[release] sudk v0.1.1

- added clippy lints and fixed the resulting issues
- moved build_possible_values_db() into the new() call
- extracted the skip_db functionality into their own functions

.cargo/config.toml

@@ -1,2 +0,0 @@
-[build]
-rustflags = ["-C", "target-cpu=native", "-C", "target-feature=+crt-static"]

Cargo.lock

@@ -4,4 +4,4 @@ version = 3
 
 [[package]]
 name = "sudk"
-version = "0.1.0"
+version = "0.1.1"

Cargo.toml

@@ -1,9 +1,14 @@
 [package]
 name = "sudk"
-version = "0.1.0"
+version = "0.1.1"
 authors = ["ddidderr <ddidderr@paul.network>"]
 edition = "2021"
 
+[lints.clippy]
+pedantic = { level = "warn", priority = -1 }
+todo = "warn"
+unwrap_used = "warn"
+
 [dependencies]
 
 [profile.release]

c_version/clangtest

@@ -1,6 +1,6 @@
 #!/bin/bash
 set -e
 
-clang -Wall -Wextra -Weverything -Werror -O3 -march=native -flto -std=c17 -fstack-protector-all -s -o sudk_c "$1"
+clang -Weverything -Wno-unsafe-buffer-usage -Werror -O3 -march=native -flto -std=c17 -fstack-protector-all -s -o sudk_c "$1"
 
 time ./sudk_c

c_version/sudk_stack.c

@@ -5,7 +5,7 @@
 #include <stdlib.h>
 #include <sys/types.h>
 
-static inline void Print_Clear() { printf("\x1b\x5b\x48\x1b\x5b\x32\x4a"); }
+static inline void Print_Clear(void) { printf("\x1b\x5b\x48\x1b\x5b\x32\x4a"); }
 
 typedef struct Sudoku {
   uint8_t *field;
@@ -258,7 +258,7 @@ static void Sudoku_Free(Sudoku *s) {
   s = NULL;
 }
 
-int main() {
+int main(void) {
   Sudoku *s = Sudoku_New(3);
   Sudoku_Print(s);
   Sudoku_SolveBacktracking(s);

rustfmt.toml

@@ -0,0 +1,3 @@
+group_imports = "StdExternalCrate"
+imports_granularity = "Crate"
+imports_layout = "HorizontalVertical"

src/main.rs

@@ -4,9 +4,26 @@ const BLOCK_SIZE: usize = 3;
 const SIZE: usize = BLOCK_SIZE * BLOCK_SIZE;
 const NUM_FIELDS: usize = SIZE * SIZE;
 
+fn print_gray() {
+    print!("\x1b\x5b\x31\x3b\x33\x30\x6d");
+}
+
+fn print_green() {
+    print!("\x1b\x5b\x31\x3b\x33\x32\x6d");
+}
+
+fn print_neutral() {
+    print!("\x1b\x5b\x31\x3b\x30\x6d");
+}
+
+fn print_clear() {
+    print!("\x1b\x5b\x48\x1b\x5b\x32\x4a");
+}
+
 struct SField {
     field: Vec<u8>,
-    fixed: Vec<bool>,
+    skip_forward: Vec<u8>,
+    skip_backward: Vec<u8>,
     pos: usize,
     possible_values: Vec<Vec<u8>>,
 }
@@ -26,32 +43,72 @@ impl SField {
             0,0,8,2,0,0,0,6,0,
         ];
 
-        let mut fixed = Vec::with_capacity(SIZE * SIZE);
-        field.iter().for_each(|e| {
-            if *e == 0 {
-                fixed.push(false);
-            } else {
-                fixed.push(true);
-            }
-        });
-
-        SField {
+        let mut sudoku = SField {
             field,
-            fixed,
+            skip_forward: vec![0; NUM_FIELDS + 1],
+            skip_backward: vec![0; NUM_FIELDS + 1],
             pos: 0,
-            possible_values: vec![vec![]; SIZE * SIZE],
+            possible_values: vec![vec![]; NUM_FIELDS],
+        };
+
+        sudoku.build_possible_values_db();
+
+        sudoku.build_skip_dbs();
+
+        sudoku
+    }
+
+    fn build_skip_dbs(&mut self) {
+        fn find_fixed_streak_forward(mut idx: usize, field: &[u8]) -> u8 {
+            let mut fixed_count = 1;
+            idx += 1;
+
+            while idx < NUM_FIELDS && field[idx] > 0 {
+                fixed_count += 1;
+                idx += 1;
+            }
+
+            fixed_count
+        }
+
+        fn find_fixed_streak_backward(mut idx: usize, field: &[u8]) -> u8 {
+            let mut fixed_count = 1;
+            idx -= 1;
+
+            while idx < NUM_FIELDS && field[idx] > 0 {
+                fixed_count += 1;
+                idx -= 1;
+            }
+
+            fixed_count
+        }
+
+        let fwd = &mut self.skip_forward;
+        for (idx, nr) in self.field.iter().enumerate() {
+            match nr {
+                0 => fwd[idx] = *nr,
+                _ => fwd[idx] = find_fixed_streak_forward(idx, &self.field),
+            }
+        }
+
+        let bwd = &mut self.skip_backward;
+        for (idx, nr) in self.field.iter().enumerate().rev() {
+            match nr {
+                0 => bwd[idx + 1] = *nr,
+                _ => bwd[idx + 1] = find_fixed_streak_backward(idx, &self.field),
+            }
         }
     }
 
