rust-postgres-array/src/array.rs at master · psqlpy-python/rust-postgres-array · GitHub

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use std::fmt;

use std::ops::{Index, IndexMut};

use std::slice;

use std::vec;

use crate::Dimension;

/// A multi-dimensional array.

#[derive(Debug, PartialEq, Eq, Clone)]

pub struct Array<T> {

dims: Vec<Dimension>,

data: Vec<T>,

}

impl<T: fmt::Display> fmt::Display for Array<T> {

fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {

if self.dims.iter().any(|dim| dim.lower_bound != 1) {

for dim in &self.dims {

write!(

fmt,

"[{}:{}]",

dim.lower_bound,

dim.lower_bound + dim.len - 1

)?;

}

write!(fmt, "=")?;

}

fmt_helper(0, &self.dims, &mut self.data.iter(), fmt)

}

fn fmt_helper<'a, T, I>(

depth: usize,

dims: &[Dimension],

data: &mut I,

fmt: &mut fmt::Formatter<'_>,

) -> fmt::Result

where

I: Iterator<Item = &'a T>,

T: 'a + fmt::Display,

{

if dims.len() == 0 {

return write!(fmt, "{{}}");

}

if depth == dims.len() {

return write!(fmt, "{}", data.next().unwrap());

}

write!(fmt, "{{")?;

for i in 0..dims[depth].len {

if i != 0 {

write!(fmt, ",")?;

}

fmt_helper(depth + 1, dims, data, fmt)?;

}

write!(fmt, "}}")

}

impl<T> Array<T> {

/// Creates a new `Array` from its underlying components.

///

/// The data array should be provided in the higher-dimensional equivalent

/// of row-major order.

///

/// # Panics

///

/// Panics if the number of elements provided does not match the number of

/// elements specified by the dimensions.

pub fn from_parts(data: Vec<T>, dimensions: Vec<Dimension>) -> Array<T> {

assert!(

(data.is_empty() && dimensions.is_empty())

|| data.len() as i32 == dimensions.iter().fold(1, |acc, i| acc * i.len),

"size mismatch"

);

Array {

dims: dimensions,

data,

}

/// Creates a new one-dimensional array.

pub fn from_vec(data: Vec<T>, lower_bound: i32) -> Array<T> {

Array {

dims: vec![Dimension {

len: data.len() as i32,

lower_bound,

}],

data,

}

/// Wraps this array in a new dimension of size 1.

///

/// For example, the one dimensional array `[1, 2]` would turn into the

/// two-dimensional array `[[1, 2]]`.

pub fn wrap(&mut self, lower_bound: i32) {

self.dims.insert(

Dimension {

len: 1,

lower_bound,

);

}

/// Consumes another array, appending it to the top level dimension of this

/// array.

///

/// The dimensions of the other array must be the same as the dimensions

/// of this array with the first dimension removed. This includes lower

/// bounds as well as lengths.

///

/// For example, if `[3, 4]` is pushed onto `[[1, 2]]`, the result is

/// `[[1, 2], [3, 4]]`.

///

/// # Panics

///

/// Panics if the dimensions of the two arrays do not match.

pub fn push(&mut self, other: Array<T>) {

assert!(

self.dims.len() - 1 == other.dims.len(),

"cannot append differently shaped arrays"

);

for (dim1, dim2) in self.dims.iter().skip(1).zip(other.dims.iter()) {

assert!(dim1 == dim2, "cannot append differently shaped arrays");

}

self.dims[0].len += 1;

self.data.extend(other.data);

}

/// Returns the dimensions of this array.

pub fn dimensions(&self) -> &[Dimension] {

&self.dims

}

fn shift_idx(&self, indices: &[i32]) -> i32 {

assert_eq!(self.dims.len(), indices.len());

self.dims

.iter()

.zip(indices.iter().cloned())

.rev()

.fold((0, 1), |(acc, stride), (dim, idx)| {

let shifted = dim.shift(idx);

(acc + shifted * stride, dim.len * stride)

})

}

/// Returns an iterator over references to the elements of the array in the

/// higher-dimensional equivalent of row-major order.

pub fn iter(&self) -> Iter<'_, T> {

Iter {

inner: self.data.iter(),

}

/// Returns an iterator over mutable references to the elements of the

/// array in the higher-dimensional equivalent of row-major order.

pub fn iter_mut(&mut self) -> IterMut<'_, T> {

IterMut {

inner: self.data.iter_mut(),

}

/// Returns the underlying data vector for this Array in the

/// higher-dimensional equivalent of row-major order.

pub fn into_inner(self) -> Vec<T> {

self.data

}

/// A trait implemented by types that can index into an `Array`.

pub trait ArrayIndex {

/// Calculates the index into the `Array`'s underlying storage specified

/// by the value of `self`.

