1 files changed, 86 insertions, 0 deletions
diff --git a/include/ptn.c b/include/ptn.c
new file mode 100644
index 0000000..58648b9
--- /dev/null
+++ b/include/ptn.c
@@ -0,0 +1,86 @@
+#include "ptn.h"
+
+#define ASSERT_NONEMPTY { if (ptn == 0 || *ptn == 0) return PTN_INVALID; }
+#define ASSERT_MORE     { if (*ptn == 0) return PTN_INVALID; }
+
+enum PTN_PARSE_RESULT
+parse_place(const uint8_t board_size, char *ptn,
+            uint8_t *location, enum STONE_VARIANT *stone) {
+
+  ASSERT_NONEMPTY;
+
+  *stone = STONE_FLAT;
+  switch (*ptn) {
+    case 'C' : { ptn++; *stone = STONE_CAPSTONE; break; };
+    case 'S' : { ptn++; *stone = STONE_STANDING; break; };
+    case 'F' : { ptn++; break; };
+  }
+
+  ASSERT_MORE;
+
+  if ( (*ptn < 'a') || (*ptn > '`' + board_size) ) return PTN_INVALID;
+  *location = *ptn - 'a';
+
+  ptn++; ASSERT_MORE;
+
+  if ( (*ptn < '1') || (*ptn > board_size + '0') ) return PTN_INVALID;
+  *location += board_size * (*ptn - '1');
+
+  if (*(++ptn) > 0) return PTN_INVALID;
+
+  return PTN_VALID;
+}
+
+enum PTN_PARSE_RESULT
+parse_move(const uint8_t board_size, char *ptn,
+           uint8_t *location, enum MOVE_DIRECTION *direction,
+           uint8_t *steps, uint8_t drops[5]) {
+
+  ASSERT_NONEMPTY;
+
+  uint8_t picked_up = 0;
+
+  if ( (*ptn >= '1') && (*ptn <= '0' + board_size)) {
+    picked_up = *ptn - '0';
+    ptn++; ASSERT_MORE;
+  }
+
+  if ( (*ptn < 'a') || (*ptn > '`' + board_size) ) return PTN_INVALID;
+  *location = *ptn - 'a';
+
+  ptn++; ASSERT_MORE;
+
+  if ( (*ptn < '1') || (*ptn > board_size + '0') ) return PTN_INVALID;
+  *location += board_size * (*ptn - '1');
+
+  ptn++; ASSERT_MORE;
+
+  switch (*ptn) {
+    case '+': { *direction = M_UP;    break; }
+    case '-': { *direction = M_DOWN;  break; }
+    case '<': { *direction = M_LEFT;  break; }
+    case '>': { *direction = M_RIGHT; break; }
+    default: return PTN_INVALID;
+  }
+
+  ptn++; ASSERT_MORE;
+
+  *steps = 0;
+  uint8_t total = 0;
+  while (*ptn) {
+      if ( (*ptn < '1') || (*ptn > '0' + board_size) ) {
+        return PTN_INVALID;
+      }
+      // TODO: Correct?
+      if ( (*steps >= board_size) && *ptn) return PTN_INVALID;
+
+      drops[*steps] = *ptn - '0';
+      total += drops[*steps];
+      *steps += 1;
+      ptn++;
+  }
+
+  if ( (picked_up > 0) && (total != picked_up) ) return PTN_INVALID;
+
+  return PTN_VALID;
+}