feat: add prepend_rows and prepend_cols

benches/benches.rs

@@ -201,6 +201,60 @@ fn criterion_benchmark(c: &mut Criterion) {
             criterion::BatchSize::SmallInput,
         )
     });
+
+    // Insert
+    c.bench_function("grid_insert_row", |b| {
+        let grid = init_grid();
+        b.iter_batched(
+            || grid.clone(),
+            |mut g| g.insert_row(rand(), vec![42; g.cols()]),
+            criterion::BatchSize::SmallInput,
+        )
+    });
+    c.bench_function("grid_insert_col", |b| {
+        let grid = init_grid();
+        b.iter_batched(
+            || grid.clone(),
+            |mut g| g.insert_col(rand(), vec![42; g.rows()]),
+            criterion::BatchSize::SmallInput,
+        )
+    });
+
+    // Expand
+    c.bench_function("grid_expand_rows", |b| {
+        let grid = init_grid();
+        b.iter_batched(
+            || grid.clone(),
+            |mut g| g.expand_rows(1),
+            criterion::BatchSize::SmallInput,
+        )
+    });
+    c.bench_function("grid_expand_cols", |b| {
+        let grid = init_grid();
+        b.iter_batched(
+            || grid.clone(),
+            |mut g| g.expand_cols(1),
+            criterion::BatchSize::SmallInput,
+        )
+    });
+
+    // Prepend
+    c.bench_function("grid_prepend_rows", |b| {
+        let grid = init_grid();
+        b.iter_batched(
+            || grid.clone(),
+            |mut g| g.prepend_rows(1),
+            criterion::BatchSize::SmallInput,
+        )
+    });
+    c.bench_function("grid_prepend_cols", |b| {
+        let grid = init_grid();
+        b.iter_batched(
+            || grid.clone(),
+            |mut g| g.prepend_cols(1),
+            criterion::BatchSize::SmallInput,
+        )
+    });
 }
 
 criterion_group!(benches, criterion_benchmark);

src/lib.rs

@@ -1698,6 +1698,100 @@ impl<T: Default> Grid<T> {
             self.cols += cols;
         }
     }
+
+    /// Expands the grid by inserting a given amount of rows at the beginning, filling the new rows with `T::default()`.
+    /// If the grid has no rows or no columns, nothing will happen.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use grid::*;
+    /// let mut grid: Grid<u8> = grid![[1, 2, 3][3, 4, 5]];
+    /// grid.prepend_rows(2);
+    /// assert_eq!(grid.rows(), 4);
+    /// assert_eq!(grid[(0, 0)], 0);
+    /// assert_eq!(grid[(0, 1)], 0);
+    /// assert_eq!(grid[(0, 2)], 0);
+    /// assert_eq!(grid[(1, 0)], 0);
+    /// assert_eq!(grid[(1, 1)], 0);
+    /// assert_eq!(grid[(1, 2)], 0);
+    /// ```
+    ///
+    /// # Performance
+    ///
+    /// This method will be significantly slower if the grid uses a column-major memory layout.
+    pub fn prepend_rows(&mut self, rows: usize) {
+        if rows > 0 && self.cols > 0 {
+            self.data
+                .resize_with(self.data.len() + rows * self.cols, T::default);
+
+            match self.order {
+                Order::RowMajor => {
+                    for i in (0..self.rows).rev() {
+                        let s = i * self.cols;
+                        let e = (i + rows + 1) * self.cols;
+                        self.data[s..e].rotate_left(self.cols);
+                    }
+                }
+                Order::ColumnMajor => {
+                    for row_added in 0..rows {
+                        for i in (0..self.cols).rev() {
+                            let total_rows = self.rows + row_added;
+                            let col_idx = i * total_rows;
+                            self.data[col_idx..=col_idx + total_rows + i].rotate_right(i + 1);
+                        }
+                    }
+                }
+            }
+            self.rows += rows;
+        }
+    }
+
+    /// Expands the grid by inserting a given amount of columns at the beginning, filling the new columns with `T::default()`.
+    /// If the grid has no rows or no columns, nothing will happen.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use grid::*;
+    /// let mut grid: Grid<u8> = grid![[1, 2, 3][3, 4, 5]];
+    /// grid.prepend_cols(2);
+    /// assert_eq!(grid.cols(), 5);
+    /// assert_eq!(grid[(0, 0)], 0);
+    /// assert_eq!(grid[(0, 1)], 0);
+    /// assert_eq!(grid[(1, 0)], 0);
+    /// assert_eq!(grid[(1, 1)], 0);
+    /// ```
+    ///
+    /// # Performance
+    ///
+    /// This method will be significantly slower if the grid uses a row-major memory layout.
+    pub fn prepend_cols(&mut self, cols: usize) {
+        if cols > 0 && self.rows > 0 {
+            self.data
+                .resize_with(self.data.len() + cols * self.rows, T::default);
+
+            match self.order {
+                Order::RowMajor => {
+                    for col_added in 0..cols {
+                        for i in (0..self.rows).rev() {
+                            let total_cols = self.cols + col_added;
+                            let row_idx = i * total_cols;
+                            self.data[row_idx..=row_idx + total_cols + i].rotate_right(i + 1);
+                        }
+                    }
+                }
+                Order::ColumnMajor => {
+                    for i in (0..self.cols).rev() {
+                        let s = i * self.rows;
+                        let e = (i + cols + 1) * self.rows;
+                        self.data[s..e].rotate_left(self.rows);
+                    }
+                }
+            }
+            self.cols += cols;
+        }
+    }
 }
 
 impl<T> Default for Grid<T> {
@@ -2757,6 +2851,102 @@ mod test {
         assert_eq!(grid.into_vec(), Vec::<u8>::new());
     }
 
