GLK: Further changeover of sub-engines to use new savegame code

22 files changed, 217 insertions, 136 deletions

diff --git a/engines/glk/POTFILES b/engines/glk/POTFILES
index 2a9e70d807..cedc0e1d66 100644
--- a/engines/glk/POTFILES
+++ b/engines/glk/POTFILES
@@ -5,6 +5,7 @@ engines/glk/advsys/advsys.cpp
 engines/glk/advsys/vm.cpp
 engines/glk/alan2/alan2.cpp
 engines/glk/frotz/detection.cpp
+engines/glk/frotz/frotz.cpp
 engines/glk/glulxe/glulxe.cpp
 engines/glk/magnetic/magnetic.cpp
 engines/glk/scott/scott.cpp
diff --git a/engines/glk/advsys/advsys.cpp b/engines/glk/advsys/advsys.cpp
index ad8412843f..51003205b1 100644
--- a/engines/glk/advsys/advsys.cpp
+++ b/engines/glk/advsys/advsys.cpp
@@ -102,11 +102,13 @@ bool AdvSys::singleAction() {
 	return true;
 }
 
-Common::Error AdvSys::loadGameData(strid_t save) {
+Common::Error AdvSys::readSaveData(Common::SeekableReadStream *rs) {
+	rs->read(_saveArea, rs->size());
 	return Common::kNoError;
 }
 
-Common::Error AdvSys::saveGameData(strid_t save, const Common::String &desc) {
+Common::Error AdvSys::writeGameData(Common::WriteStream *ws) {
+	ws->write(_saveArea, _saveSize);
 	return Common::kNoError;
 }
 
diff --git a/engines/glk/advsys/advsys.h b/engines/glk/advsys/advsys.h
index 688a8fe094..8b7b7fb56b 100644
--- a/engines/glk/advsys/advsys.h
+++ b/engines/glk/advsys/advsys.h
@@ -67,14 +67,15 @@ public:
 	}
 
 	/**
-	 * Load a savegame from the passed stream
+	 * Load a savegame from the passed Quetzal file chunk stream
 	 */
-	virtual Common::Error loadGameData(strid_t save) override;
+	virtual Common::Error readSaveData(Common::SeekableReadStream *rs) override;
 
 	/**
-	 * Save the game to the passed stream
+	 * Save the game. The passed write stream represents access to the UMem chunk
+	 * in the Quetzal save file that will be created
 	 */
-	virtual Common::Error saveGameData(strid_t save, const Common::String &desc) override;
+	virtual Common::Error writeGameData(Common::WriteStream *ws) override;
 };
 
 } // End of namespace AdvSys
diff --git a/engines/glk/alan2/alan2.cpp b/engines/glk/alan2/alan2.cpp
index da9dbf1115..492d425d98 100644
--- a/engines/glk/alan2/alan2.cpp
+++ b/engines/glk/alan2/alan2.cpp
@@ -61,14 +61,14 @@ void Alan2::runGame() {
 	// TODO
 }
 
-Common::Error Alan2::loadGameData(strid_t file) {
+Common::Error Alan2::readSaveData(Common::SeekableReadStream *rs) {
 	// TODO
-	return Common::kNoError;
+	return Common::kReadingFailed;
 }
 
-Common::Error Alan2::saveGameData(strid_t file, const Common::String &desc) {
+Common::Error Alan2::writeGameData(Common::WriteStream *ws) {
 	// TODO
-	return Common::kNoError;
+	return Common::kWritingFailed;
 }
 
 bool Alan2::is_gamefile_valid() {
diff --git a/engines/glk/alan2/alan2.h b/engines/glk/alan2/alan2.h
index a6ded4304a..a8e500a0dd 100644
--- a/engines/glk/alan2/alan2.h
+++ b/engines/glk/alan2/alan2.h
@@ -68,14 +68,15 @@ public:
 	virtual InterpreterType getInterpreterType() const override { return INTERPRETER_ALAN2; }
 
 	/**
-	 * Load a savegame from the passed stream
+	 * Load a savegame from the passed Quetzal file chunk stream
 	 */
-	virtual Common::Error loadGameData(strid_t file) override;
+	virtual Common::Error readSaveData(Common::SeekableReadStream *rs) override;
 
 	/**
-	 * Save the game to the passed stream
+	 * Save the game. The passed write stream represents access to the UMem chunk
+	 * in the Quetzal save file that will be created
 	 */
-	virtual Common::Error saveGameData(strid_t file, const Common::String &desc) override;
+	virtual Common::Error writeGameData(Common::WriteStream *ws) override;
 
