Partitioned Tortuga's map system into a library

region_pager_lua.cpp

@@ -0,0 +1,208 @@
+/* Copyright: (c) Kayne Ruse 2013-2016
+ * 
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ * 
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ * 
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ * 
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 
+ * 3. This notice may not be removed or altered from any source
+ * distribution.
+*/
+#include "region_pager_lua.hpp"
+
+#include <stdexcept>
+
+RegionPagerLua::~RegionPagerLua() {
+	//unload all regions
+	UnloadAll();
+	//clear any stored functions
+	luaL_unref(lua, LUA_REGISTRYINDEX, loadRef);
+	luaL_unref(lua, LUA_REGISTRYINDEX, saveRef);
+	luaL_unref(lua, LUA_REGISTRYINDEX, createRef);
+	luaL_unref(lua, LUA_REGISTRYINDEX, unloadRef);
+}
+
+//return the loaded region, or nullptr on failure
+Region* RegionPagerLua::LoadRegion(int x, int y) {
+	//get the pager's function from the registry
+	lua_rawgeti(lua, LUA_REGISTRYINDEX, loadRef);
+
+	//check if this function is available
+	if (lua_isnil(lua, -1)) {
+		lua_pop(lua, 1);
+		//signal that there is no load function
+		return nullptr;
+	}
+
+	//something to work on
+	Region tmpRegion(x, y);
+	lua_pushlightuserdata(lua, &tmpRegion);
+
+	//call the funtion, 1 arg, 1 return
+	if (lua_pcall(lua, 1, 1, 0) != LUA_OK) {
+		throw(std::runtime_error(std::string() + "Lua error: " + lua_tostring(lua, -1) ));
+	}
+
+	//check the return value, success or failure
+	if (lua_isboolean(lua, -1) && lua_toboolean(lua, -1)) {
+		lua_pop(lua, 1);
+		//push and return the loaded region
+		regionList.push_front(tmpRegion);
+		return &regionList.front();
+	}
+	else {
+		lua_pop(lua, 1);
+		//signal a failure
+		return nullptr;
+	}
+}
+
+//NOTE: this return value seems strange; could replace it with a boolean
+//return the saved region, or nullptr on failure
+Region* RegionPagerLua::SaveRegion(int x, int y) {
+	//get the pager's function from the registry
+	lua_rawgeti(lua, LUA_REGISTRYINDEX, saveRef);
+
+	//check if this function is available
+	if (lua_isnil(lua, -1)) {
+		lua_pop(lua, 1);
+		//signal that the region wasn't saved
+		return nullptr;
+	}
+
+	//find the specified region
+	Region* ptr = FindRegion(x, y);
+	if (!ptr) {
+		lua_pop(lua, 1);
+		//signal that there is no save function
+		return nullptr;
+	}
+	lua_pushlightuserdata(lua, ptr);
+
+	//call the function, 1 arg, 1 return
+	if (lua_pcall(lua, 1, 1, 0) != LUA_OK) {
+		throw(std::runtime_error(std::string() + "Lua error: " + lua_tostring(lua, -1) ));
+	}
+
+	//check the return value, success or failure
+	if (lua_isboolean(lua, -1) && lua_toboolean(lua, -1)) {
+		lua_pop(lua, 1);
+		//return the specified region that was saved
+		return ptr;
+	}
+	else {
+		lua_pop(lua, 1);
+		//signal a failure
+		return nullptr;
+	}
+}
+
+//DOCS: since this method is the last ditch call from GetRegion, it must return a valid region object, even if the create function hasn't been set.
+//return a new region, throwing an error on failure
+Region* RegionPagerLua::CreateRegion(int x, int y) {
+	if (FindRegion(x, y)) {
+		throw(std::logic_error("Cannot overwrite an existing region"));
+	}
+
+	//get the pager's function from the registry
+	lua_rawgeti(lua, LUA_REGISTRYINDEX, createRef);
+
+	//check if this function is available
+	if (lua_isnil(lua, -1)) {
+		lua_pop(lua, 1);
+		//return an empty region object
+		regionList.emplace_front(x, y);
+		return &regionList.front();
+	}
+
+	//something to work on
+	Region tmpRegion(x, y);
+	lua_pushlightuserdata(lua, &tmpRegion);
+
+	//call the function, 1 arg, 0 return
+	if (lua_pcall(lua, 1, 0, 0) != LUA_OK) {
+		throw(std::runtime_error(std::string() + "Lua error: " + lua_tostring(lua, -1) ));
+	}
+
+	//return the new region
+	regionList.push_front(tmpRegion);
+	return &regionList.front();
+}
+
+//no return
+void RegionPagerLua::UnloadIf(std::function<bool(Region const&)> fn) {
+	//get the pager's function from the registry
+	lua_rawgeti(lua, LUA_REGISTRYINDEX, unloadRef);
+
+	//check if this function is available
+	if (lua_isnil(lua, -1)) {
+		lua_pop(lua, 1);
+		//remove the regions anyway
+		regionList.remove_if(fn);
+		return;
+	}
+
+	//run each region through this lambda
+	regionList.remove_if([&](Region& region) -> bool {
+		if (fn(region)) {
+
+			//push a copy of the function onto the stack with the region
+			lua_pushvalue(lua, -1);
+			lua_pushlightuserdata(lua, static_cast<void*>(&region));
+
+			//call the function, 1 arg, 0 return
+			if (lua_pcall(lua, 1, 0, 0) != LUA_OK) {
+				throw(std::runtime_error(std::string() + "Lua error: " + lua_tostring(lua, -1) ));
+			}
+
+			//signal to the container
+			return true;
+		}
+		//signal to the container
+		return false;
+	});
+
+	//pop the base copy of the function
+	lua_pop(lua, 1);
+}
+
+void RegionPagerLua::UnloadAll() {
+	//get the pager's function from the registry
+	lua_rawgeti(lua, LUA_REGISTRYINDEX, unloadRef);
+
+	//check if this function is available
+	if (lua_isnil(lua, -1)) {
+		lua_pop(lua, 1);
+		//remove the regions anyway
+		regionList.clear();
+		return;
+	}
+
+	for (auto& it : regionList) {
+		//push a copy of the function onto the stack with the region
+		lua_pushvalue(lua, -1);
+		lua_pushlightuserdata(lua, &it);
+
+		//call the function, 1 arg, 0 return
+		if (lua_pcall(lua, 1, 0, 0) != LUA_OK) {
+			throw(std::runtime_error(std::string() + "Lua error: " + lua_tostring(lua, -1) ));
+		}
+	}
+
+	//pop the base copy of the function
+	lua_pop(lua, 1);
+
+	//remove from memory
+	regionList.clear();
+}