Add enum unit_dir and make direction functions use it

Without a doubt the readability of code will be increased by this greatly

5 files changed, 135 insertions, 57 deletions

diff --git a/src/map/map.c b/src/map/map.c
index 70623ae22..9637609ec 100644
--- a/src/map/map.c
+++ b/src/map/map.c
@@ -2845,63 +2845,70 @@ static int map_mapname2ipport(unsigned short name, uint32 *ip, uint16 *port)
 	return 0;
 }
 
-/*==========================================
+/**
  * Checks if both dirs point in the same direction.
- *------------------------------------------*/
-static int map_check_dir(int s_dir, int t_dir)
+ * @param s_dir: direction source is facing
+ * @param t_dir: direction target is facing
+ * @return 0: success(both face the same direction), 1: failure
+ **/
+static int map_check_dir(enum unit_dir s_dir, enum unit_dir t_dir)
 {
-	if(s_dir == t_dir)
+	if (s_dir == t_dir || ((t_dir + UNIT_DIR_MAX - 1) % UNIT_DIR_MAX) == s_dir
+	    || ((t_dir + UNIT_DIR_MAX + 1) % UNIT_DIR_MAX) == s_dir)
 		return 0;
-	switch(s_dir) {
-		case 0: if(t_dir == 7 || t_dir == 1 || t_dir == 0) return 0; break;
-		case 1: if(t_dir == 0 || t_dir == 2 || t_dir == 1) return 0; break;
-		case 2: if(t_dir == 1 || t_dir == 3 || t_dir == 2) return 0; break;
-		case 3: if(t_dir == 2 || t_dir == 4 || t_dir == 3) return 0; break;
-		case 4: if(t_dir == 3 || t_dir == 5 || t_dir == 4) return 0; break;
-		case 5: if(t_dir == 4 || t_dir == 6 || t_dir == 5) return 0; break;
-		case 6: if(t_dir == 5 || t_dir == 7 || t_dir == 6) return 0; break;
-		case 7: if(t_dir == 6 || t_dir == 0 || t_dir == 7) return 0; break;
-	}
 	return 1;
 }
 
-/*==========================================
+/**
  * Returns the direction of the given cell, relative to 'src'
- *------------------------------------------*/
-static uint8 map_calc_dir(struct block_list *src, int16 x, int16 y)
+ * @param src: object to put in relation between coordinates
+ * @param x: x-coordinate of cell
+ * @param y: y-coordinate of cell
+ * @return the direction of the given cell, relative to 'src'
+ **/
+static enum unit_dir map_calc_dir(struct block_list *src, int16 x, int16 y)
 {
-	uint8 dir = 0;
-	int dx, dy;
-
-	nullpo_ret(src);
+	nullpo_retr(UNIT_DIR_NORTH, src);
+	enum unit_dir dir = UNIT_DIR_NORTH;
 