     fn build_possible_values_db(&mut self) {
         for idx in 0..NUM_FIELDS {
-            if self.fixed[idx] {
+            if self.field[idx] != 0 {
                 continue;
             }
             self.pos = idx;
             // try all values between 1 and =self.size and remember the good ones
             let mut good_ones = Vec::with_capacity(SIZE);
-            for nr in 1..=(SIZE as u8) {
+            for nr in 1..=(u8::try_from(SIZE).expect("SIZE is too big")) {
                 if self.ok(nr) {
                     good_ones.push(nr);
                 }
@@ -63,71 +120,35 @@ impl SField {
 
     pub fn solve_backtracking(&mut self) -> bool {
         let mut num_solutions = 0;
+
         loop {
-            if self.is_end() {
-                num_solutions += 1;
-
-                if num_solutions % 10_000 == 0 {
-                    self.print_clear();
-                    self.print();
-                    println!("Number of solutions: {}", num_solutions);
-                }
-
-                if self.is_fixed() {
-                    continue;
-                }
+            if !self.put_valid_nr() {
                 self.clear_current_field();
-                self.prev();
-                self.goto_prev_free_field();
-            }
-
-            if self.is_fixed() {
-                self.next();
+                if !self.prev() {
+                    print_clear();
+                    self.print();
+                    println!("Number of solutions: {num_solutions}");
+                    break;
+                }
                 continue;
             }
 
-            if self.goto_next_free_field() {
-                if self.put_valid_nr() {
-                    self.next();
-                    continue;
-                } else {
-                    self.clear_current_field();
-                    if !self.prev() {
-                        println!("Number of solutions: {}", num_solutions);
-                        break;
-                    }
-                    if !self.goto_prev_free_field() {
-                        println!("Number of solutions: {}", num_solutions);
-                        break;
-                    }
+            if !self.next() {
+                num_solutions += 1;
+                if num_solutions % 10_000 == 0 {
+                    print_clear();
+                    self.print();
+                    println!("Number of solutions: {num_solutions}");
                 }
+
+                self.clear_current_field();
+                self.prev();
             }
         }
 
         num_solutions > 0
     }
 
-    #[inline(always)]
-    fn print_gray(&self) {
-        print!("\x1b\x5b\x31\x3b\x33\x30\x6d");
-    }
-
-    #[inline(always)]
-    fn print_green(&self) {
-        print!("\x1b\x5b\x31\x3b\x33\x32\x6d");
-    }
-
-    #[inline(always)]
-    fn print_neutral(&self) {
-        print!("\x1b\x5b\x31\x3b\x30\x6d");
-    }
-
-    #[inline(always)]
-    fn print_clear(&self) {
-        print!("\x1b\x5b\x48\x1b\x5b\x32\x4a");
-    }
-
-    #[inline(always)]
     fn print(&self) {
         for i in 0..NUM_FIELDS {
             if i != 0 && i % SIZE == 0 {
@@ -135,73 +156,33 @@ impl SField {
             }
 
             if i == self.pos {
-                self.print_green();
+                print_green();
             } else if self.get_field_at_pos(i) == 0 {
-                self.print_gray();
+                print_gray();
             }
 
             print!("{:2} ", self.get_field_at_pos(i));
 
             if i == self.pos || self.get_field_at_pos(i) == 0 {
-                self.print_neutral();
+                print_neutral();
             }
         }
         println!();
     }
 
-    #[inline(always)]
     fn clear_current_field(&mut self) {
         self.set(0);
     }
 
-    #[inline(always)]
-    fn goto_prev_free_field(&mut self) -> bool {
-        while {
-            if !self.is_fixed() {
-                return true;
-            }
-            self.prev()
-        } {}
-
-        false
-    }
-
-    #[inline(always)]
-    fn goto_next_free_field(&mut self) -> bool {
-        while {
-            if !self.is_fixed() {
-                return true;
-            }
-            self.next()
-        } {}
-
-        false
-    }
-
-    #[inline(always)]
-    fn _put_valid_nr(&mut self) -> bool {
-        let current_nr = self.get_field_at_pos(self.pos);
-
-        for nr in current_nr..(SIZE + 1) as u8 {
-            if self.ok(nr) {
-                self.set(nr);
-                return true;
-            }
-        }
-
-        false
-    }
-
-    #[inline(always)]
     fn put_valid_nr(&mut self) -> bool {
         let current_nr = self.get_field_at_pos(self.pos);
 
