Merge the "solver-experiments" branch that I have been working on for

a few weeks. This include mainly three things:

1. Various tweaks for a total performance gain of around 30%.
2. Take into account symmetries and avoid repeated work. This
   required a re-work of the splitting into tasks before the solve.
3. Add a second fallback table (eoesep). This gives huge performance
   gains for particular scrambles (e.g. superflip).

After merging this commit, remove and re-generate all pruning tables.

Squashed commit of the following:

commit 60f0705d2d69050e6a30581a2810f686d6f69b80
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Sat Dec 7 16:06:48 2024 +0100

    Fix indentation

commit cc5d489a251812b6188c0ba264ac6cb2236f1afe
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Sat Dec 7 15:56:19 2024 +0100

    Updated documentation

commit a3f605dd628546e52564f82b139feb473b0725f3
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Sat Dec 7 14:01:11 2024 +0100

    use eoesep table as second fallback

commit c75e43c9116c64f97e92b0fe038be8a032925a72
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Fri Dec 6 16:13:23 2024 +0100

    First commit for gendata_eoesep

commit fea7688ab8bdc5ae0c3480622e2510a3bcd39248
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Tue Dec 3 17:31:00 2024 +0100

    Add scramble to tool

commit 66866cb71dea4ca8278ecb9e90ff4295771feb42
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Tue Dec 3 17:22:59 2024 +0100

    Added tool to check multiple solutions

commit ef65611c772c3996bddca8d181da3538e0af1674
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Tue Dec 3 17:16:20 2024 +0100

    Write all solutions for symmetric positions

commit e3ded26db7d7d4ae7c0e2488151ed14f581f7b8e
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Tue Nov 26 09:14:54 2024 +0100

    Added symmetry filter (TODO: print excluded solutions)

commit 864c437a9751c58d58562650ca9eba4a9e6ad3eb
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Mon Nov 25 14:51:13 2024 +0100

    Improved task split

commit b88926d36d7ab0c64c5fe3bb954fd15d41267fba
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Fri Nov 22 19:06:41 2024 +0100

    Reworked tasks for multi-threading in view of symmetry filter

commit 26fa653f97df8cd601aecb80eaf89f0a00e9ba9f
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Thu Oct 31 15:37:43 2024 +0100

    Added transform move

commit 19f655ef94d658eaa2fefb5cea3c167a3ec58db6
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Thu Oct 31 09:29:15 2024 +0100

    Clarified doc

commit 3b0fe1e5ef8b628854e30f0f0067300e2763c954
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Thu Oct 31 08:36:58 2024 +0100

    Handle solved cube correctly

commit 57705cbc4982e3abe97a36ed64871738d4f721c0
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Thu Oct 31 08:24:30 2024 +0100

    Close file

commit fc7d462b58bcf3d3a3fbf26c1f3bd04c640a4898
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Tue Oct 29 15:05:48 2024 +0100

    Removed stats tool

commit 359bf7cb49ef405ee76ed662207d47cb2abcc5a9
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Tue Oct 29 15:01:51 2024 +0100

    Updated theory doc

commit 39c315af562bc4ce896f41004388a4c34d475d37
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Tue Oct 29 14:51:40 2024 +0100

    Remove unused constants

commit 57a5d24538aa59a4df9221dad2f99e9f0286bd9d
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Tue Oct 29 10:20:38 2024 +0100

    Add tool to solve scrambles from file

commit 07e2918c216636891b1fa6adecc9756086a901e9
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Mon Oct 28 17:00:00 2024 +0100

    Add make table to tool

commit f5e5266c654eb027a5a35c57cc618555246f5e5e
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Mon Oct 28 09:35:49 2024 +0100

    Remove old solver, other small things

commit a1ec78025b7959dbb845213f7f4e6851ecebc204
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Sun Oct 27 02:00:29 2024 +0200

    Improvements

commit 8eea23dbe888d923e662e24ae969130e2c67b999
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Sat Oct 26 12:24:19 2024 +0200

    Makefile fix

commit 3fc3927beacc78971cefeb42da8d71fe6c015fc1
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Fri Oct 25 18:25:09 2024 +0200

    More performance gains

commit 7b4efa1f9af9722de1ab9ccfc27899825a0d12c4
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Fri Oct 25 15:53:20 2024 +0200

    Alternative solver implementation, small performance gain

1 files changed, 37 insertions, 43 deletions

diff --git a/src/nissy.c b/src/nissy.c
index c09c99e..f933cab 100644
--- a/src/nissy.c
+++ b/src/nissy.c
@@ -12,12 +12,15 @@
 #include "core/core.h"
 #include "solvers/solvers.h"
 