-	dx = x-src->x;
-	dy = y-src->y;
+	int dx = x - src->x;
+	int dy = y - src->y;
 	if (dx == 0 && dy == 0) {
 		// both are standing on the same spot.
 		// aegis-style, makes knockback default to the left.
 		// athena-style, makes knockback default to behind 'src'.
-		dir = (battle_config.knockback_left ? 6 : unit->getdir(src));
-	} else if (dx >= 0 && dy >=0) {
-		// upper-right
-		if( dx*2 < dy || dx == 0 )         dir = 0; // up
-		else if( dx > dy*2+1 || dy == 0 )  dir = 6; // right
-		else                               dir = 7; // up-right
+		if (battle_config.knockback_left != 0)
+			dir = UNIT_DIR_EAST;
+		else
+			dir = unit->getdir(src);
+	} else if (dx >= 0 && dy >= 0) {
+		if (dx * 2 < dy || dx == 0)
+			dir = UNIT_DIR_NORTH;
+		else if (dx > dy * 2 + 1 || dy == 0)
+			dir = UNIT_DIR_EAST;
+		else
+			dir = UNIT_DIR_NORTHEAST;
 	} else if (dx >= 0 && dy <= 0) {
-		// lower-right
-		if( dx*2 < -dy || dx == 0 )        dir = 4; // down
-		else if( dx > -dy*2+1 || dy == 0 ) dir = 6; // right
-		else                               dir = 5; // down-right
+		if (dx * 2 < -dy || dx == 0)
+			dir = UNIT_DIR_SOUTH;
+		else if (dx > -dy * 2 + 1 || dy == 0)
+			dir = UNIT_DIR_EAST;
+		else
+			dir = UNIT_DIR_SOUTHEAST;
 	} else if (dx <= 0 && dy <= 0) {
-		// lower-left
-		if( dx*2 > dy || dx == 0 )         dir = 4; // down
-		else if( dx < dy*2-1 || dy == 0 )  dir = 2; // left
-		else                               dir = 3; // down-left
+		if (dx * 2 > dy || dx == 0 )
+			dir = UNIT_DIR_SOUTH;
+		else if (dx < dy * 2 + 1 || dy == 0)
+			dir = UNIT_DIR_WEST;
+		else
+			dir = UNIT_DIR_SOUTHWEST;
 	} else {
-		// upper-left
-		if( -dx*2 < dy || dx == 0 )        dir = 0; // up
-		else if( -dx > dy*2+1 || dy == 0)  dir = 2; // left
-		else                               dir = 1; // up-left
+		if (-dx * 2 < dy || dx == 0 )
+			dir = UNIT_DIR_NORTH;
+		else if (-dx > dy * 2 + 1 || dy == 0)
+			dir = UNIT_DIR_WEST;
+		else
+			dir = UNIT_DIR_NORTHWEST;
 	}
 	return dir;
 }
diff --git a/src/map/map.h b/src/map/map.h
index dbd9c0fba..e0fbcf9b2 100644
--- a/src/map/map.h
+++ b/src/map/map.h
@@ -27,6 +27,7 @@
 #include "common/db.h"
 #include "common/mapindex.h"
 #include "common/mmo.h"
+#include "map/unitdefines.h"  // enum unit_dir
 
 #include <stdio.h>
 #include <stdarg.h>
@@ -1216,8 +1217,8 @@ END_ZEROED_BLOCK;
 	// reload config file looking only for npcs
 	void (*reloadnpc) (bool clear);
 
-	int (*check_dir) (int s_dir,int t_dir);
-	uint8 (*calc_dir) (struct block_list *src,int16 x,int16 y);
+	int (*check_dir) (enum unit_dir s_dir, enum unit_dir t_dir);
+	enum unit_dir (*calc_dir) (struct block_list *src, int16 x, int16 y);
 	int (*random_dir) (struct block_list *bl, short *x, short *y); // [Skotlex]
 
 	int (*cleanup_sub) (struct block_list *bl, va_list ap);
diff --git a/src/map/unit.c b/src/map/unit.c
index 235a843eb..3a940665d 100644
--- a/src/map/unit.c
+++ b/src/map/unit.c
@@ -832,12 +832,18 @@ static int unit_movepos(struct block_list *bl, short dst_x, short dst_y, int eas
 	return 1;
 }
 
-static int unit_setdir(struct block_list *bl, unsigned char dir)
+/**
+ * Sets the facing direction of a unit
+ * @param bl: unit to modify
+ * @param dir: the facing direction @see enum unit_dir
+ * @return 0: success, 1: failure
+ */
+static int unit_setdir(struct block_list *bl, enum unit_dir dir)
 {
-	struct unit_data *ud;
-	nullpo_ret(bl );
-	ud = unit->bl2ud(bl);
-	if (!ud) return 0;
+	nullpo_retr(1, bl);
+	struct unit_data *ud = unit->bl2ud(bl);
+	if (ud == NULL)
+		return 1;
 	ud->dir = dir;
 	if (bl->type == BL_PC)
 		BL_UCAST(BL_PC, bl)->head_dir = 0;
@@ -845,15 +851,20 @@ static int unit_setdir(struct block_list *bl, unsigned char dir)
 	return 0;
 }
 
-static uint8 unit_getdir(struct block_list *bl)
+/**
+ * Get the facing direction of a unit
+ * @param bl: unit to request data from
+ * @return the facing direction @see enum unit_dir
+ */
+static enum unit_dir unit_getdir(struct block_list *bl)
 {
-	struct unit_data *ud;
-	nullpo_ret(bl);
+	nullpo_retr(UNIT_DIR_NORTH, bl);
 
