6 files changed, 31 insertions, 40 deletions

diff --git a/src/nissy.c b/src/nissy.c
index a7f8432..ba43e5d 100644
--- a/src/nissy.c
+++ b/src/nissy.c
@@ -534,8 +534,8 @@ nissy_solve(
         unsigned minmoves,
         unsigned maxmoves,
         unsigned maxsols,
-        int optimal,
-        int threads,
+        unsigned optimal,
+        unsigned threads,
         unsigned long long data_size,
         const char data[data_size],
         unsigned sols_size,
@@ -546,7 +546,7 @@ nissy_solve(
         cube_t c;
         long long parse_ret;
         uint8_t h, k;
-        int t, opt;
+        int t;
 
         if (solver == NULL) {
                 LOG("Error: 'solver' argument is NULL\n");
@@ -573,8 +573,6 @@ nissy_solve(
                 return 0;
         }
 
-        opt = optimal < 0 ? MAXLEN : optimal;
-
         t = threads == 0 ? THREADS : threads;
         if (t < 0) {
                 LOG("solve: 'threads' is negative. Please provide a "
@@ -597,10 +595,10 @@ nissy_solve(
                 if (parse_ret != NISSY_OK)
                         return parse_ret;
                 return solve_h48(c, minmoves, maxmoves, maxsols,
-                    opt, t, data_size, data, sols_size, sols, stats);
+                    optimal, t, data_size, data, sols_size, sols, stats);
         } else if (!strncmp(solver, "coord_", 6)) {
                 return solve_coord_dispatch(c, solver + 6, nissflag,
-                    minmoves, maxmoves, maxsols, opt, t, data_size, data,
+                    minmoves, maxmoves, maxsols, optimal, t, data_size, data,
                     sols_size, sols);
         } else {
                 LOG("solve: unknown solver '%s'\n", solver);
diff --git a/src/nissy.h b/src/nissy.h
index b13f417..c23f338 100644
--- a/src/nissy.h
+++ b/src/nissy.h
@@ -360,8 +360,7 @@ Parameters:
    minmoves  - The minimum number of moves for a solution.
    maxmoves  - The maximum number of moves for a solution.
    maxsols   - The maximum number of solutions.
-   optimal   - If set to a non-negative value, the maximum number of moves
-               above the optimal solution length.
+   optimal   - The maximum number of moves above the optimal solution length.
    threads   - The number of threads to use. Must be less than or equalt to
                the value of the compile-time constant THREADS. If set to 0,
                the default value THREADS will be used.
@@ -393,8 +392,8 @@ nissy_solve(
         unsigned minmoves,
         unsigned maxmoves,
         unsigned maxsolutions,
-        int optimal,
-        int threads,
+        unsigned optimal,
+        unsigned threads,
         unsigned long long data_size,
         const char data[data_size],
         unsigned sols_size,
diff --git a/src/solvers/coord/solve.h b/src/solvers/coord/solve.h
index 464f7bd..b289e3f 100644
--- a/src/solvers/coord/solve.h
+++ b/src/solvers/coord/solve.h
@@ -13,10 +13,11 @@ typedef struct {
 } dfsarg_solve_coord_t;
 
 STATIC int64_t solve_coord(cube_t, coord_t [static 1], uint8_t, uint8_t,
-    uint8_t, uint8_t, uint64_t, int8_t, int, uint64_t, const void *,
+    uint8_t, uint8_t, uint64_t, uint8_t, uint8_t, uint64_t, const void *,
     size_t n, char [n]);
 STATIC int64_t solve_coord_dispatch(cube_t, const char *, uint8_t, uint8_t,
-    uint8_t, uint64_t, int8_t, int, uint64_t, const void *, size_t n, char [n]);
+    uint8_t, uint64_t, uint8_t, uint8_t, uint64_t, const void *, size_t n,
+    char [n]);
 STATIC bool coord_solution_admissible(const dfsarg_solve_coord_t [static 1]);
 STATIC bool solve_coord_dfs_stop(const dfsarg_solve_coord_t [static 1]);
 STATIC bool coord_continue_onnormal(const dfsarg_solve_coord_t [static 1]);
@@ -204,8 +205,8 @@ solve_coord_dispatch(
         uint8_t minmoves,
         uint8_t maxmoves,
         uint64_t maxsolutions,
-        int8_t optimal,
-        int threads,
+        uint8_t optimal,
+        uint8_t threads,
         uint64_t data_size,
         const void *data,
         size_t solutions_size,
@@ -242,8 +243,8 @@ solve_coord(
         uint8_t minmoves,
         uint8_t maxmoves,
         uint64_t maxsolutions,
-        int8_t optimal,
-        int threads,
+        uint8_t optimal,
+        uint8_t threads,
         uint64_t data_size,
         const void *data,
         size_t solutions_size,
diff --git a/src/solvers/h48/solve.h b/src/solvers/h48/solve.h
index f076f11..78b4c97 100644
--- a/src/solvers/h48/solve.h
+++ b/src/solvers/h48/solve.h
@@ -52,7 +52,7 @@ STATIC int64_t solve_h48_maketasks(
     solve_h48_task_t [static STARTING_CUBES], int [static 1]);
 STATIC void *solve_h48_runthread(void *);
 STATIC int64_t solve_h48_dfs(dfsarg_solve_h48_t [static 1]);
-STATIC int64_t solve_h48(cube_t, int8_t, int8_t, uint64_t, int8_t, int8_t,
+STATIC int64_t solve_h48(cube_t, uint8_t, uint8_t, uint8_t, uint8_t, uint8_t,
     uint64_t, const void *, size_t n, char [n],
     long long [static NISSY_SIZE_SOLVE_STATS]);
 