-int parse_h48_solver(const char *, uint8_t [static 1], uint8_t [static 1]);
+long long parse_h48_solver(
+    const char *, uint8_t [static 1], uint8_t [static 1]);
 STATIC bool checkdata(const char *, const tableinfo_t *);
 STATIC bool distribution_equal(const uint64_t [static INFO_DISTRIBUTION_LEN],
     const uint64_t [static INFO_DISTRIBUTION_LEN], uint8_t);
 STATIC long long write_result(cube_t, char [static NISSY_SIZE_B32]);
 STATIC size_t my_strnlen(const char *, size_t); 
+STATIC long long nissy_gendata_unsafe(
+    const char *, unsigned long long, char *);
 
 #define GETCUBE_OPTIONS(S, F) { .option = S, .fix = F }
 struct {
@@ -28,19 +31,13 @@ struct {
         GETCUBE_OPTIONS(NULL, NULL)
 };
 
-int
+long long
 parse_h48_solver(const char *buf, uint8_t h[static 1], uint8_t k[static 1])
 {
         const char *fullbuf = buf;
 
         buf += 3;
 
-        if (!strcmp(buf, "stats")) {
-                *h = 0;
-                *k = 4;
-                return 0;
-        }
-
         if (*buf != 'h')
                 goto parse_h48_solver_error;
         buf++;
@@ -62,9 +59,9 @@ parse_h48_solver(const char *buf, uint8_t h[static 1], uint8_t k[static 1])
 parse_h48_solver_error:
         *h = 0;
         *k = 0;
-        LOG("Error parsing solver: must be in \"h48h*k*\" format"
-            " or \"h48stats\", but got %s\n", fullbuf);
-        return -1;
+        LOG("Error parsing solver: must be in \"h48h*k*\" format,"
+            " but got %s\n", fullbuf);
+        return NISSY_ERROR_INVALID_SOLVER;
 }
 
 STATIC bool
@@ -360,20 +357,6 @@ nissy_getcube(
 }
 
 long long
-nissy_datasize(
-        const char *solver
-)
-{
-        if (solver == NULL) {
-                LOG("Error: 'solver' argument is NULL\n");
-                return NISSY_ERROR_NULL_POINTER;
-        }
-
-        /* gendata() handles a NULL *data as a "dryrun" request */
-        return nissy_gendata(solver, 0, NULL);
-}
-
-long long
 nissy_datainfo(
         uint64_t data_size,
         const char data[data_size],
@@ -423,13 +406,32 @@ nissy_datainfo(
 }
 
 long long
+nissy_datasize(
+        const char *solver
+)
+{
+        /* gendata() handles a NULL *data as a "dryrun" request */
+        return nissy_gendata_unsafe(solver, 0, NULL);
+}
+
+long long
 nissy_gendata(
         const char *solver,
         unsigned long long data_size,
         char data[data_size]
 )
 {
-        int p;
+        return nissy_gendata_unsafe(solver, data_size, data);
+}
+
+STATIC long long
+nissy_gendata_unsafe(
+        const char *solver,
+        unsigned long long data_size,
+        char *data
+)
+{
+        long long parse_ret;
         gendata_h48_arg_t arg;
 
         if (solver == NULL) {
@@ -440,10 +442,10 @@ nissy_gendata(
         arg.buf_size = data_size;
         arg.buf = data;
         if (!strncmp(solver, "h48", 3)) {
-                p = parse_h48_solver(solver, &arg.h, &arg.k);
+                parse_ret = parse_h48_solver(solver, &arg.h, &arg.k);
                 arg.maxdepth = 20;
-                if (p != 0)
-                        return NISSY_ERROR_UNKNOWN;
+                if (parse_ret != NISSY_OK)
+                        return parse_ret;
                 return gendata_h48(&arg);
         } else {
                 LOG("gendata: unknown solver %s\n", solver);
@@ -495,7 +497,7 @@ nissy_solve(
 )
 {
         cube_t c;
-        int p;
+        long long parse_ret;
         uint8_t h, k;
 
         if (solver == NULL) {
@@ -521,20 +523,12 @@ nissy_solve(
         }
 
         if (!strncmp(solver, "h48", 3)) {
-                if (!strcmp(solver, "h48stats"))
-                        return solve_h48stats(c, maxmoves, data, sols);
-
-                p = parse_h48_solver(solver, &h, &k);
-                if (p != 0) {
-                        LOG("solve: unknown solver %s\n", solver);
-                        return NISSY_ERROR_INVALID_SOLVER;
-                } else {
-                        return THREADS > 1 ?
-                            solve_h48_multithread(c, minmoves, maxmoves,
-                                maxsols, data_size, data, sols_size, sols, stats) :
-                            solve_h48(c, minmoves, maxmoves, maxsols,
+                parse_ret = parse_h48_solver(solver, &h, &k);
+                if (parse_ret == NISSY_OK)
+                        return solve_h48(c, minmoves, maxmoves, maxsols,
                                 data_size, data, sols_size, sols, stats);
-                }
+                else
+                        return parse_ret;
         } else {
                 LOG("solve: unknown solver '%s'\n", solver);
                 return NISSY_ERROR_INVALID_SOLVER;