-	if( bl->type == BL_NPC )
+	if (bl->type == BL_NPC)
 		return BL_UCCAST(BL_NPC, bl)->dir;
-	ud = unit->bl2ud(bl);
-	if (!ud) return 0;
+	struct unit_data *ud = unit->bl2ud(bl);
+	if (ud == NULL)
+		return UNIT_DIR_NORTH;
 	return ud->dir;
 }
 
diff --git a/src/map/unit.h b/src/map/unit.h
index 315cc0515..bdee032f8 100644
--- a/src/map/unit.h
+++ b/src/map/unit.h
@@ -24,6 +24,7 @@
 #include "map/clif.h"  // clr_type
 #include "map/path.h" // struct walkpath_data
 #include "map/skill.h" // 'MAX_SKILLTIMERSKILL, struct skill_timerskill, struct skill_unit_group, struct skill_unit_group_tickset
+#include "map/unitdefines.h" // enum unit_dir
 #include "common/hercules.h"
 
 struct map_session_data;
@@ -67,7 +68,7 @@ struct unit_data {
 	int64 attackabletime;
 	int64 canact_tick;
 	int64 canmove_tick;
-	uint8 dir;
+	enum unit_dir dir;
 	unsigned char walk_count;
 	unsigned char target_count;
 	struct {
@@ -115,8 +116,8 @@ struct unit_interface {
 	void (*run_hit) (struct block_list *bl, struct status_change *sc, struct map_session_data *sd, enum sc_type type);
 	int (*escape) (struct block_list *bl, struct block_list *target, short dist);
 	int (*movepos) (struct block_list *bl, short dst_x, short dst_y, int easy, bool checkpath);
-	int (*setdir) (struct block_list *bl, unsigned char dir);
-	uint8 (*getdir) (struct block_list *bl);
+	int (*setdir) (struct block_list *bl, enum unit_dir dir);
+	enum unit_dir (*getdir) (struct block_list *bl);
 	int (*blown) (struct block_list *bl, int dx, int dy, int count, int flag);
 	int (*warp) (struct block_list *bl, short m, short x, short y, enum clr_type type);
 	int (*warpto_master) (struct block_list *master_bl, struct block_list *slave_bl);
diff --git a/src/map/unitdefines.h b/src/map/unitdefines.h
new file mode 100644
index 000000000..70b6e8d4d
--- /dev/null
+++ b/src/map/unitdefines.h
@@ -0,0 +1,58 @@
+/**
+ * This file is part of Hercules.
+ * http://herc.ws - http://github.com/HerculesWS/Hercules
+ *
+ * Copyright (C) 2012-2019 Hercules Dev Team
+ * Copyright (C)  Athena Dev Teams
+ *
+ * Hercules is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef UNIT_UNITDEFINES_H
+#define UNIT_UNITDEFINES_H
+
+/**
+ * Used for directions, @see unit_data.dir
+ */
+enum unit_dir {
+	UNIT_DIR_UNDEFINED = -1,
+	UNIT_DIR_FIRST     = 0,
+	UNIT_DIR_NORTH     = 0,
+	UNIT_DIR_NORTHWEST = 1,
+	UNIT_DIR_WEST      = 2,
+	UNIT_DIR_SOUTHWEST = 3,
+	UNIT_DIR_SOUTH     = 4,
+	UNIT_DIR_SOUTHEAST = 5,
+	UNIT_DIR_EAST      = 6,
+	UNIT_DIR_NORTHEAST = 7,
+	UNIT_DIR_MAX       = 8,
+	/* IMPORTANT: Changing the order would break the above macros
+	 * and several usages of directions anywhere */
+};
+
+/* Returns the opposite of the facing direction */
+#define unit_get_opposite_dir(dir) ( ((dir) + 4) % UNIT_DIR_MAX )
+
+/* Returns true when direction is diagonal/combined (ex. UNIT_DIR_NORTHWEST, UNIT_DIR_SOUTHWEST, ...) */
+#define unit_is_diagonal_dir(dir) ( ((dir) % 2) == UNIT_DIR_NORTHWEST )
+
+/* Returns true if direction equals val or the opposite direction of val */
+#define unit_is_dir_or_opposite(dir, val) ( ((dir) % 4) == (val) )
+
+/* Returns the next direction after 90° CCW on a compass */
+#define unit_get_ccw90_dir(dir) ( ((dir) + 2) % UNIT_DIR_MAX )
+
+/* Returns a random diagonal direction */
+#define unit_get_rnd_diagonal_dir() ( UNIT_DIR_NORTHWEST + 2 * (rnd() % 4) )
+
+#endif /* UNIT_UNITDEFINES_H */