Allow using the skill DB accessors on non-skill attacks (skill_id = 0)

This suppresses an assertion in the skill DB accessors when called with
`skill_id = 0` (such as during normal attacks). In such case, they'll
now return an appropriate zero value, as it happened before 2b4bfa5d0.

Fixes #1909

Signed-off-by: Haru <haru@dotalux.com>

3 files changed, 188 insertions, 54 deletions

diff --git a/src/map/battle.h b/src/map/battle.h
index 4a63887c4..3ab3e2ddd 100644
--- a/src/map/battle.h
+++ b/src/map/battle.h
@@ -54,6 +54,7 @@ struct status_data;
 
 enum {
 	// Flag of the final calculation
+	BF_NONE       = 0x0000,
 	BF_WEAPON     = 0x0001,
 	BF_MAGIC      = 0x0002,
 	BF_MISC       = 0x0004,
diff --git a/src/map/skill.c b/src/map/skill.c
index d20178a34..1bf1880e8 100644
--- a/src/map/skill.c
+++ b/src/map/skill.c
@@ -161,23 +161,32 @@ const char *skill_get_desc(int skill_id)
 
 int skill_get_hit(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	return skill->dbs->db[idx].hit;
 }
 
 int skill_get_inf(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
-	Assert_ret(idx != 0);
+	int idx;
+	if (skill_id == 0)
+		return INF_NONE;
+	idx = skill->get_index(skill_id);
+	Assert_retr(INF_NONE, idx != 0);
 	return skill->dbs->db[idx].inf;
 }
 
 int skill_get_ele(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
-	Assert_ret(idx != 0);
-	Assert_ret(skill_lv > 0);
+	int idx;
+	if (skill_id == 0)
+		return ELE_NEUTRAL;
+	idx = skill->get_index(skill_id);
+	Assert_retr(ELE_NEUTRAL, idx != 0);
+	Assert_retr(ELE_NEUTRAL, skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
 		int val = skill->dbs->db[idx].element[skill_get_lvl_idx(skill_lv)];
 		return skill_adjust_over_level(val, skill_lv, skill->dbs->db[idx].max);
@@ -187,21 +196,30 @@ int skill_get_ele(int skill_id, int skill_lv)
 
 int skill_get_nk(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
-	Assert_ret(idx != 0);
+	int idx;
+	if (skill_id == 0)
+		return NK_NONE;
+	idx = skill->get_index(skill_id);
+	Assert_retr(NK_NONE, idx != 0);
 	return skill->dbs->db[idx].nk;
 }
 
 int skill_get_max(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	return skill->dbs->db[idx].max;
 }
 
 int skill_get_range(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -213,7 +231,10 @@ int skill_get_range(int skill_id, int skill_lv)
 
 int skill_get_splash(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -225,7 +246,10 @@ int skill_get_splash(int skill_id, int skill_lv)
 
 int skill_get_hp(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -237,7 +261,10 @@ int skill_get_hp(int skill_id, int skill_lv)
 
 int skill_get_sp(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -249,7 +276,10 @@ int skill_get_sp(int skill_id, int skill_lv)
 
 int skill_get_hp_rate(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -261,7 +291,10 @@ int skill_get_hp_rate(int skill_id, int skill_lv)
 
 int skill_get_sp_rate(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -273,14 +306,20 @@ int skill_get_sp_rate(int skill_id, int skill_lv)
 
 int skill_get_state(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
-	Assert_ret(idx != 0);
+	int idx;
+	if (skill_id == 0)
+		return ST_NONE;
+	idx = skill->get_index(skill_id);
+	Assert_retr(ST_NONE, idx != 0);
 	return skill->dbs->db[idx].state;
 }
 
 int skill_get_spiritball(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -292,7 +331,10 @@ int skill_get_spiritball(int skill_id, int skill_lv)
 