 	/**
 	 * Output a string to the screen
diff --git a/engines/glk/frotz/frotz.cpp b/engines/glk/frotz/frotz.cpp
index 0c33f417ec..02ee0900c9 100644
--- a/engines/glk/frotz/frotz.cpp
+++ b/engines/glk/frotz/frotz.cpp
@@ -26,6 +26,7 @@
 #include "glk/frotz/quetzal.h"
 #include "engines/util.h"
 #include "common/config-manager.h"
+#include "common/translation.h"
 
 namespace Glk {
 namespace Frotz {
@@ -90,17 +91,13 @@ void Frotz::initialize() {
 	z_restart();
 }
 
-Common::Error Frotz::saveGameData(strid_t file, const Common::String &desc) {
-	Quetzal q(story_fp);
-	bool success = q.save(*file, this, desc);
+Common::Error Frotz::loadGameState(int slot) {
+	FileReference ref(slot, "", fileusage_SavedGame | fileusage_TextMode);
 
-	if (!success)
-		print_string("Error writing save file\n");
+	strid_t file = _streams->openFileStream(&ref, filemode_Read);
+	if (file == nullptr)
+		return Common::kReadingFailed;
 
-	return Common::kNoError;
-}
-
-Common::Error Frotz::loadGameData(strid_t file) {
 	Quetzal q(story_fp);
 	bool success = q.restore(*file, this) == 2;
 
@@ -123,14 +120,32 @@ Common::Error Frotz::loadGameData(strid_t file) {
 		 * seems to cover up most of the resulting badness.
 		 */
 		if (h_version > V3 && h_version != V6 && (h_screen_rows != old_screen_rows
-					|| h_screen_cols != old_screen_cols))
+			|| h_screen_cols != old_screen_cols))
 			erase_window(1);
 	} else {
-		error("Error reading save file");
+		error(_("Error reading save file"));
 	}
 
 	return Common::kNoError;
 }
 
+Common::Error Frotz::saveGameState(int slot, const Common::String &desc) {
+	Common::String msg;
+	FileReference ref(slot, desc, fileusage_BinaryMode | fileusage_SavedGame);
+
+	strid_t file = _streams->openFileStream(&ref, filemode_Write);
+	if (file == nullptr)
+		return Common::kWritingFailed;
+
+	Quetzal q(story_fp);
+	bool success = q.save(*file, this, desc);
+
+	if (!success)
+		print_string(_("Error writing save file\n"));
+
+	return Common::kNoError;
+
+}
+
 } // End of namespace Frotz
 } // End of namespace Glk
diff --git a/engines/glk/frotz/frotz.h b/engines/glk/frotz/frotz.h
index 8312e16b49..a8083a3093 100644
--- a/engines/glk/frotz/frotz.h
+++ b/engines/glk/frotz/frotz.h
@@ -72,14 +72,25 @@ public:
 	virtual void runGame() override;
 
 	/**
-	 * Load a savegame from the passed stream
+	 * Load a savegame from a given slot
 	 */
-	virtual Common::Error loadGameData(strid_t file) override;
+	virtual Common::Error loadGameState(int slot) override;
 
 	/**
-	 * Save the game to the passed stream
+	 * Save the game to a given slot
 	 */
-	virtual Common::Error saveGameData(strid_t file, const Common::String &desc) override;
+	virtual Common::Error saveGameState(int slot, const Common::String &desc) override;
+
+	/**
+	 * Loading method not used for Frotz sub-engine
+	 */
+	virtual Common::Error readSaveData(Common::SeekableReadStream *rs) override { return Common::kReadingFailed; }
+
+	/**
+	 * Saving method not used for Frotz sub-engine
+	 */
+	virtual Common::Error writeGameData(Common::WriteStream *ws) override { return Common::kWritingFailed; }
+
 };
 
 extern Frotz *g_vm;
diff --git a/engines/glk/glk.cpp b/engines/glk/glk.cpp
index 7155cd8190..b3760cafd4 100644
--- a/engines/glk/glk.cpp
+++ b/engines/glk/glk.cpp
@@ -33,6 +33,7 @@
 #include "glk/conf.h"
 #include "glk/events.h"
 #include "glk/picture.h"
+#include "glk/quetzal.h"
 #include "glk/screen.h"
 #include "glk/selection.h"
 #include "glk/sound.h"
@@ -182,10 +183,32 @@ Common::Error GlkEngine::loadGameState(int slot) {
 	if (file == nullptr)
 		return Common::kReadingFailed;
 
