Adds isUnitInBox to Units module

docs/Lua API.rst

@@ -1192,6 +1192,10 @@ Units module
 
   Returns true *x,y,z* of the unit, or *nil* if invalid; may be not equal to unit.pos if caged.
 
+* ``dfhack.units.isUnitInBox(unit,x1,y1,z1,x2,y2,z2)``
+
+  Returns true if the unit is within the specified coordinates.
+
 * ``dfhack.units.getUnitsInBox(x1,y1,z1,x2,y2,z2[,filter])``
 
   Returns a table of all units within the specified coordinates. If the ``filter``

docs/changelog.txt

@@ -73,6 +73,7 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 - ``Lua::PushInterfaceKeys()``: transforms viewscreen ``feed()`` keys into something that can be interpreted by lua-based widgets
 - ``Lua::Push()``: now handles maps with otherwise supported keys and values
 - Units module: added new checks
+  - ``isUnitInBox()``
   - ``isAnimal()``
   - ``isVisiting()`` any visiting unit (diplomat, merchant, visitor)
   - ``isVisitor()`` ie. not merchants or diplomats

library/LuaApi.cpp

@@ -1559,6 +1559,7 @@ static const luaL_Reg dfhack_job_funcs[] = {
 /***** Units module *****/
 
 static const LuaWrapper::FunctionReg dfhack_units_module[] = {
+    WRAPM(Units, isUnitInBox),
     WRAPM(Units, teleport),
     WRAPM(Units, getGeneralRef),
     WRAPM(Units, getSpecificRef),
@@ -1716,6 +1717,8 @@ static int units_getUnitsInBox(lua_State *state)
     {
         luaL_checktype(state, 7, LUA_TFUNCTION);
         units.erase(std::remove_if(units.begin(), units.end(), [&state](df::unit *unit) -> bool {
+            // todo: merging this filter into the base function would be welcomed by plugins
+            //  (it would also be faster, and less obfuscated than this [ie. erase(remove_if)])
             lua_dup(state); // copy function
             Lua::PushDFObject(state, unit);
             lua_call(state, 1, 1);

library/include/modules/Units.h

@@ -73,6 +73,9 @@ static const int MAX_COLORS = 15;
 // found. Call repeatedly do get all units in a specified box (uses tile coords)
 DFHACK_EXPORT int32_t getNumUnits();
 DFHACK_EXPORT df::unit *getUnit(const int32_t index);
+DFHACK_EXPORT bool isUnitInBox(df::unit* u,
+    int16_t x1, int16_t y1, int16_t z1,
+    int16_t x2, int16_t y2, int16_t z2);
 DFHACK_EXPORT bool getUnitsInBox(std::vector<df::unit*> &units,
     int16_t x1, int16_t y1, int16_t z1,
     int16_t x2, int16_t y2, int16_t z2);

library/modules/Units.cpp

@@ -98,6 +98,23 @@ df::unit *Units::getUnit (const int32_t index)
     return vector_get(world->units.all, index);
 }
 
+bool Units::isUnitInBox(df::unit* u,
+             int16_t x1, int16_t y1, int16_t z1,
+             int16_t x2, int16_t y2, int16_t z2) {
+
+    if (x1 > x2) swap(x1, x2);
+    if (y1 > y2) swap(y1, y2);
+    if (z1 > z2) swap(z1, z2);
+    if (u->pos.x >= x1 && u->pos.x <= x2) {
+        if (u->pos.y >= y1 && u->pos.y <= y2) {
+            if (u->pos.z >= z1 && u->pos.z <= z2) {
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
 // returns index of creature actually read or -1 if no creature can be found
 bool Units::getUnitsInBox (std::vector<df::unit*> &units,
     int16_t x1, int16_t y1, int16_t z1,
@@ -106,22 +123,12 @@ bool Units::getUnitsInBox (std::vector<df::unit*> &units,
     if (!world)
         return false;
 
-    if (x1 > x2) swap(x1, x2);
-    if (y1 > y2) swap(y1, y2);
-    if (z1 > z2) swap(z1, z2);
-
     units.clear();
     for (df::unit *u : world->units.all)
     {
-        if (u->pos.x >= x1 && u->pos.x <= x2)
+        if (isUnitInBox(u, x1, y1, z1, x2, y2, z2))
         {
-            if (u->pos.y >= y1 && u->pos.y <= y2)
-            {
-                if (u->pos.z >= z1 && u->pos.z <= z2)
-                {
-                    units.push_back(u);
-                }
-            }
+            units.push_back(u);
         }
     }
     return true;