///

/// # Panics

///

/// Panics if the value of `self` does not correspond to an in-bounds

/// element of the `Array`.

fn index<T>(&self, array: &Array<T>) -> i32;

}

impl<'a> ArrayIndex for &'a [i32] {

fn index<T>(&self, array: &Array<T>) -> i32 {

array.shift_idx(*self)

}

impl ArrayIndex for i32 {

fn index<T>(&self, array: &Array<T>) -> i32 {

let slice: &[i32] = &[*self];

ArrayIndex::index(&slice, array)

}

macro_rules! tuple_impl {

($($name:ident : $t:ty),+) => {

impl ArrayIndex for ($($t,)+) {

fn index<T>(&self, array: &Array<T>) -> i32 {

let ($($name,)+) = *self;

let slice: &[i32] = &[$($name),+];

ArrayIndex::index(&slice, array)

}

tuple_impl!(a: i32);

tuple_impl!(a: i32, b: i32);

tuple_impl!(a: i32, b: i32, c: i32);

tuple_impl!(a: i32, b: i32, c: i32, d: i32);

tuple_impl!(a: i32, b: i32, c: i32, d: i32, e: i32);

tuple_impl!(a: i32, b: i32, c: i32, d: i32, e: i32, f: i32);

tuple_impl!(a: i32, b: i32, c: i32, d: i32, e: i32, f: i32, g: i32);

tuple_impl!(

a: i32,

b: i32,

c: i32,

d: i32,

e: i32,

f: i32,

g: i32,

h: i32

);

tuple_impl!(

a: i32,

b: i32,

c: i32,

d: i32,

e: i32,

f: i32,

g: i32,

h: i32,

i: i32

);

/// Indexes into the `Array`, retrieving a reference to the contained

/// value.

///

/// Since `Array`s can be multi-dimensional, the `Index` trait is

/// implemented for a variety of index types. In the most generic case, a

/// `&[i32]` can be used. In addition, a bare `i32` as well as tuples

/// of up to 10 `i32` values may be used for convenience.

///

/// # Panics

///

/// Panics if the index does not correspond to an in-bounds element of the

/// `Array`.

///

/// # Examples

///

/// ```rust

/// # use postgres_array::Array;

/// let mut array = Array::from_vec(vec![0i32, 1, 2, 3], 0);

/// assert_eq!(2, array[2]);

///

/// array.wrap(0);

/// array.push(Array::from_vec(vec![4, 5, 6, 7], 0));

///

/// assert_eq!(6, array[(1, 2)]);

/// ```

impl<T, I: ArrayIndex> Index<I> for Array<T> {

type Output = T;

fn index(&self, idx: I) -> &T {

let idx = idx.index(self);

&self.data[idx as usize]

}

impl<T, I: ArrayIndex> IndexMut<I> for Array<T> {

fn index_mut(&mut self, idx: I) -> &mut T {

let idx = idx.index(self);

&mut self.data[idx as usize]

}

impl<'a, T: 'a> IntoIterator for &'a Array<T> {

type Item = &'a T;

type IntoIter = Iter<'a, T>;

fn into_iter(self) -> Iter<'a, T> {

self.iter()

}

impl<'a, T: 'a> IntoIterator for &'a mut Array<T> {

type Item = &'a mut T;

type IntoIter = IterMut<'a, T>;

fn into_iter(self) -> IterMut<'a, T> {

self.iter_mut()

}

impl<T> IntoIterator for Array<T> {

type Item = T;

type IntoIter = IntoIter<T>;

fn into_iter(self) -> IntoIter<T> {

IntoIter {

inner: self.data.into_iter(),

}

/// An iterator over references to values of an `Array` in the

/// higher-dimensional equivalent of row-major order.

pub struct Iter<'a, T> {

inner: slice::Iter<'a, T>,

}

impl<'a, T: 'a> Iterator for Iter<'a, T> {

type Item = &'a T;

fn next(&mut self) -> Option<&'a T> {

self.inner.next()

}

fn size_hint(&self) -> (usize, Option<usize>) {

self.inner.size_hint()

}

impl<'a, T: 'a> DoubleEndedIterator for Iter<'a, T> {

fn next_back(&mut self) -> Option<&'a T> {

self.inner.next_back()

}

impl<'a, T: 'a> ExactSizeIterator for Iter<'a, T> {

fn len(&self) -> usize {

self.inner.len()

}

/// An iterator over mutable references to values of an `Array` in the

/// higher-dimensional equivalent of row-major order.

pub struct IterMut<'a, T> {

inner: slice::IterMut<'a, T>,

}

impl<'a, T: 'a> Iterator for IterMut<'a, T> {

type Item = &'a mut T;

fn next(&mut self) -> Option<&'a mut T> {

self.inner.next()

}

fn size_hint(&self) -> (usize, Option<usize>) {

self.inner.size_hint()

}

impl<'a, T: 'a> DoubleEndedIterator for IterMut<'a, T> {

fn next_back(&mut self) -> Option<&'a mut T> {

self.inner.next_back()

}

impl<'a, T: 'a> ExactSizeIterator for IterMut<'a, T> {

fn len(&self) -> usize {

self.inner.len()

}

/// An iterator over values of an `Array` in the higher-dimensional

/// equivalent of row-major order.

pub struct IntoIter<T> {

inner: vec::IntoIter<T>,

}

impl<T> Iterator for IntoIter<T> {

type Item = T;

fn next(&mut self) -> Option<T> {

self.inner.next()

}

fn size_hint(&self) -> (usize, Option<usize>) {

self.inner.size_hint()

}

impl<T> DoubleEndedIterator for IntoIter<T> {

fn next_back(&mut self) -> Option<T> {

self.inner.next_back()

}

impl<T> ExactSizeIterator for IntoIter<T> {

fn len(&self) -> usize {

self.inner.len()

}

rust-postgres-array/src/array.rs at master · psqlpy-python/rust-postgres-array · GitHub

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