-	Common::Error result = loadGameData(file);
+	Common::ErrorCode errCode = Common::kNoError;
+	QuetzalReader r;
+	if (r.open(*file, ID_IFSF)) {
+		// First scan for a SCVM chunk. It has information of the game the save is for,
+		// so if present we can validate the save is for this game
+		for (QuetzalReader::Iterator it = r.begin(); it != r.end(); ++it) {
+			if ((*it)._id == ID_SCVM) {
+
+			}
+		}
+
+		if (errCode != Common::kNoError) {
+			// Scan for an uncompressed memory chunk
+			errCode = Common::kReadingFailed;		// Presume we won't find chunk
+			for (QuetzalReader::Iterator it = r.begin(); it != r.end(); ++it) {
+				if ((*it)._id == ID_UMem) {
+					Common::SeekableReadStream *rs = it.getStream();
+					errCode = readSaveData(rs).getCode();
+					delete rs;
+				}
+			}
+		}
+	}
 
 	file->close();
-	return result;
+	return errCode;
 }
 
 Common::Error GlkEngine::saveGameState(int slot, const Common::String &desc) {
@@ -196,10 +219,21 @@ Common::Error GlkEngine::saveGameState(int slot, const Common::String &desc) {
 	if (file == nullptr)
 		return Common::kWritingFailed;
 
-	Common::Error result = saveGameData(file, desc);
+	Common::ErrorCode errCode = Common::kNoError;
+	QuetzalWriter w;
+
+	// Add the uncompressed memory chunk with the game's save data
+	{
+		Common::WriteStream &ws = w.add(ID_UMem);
+		errCode = writeGameData(&ws).getCode();
+	}
+
+	if (errCode != Common::kNoError) {
+		w.save(*file, desc);
+	}
 
 	file->close();
-	return result;
+	return errCode;
 }
 
 void GlkEngine::beep() {
diff --git a/engines/glk/glk.h b/engines/glk/glk.h
index f96f384027..739f1774d9 100644
--- a/engines/glk/glk.h
+++ b/engines/glk/glk.h
@@ -198,14 +198,15 @@ public:
 	virtual Common::Error saveGameState(int slot, const Common::String &desc) override;
 
 	/**
-	 * Load a savegame from the passed file
+	 * Load a savegame from the passed Quetzal file chunk stream
 	 */
-	virtual Common::Error loadGameData(strid_t file) = 0;
+	virtual Common::Error readSaveData(Common::SeekableReadStream *rs) = 0;
 
 	/**
-	 * Save the game to the passed file
+	 * Save the game. The passed write stream represents access to the UMem chunk
+	 * in the Quetzal save file that will be created
 	 */
-	virtual Common::Error saveGameData(strid_t file, const Common::String &desc) = 0;
+	virtual Common::Error writeGameData(Common::WriteStream *ws) = 0;
 
 	/**
 	 * Generate a beep
diff --git a/engines/glk/glulxe/exec.cpp b/engines/glk/glulxe/exec.cpp
index 5fd15a3be6..cd26241700 100644
--- a/engines/glk/glulxe/exec.cpp
+++ b/engines/glk/glulxe/exec.cpp
@@ -681,12 +681,20 @@ PerformJump: /* goto label for successful jumping... ironic, no? */
 
 			case op_save:
 				push_callstub(inst[1].desttype, inst[1].value);
+#ifdef TODO
 				value = saveGameData(find_stream_by_id(inst[0].value), "Savegame").getCode() == Common::kNoError ? 0 : 1;
+#else
+				error("TODO");
+#endif
 				pop_callstub(value);
 				break;
 
 			case op_restore:
+#ifdef TODO
 				value = loadGameData(find_stream_by_id(inst[0].value)).getCode() == Common::kNoError ? 0 : 1;
+#else
+				error("TODO");
+#endif
 				if (value == 0) {
 					/* We've succeeded, and the stack now contains the callstub
 					   saved during saveundo. Ignore this opcode's operand. */
diff --git a/engines/glk/glulxe/glulxe.h b/engines/glk/glulxe/glulxe.h
index 56a912eeca..bf1bad9afe 100644
--- a/engines/glk/glulxe/glulxe.h
+++ b/engines/glk/glulxe/glulxe.h
@@ -407,14 +407,15 @@ public:
 	}
 
 	/**
-	 * Load a savegame from the passed stream
+	 * Load a savegame from the passed Quetzal file chunk stream
 	 */
-	virtual Common::Error loadGameData(strid_t str) override;
+	virtual Common::Error readSaveData(Common::SeekableReadStream *rs) override;
 
 	/**
-	 * Save the game to the passed stream
+	 * Save the game. The passed write stream represents access to the UMem chunk
+	 * in the Quetzal save file that will be created
 	 */
-	virtual Common::Error saveGameData(strid_t str, const Common::String &desc) override;
+	virtual Common::Error writeGameData(Common::WriteStream *ws) override;
 
 	/**
 	 * \defgroup Main access methods
diff --git a/engines/glk/glulxe/serial.cpp b/engines/glk/glulxe/serial.cpp
index d485160302..81cfa9e41b 100644
--- a/engines/glk/glulxe/serial.cpp
+++ b/engines/glk/glulxe/serial.cpp
@@ -232,13 +232,13 @@ uint Glulxe::perform_restoreundo() {
 	return res;
 }
 