@@ -67,7 +67,9 @@ solve_h48_stop(dfsarg_solve_h48_t arg[static 1])
         n = arg->solution_moves->nmoves + arg->solution_moves->npremoves;
         target = arg->target_depth - n;
         if (target <= 0 ||
-            arg->solution_list->nsols == arg->solution_settings->maxsolutions)
+            arg->solution_list->nsols >= arg->solution_settings->maxsolutions ||
+            n > arg->solution_list->shortest_sol +
+                arg->solution_settings->optimal)
                 return true;
 
         arg->movemask_normal = arg->movemask_inverse = MM_ALLMOVES;
@@ -283,8 +285,8 @@ solve_h48_maketasks(
         if (issolved(maketasks_arg->cube)) {
                 if (maketasks_arg->nmoves > maketasks_arg->maxmoves ||
                     maketasks_arg->nmoves < maketasks_arg->minmoves ||
-                    solve_arg->solution_list->nsols >=
-                        solve_arg->solution_settings->maxsolutions)
+                    solutions_done(solve_arg->solution_list,
+                        solve_arg->solution_settings, maketasks_arg->nmoves))
                         return NISSY_OK;
 
                 solution_moves_reset(&moves);
@@ -341,11 +343,11 @@ solve_h48_maketasks(
 STATIC int64_t
 solve_h48(
         cube_t cube,
-        int8_t minmoves,
-        int8_t maxmoves,
-        uint64_t maxsolutions,
-        int8_t optimal,
-        int8_t threads,
+        uint8_t minmoves,
+        uint8_t maxmoves,
+        uint8_t maxsolutions,
+        uint8_t optimal,
+        uint8_t threads,
         uint64_t data_size,
         const void *data,
         size_t solutions_size,
@@ -448,7 +450,7 @@ solve_h48(
         solve_h48_maketasks(&arg[0], &maketasks_arg, tasks, &ntasks);
         if (ntasks < 0)
                 goto solve_h48_error_solutions_buffer;
-        if (sollist.nsols >= maxsolutions)
+        if (solutions_done(&sollist, &settings, MAX(minmoves, STARTING_MOVES)))
                 goto solve_h48_done;
 
         for (i = 0; i < threads; i++) {
diff --git a/src/solvers/solutions.h b/src/solvers/solutions.h
index e65f299..95c1d1a 100644
--- a/src/solvers/solutions.h
+++ b/src/solvers/solutions.h
@@ -43,8 +43,6 @@ solution_list_init(solution_list_t sols[static 1], size_t n, char buf[n])
         sols->size = n;
         sols->used = 0;
         sols->buf = buf;
-
-        /* Ensure string buffer is NULL-terminated */
         sols->buf[0] = '\0';
 
         return true;
@@ -215,15 +213,8 @@ solutions_done(
         int8_t depth
 )
 {
-        if (list->nsols >= settings->maxsolutions)
-                return true;
-
-        if (depth > settings->maxmoves)
-                return true;
 
-        if (list->nsols > 0 && settings->optimal >= 0 &&
-            depth > list->shortest_sol + settings->optimal)
-                return true;
-
-        return false;
+        return depth > settings->maxmoves ||
+            depth > list->shortest_sol + settings->optimal ||
+            list->nsols >= settings->maxsolutions;
 }
diff --git a/src/solvers/solutions_types_macros.h b/src/solvers/solutions_types_macros.h
index 06e099b..9b1431f 100644
--- a/src/solvers/solutions_types_macros.h
+++ b/src/solvers/solutions_types_macros.h
@@ -12,7 +12,7 @@ typedef struct {
         bool unniss;
         uint8_t maxmoves;
         uint64_t maxsolutions;
-        int8_t optimal;
+        uint8_t optimal;
 } solution_settings_t;
 
 typedef struct {