servicepoint-binding-c/src/bitvec.rs

//! C functions for interacting with [SPBitVec]s
//!
//! prefix `sp_bitvec_`

use crate::SPByteSlice;
use std::ptr::NonNull;

/// A vector of bits
///
/// # Examples
/// ```C
/// SPBitVec vec = sp_bitvec_new(8);
/// sp_bitvec_set(vec, 5, true);
/// sp_bitvec_free(vec);
/// ```
pub struct SPBitVec(pub(crate) servicepoint::BitVecU8Msb0);

impl Clone for SPBitVec {
    fn clone(&self) -> Self {
        SPBitVec(self.0.clone())
    }
}

/// Creates a new [SPBitVec] instance.
///
/// # Arguments
///
/// - `size`: size in bits.
///
/// returns: [SPBitVec] with all bits set to false. Will never return NULL.
///
/// # Panics
///
/// - when `size` is not divisible by 8.
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - the returned instance is freed in some way, either by using a consuming function or
///   by explicitly calling `sp_bitvec_free`.
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_new(size: usize) -> NonNull<SPBitVec> {
    let result =
        Box::new(SPBitVec(servicepoint::BitVecU8Msb0::repeat(false, size)));
    NonNull::from(Box::leak(result))
}

/// Interpret the data as a series of bits and load then into a new [SPBitVec] instance.
///
/// returns: [SPBitVec] instance containing data. Will never return NULL.
///
/// # Panics
///
/// - when `data` is NULL
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `data` points to a valid memory location of at least `data_length`
///   bytes in size.
/// - the returned instance is freed in some way, either by using a consuming function or
///   by explicitly calling `sp_bitvec_free`.
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_load(
    data: SPByteSlice,
) -> NonNull<SPBitVec> {
    let data = unsafe { data.as_slice() };
    let result =
        Box::new(SPBitVec(servicepoint::BitVecU8Msb0::from_slice(data)));
    NonNull::from(Box::leak(result))
}

/// Clones a [SPBitVec].
///
/// returns: new [SPBitVec] instance. Will never return NULL.
///
/// # Panics
///
/// - when `bit_vec` is NULL
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `bit_vec` points to a valid [SPBitVec]
/// - `bit_vec` is not written to concurrently
/// - the returned instance is freed in some way, either by using a consuming function or
///   by explicitly calling `sp_bitvec_free`.
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_clone(
    bit_vec: NonNull<SPBitVec>,
) -> NonNull<SPBitVec> {
    let result = Box::new(unsafe { bit_vec.as_ref().clone() });
    NonNull::from(Box::leak(result))
}

/// Deallocates a [SPBitVec].
///
/// # Panics
///
/// - when `but_vec` is NULL
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `bit_vec` points to a valid [SPBitVec]
/// - `bit_vec` is not used concurrently or after this call
/// - `bit_vec` was not passed to another consuming function, e.g. to create a [TypedCommand]
///
/// [TypedCommand]: [crate::TypedCommand]
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_free(bit_vec: NonNull<SPBitVec>) {
    _ = unsafe { Box::from_raw(bit_vec.as_ptr()) };
}

/// Gets the value of a bit from the [SPBitVec].
///
/// # Arguments
///
/// - `bit_vec`: instance to read from
/// - `index`: the bit index to read
///
/// returns: value of the bit
///
/// # Panics
///
/// - when `bit_vec` is NULL
/// - when accessing `index` out of bounds
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `bit_vec` points to a valid [SPBitVec]
/// - `bit_vec` is not written to concurrently
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_get(
    bit_vec: NonNull<SPBitVec>,
    index: usize,
) -> bool {
    unsafe { *bit_vec.as_ref().0.get(index).unwrap() }
}

/// Sets the value of a bit in the [SPBitVec].
///
/// # Arguments
///
/// - `bit_vec`: instance to write to
/// - `index`: the bit index to edit
/// - `value`: the value to set the bit to
///
/// # Panics
///
/// - when `bit_vec` is NULL
/// - when accessing `index` out of bounds
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `bit_vec` points to a valid [SPBitVec]
/// - `bit_vec` is not written to or read from concurrently
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_set(
    bit_vec: NonNull<SPBitVec>,
    index: usize,
    value: bool,
) {
    unsafe { (*bit_vec.as_ptr()).0.set(index, value) }
}

/// Sets the value of all bits in the [SPBitVec].
///
/// # Arguments
///
/// - `bit_vec`: instance to write to
/// - `value`: the value to set all bits to
///
/// # Panics
///
/// - when `bit_vec` is NULL
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `bit_vec` points to a valid [SPBitVec]
/// - `bit_vec` is not written to or read from concurrently
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_fill(
    bit_vec: NonNull<SPBitVec>,
    value: bool,
) {
    unsafe { (*bit_vec.as_ptr()).0.fill(value) }
}

/// Gets the length of the [SPBitVec] in bits.
///
/// # Arguments
///
/// - `bit_vec`: instance to write to
///
/// # Panics
///
/// - when `bit_vec` is NULL
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `bit_vec` points to a valid [SPBitVec]
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_len(bit_vec: NonNull<SPBitVec>) -> usize {
    unsafe { bit_vec.as_ref().0.len() }
}

/// Returns true if length is 0.
///
/// # Arguments
///
/// - `bit_vec`: instance to write to
///
/// # Panics
///
/// - when `bit_vec` is NULL
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `bit_vec` points to a valid [SPBitVec]
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_is_empty(
    bit_vec: NonNull<SPBitVec>,
) -> bool {
    unsafe { bit_vec.as_ref().0.is_empty() }
}

/// Gets an unsafe reference to the data of the [SPBitVec] instance.
///
/// # Arguments
///
/// - `bit_vec`: instance to write to
///
/// # Panics
///
/// - when `bit_vec` is NULL
///
/// ## Safety
///
/// The caller has to make sure that:
///
/// - `bit_vec` points to a valid [SPBitVec]
/// - the returned memory range is never accessed after the passed [SPBitVec] has been freed
/// - the returned memory range is never accessed concurrently, either via the [SPBitVec] or directly
#[no_mangle]
pub unsafe extern "C" fn sp_bitvec_unsafe_data_ref(
    bit_vec: NonNull<SPBitVec>,
) -> SPByteSlice {
    unsafe { SPByteSlice::from_slice((*bit_vec.as_ptr()).0.as_raw_mut_slice()) }
}