const Detail) };
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detail.len
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}
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pub fn next(&mut self, n: isize) -> Option<&AMmapItem> {
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let detail = unsafe { &mut *(self.detail.as_mut_ptr() as *mut Detail) };
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detail.next(n)
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}
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pub fn prev(&mut self, n: isize) -> Option<&AMmapItem> {
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let detail = unsafe { &mut *(self.detail.as_mut_ptr() as *mut Detail) };
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detail.prev(n)
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}
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pub fn reversed(&self) -> Self {
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let detail = unsafe { &*(self.detail.as_ptr() as *const Detail) };
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Self {
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detail: detail.reversed().into(),
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}
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}
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pub fn rewound(&self) -> Self {
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let detail = unsafe { &*(self.detail.as_ptr() as *const Detail) };
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Self {
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detail: detail.rewound().into(),
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}
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}
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}
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impl AsRef<[AMmapItem]> for AMmapItems {
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fn as_ref(&self) -> &[AMmapItem] {
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let detail = unsafe { &*(self.detail.as_ptr() as *const Detail) };
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unsafe { std::slice::from_raw_parts(detail.ptr as *const AMmapItem, detail.len) }
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}
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}
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impl Default for AMmapItems {
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fn default() -> Self {
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Self {
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detail: [0; USIZE_USIZE_USIZE_],
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}
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}
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}
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/// \memberof AMmapItems
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/// \brief Advances an iterator over a sequence of map object items by at most
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/// \p |n| positions where the sign of \p n is relative to the
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/// iterator's direction.
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///
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/// \param[in,out] map_items A pointer to an `AMmapItems` struct.
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/// \param[in] n The direction (\p -n -> opposite, \p n -> same) and maximum
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/// number of positions to advance.
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/// \pre \p map_items `!= NULL`.
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/// \internal
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///
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/// #Safety
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/// map_items must be a valid pointer to an AMmapItems
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#[no_mangle]
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pub unsafe extern "C" fn AMmapItemsAdvance(map_items: *mut AMmapItems, n: isize) {
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if let Some(map_items) = map_items.as_mut() {
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map_items.advance(n);
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};
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}
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/// \memberof AMmapItems
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/// \brief Tests the equality of two sequences of map object items underlying
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/// a pair of iterators.
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///
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/// \param[in] map_items1 A pointer to an `AMmapItems` struct.
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/// \param[in] map_items2 A pointer to an `AMmapItems` struct.
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/// \return `true` if \p map_items1 `==` \p map_items2 and `false` otherwise.
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/// \pre \p map_items1 `!= NULL`.
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/// \pre \p map_items2 `!= NULL`.
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/// \internal
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///
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/// #Safety
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/// map_items1 must be a valid pointer to an AMmapItems
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/// map_items2 must be a valid pointer to an AMmapItems
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#[no_mangle]
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pub unsafe extern "C" fn AMmapItemsEqual(
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map_items1: *const AMmapItems,
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map_items2: *const AMmapItems,
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) -> bool {
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match (map_items1.as_ref(), map_items2.as_ref()) {
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(Some(map_items1), Some(map_items2)) => map_items1.as_ref() == map_items2.as_ref(),
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(None, Some(_)) | (Some(_), None) | (None, None) => false,
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}
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}
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/// \memberof AMmapItems
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/// \brief Gets the map object item at the current position of an iterator
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/// over a sequence of map object items and then advances it by at most
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/// \p |n| positions where the sign of \p n is relative to the
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/// iterator's direction.
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///
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/// \param[in,out] map_items A pointer to an `AMmapItems` struct.
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/// \param[in] n The direction (\p -n -> opposite, \p n -> same) and maximum
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/// number of positions to advance.
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/// \return A pointer to an `AMmapItem` struct that's `NULL` when \p map_items
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/// was previously advanced past its forward/reverse limit.
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/// \pre \p map_items `!= NULL`.
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/// \internal
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///
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/// #Safety
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/// map_items must be a valid pointer to an AMmapItems
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#[no_mangle]
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pub unsafe extern "C" fn AMmapItemsNext(map_items: *mut AMmapItems, n: isize) -> *const AMmapItem {
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if let Some(map_items) = map_items.as_mut() {
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if let Some(map_item) = map_items.next(n) {
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return map_item;
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}
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}
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std::ptr::null()
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}
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/// \memberof AMmapItems
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/// \brief Advances an iterator over a sequence of map object items by at most
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/// \p |n| positions where the sign of \p n is relative to the
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/// iterator's direction and then gets the map object item at its new
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/// position.
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///
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/// \param[in,out] map_items A pointer to an `AMmapItems` struct.
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/// \param[in] n The direction (\p -n -> opposite, \p n -> same) and maximum
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/// number of positions to advance.
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/// \return A pointer to an `AMmapItem` struct that's `NULL` when \p map_items
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/// is presently advanced past its forward/reverse limit.
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/// \pre \p map_items `!= NULL`.
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/// \internal
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///
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/// #Safety
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/// map_items must be a valid pointer to an AMmapItems
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#[no_mangle]
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pub unsafe extern "C" fn AMmapItemsPrev(map_items: *mut AMmapItems, n: isize) -> *const AMmapItem {
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if let Some(map_items) = map_items.as_mut() {
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if let Some(map_item) = map_items.prev(n) {
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return map_item;
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}
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}
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std::ptr::null()
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}
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/// \memberof AMmapItems
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/// \brief Gets the size of the sequence of map object items underlying an
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/// iterator.
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///
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/// \param[in] map_items A pointer to an `AMmapItems` struct.
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/// \return The count of values in \p map_items.
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/// \pre \p map_items `!= NULL`.
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/// \internal
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///
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/// #Safety
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/// map_items must be a valid pointer to an AMmapItems
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#[no_mangle]
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pub unsafe extern "C" fn AMmapItemsSize(map_items: *const AMmapItems) -> usize {
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if let Some(map_items) = map_items.as_ref() {
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map_items.len()
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} else {
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0
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}
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}
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/// \memberof AMmapItems
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/// \brief Creates an iterator over the same sequence of map object items as
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/// the given one but with the opposite position and direction.
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///
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/// \param[in] map_items A pointer to an `AMmapItems` struct.
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/// \return An `AMmapItems` struct
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/// \pre \p map_items `!= NULL`.
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/// \internal
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///
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/// #Safety
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/// map_items must be a valid pointer to an AMmapItems
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#[no_mangle]
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pub unsafe extern "C" fn AMmapItemsReversed(map_items: *const AMmapItems) -> AMmapItems {
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if let Some(map_items) = map_items.as_ref() {
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map_items.reversed()
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} else {
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AMmapItems::default()
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}
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}
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/// \memberof AMmapItems
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/// \brief Creates an iterator at the starting position over the same sequence of map object items as the given one.
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///
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/// \param[in] map_items A pointer to an `AMmapItems` struct.
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/// \return An `AMmapItems` struct
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/// \pre \p map_items `!= NULL`.
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/// \internal
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///
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/// #Safety
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/// map_items must be a valid pointer to an AMmapItems
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#[no_mangle]
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pub unsafe extern "C" fn AMmapItemsRewound(map_items: *const AMmapItems) -> AMmapItems {
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if let Some(map_items) = map_items.as_ref() {
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map_items.rewound()
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} else {
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AMmapItems::default()
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}
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}
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