 int skill_get_itemid(int skill_id, int item_idx)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(item_idx >= 0 && item_idx < MAX_SKILL_ITEM_REQUIRE);
 	return skill->dbs->db[idx].itemid[item_idx];
@@ -300,7 +342,10 @@ int skill_get_itemid(int skill_id, int item_idx)
 
 int skill_get_itemqty(int skill_id, int item_idx)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(item_idx >= 0 && item_idx < MAX_SKILL_ITEM_REQUIRE);
 	return skill->dbs->db[idx].amount[item_idx];
@@ -308,7 +353,10 @@ int skill_get_itemqty(int skill_id, int item_idx)
 
 int skill_get_zeny(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -320,7 +368,10 @@ int skill_get_zeny(int skill_id, int skill_lv)
 
 int skill_get_num(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -332,7 +383,10 @@ int skill_get_num(int skill_id, int skill_lv)
 
 int skill_get_cast(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -344,7 +398,10 @@ int skill_get_cast(int skill_id, int skill_lv)
 
 int skill_get_delay(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -356,7 +413,10 @@ int skill_get_delay(int skill_id, int skill_lv)
 
 int skill_get_walkdelay(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -368,7 +428,10 @@ int skill_get_walkdelay(int skill_id, int skill_lv)
 
 int skill_get_time(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -380,7 +443,10 @@ int skill_get_time(int skill_id, int skill_lv)
 
 int skill_get_time2(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -392,28 +458,40 @@ int skill_get_time2(int skill_id, int skill_lv)
 
 int skill_get_castdef(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	return skill->dbs->db[idx].cast_def_rate;
 }
 
 int skill_get_weapontype(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	return skill->dbs->db[idx].weapon;
 }
 
 int skill_get_ammotype(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	return skill->dbs->db[idx].ammo;
 }
 
 int skill_get_ammo_qty(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -425,21 +503,30 @@ int skill_get_ammo_qty(int skill_id, int skill_lv)
 
 int skill_get_inf2(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
-	Assert_ret(idx != 0);
+	int idx;
+	if (skill_id == 0)
+		return INF2_NONE;
+	idx = skill->get_index(skill_id);
+	Assert_retr(INF2_NONE, idx != 0);
 	return skill->dbs->db[idx].inf2;
 }
 
 int skill_get_castcancel(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	return skill->dbs->db[idx].castcancel;
 }
 
 int skill_get_maxcount(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -451,7 +538,10 @@ int skill_get_maxcount(int skill_id, int skill_lv)
 
 int skill_get_blewcount(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -463,7 +553,10 @@ int skill_get_blewcount(int skill_id, int skill_lv)
 
 int skill_get_mhp(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -475,7 +568,10 @@ int skill_get_mhp(int skill_id, int skill_lv)
 
 int skill_get_castnodex(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -487,7 +583,10 @@ int skill_get_castnodex(int skill_id, int skill_lv)
 
 int skill_get_delaynodex(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -499,14 +598,20 @@ int skill_get_delaynodex(int skill_id, int skill_lv)
 
 int skill_get_type(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
-	Assert_ret(idx != 0);
+	int idx;
+	if (skill_id == 0)
+		return BF_NONE;
+	idx = skill->get_index(skill_id);
+	Assert_retr(BF_NONE, idx != 0);
 	return skill->dbs->db[idx].skill_type;
 }
 
 int skill_get_unit_id(int skill_id, int flag)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(flag >= 0 && flag < ARRAYLENGTH(skill->dbs->db[0].unit_id));
 	return skill->dbs->db[idx].unit_id[flag];
@@ -514,14 +619,20 @@ int skill_get_unit_id(int skill_id, int flag)
 
 int skill_get_unit_interval(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	return skill->dbs->db[idx].unit_interval;
 }
 
 int skill_get_unit_range(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -533,28 +644,40 @@ int skill_get_unit_range(int skill_id, int skill_lv)
 
