Store the lines in LuaAssFile in a vector

This makes the implementation better match the exposed interface and
simplifies some of the code.

aegisub/src/auto4_lua.h

@@ -55,7 +55,7 @@ namespace Automation4 {
 		struct PendingCommit {
 			wxString mesage;
 			int modification_type;
-			std::list<AssEntry*> lines;
+			std::vector<AssEntry*> lines;
 		};
 
 		/// Pointer to file being modified
@@ -70,6 +70,8 @@ namespace Automation4 {
 		bool can_set_undo;
 		/// throws an error if modification is disallowed
 		void CheckAllowModify();
+		/// throws an error if the line index is out of bounds
+		void CheckBounds(int idx);
 
 		/// How ass file been modified by the script since the last commit
 		int modification_type;
@@ -79,19 +81,12 @@ namespace Automation4 {
 		int references;
 
 		/// Set of subtitle lines being modified; initially a shallow copy of ass->Line
-		std::list<AssEntry*> lines;
+		std::vector<AssEntry*> lines;
 		/// Commits to apply once processing completes successfully
 		std::deque<PendingCommit> pending_commits;
 		/// Lines to delete once processing complete successfully
 		std::deque<AssEntry*> lines_to_delete;
 
-		/// Cursor for last access into file
-		std::list<AssEntry*>::iterator last_entry_ptr;
-		/// Index for last access into file
-		int last_entry_id;
-		/// Move last_entry_ptr to 1-based index n
-		void SeekCursorTo(int n);
-
 		int ObjectIndexRead(lua_State *L);
 		void ObjectIndexWrite(lua_State *L);
 		int ObjectGetLen(lua_State *L);

aegisub/src/auto4_lua_assfile.cpp

@@ -183,6 +183,12 @@ namespace Automation4 {
 			luaL_error(L, "Attempt to modify subtitles in read-only feature context.");
 	}
 
+	void LuaAssFile::CheckBounds(int idx)
+	{
+		if (idx <= 0 || idx > (int)lines.size())
+			luaL_error(L, "Requested out-of-range line from subtitle file: %d", idx);
+	}
+
 	void LuaAssFile::AssEntryToLua(lua_State *L, AssEntry *e)
 	{
 		lua_newtable(L);
@@ -371,35 +377,17 @@ namespace Automation4 {
 		}
 	}
 
-	void LuaAssFile::SeekCursorTo(int n)
-	{
-		if (n <= 0 || n > (int)lines.size())
-			luaL_error(L, "Requested out-of-range line from subtitle file: %d", n);
-
-		if (n < last_entry_id - n) {
-			// fastest to search from start
-			last_entry_ptr = lines.begin();
-			last_entry_id = 1;
-		}
-		else if ((int)lines.size() - last_entry_id < abs(last_entry_id - n)) {
-			// fastest to search from end
-			last_entry_ptr = lines.end();
-			last_entry_id = lines.size() + 1;
-		}
-		// otherwise fastest to search from cursor
-
-		advance(last_entry_ptr, n - last_entry_id);
-		last_entry_id = n;
-	}
-
 	int LuaAssFile::ObjectIndexRead(lua_State *L)
 	{
 		switch (lua_type(L, 2)) {
 			case LUA_TNUMBER:
+			{
 				// read an indexed AssEntry
-				SeekCursorTo(lua_tointeger(L, 2));
-				AssEntryToLua(L, *last_entry_ptr);
+				int idx = lua_tointeger(L, 2);
+				CheckBounds(idx);
+				AssEntryToLua(L, lines[idx - 1]);
 				return 1;
+			}
 
 			case LUA_TSTRING:
 			{
@@ -466,9 +454,9 @@ namespace Automation4 {
 				// insert
 				AssEntry *e = LuaToAssEntry(L);
 				modification_type |= modification_mask(e);
-				SeekCursorTo(n);
-				lines_to_delete.push_back(*last_entry_ptr);
-				*last_entry_ptr = e;
+				CheckBounds(n);
+				lines_to_delete.push_back(lines[n - 1]);
+				lines[n - 1] = e;
 			}
 			else {
 				// delete
@@ -497,40 +485,43 @@ namespace Automation4 {
 		while (itemcount > 0) {
 			int n = luaL_checkint(L, itemcount);
 			luaL_argcheck(L, n > 0 && n <= (int)lines.size(), itemcount, "Out of range line index");
-			ids.push_back(n);
+			ids.push_back(n - 1);
 			--itemcount;
 		}
 
-		// sort the item id's so we can delete from last to first to preserve original numbering
 		sort(ids.begin(), ids.end());
 
