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use array_trait::Array;
use slice_ops::AsSlice;
#[const_trait]
pub trait ArrayPermute<T, const N: usize>: Array + AsSlice<Item = T>
{
/// Performs the bit-reverse permutation. Length must be a power of 2.
///
/// This moves around all the values in the array such that its indices have their bits reversed.
///
/// # Examples
/// ```rust
/// #![feature(generic_const_exprs)]
///
/// use array__ops::ops::*;
///
/// let mut arr = [0b000, 0b001, 0b010, 0b011, 0b100, 0b101, 0b110, 0b111];
///
/// arr.bit_rev_permutation();
///
/// assert_eq!(arr, [0b000, 0b100, 0b010, 0b110, 0b001, 0b101, 0b011, 0b111])
/// ```
fn bit_rev_permutation(&mut self)
where
[(); slice_ops::is_power_of(N, 2) as usize - 1]:;
/// Performs the digit-reverse permutation with a given radix. Length must be a power of the radix.
///
/// This moves around all the values in the array such that its indices have their digit representation reversed using the given radix.
///
/// With radix 2, this is equivalent to a bit-reverse permutation (see [ArrayPermute::bit_rev_permutation]).
///
/// # Examples
///
/// ## Radix 3
///
/// ```rust
/// #![feature(generic_const_exprs)]
///
/// use array__ops::ops::*;
///
/// let mut a = [1, 2, 3, 4, 5, 6, 7, 8, 9];
///
/// a.digit_rev_permutation::<3>();
///
/// assert_eq!(a, [1, 4, 7, 2, 5, 8, 3, 6, 9])
/// ```
///
/// ## Radix 16
///
/// ```rust
/// #![feature(generic_const_exprs)]
///
/// use array__ops::ops::*;
///
/// let mut a = [
/// 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
/// 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
/// 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
/// 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
/// 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
/// 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
/// 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F,
/// 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
/// 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,
/// 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F,
/// 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
/// 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
/// 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
/// 0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
/// 0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF,
/// 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF,
/// ];
///
/// a.digit_rev_permutation::<16>();
///
/// assert_eq!(
/// a,
/// [
/// 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
/// 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71, 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
/// 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72, 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
/// 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73, 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
/// 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74, 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
/// 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75, 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
/// 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76, 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
/// 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77, 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
/// 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78, 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
/// 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79, 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
/// 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A, 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
/// 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B, 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
/// 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C, 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
/// 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D, 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
/// 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E, 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
/// 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F, 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF,
/// ]
/// );
/// ```
fn digit_rev_permutation<const R: usize>(&mut self)
where
[(); slice_ops::is_power_of(N, R) as usize - 1]:;
/// Performs the grey code permutation. Length must be a power of 2.
///
/// # Examples
/// ```rust
/// #![feature(generic_const_exprs)]
///
/// use array__ops::ops::*;
///
/// let mut arr = [0b000, 0b001, 0b010, 0b011, 0b100, 0b101, 0b110, 0b111];
///
/// arr.grey_code_permutation();
///
/// assert_eq!(arr, [0b000, 0b001, 0b011, 0b010, 0b110, 0b111, 0b101, 0b100])
/// ```
fn grey_code_permutation(&mut self)
where
[(); N.is_power_of_two() as usize - 1]:;
}
impl<T, const N: usize> const ArrayPermute<T, N> for [T; N]
{
fn bit_rev_permutation(&mut self)
where
[(); slice_ops::is_power_of(N, 2) as usize - 1]:
{
self.digit_rev_permutation::<2>()
}
fn digit_rev_permutation<const R: usize>(&mut self)
where
[(); slice_ops::is_power_of(N, R) as usize - 1]:
{
if N <= R
{
return;
}
let mut i = 1;
let mut j = N/R + 1;
while i < N - 1
{
if i < j - 1
{
self.swap(i, j - 1);
}
let mut k = N/R;
while k*(R - 1) < j
{
j -= k*(R - 1);
k /= R;
}
j += k;
i += 1;
}
}
fn grey_code_permutation(&mut self)
where
[(); N.is_power_of_two() as usize - 1]:
{
let mut i = 2;
while i < N
{
let mut j = i ^ (i >> 1);
while j < i
{
j = j ^ (j >> 1);
}
if j != i
{
self.swap(i, j);
}
i += 1;
}
}
}
#[cfg(test)]
mod test
{
use crate::ops::ArrayPermute;
#[test]
fn bit_rev()
{
let mut a = [1, 2, 3, 4, 5, 6, 7, 8, 9];
a.digit_rev_permutation::<3>();
assert_eq!(a, [1, 4, 7, 2, 5, 8, 3, 6, 9])
}
#[test]
fn digit_rev16()
{
let mut a = [
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F,
0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F,
0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF,
0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF,
];
a.digit_rev_permutation::<16>();
assert_eq!(
a,
[
0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71, 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72, 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73, 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74, 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75, 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76, 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77, 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78, 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79, 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A, 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B, 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C, 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D, 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E, 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F, 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF,
]
);
}
#[test]
fn grey_code()
{
let mut a = [1, 2, 3, 4, 5, 6, 7, 8];
a.grey_code_permutation();
assert_eq!(a, [1, 2, 4, 3, 7, 8, 6, 5]);
}
}