+    #[test]
+    fn prepend_rows() {
+        let mut grid = Grid::from_vec_with_order(vec![1, 1, 1, 2, 2, 2], 3, Order::RowMajor);
+        grid.prepend_rows(2);
+
+        assert_eq!(grid.size(), (4, 3));
+        assert_eq!(grid.order, Order::RowMajor);
+        assert_eq!(grid.rows(), 4);
+        assert_eq!(grid.cols(), 3);
+        assert_eq!(grid.into_vec(), vec![0, 0, 0, 0, 0, 0, 1, 1, 1, 2, 2, 2]);
+    }
+
+    #[test]
+    fn prepend_rows_column_major() {
+        let mut grid = Grid::from_vec_with_order(vec![1, 2, 1, 2, 1, 2], 3, Order::ColumnMajor);
+        grid.prepend_rows(2);
+
+        assert_eq!(grid.size(), (4, 3));
+        assert_eq!(grid.order, Order::ColumnMajor);
+        assert_eq!(grid.rows(), 4);
+        assert_eq!(grid.cols(), 3);
+        assert_eq!(grid.into_vec(), vec![0, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2]);
+    }
+
+    #[test]
+    fn prepend_rows_zero() {
+        let mut grid = Grid::from_vec_with_order(vec![1, 1, 1], 3, Order::RowMajor);
+        grid.prepend_rows(0);
+
+        assert_eq!(grid.size(), (1, 3));
+        assert_eq!(grid.order, Order::RowMajor);
+        assert_eq!(grid.rows(), 1);
+        assert_eq!(grid.cols(), 3);
+        assert_eq!(grid.into_vec(), vec![1, 1, 1]);
+    }
+
+    #[test]
+    fn prepend_rows_empty_grid() {
+        let mut grid: Grid<u8> = Grid::init(0, 0, 0);
+        grid.prepend_rows(2);
+
+        assert_eq!(grid.size(), (0, 0));
+        assert_eq!(grid.order, Order::RowMajor);
+        assert_eq!(grid.rows(), 0);
+        assert_eq!(grid.cols(), 0);
+        assert_eq!(grid.into_vec(), Vec::<u8>::new());
+    }
+
+    #[test]
+    fn prepend_cols() {
+        let mut grid = Grid::from_vec_with_order(vec![1, 1, 1, 2, 2, 2], 3, Order::RowMajor);
+        grid.prepend_cols(2);
+
+        assert_eq!(grid.size(), (2, 5));
+        assert_eq!(grid.order, Order::RowMajor);
+        assert_eq!(grid.rows(), 2);
+        assert_eq!(grid.cols(), 5);
+        assert_eq!(grid.into_vec(), vec![0, 0, 1, 1, 1, 0, 0, 2, 2, 2]);
+    }
+
+    #[test]
+    fn prepend_cols_column_major() {
+        let mut grid = Grid::from_vec_with_order(vec![1, 2, 1, 2, 1, 2], 3, Order::ColumnMajor);
+        grid.prepend_cols(2);
+
+        assert_eq!(grid.size(), (2, 5));
+        assert_eq!(grid.order, Order::ColumnMajor);
+        assert_eq!(grid.rows(), 2);
+        assert_eq!(grid.cols(), 5);
+        assert_eq!(grid.into_vec(), vec![0, 0, 0, 0, 1, 2, 1, 2, 1, 2]);
+    }
+
+    #[test]
+    fn prepend_cols_zero() {
+        let mut grid = Grid::from_vec_with_order(vec![1, 2, 1, 2], 2, Order::RowMajor);
+        grid.prepend_cols(0);
+
+        assert_eq!(grid.size(), (2, 2));
+        assert_eq!(grid.order, Order::RowMajor);
+        assert_eq!(grid.rows(), 2);
+        assert_eq!(grid.cols(), 2);
+        assert_eq!(grid.into_vec(), vec![1, 2, 1, 2]);
+    }
+
+    #[test]
+    fn prepend_cols_empty_grid() {
+        let mut grid: Grid<u8> = Grid::init(0, 0, 0);
+        grid.prepend_cols(2);
+
+        assert_eq!(grid.size(), (0, 0));
+        assert_eq!(grid.order, Order::RowMajor);
+        assert_eq!(grid.rows(), 0);
+        assert_eq!(grid.cols(), 0);
+        assert_eq!(grid.into_vec(), Vec::<u8>::new());
+    }
+
     #[test]
     fn iter_row() {
         let grid = Grid::from_vec_with_order(vec![1, 2, 3, 4, 5, 6], 3, Order::RowMajor);