-		// now delete the id's backwards
-		SeekCursorTo(ids.back());
-		for (size_t i = ids.size(); i > 0; --i) {
-			while (last_entry_id > ids[i - 1]) {
-				--last_entry_ptr;
-				--last_entry_id;
+		size_t id_idx = 0, out = 0;
+		for (size_t i = 0; i < lines.size(); ++i) {
+			if (id_idx < ids.size() && ids[id_idx] == i) {
+				modification_type |= modification_mask(lines[i]);
+				lines_to_delete.push_back(lines[i]);
+				++id_idx;
+			}
+			else {
+				lines[out++] = lines[i];
 			}
-			modification_type |= modification_mask(*last_entry_ptr);
-			lines_to_delete.push_back(*last_entry_ptr);
-			lines.erase(last_entry_ptr++);
 		}
+
+		lines.erase(lines.begin() + out, lines.end());
 	}
 
 	void LuaAssFile::ObjectDeleteRange(lua_State *L)
 	{
 		CheckAllowModify();
 
-		int a = std::max<int>(luaL_checkinteger(L, 1), 1);
-		int b = std::min<int>(luaL_checkinteger(L, 2), lines.size());
+		size_t a = std::max<size_t>(luaL_checkinteger(L, 1), 1) - 1;
+		size_t b = std::min<size_t>(luaL_checkinteger(L, 2), lines.size());
 
-		SeekCursorTo(a);
+		if (a >= b) return;
 
-		while (a++ <= b) {
-			modification_type |= modification_mask(*last_entry_ptr);
-			lines_to_delete.push_back(*last_entry_ptr);
-			lines.erase(last_entry_ptr++);
+		for (; b < lines.size(); ++a, ++b) {
+			modification_type |= modification_mask(lines[a]);
+			lines_to_delete.push_back(lines[a]);
+			lines[a] = lines[b];
 		}
+
+		lines.erase(lines.begin() + a, lines.end());
 	}
 
 	void LuaAssFile::ObjectAppend(lua_State *L)
@@ -539,18 +530,13 @@ namespace Automation4 {
 
 		int n = lua_gettop(L);
 
-		if (last_entry_ptr != lines.begin()) {
-			--last_entry_ptr;
-			--last_entry_id;
-		}
-
 		for (int i = 1; i <= n; i++) {
 			lua_pushvalue(L, i);
 			AssEntry *e = LuaToAssEntry(L);
 			modification_type |= modification_mask(e);
 
 			// Find the appropriate place to put it
-			std::list<AssEntry*>::iterator it = lines.end();
+			std::vector<AssEntry*>::iterator it = lines.end();
 			if (!lines.empty()) {
 				do {
 					--it;
@@ -574,11 +560,6 @@ namespace Automation4 {
 				lines.insert(it, e);
 			}
 		}
-
-		// If last_entry_ptr is end, the file was empty but no longer is, so
-		// last_entry_id is wrong
-		if (last_entry_ptr == lines.end())
-			last_entry_id = lines.size() + 1;
 	}
 
 	void LuaAssFile::ObjectInsert(lua_State *L)
@@ -597,18 +578,16 @@ namespace Automation4 {
 			return;
 		}
 
-		SeekCursorTo(before);
-
 		int n = lua_gettop(L);
+		std::vector<AssEntry *> new_entries(n - 1, (AssEntry *)0);
 		for (int i = 2; i <= n; i++) {
 			lua_pushvalue(L, i);
 			AssEntry *e = LuaToAssEntry(L);
 			modification_type |= modification_mask(e);
-			lines.insert(last_entry_ptr, e);
+			new_entries[i - 2] = e;
 			lua_pop(L, 1);
 		}
-
-		last_entry_id += n - 1;
+		lines.insert(lines.begin() + before - 1, new_entries.begin(), new_entries.end());
 	}
 
 	void LuaAssFile::ObjectGarbageCollect(lua_State *L)
@@ -680,13 +659,16 @@ namespace Automation4 {
 	{
 		// Apply any pending commits
 		for (std::deque<PendingCommit>::iterator it = pending_commits.begin(); it != pending_commits.end(); ++it) {
-			swap(ass->Line, it->lines);
+			ass->Line.clear();
+			ass->Line.insert(ass->Line.end(), it->lines.begin(), it->lines.end());
 			ass->Commit(it->mesage, it->modification_type);
 		}
 
 		// Commit any changes after the last undo point was set
-		if (modification_type)
-			swap(ass->Line, lines);
+		if (modification_type) {
+			ass->Line.clear();
+			ass->Line.insert(ass->Line.end(), lines.begin(), lines.end());
+		}
 		if (modification_type && can_set_undo && !undo_description.empty())
 			ass->Commit(undo_description, modification_type);
 
@@ -709,9 +691,7 @@ namespace Automation4 {
 	, can_set_undo(can_set_undo)
 	, modification_type(0)
 	, references(2)
-	, lines(ass->Line)
-	, last_entry_ptr(lines.begin())
-	, last_entry_id(1)
+	, lines(ass->Line.begin(), ass->Line.end())
 	{
 		// prepare userdata object
 		*static_cast<LuaAssFile**>(lua_newuserdata(L, sizeof(LuaAssFile*))) = this;