-Common::Error Glulxe::saveGameData(strid_t str, const Common::String &desc) {
+Common::Error Glulxe::writeGameData(Common::WriteStream *ws) {
 	dest_t dest;
 	int ix;
-	uint res, lx, val;
+	uint res = 0, lx, val;
 	uint memstart = 0, memlen = 0, stackstart = 0, stacklen = 0;
 	uint heapstart = 0, heaplen = 0, filestart = 0, filelen = 0;
-
+#ifdef TODO
 	stream_get_iosys(&val, &lx);
 	if (val != 2) {
 		/* Not using the Glk I/O system, so bail. This function only
@@ -246,14 +246,14 @@ Common::Error Glulxe::saveGameData(strid_t str, const Common::String &desc) {
 		fatal_error("Streams are only available in Glk I/O system.");
 	}
 
-	if (str == nullptr)
+	if (ws == nullptr)
 		return Common::kUnknownError;
 
 	dest.ismem = false;
 	dest.size = 0;
 	dest.pos = 0;
 	dest.ptr = nullptr;
-	dest.str = str;
+	dest.str = ws;
 
 	res = 0;
 
@@ -357,11 +357,11 @@ Common::Error Glulxe::saveGameData(strid_t str, const Common::String &desc) {
 	}
 
 	/* All done. */
-
+#endif
 	return res ? Common::kUnknownError : Common::kNoError;
 }
 
-Common::Error Glulxe::loadGameData(strid_t str) {
+Common::Error Glulxe::readSaveData(Common::SeekableReadStream *rs) {
 	dest_t dest;
 	int ix;
 	uint lx, res, val;
@@ -369,7 +369,7 @@ Common::Error Glulxe::loadGameData(strid_t str) {
 	uint heapsumlen = 0;
 	uint *heapsumarr = nullptr;
 	bool fromshell = false;
-
+#ifdef TODO
 	/* If profiling is enabled and active then fail. */
 #if VM_PROFILING
 	if (profile_profiling_active())
@@ -475,7 +475,7 @@ Common::Error Glulxe::loadGameData(strid_t str) {
 
 	if (res)
 		return Common::kUnknownError;
-
+#endif
 	return Common::kNoError;
 }
 
diff --git a/engines/glk/hugo/hugo.cpp b/engines/glk/hugo/hugo.cpp
index cd4660d0ef..72db1a2489 100644
--- a/engines/glk/hugo/hugo.cpp
+++ b/engines/glk/hugo/hugo.cpp
@@ -152,7 +152,7 @@ void Hugo::runGame() {
 	hugo_closefiles();
 }
 
-Common::Error Hugo::loadGameData(strid_t save) {
+Common::Error Hugo::readSaveData(Common::SeekableReadStream *rs) {
 	char testid[3], testserial[9];
 	int lbyte, hbyte;
 	int j;
@@ -160,18 +160,18 @@ Common::Error Hugo::loadGameData(strid_t save) {
 	long i;
 
 	/* Check ID */
-	testid[0] = (char)hugo_fgetc(save);
-	testid[1] = (char)hugo_fgetc(save);
+	testid[0] = (char)hugo_fgetc(rs);
+	testid[1] = (char)hugo_fgetc(rs);
 	testid[2] = '\0';
-	if (hugo_ferror(save)) goto RestoreError;
+	if (hugo_ferror(rs)) goto RestoreError;
 
 	if (strcmp(testid, id)) {
-		GUIErrorMessage("Incorrect save file.");
+		GUIErrorMessage("Incorrect rs file.");
 		goto RestoreError;
 	}
 
 	/* Check serial number */
-	if (!hugo_fgets(testserial, 9, save)) goto RestoreError;
+	if (!hugo_fgets(testserial, 9, rs)) goto RestoreError;
 	if (strcmp(testserial, serial))
 	{
 		GUIErrorMessage("Save file created by different version.");
@@ -181,7 +181,7 @@ Common::Error Hugo::loadGameData(strid_t save) {
 	/* Restore variables */
 	for (k=0; k<MAXGLOBALS+MAXLOCALS; k++)
 	{
-		if ((lbyte = hugo_fgetc(save))==EOF || (hbyte = hugo_fgetc(save))==EOF)
+		if ((lbyte = hugo_fgetc(rs))==EOF || (hbyte = hugo_fgetc(rs))==EOF)
 			goto RestoreError;
 		var[k] = lbyte + hbyte * 256;
 	}
@@ -193,11 +193,11 @@ Common::Error Hugo::loadGameData(strid_t save) {
 
 	while (i<codeend-(long)(objtable*16L))
 	{
-		if ((hbyte = hugo_fgetc(save))==EOF && hugo_ferror(save)) goto RestoreError;
+		if ((hbyte = hugo_fgetc(rs))==EOF && hugo_ferror(rs)) goto RestoreError;
 
 		if (hbyte==0)
 		{
-			if ((lbyte = hugo_fgetc(save))==EOF && hugo_ferror(save)) goto RestoreError;
+			if ((lbyte = hugo_fgetc(rs))==EOF && hugo_ferror(rs)) goto RestoreError;
 			SETMEM(objtable*16L+i, (unsigned char)lbyte);
 			i++;
 
