add draw.setcursor() to change the mouse cursor

	the function expects a table replicating the Cursor C struct:
		{ offset = { x = INT, y = INT }, clr = INT[32], set = INT[32] }

	If the function is called with no parameter or nil it will reset the cursor
	to its default.

Author: telephil9

a.h

@@ -3,6 +3,7 @@
 #include <draw.h>
 #include <keyboard.h>
 #include <event.h>
+#include <cursor.h>
 #include <plumb.h>
 #include <lua.h>
 #include <lauxlib.h>

draw.c

@@ -580,6 +580,55 @@ lreadimage(lua_State *L)
 	return 1;
 }
 
+static int
+lsetcursor(lua_State *L)
+{
+	Cursor c;
+	int n, i;
+
+	if(lua_isnoneornil(L, 1)){
+		esetcursor(nil);
+		return 0;
+	}
+	lua_pushstring(L, "offset");
+	lua_gettable(L, 1);
+	lua_pushstring(L, "x");
+	lua_gettable(L, -2);
+	c.offset.x = luaL_checkinteger(L, -1);
+	lua_pushstring(L, "y");
+	lua_gettable(L, -3);
+	c.offset.y = luaL_checkinteger(L, -1);
+	lua_pop(L, 3); /* remove table|x|y */
+	lua_pushstring(L, "clr");
+	lua_gettable(L, 1);
+	n = luaL_len(L, 2);
+	if(n != 32){
+		lua_pushfstring(L, "clr table has len %d but should be 32", n);
+		return lua_error(L);
+	}
+	for(i = 1; i <= n; i++){
+		lua_geti(L, 2, i);
+		c.clr[i-1] = (uchar)luaL_checkinteger(L, 3); /* FIXME: overflow !!! */
+		lua_pop(L, 1);
+	}
+	lua_pop(L, 1); /* remove clr table */
+	lua_pushstring(L, "set");
+	lua_gettable(L, 1);
+	n = luaL_len(L, 2);
+	if(n != 32){
+		lua_pushfstring(L, "set table has len %d but should be 32", n);
+		return lua_error(L);
+	}
+	for(i = 1; i <= n; i++){
+		lua_geti(L, 2, i);
+		c.set[i-1] = (uchar)luaL_checkinteger(L, 3); /* FIXME: overflow !!! */
+		lua_pop(L, 1);
+	}
+	lua_pop(L, 1); /* remove set table */
+	esetcursor(&c);
+	return 0;
+}
+
 static const struct luaL_Reg libdraw [] = {
 	{ "init",        linitdraw },
 	{ "draw",        ldraw },
@@ -612,6 +661,7 @@ static const struct luaL_Reg libdraw [] = {
 	{ "allocimage",  lallocimage },
 	{ "allocimagemix", lallocimagemix },
 	{ "readimage", lreadimage },
+	{ "setcursor", lsetcursor },
 	{ NULL, NULL }
 };