         // safety:
         //     self.possible_vals is initialized with self.size * self.size
         //     so self.pos can safely be used to index here
-        let possible_vals = unsafe { self.possible_values.get_unchecked(self.pos) };
+        let possible_vals = &self.possible_values[self.pos];
 
-        for nr in possible_vals.iter() {
+        for nr in possible_vals {
             if *nr <= current_nr {
                 continue;
             }
@@ -214,32 +195,10 @@ impl SField {
         false
     }
 
-    #[inline(always)]
-    fn is_end(&self) -> bool {
-        !self.field.contains(&0)
-    }
-
-    #[inline(always)]
     fn ok(&self, nr: u8) -> bool {
         self.block_ok(nr) && self.row_ok(nr) && self.col_ok(nr)
     }
 
-    #[inline(always)]
-    fn _pos_to_xy(&self) -> (usize, usize) {
-        let y = self.pos / SIZE;
-        let x = self.pos % SIZE;
-        (x + 1, y + 1)
-    }
-
-    #[inline(always)]
-    fn is_fixed(&self) -> bool {
-        // safety: self.pos can be used to index the field unchecked
-        //         since the only methods modifying self.pos are
-        //         `next()` and `prev()` and they do bounds checking
-        unsafe { *self.fixed.get_unchecked(self.pos) }
-    }
-
-    #[inline(always)]
     fn get_field_at_pos(&self, pos: usize) -> u8 {
         // safety:
         //     TODO
@@ -248,26 +207,22 @@ impl SField {
         unsafe { *self.field.get_unchecked(pos) }
     }
 
-    #[inline(always)]
     fn set(&mut self, nr: u8) {
         self.field[self.pos] = nr;
     }
 
-    #[inline(always)]
     fn get_row(&self, row: &mut [u8; SIZE]) {
         for (idx, row_elem) in row.iter_mut().enumerate() {
             *row_elem = self.get_field_at_pos((self.pos / SIZE) * SIZE + idx);
         }
     }
 
-    #[inline(always)]
     fn get_col(&self, col: &mut [u8; SIZE]) {
         for (idx, col_elem) in col.iter_mut().enumerate() {
             *col_elem = self.get_field_at_pos(idx * SIZE + self.pos % SIZE);
         }
     }
 
-    #[inline(always)]
     fn get_block(&self, block: &mut [u8; SIZE]) {
         let block_start_row = self.pos / SIZE / BLOCK_SIZE * BLOCK_SIZE;
         let block_start_col = self.pos % SIZE / BLOCK_SIZE * BLOCK_SIZE;
@@ -280,48 +235,46 @@ impl SField {
         }
     }
 
-    #[inline(always)]
     fn block_ok(&self, nr: u8) -> bool {
         let mut block = [0; SIZE];
         self.get_block(&mut block);
         !block.contains(&nr)
     }
 
-    #[inline(always)]
     fn row_ok(&self, nr: u8) -> bool {
         let mut row = [0; SIZE];
         self.get_row(&mut row);
         !row.contains(&nr)
     }
 
-    #[inline(always)]
     fn col_ok(&self, nr: u8) -> bool {
         let mut col = [0; SIZE];
         self.get_col(&mut col);
         !col.contains(&nr)
     }
 
-    #[inline(always)]
     fn next(&mut self) -> bool {
-        if self.pos == NUM_FIELDS - 1 {
+        let new_pos = self.pos + 1 + self.skip_forward[self.pos + 1] as usize;
+
+        if new_pos >= NUM_FIELDS {
             return false;
         }
 
-        self.pos += 1;
+        self.pos = new_pos;
         true
     }
 
-    #[inline(always)]
     fn prev(&mut self) -> bool {
-        if self.pos == 0 {
+        let new_pos = self.pos - 1 - self.skip_backward[self.pos] as usize;
+
+        if new_pos >= NUM_FIELDS {
             return false;
         }
 
-        self.pos -= 1;
+        self.pos = new_pos;
         true
     }
 
-    #[inline(always)]
     fn solve(&mut self) {
         let now = Instant::now();
         if !self.solve_backtracking() {
@@ -331,17 +284,7 @@ impl SField {
     }
 }
 
-fn run() -> Result<(), String> {
-    let mut field = SField::new();
-
-    field.build_possible_values_db();
-
-    field.solve();
-    Ok(())
-}
-
 fn main() {
-    if let Err(e) = run() {
-        println!("{}", e)
-    }
+    let mut field = SField::new();
+    field.solve();
 }