@@ -217,28 +217,25 @@ Common::Error Hugo::loadGameData(strid_t save) {
 	}
 
 	/* Restore undo data */
-	if ((lbyte = hugo_fgetc(save))==EOF || (hbyte = hugo_fgetc(save))==EOF)
+	if ((lbyte = hugo_fgetc(rs))==EOF || (hbyte = hugo_fgetc(rs))==EOF)
 		goto RestoreError;
 	undosize = lbyte + hbyte*256;
 
 	/* We can only restore undo data if it was saved by a port with
 	   the same MAXUNDO as us */
-	if (undosize==MAXUNDO)
-	{
-		for (k=0; k<MAXUNDO; k++)
-		{
-			for (j=0; j<5; j++)
-			{
-				if ((lbyte = hugo_fgetc(save))==EOF || (hbyte = hugo_fgetc(save))==EOF)
+	if (undosize == MAXUNDO) {
+		for (k = 0; k < MAXUNDO; k++) {
+			for (j=0; j<5; j++) {
+				if ((lbyte = hugo_fgetc(rs))==EOF || (hbyte = hugo_fgetc(rs))==EOF)
 					goto RestoreError;
 				undostack[k][j] = lbyte + hbyte*256;
 			}
 		}
-		if ((lbyte = hugo_fgetc(save))==EOF || (hbyte = hugo_fgetc(save))==EOF) goto RestoreError;
+		if ((lbyte = hugo_fgetc(rs))==EOF || (hbyte = hugo_fgetc(rs))==EOF) goto RestoreError;
 		undoptr = lbyte + hbyte*256;
-		if ((lbyte = hugo_fgetc(save))==EOF || (hbyte = hugo_fgetc(save))==EOF) goto RestoreError;
+		if ((lbyte = hugo_fgetc(rs))==EOF || (hbyte = hugo_fgetc(rs))==EOF) goto RestoreError;
 		undoturn = lbyte + hbyte*256;
-		if ((lbyte = hugo_fgetc(save))==EOF || (hbyte = hugo_fgetc(save))==EOF) goto RestoreError;
+		if ((lbyte = hugo_fgetc(rs))==EOF || (hbyte = hugo_fgetc(rs))==EOF) goto RestoreError;
 		undoinvalid = (unsigned char)lbyte, undorecord = (unsigned char)hbyte;
 	}
 	else undoinvalid = true;
@@ -249,32 +246,31 @@ RestoreError:
 	return Common::kReadingFailed;
 }
 
-Common::Error Hugo::saveGameData(strid_t save, const Common::String &desc) {
+Common::Error Hugo::writeGameData(Common::WriteStream *ws) {
 	int c, j;
 	int lbyte, hbyte;
 	long i;
 	int samecount = 0;
 
 	/* Write ID */
-	if (hugo_fputc(id[0], save) == EOF || hugo_fputc(id[1], save) == EOF) goto SaveError;
+	if (hugo_fputc(id[0], ws) == EOF || hugo_fputc(id[1], ws) == EOF) goto SaveError;
 
 	/* Write serial number */
-	if (hugo_fputs(serial, save) == EOF) goto SaveError;
+	if (hugo_fputs(serial, ws) == EOF) goto SaveError;
 
 	/* Save variables */
 	for (c = 0; c<MAXGLOBALS + MAXLOCALS; c++)
 	{
 		hbyte = (unsigned int)var[c] / 256;
 		lbyte = (unsigned int)var[c] - hbyte * 256;
-		if (hugo_fputc(lbyte, save) == EOF || hugo_fputc(hbyte, save) == EOF) goto SaveError;
+		if (hugo_fputc(lbyte, ws) == EOF || hugo_fputc(hbyte, ws) == EOF) goto SaveError;
 	}
 
 	/* Save objtable to end of code space */
 
 	if (hugo_fseek(game, objtable * 16L, SEEK_SET)) goto SaveError;
 
-	for (i = 0; i <= codeend - (long)(objtable * 16L); i++)
-	{
+	for (i = 0; i <= codeend - (long)(objtable * 16L); i++) {
 		if ((lbyte = hugo_fgetc(game)) == EOF) goto SaveError;
 		hbyte = MEM(objtable * 16L + i);
 
@@ -282,45 +278,42 @@ Common::Error Hugo::saveGameData(strid_t save, const Common::String &desc) {
 		if (lbyte == hbyte && samecount<255) samecount++;
 
