feat: replace simpleerror with thiserror

Cargo.toml

@@ -13,7 +13,7 @@ getrandom = { version = "0.2.15", features = ["js"] }
 log = "0.4.22"
 rand = "0.8.5"
 rustc-hash = "2.0.0"
-simple-error = "0.3.1"
+thiserror = "1.0.64"
 wasm-bindgen = "0.2.95"
 wasm-logger = "0.2.0"
 web-sys = { version = "0.3.72", features = [

benches/solver_benchmark.rs

@@ -16,6 +16,8 @@ lazy_static::lazy_static! {
     };
 }
 
+const MAX_NUM_STEPS_OPTIMAL: usize = 2_000_000;
+
 fn criterion_benchmark(c: &mut Criterion) {
     let mut group100 = c.benchmark_group("100 samples");
     group100.sample_size(100);
@@ -27,6 +29,7 @@ fn criterion_benchmark(c: &mut Criterion) {
                 black_box(&PUZZLE_3X3_16.0),
                 black_box(PUZZLE_3X3_16.1),
                 black_box(PUZZLE_3X3_16.2),
+                MAX_NUM_STEPS_OPTIMAL,
             )
         })
     });
@@ -38,6 +41,7 @@ fn criterion_benchmark(c: &mut Criterion) {
                 black_box(&PUZZLE_4X4_10.0),
                 black_box(PUZZLE_4X4_10.1),
                 black_box(PUZZLE_4X4_10.2),
+                MAX_NUM_STEPS_OPTIMAL,
             )
         })
     });
@@ -77,11 +81,12 @@ fn criterion_benchmark(c: &mut Criterion) {
                 black_box(&PUZZLE_4X4_17.0),
                 black_box(PUZZLE_4X4_17.1),
                 black_box(PUZZLE_4X4_17.2),
+                MAX_NUM_STEPS_OPTIMAL,
             )
         })
     });
 
-    group_slow.bench_function("4x4 10 steps divide and conquer", |b| {
+    group_slow.bench_function("4x4 17 steps divide and conquer", |b| {
         b.iter(|| {
             let mut solver = DacPuzzleSolver::new(
                 black_box(&PUZZLE_4X4_17.0),

src/board.rs

@@ -1,7 +1,6 @@
 use rand::prelude::SliceRandom;
-use simple_error::simple_error;
 
-use crate::Error;
+use crate::error::LibError;
 
 #[derive(Debug)]
 pub(crate) struct Board {
@@ -111,23 +110,23 @@ where
     t_zero <= row && row < height && t_zero <= col && col < width
 }
 
+/// Initialize fields as vector.
+pub(crate) fn initialize_fields(num_elements: usize) -> Vec<u8> {
+    let num_elements = usize::min(num_elements, u8::MAX as usize) as u8;
+    (0..num_elements).collect()
+}
+
 /// Get the index of a value in a slice.
 ///
 /// This is a convenience wrapper which should not be used in a hot path.
-pub(crate) fn get_idx_of_val(slice: &[u8], value: u8) -> Result<usize, Error> {
+pub(crate) fn get_idx_of_val(slice: &[u8], value: u8) -> Result<usize, LibError> {
     slice
         .iter()
         .position(|&v| v == value)
-        .ok_or_else(|| simple_error!("value not found").into())
-}
-
-/// Initialize fields as vector.
-pub(crate) fn initialize_fields(num_elements: usize) -> Vec<u8> {
-    let num_elements = usize::min(num_elements, u8::MAX as usize) as u8;
-    (0..num_elements).collect()
+        .ok_or(LibError::ValueNotFound(value))
 }
 
-pub(crate) fn get_empty_field_idx(fields: &[u8]) -> Result<usize, Error> {
+pub(crate) fn get_empty_field_idx(fields: &[u8]) -> Result<usize, LibError> {
     get_idx_of_val(fields, fields.len() as u8 - 1)
 }
 
@@ -168,7 +167,7 @@ pub(crate) fn get_shuffle_sequence(
     size: usize,
     mut empty_field_idx: usize,
     num_swaps: usize,
-) -> Result<Vec<(usize, usize)>, Error> {
+) -> Vec<(usize, usize)> {
     let mut swaps = Vec::with_capacity(num_swaps);
 
     // We want to avoid swapping fields back and forth like (2, 1), (1, 2)
@@ -182,11 +181,11 @@ pub(crate) fn get_shuffle_sequence(
             .collect();
         let chosen_neighbour = swappable_neighbours
             .choose(&mut rand::thread_rng())
-            .ok_or_else(|| simple_error!("no random neighbour to choose"))?;
+            .expect("should always have a neighbour to swap");
         swaps.push((empty_field_idx, *chosen_neighbour));
         prev_empty_field_idx = empty_field_idx;
         empty_field_idx = *chosen_neighbour;
     }
 
-    Ok(swaps)
+    swaps
 }

src/error.rs

@@ -0,0 +1,17 @@
+#[derive(thiserror::Error, Debug)]
+pub enum LibError {
+    #[error("value {0} not found")]
+    ValueNotFound(u8),
+    #[error("pos (row: {row}, col: {col}) out of bounds")]
+    PosOutOfBounds { row: i32, col: i32 },
+    #[error("algorithm terminated without finding a solution")]
+    TerminatedWithoutSolution,
+    #[error("maximum number of steps ({0}) reached without finding a solution")]
+    MaxNumStepsReached(usize),
+    #[error("board is not square with width {width} and height {height}")]
+    NotSquare { width: i32, height: i32 },
+    #[error("fields slice with {len} fields does not match board expecting {expected} fields")]
+    FieldsBoardMismatch { len: usize, expected: i32 },
+    #[error("boards below 3x3 are not supported")]
+    Below3x3,
+}

src/lib.rs

@@ -10,6 +10,7 @@ use ui::{
 use wasm_bindgen::prelude::*;
 
 pub mod board;
+pub mod error;
 pub mod solver;
 pub mod ui;