From 49d4f7867927a47d9a9b598236f76b509cc9b7b5 Mon Sep 17 00:00:00 2001
From: tslil <tslil@posteo.de>
Date: Tue, 22 Dec 2020 22:40:31 -0500
Subject: Init

---
 include/tak.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 include/tak.c

(limited to 'include/tak.c')

diff --git a/include/tak.c b/include/tak.c
new file mode 100644
index 0000000..a4c053b
--- /dev/null
+++ b/include/tak.c
@@ -0,0 +1,59 @@
+#include "tak.h"
+
+// Be sure not to set higher bits in colour than LSB
+void set_stone(board_t board, bit_board_t *capstand,
+               const uint8_t location,
+               const uint8_t colour,
+               const enum STONE_VARIANT stone) {
+
+  board[location] = (STONE_IS_CAPSTAND(stone) ? CELL_MASK_CAPSTAND : 0x0000)
+    | CELL_COUNT_INC | colour;
+  if (stone == STONE_CAPSTONE) BITBOARD_SET(*capstand, location);
+}
+
+// This can overflow, checks are elsewhere
+void push_cells_stack(board_t board, bit_board_t *capstand,
+                      const uint8_t location, const uint8_t count,
+                      const uint8_t colours,
+                      const enum STONE_VARIANT top_stone) {
+
+  if (top_stone == STONE_CAPSTONE) BITBOARD_RST(*capstand, location);
+
+  const cell_t cell = board[location];
+  const uint8_t new_count = CELL_GET_COUNT(cell) + count;
+  const uint8_t new_stack = (CELL_GET_STACK(cell) << count) | colours;
+
+  board[location] = (STONE_IS_CAPSTAND(top_stone) ? CELL_MASK_CAPSTAND : 0x0000)
+    | ((new_count > 0xA) ? 0xA : new_count)
+    | (new_stack & CELL_MASK_STACK);
+}
+
+// Calling this with count = 0 is destructive
+void drop_cells_stack(board_t board, bit_board_t *capstand,
+                     const uint8_t location, const uint8_t count) {
+
+  // NOTE: We always clear the bitboard and capstand flags as it's not
+  // possible that those stones are underneath anything.
+
+  BITBOARD_RST(*capstand, location);
+  const uint8_t cur_count = CELL_GET_COUNT(board[location]);
+  if (count >= cur_count) {
+    board[location] = CELL_EMPTY_VALUE;
+  } else {
+    board[location] = ((cur_count - count) << CELL_COUNT_SHIFT)
+      | (CELL_GET_STACK(board[location]) >> count);
+  }
+}
+
+enum ACTION_RESULT try_place_stone(board_t board, bit_board_t *capstand,
+                                   const uint8_t location, const uint8_t colour,
+                                   const enum STONE_VARIANT stone)
+{
+  // Can't place on an occupied square
+  if (CELL_IS_EMPTY(board[location])) {
+    set_stone(board, capstand, location, colour, stone);
+    return A_OK;
+  } else {
+    return A_ILLEGAL;
+  }
+}
-- 
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