 		/* If memory differs (or samecount exceeds 1 byte) */
-		else
-		{
+		else {
 			if (samecount)
-				if (hugo_fputc(samecount, save) == EOF) goto SaveError;
+				if (hugo_fputc(samecount, ws) == EOF) goto SaveError;
 
 			if (lbyte != hbyte)
 			{
-				if (hugo_fputc(0, save) == EOF) goto SaveError;
-				if (hugo_fputc(hbyte, save) == EOF) goto SaveError;
+				if (hugo_fputc(0, ws) == EOF) goto SaveError;
+				if (hugo_fputc(hbyte, ws) == EOF) goto SaveError;
 				samecount = 0;
 			}
 			else samecount = 1;
 		}
 	}
 	if (samecount)
-		if (hugo_fputc(samecount, save) == EOF) goto SaveError;
+		if (hugo_fputc(samecount, ws) == EOF) goto SaveError;
 
 	/* Save undo data */
 
 	/* Save the number of turns in this port's undo stack */
 	hbyte = (unsigned int)MAXUNDO / 256;
 	lbyte = (unsigned int)MAXUNDO - hbyte * 256;
-	if (hugo_fputc(lbyte, save) == EOF || hugo_fputc(hbyte, save) == EOF)
+	if (hugo_fputc(lbyte, ws) == EOF || hugo_fputc(hbyte, ws) == EOF)
 		goto SaveError;
-	for (c = 0; c<MAXUNDO; c++)
-	{
-		for (j = 0; j<5; j++)
-		{
+	for (c = 0; c < MAXUNDO; c++) {
+		for (j = 0; j < 5; j++) {
 			hbyte = (unsigned int)undostack[c][j] / 256;
 			lbyte = (unsigned int)undostack[c][j] - hbyte * 256;
-			if (hugo_fputc(lbyte, save) == EOF || hugo_fputc(hbyte, save) == EOF)
+			if (hugo_fputc(lbyte, ws) == EOF || hugo_fputc(hbyte, ws) == EOF)
 				goto SaveError;
 		}
 	}
-	if (hugo_fputc(undoptr - (undoptr / 256) * 256, save) == EOF || hugo_fputc(undoptr / 256, save) == EOF)
+	if (hugo_fputc(undoptr - (undoptr / 256) * 256, ws) == EOF || hugo_fputc(undoptr / 256, ws) == EOF)
 		goto SaveError;
-	if (hugo_fputc(undoturn - (undoturn / 256) * 256, save) == EOF || hugo_fputc(undoturn / 256, save) == EOF)
+	if (hugo_fputc(undoturn - (undoturn / 256) * 256, ws) == EOF || hugo_fputc(undoturn / 256, ws) == EOF)
 		goto SaveError;
-	if (hugo_fputc(undoinvalid, save) == EOF || hugo_fputc(undorecord, save) == EOF)
+	if (hugo_fputc(undoinvalid, ws) == EOF || hugo_fputc(undorecord, ws) == EOF)
 		goto SaveError;
 
 	return Common::kNoError;
diff --git a/engines/glk/hugo/hugo.h b/engines/glk/hugo/hugo.h
index f2d83b895b..1cd1682344 100644
--- a/engines/glk/hugo/hugo.h
+++ b/engines/glk/hugo/hugo.h
@@ -1191,14 +1191,15 @@ public:
 	virtual InterpreterType getInterpreterType() const override { return INTERPRETER_HUGO; }
 
 	/**
-	 * Load a savegame from the passed stream
+	 * Load a savegame from the passed Quetzal file chunk stream
 	 */
-	virtual Common::Error loadGameData(strid_t save) override;
+	virtual Common::Error readSaveData(Common::SeekableReadStream *rs) override;
 
 	/**
-	 * Save the game to the passed stream
+	 * Save the game. The passed write stream represents access to the UMem chunk
+	 * in the Quetzal save file that will be created
 	 */
-	virtual Common::Error saveGameData(strid_t save, const Common::String &desc) override;
+	virtual Common::Error writeGameData(Common::WriteStream *ws) override;
 };
 
 } // End of namespace Hugo
diff --git a/engines/glk/magnetic/magnetic.cpp b/engines/glk/magnetic/magnetic.cpp
index c658b8c5fd..7bd3fd686d 100644
--- a/engines/glk/magnetic/magnetic.cpp
+++ b/engines/glk/magnetic/magnetic.cpp
@@ -58,14 +58,14 @@ void Magnetic::runGame() {
 	// TODO
 }
 
-Common::Error Magnetic::loadGameData(strid_t file) {
+Common::Error Magnetic::readSaveData(Common::SeekableReadStream *rs) {
 	// TODO
-	return Common::kNoError;
+	return Common::kReadingFailed;
 }
 
