switch to explicit game state & important bug fix & clang format

Previously the code base assumed that there was a single, global game
state which was the implicit target of all actions taken. Looking
ahead at architectural improvements, this has now been (almost
entirely) made explicit and functions take tak_state_p where
necessary (and also where unnecessary).

Two important fixes to actions.c were made:

- Previously when generating the possible stack moves, stack height
overflows (> 15) were not taken into account and this resulted in the
tree search corrupting the board state. Now action search does not
list all legal actions, rather the subset of these encodeable by the
implementation.

- The check for crushing on a stack move was incorrect (too strict),
and this resulted in many legitimate moves being igonored.

Finally, in other changes, weights have also been improved by training
all games instead of some subset for chosen players, and clang-format
was run on the codebase.

1 files changed, 12 insertions, 11 deletions

diff --git a/include/zobrist.c b/include/zobrist.c
index 1fdd8a9..d8d1856 100644
--- a/include/zobrist.c
+++ b/include/zobrist.c
@@ -27,13 +27,14 @@ static uint64_t *zobrist;
 // Exported method implementations
 // ===================================================================
 
-int zobrist_init(void) {
-  if (zobrist != NULL) return EXIT_FAILURE;
+int zobrist_init(const uint8_t board_size) {
+  if (zobrist != NULL)
+    return EXIT_FAILURE;
 
-  zobrist = malloc(sizeof(uint64_t)*board_size*board_size*(15*2*3));
+  zobrist = malloc(sizeof(uint64_t) * board_size * board_size * (15 * 2 * 3));
   // TODO: trap errno
 
-  for (int k=0; k<board_size*board_size*(15*2*3); k++) {
+  for (int k = 0; k < board_size * board_size * (15 * 2 * 3); k++) {
     XORSHIFT64;
     zobrist[k] = RANDOM64;
   }
@@ -48,14 +49,14 @@ void zobrist_free(void) {
   }
 }
 
-uint64_t zobrist_compute(void) {
+uint64_t zobrist_compute(tak_state_p state) {
   uint64_t hash = 0;
-  for (uint8_t l=0; l<board_size*board_size; l++) {
-    colour_stack_t c = colours[l];
-    const uint8_t count = COUNT_AT(l);
-    enum STONE_VARIANT s = STONE_AT(l);
-    for (uint8_t h=0; h<count; h++, c >>= 1)
-      hash ^= zobrist[l*(15*2*3)+h*2*3+(c&1)*3+s];
+  for (uint8_t l = 0; l < state->board_size * state->board_size; l++) {
+    colour_stack_t c = state->colours[l];
+    const uint8_t count = COUNT_AT(state, l);
+    enum STONE_VARIANT s = STONE_AT(state, l);
+    for (uint8_t h = 0; h < count; h++, c >>= 1)
+      hash ^= zobrist[l * (15 * 2 * 3) + h * 2 * 3 + (c & 1) * 3 + s];
   }
   return hash;
 }