 int skill_get_unit_target(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
-	Assert_ret(idx != 0);
+	int idx;
+	if (skill_id == 0)
+		return BCT_NOONE;
+	idx = skill->get_index(skill_id);
+	Assert_retr(BCT_NOONE, idx != 0);
 	return skill->dbs->db[idx].unit_target & BCT_ALL;
 }
 
 int skill_get_unit_bl_target(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
-	Assert_ret(idx != 0);
+	int idx;
+	if (skill_id == 0)
+		return BL_NUL;
+	idx = skill->get_index(skill_id);
+	Assert_retr(BL_NUL, idx != 0);
 	return skill->dbs->db[idx].unit_target & BL_ALL;
 }
 
 int skill_get_unit_flag(int skill_id)
 {
-	int idx = skill->get_index(skill_id);
-	Assert_ret(idx != 0);
+	int idx;
+	if (skill_id == 0)
+		return UF_NONE;
+	idx = skill->get_index(skill_id);
+	Assert_retr(UF_NONE, idx != 0);
 	return skill->dbs->db[idx].unit_flag;
 }
 
 int skill_get_unit_layout_type(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -566,7 +689,10 @@ int skill_get_unit_layout_type(int skill_id, int skill_lv)
 
 int skill_get_cooldown(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 	if (skill_lv > MAX_SKILL_LEVEL) {
@@ -578,7 +704,10 @@ int skill_get_cooldown(int skill_id, int skill_lv)
 
 int skill_get_fixed_cast(int skill_id, int skill_lv)
 {
-	int idx = skill->get_index(skill_id);
+	int idx;
+	if (skill_id == 0)
+		return 0;
+	idx = skill->get_index(skill_id);
 	Assert_ret(idx != 0);
 	Assert_ret(skill_lv > 0);
 #ifdef RENEWAL_CAST
diff --git a/src/map/skill.h b/src/map/skill.h
index a0591de74..1e00e488f 100644
--- a/src/map/skill.h
+++ b/src/map/skill.h
@@ -76,6 +76,7 @@ struct status_change_entry;
 
 //Constants to identify the skill's inf value:
 enum e_skill_inf {
+	INF_NONE          = 0x00,
 	INF_ATTACK_SKILL  = 0x01,
 	INF_GROUND_SKILL  = 0x02,
 	INF_SELF_SKILL    = 0x04, // Skills casted on self where target is automatically chosen
@@ -88,6 +89,7 @@ enum e_skill_inf {
 //The NK value applies only to non INF_GROUND_SKILL skills
 //when determining skill castend function to invoke.
 enum e_skill_nk {
+	NK_NONE           = 0x00,
 	NK_NO_DAMAGE      = 0x01,
 	NK_SPLASH         = 0x02|0x04, // 0x4 = splash & split
 	NK_SPLASH_ONLY    = 0x02,
@@ -102,6 +104,7 @@ enum e_skill_nk {
 //A skill with 3 would be no damage + splash: area of effect.
 //Constants to identify a skill's inf2 value.
 enum e_skill_inf2 {
+	INF2_NONE              = 0x00000,
 	INF2_QUEST_SKILL       = 0x00001,
 	INF2_NPC_SKILL         = 0x00002, // NPC skills are those that players can't have in their skill tree.
 	INF2_WEDDING_SKILL     = 0x00004,
@@ -132,6 +135,7 @@ enum e_skill_display {
 };
 
 enum {
+	UF_NONE             = 0x0000,
 	UF_DEFNOTENEMY      = 0x0001, // If 'defunit_not_enemy' is set, the target is changed to 'friend'
 	UF_NOREITERATION    = 0x0002, // Spell cannot be stacked
 	UF_NOFOOTSET        = 0x0004, // Spell cannot be cast near/on targets
@@ -158,7 +162,7 @@ enum wl_spheres {
 };
 
 enum {
-	ST_NONE,
+	ST_NONE = 0,
 	ST_HIDING,
 	ST_CLOAKING,
 	ST_HIDDEN,