-Common::Error Magnetic::saveGameData(strid_t file, const Common::String &desc) {
+Common::Error Magnetic::writeGameData(Common::WriteStream *ws) {
 	// TODO
-	return Common::kNoError;
+	return Common::kWritingFailed;
 }
 
 bool Magnetic::is_gamefile_valid() {
diff --git a/engines/glk/magnetic/magnetic.h b/engines/glk/magnetic/magnetic.h
index 04f13331bf..c926ede9e6 100644
--- a/engines/glk/magnetic/magnetic.h
+++ b/engines/glk/magnetic/magnetic.h
@@ -191,14 +191,15 @@ public:
 	virtual InterpreterType getInterpreterType() const override { return INTERPRETER_MAGNETIC; }
 
 	/**
-	 * Load a savegame from the passed stream
+	 * Load a savegame from the passed Quetzal file chunk stream
 	 */
-	virtual Common::Error loadGameData(strid_t file) override;
+	virtual Common::Error readSaveData(Common::SeekableReadStream *rs) override;
 
 	/**
-	 * Save the game to the passed stream
+	 * Save the game. The passed write stream represents access to the UMem chunk
+	 * in the Quetzal save file that will be created
 	 */
-	virtual Common::Error saveGameData(strid_t file, const Common::String &desc) override;
+	virtual Common::Error writeGameData(Common::WriteStream *ws) override;
 };
 
 } // End of namespace Magnetic
diff --git a/engines/glk/quetzal.cpp b/engines/glk/quetzal.cpp
index 1dd93a892d..ae81d8818d 100644
--- a/engines/glk/quetzal.cpp
+++ b/engines/glk/quetzal.cpp
@@ -29,15 +29,6 @@
 
 namespace Glk {
 
-static Common::String readString(Common::ReadStream *src) {
-	char c;
-	Common::String result;
-	while ((c = src->readByte()) != 0)
-		result += c;
-
-	return result;
-}
-
 void QuetzalReader::clear() {
 	_chunks.clear();
 	_stream = nullptr;
@@ -141,6 +132,15 @@ bool QuetzalReader::getSavegameMetaInfo(Common::SeekableReadStream *rs, SaveStat
 	return true;
 }
 
+Common::String QuetzalReader::readString(Common::ReadStream *src) {
+	char c;
+	Common::String result;
+	while ((c = src->readByte()) != 0)
+		result += c;
+
+	return result;
+}
+
 /*--------------------------------------------------------------------------*/
 
 Common::WriteStream &QuetzalWriter::add(uint32 chunkId) {
diff --git a/engines/glk/quetzal.h b/engines/glk/quetzal.h
index b398571f38..7f2dd30a71 100644
--- a/engines/glk/quetzal.h
+++ b/engines/glk/quetzal.h
@@ -143,6 +143,11 @@ public:
 	 * Loads a Quetzal save and extract's it's description and meta info
 	 */
 	static bool getSavegameMetaInfo(Common::SeekableReadStream *rs, SaveStateDescriptor &ssd);
+
+	/**
+	 * Support method for reading a string from a stream
+	 */
+	static Common::String readString(Common::ReadStream *src);
 };
 
 /**
diff --git a/engines/glk/scott/scott.cpp b/engines/glk/scott/scott.cpp
index b918f8cda2..11b01c9e7e 100644
--- a/engines/glk/scott/scott.cpp
+++ b/engines/glk/scott/scott.cpp
@@ -21,6 +21,7 @@
  */
 
 #include "glk/scott/scott.h"
+#include "glk/quetzal.h"
 #include "common/config-manager.h"
 #include "common/translation.h"
 
@@ -508,41 +509,44 @@ void Scott::lineInput(char *buf, size_t n) {
 	buf[ev.val1] = 0;
 }
 
-Common::Error Scott::saveGameData(strid_t file, const Common::String &desc) {
+Common::Error Scott::writeGameData(Common::WriteStream *ws) {
 	Common::String msg;
 
 	for (int ct = 0; ct < 16; ct++) {
 		msg = Common::String::format("%d %d\n", _counters[ct], _roomSaved[ct]);
-		glk_put_string_stream(file, msg.c_str());
+		ws->write(msg.c_str(), msg.size());
+		ws->writeByte(0);
 	}
 
 	msg = Common::String::format("%u %d %d %d %d %d\n",
 								 _bitFlags, (_bitFlags & (1 << DARKBIT)) ? 1 : 0,
 								 MY_LOC, _currentCounter, _savedRoom, _gameHeader._lightTime);
-	glk_put_string_stream(file, msg.c_str());
+	ws->write(msg.c_str(), msg.size());
+	ws->writeByte(0);
 
 	for (int ct = 0; ct <= _gameHeader._numItems; ct++) {
 		msg = Common::String::format("%hd\n", (short)_items[ct]._location);
-		glk_put_string_stream(file, msg.c_str());
+		ws->write(msg.c_str(), msg.size());
+		ws->writeByte(0);
 	}
 
 	output(_("Saved.\n"));
 	return Common::kNoError;
 }
 
-Common::Error Scott::loadGameData(strid_t file) {
-	char buf[128];
+Common::Error Scott::readSaveData(Common::SeekableReadStream *rs) {
+	Common::String line;
 	int ct = 0;
 	short lo;
 	short darkFlag;
 
 	for (ct = 0; ct < 16; ct++) {
-		glk_get_line_stream(file, buf, sizeof buf);
-		sscanf(buf, "%d %d", &_counters[ct], &_roomSaved[ct]);
+		line = QuetzalReader::readString(rs);
+		sscanf(line.c_str(), "%d %d", &_counters[ct], &_roomSaved[ct]);
 	}
 
-	glk_get_line_stream(file, buf, sizeof buf);
-	sscanf(buf, "%u %hd %d %d %d %d\n",
+	line = QuetzalReader::readString(rs);
+	sscanf(line.c_str(), "%u %hd %d %d %d %d\n",
 		   &_bitFlags, &darkFlag, &MY_LOC, &_currentCounter, &_savedRoom,
 		   &_gameHeader._lightTime);
 
@@ -550,8 +554,8 @@ Common::Error Scott::loadGameData(strid_t file) {
 	if (darkFlag)
 		_bitFlags |= (1 << 15);
 	for (ct = 0; ct <= _gameHeader._numItems; ct++) {
-		glk_get_line_stream(file, buf, sizeof buf);
-		sscanf(buf, "%hd\n", &lo);
+		line = QuetzalReader::readString(rs);
+		sscanf(line.c_str(), "%hd\n", &lo);
 		_items[ct]._location = (unsigned char)lo;
 	}
 
diff --git a/engines/glk/scott/scott.h b/engines/glk/scott/scott.h
index 4739e9470a..b7527fe6fc 100644
--- a/engines/glk/scott/scott.h
+++ b/engines/glk/scott/scott.h
@@ -177,14 +177,15 @@ public:
 	virtual void runGame() override;
 
 	/**
-	 * Load a savegame from the passed stream
+	 * Load a savegame from the passed Quetzal file chunk stream
 	 */
-	virtual Common::Error loadGameData(strid_t file) override;
+	virtual Common::Error readSaveData(Common::SeekableReadStream *rs) override;
 
 	/**
-	 * Save the game to the passed stream
+	 * Save the game. The passed write stream represents access to the UMem chunk
+	 * in the Quetzal save file that will be created
 	 */
-	virtual Common::Error saveGameData(strid_t file, const Common::String &desc) override;
+	virtual Common::Error writeGameData(Common::WriteStream *ws) override;
 };
 
 } // End of namespace Scott
diff --git a/engines/glk/tads/tads.cpp b/engines/glk/tads/tads.cpp
index 6ce2915469..fc598dbf4a 100644
--- a/engines/glk/tads/tads.cpp
+++ b/engines/glk/tads/tads.cpp
@@ -42,14 +42,14 @@ bool TADS::hasFeature(EngineFeature f) const {
 	return GlkAPI::hasFeature(f);
 }
 
-Common::Error TADS::loadGameData(strid_t file) {
+Common::Error TADS::readSaveData(Common::SeekableReadStream *rs) {
 	// TODO
-	return Common::kNoError;
+	return Common::kReadingFailed;
 }
 
-Common::Error TADS::saveGameData(strid_t file, const Common::String &desc) {
+Common::Error TADS::writeGameData(Common::WriteStream *ws) {
 	// TODO
-	return Common::kNoError;
+	return Common::kWritingFailed;
 }
 
 } // End of namespace TADS
diff --git a/engines/glk/tads/tads.h b/engines/glk/tads/tads.h
index 6ad8780a2b..f30cf9f10d 100644
--- a/engines/glk/tads/tads.h
+++ b/engines/glk/tads/tads.h
@@ -54,14 +54,15 @@ public:
 	virtual bool hasFeature(EngineFeature f) const override;
 
 	/**
-	 * Load a savegame from the passed stream
+	 * Load a savegame from the passed Quetzal file chunk stream
 	 */
-	virtual Common::Error loadGameData(strid_t file) override;
+	virtual Common::Error readSaveData(Common::SeekableReadStream *rs) override;
 
 	/**
-	 * Save the game to the passed stream
+	 * Save the game. The passed write stream represents access to the UMem chunk
+	 * in the Quetzal save file that will be created
 	 */
-	virtual Common::Error saveGameData(strid_t file, const Common::String &desc) override;
+	virtual Common::Error writeGameData(Common::WriteStream *ws) override;
 };
 
 extern TADS *g_vm;