Renamed gpldisasm.* to script.* in anticipation of using it as a script intepreter.

svn-id: r41918

1 files changed, 319 insertions, 0 deletions

diff --git a/engines/draci/script.cpp b/engines/draci/script.cpp
new file mode 100644
index 0000000000..ee7b128529
--- /dev/null
+++ b/engines/draci/script.cpp
@@ -0,0 +1,319 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#include "common/debug.h"
+#include "common/stream.h"
+#include "common/stack.h"
+
+#include "draci/gpldisasm.h"
+#include "draci/draci.h"
+
+namespace Draci {
+
+// FIXME: Change parameter types to names once I figure out what they are exactly
+
+/** A table of all the commands the game player uses */
+GPL2Command gplCommands[] = {
+	{ 0,  0, "gplend",				0, { 0 } },
+	{ 0,  1, "exit",				0, { 0 } },
+	{ 1,  1, "goto", 				1, { 3 } },
+	{ 2,  1, "Let", 				2, { 3, 4 } },
+	{ 3,  1, "if", 					2, { 4, 3 } },
+	{ 4,  1, "Start", 				2, { 3, 2 } },
+	{ 5,  1, "Load", 				2, { 3, 2 } },
+	{ 5,  2, "StartPlay", 			2, { 3, 2 } },
+	{ 5,  3, "JustTalk", 			0, { 0 } },
+	{ 5,  4, "JustStay", 			0, { 0 } },
+	{ 6,  1, "Talk", 				2, { 3, 2 } },
+	{ 7,  1, "ObjStat", 			2, { 3, 3 } },
+	{ 7,  2, "ObjStat_On", 			2, { 3, 3 } },
+	{ 8,  1, "IcoStat", 			2, { 3, 3 } },
+	{ 9,  1, "Dialogue", 			1, { 2 } },
+	{ 9,  2, "ExitDialogue", 		0, { 0 } },
+	{ 9,  3, "ResetDialogue", 		0, { 0 } },
+	{ 9,  4, "ResetDialogueFrom", 	0, { 0 } },
+	{ 9,  5, "ResetBlock", 			1, { 3 } },
+	{ 10, 1, "WalkOn", 				3, { 1, 1, 3 } },
+	{ 10, 2, "StayOn", 				3, { 1, 1, 3 } },
+	{ 10, 3, "WalkOnPlay", 			3, { 1, 1, 3 } },
+	{ 11, 1, "LoadPalette", 		1, { 2 } },
+	{ 12, 1, "SetPalette", 			0, { 0 } },
+	{ 12, 2, "BlackPalette", 		0, { 0 } },
+	{ 13, 1, "FadePalette", 		3, { 1, 1, 1 } },
+	{ 13, 2, "FadePalettePlay", 	3, { 1, 1, 1 } },
+	{ 14, 1, "NewRoom", 			2, { 3, 1 } },
+	{ 15, 1, "ExecInit", 			1, { 3 } },
+	{ 15, 2, "ExecLook", 			1, { 3 } },
+	{ 15, 3, "ExecUse", 			1, { 3 } },
+	{ 16, 1, "RepaintInventory", 	0, { 0 } },
+	{ 16, 2, "ExitInventory", 		0, { 0 } },
+	{ 17, 1, "ExitMap", 			0, { 0 } },
+	{ 18, 1, "LoadMusic", 			1, { 2 } },
+	{ 18, 2, "StartMusic", 			0, { 0 } },
+	{ 18, 3, "StopMusic", 			0, { 0 } },
+	{ 18, 4, "FadeOutMusic",		1, { 1 } },
+	{ 18, 5, "FadeInMusic", 		1, { 1 } },
+	{ 19, 1, "Mark", 				0, { 0 } },
+	{ 19, 2, "Release", 			0, { 0 } },
+	{ 20, 1, "Play", 				0, { 0 } },
+	{ 21, 1, "LoadMap", 			1, { 2 } },
+	{ 21, 2, "RoomMap", 			0, { 0 } },
+	{ 22, 1, "DisableQuickHero", 	0, { 0 } },
+	{ 22, 2, "EnableQuickHero", 	0, { 0 } },
+	{ 23, 1, "DisableSpeedText", 	0, { 0 } },
+	{ 23, 2, "EnableSpeedText", 	0, { 0 } },
+	{ 24, 1, "QuitGame", 			0, { 0 } },
+	{ 25, 1, "PushNewRoom", 		0, { 0 } },
+	{ 25, 2, "PopNewRoom", 			0, { 0 } },
+	{ 26, 1, "ShowCheat", 			0, { 0 } },
+	{ 26, 2, "HideCheat", 			0, { 0 } },
+	{ 26, 3, "ClearCheat", 			1, { 1 } },
+	{ 27, 1, "FeedPassword", 		3, { 1, 1, 1 } }
+};
+
+/** Operators used by the mathematical evaluator */
+Common::String operators[] = {
+	"oper_and",
+	"oper_or",
+	"oper_xor",
+	"oper_equals",
+	"oper_not_equal",
+	"oper_less_than",
+	"oper_greater_than",
+	"oper_less_or_equal",
+	"oper_greater_or_equal",
+	"oper_multiply",
+	"oper_divide",
+	"oper_remainder",
+	"oper_plus",
+	"oper_minus"
+};
+
+/** Functions used by the mathematical evaluator */
+Common::String functions[] = {
+	"F_Not",
+	"F_Random",
+	"F_IsIcoOn",
+	"F_IsIcoAct",
+	"F_IcoStat",
+	"F_ActIco",
+	"F_IsObjOn",
+	"F_IsObjOff",
+	"F_IsObjAway",
+	"F_ObjStat",
+	"F_LastBlock",
+	"F_AtBegin",
+	"F_BlockVar",
+	"F_HasBeen",
+	"F_MaxLine",
+	"F_ActPhase",
+	"F_Cheat"
+};
+
+const unsigned int kNumCommands = sizeof gplCommands / sizeof gplCommands[0];
+
+/** Type of mathematical object */
+enum mathExpressionObject {
+	kMathEnd,
+	kMathNumber,
+	kMathOperator,
+	kMathFunctionCall,
+	kMathVariable
+};
+
+// FIXME: The evaluator is now complete but I still need to implement callbacks
+
+/**
+ * @brief Evaluates mathematical expressions
+ * @param reader Stream reader set to the beginning of the expression
+ */
+
+void handleMathExpression(Common::MemoryReadStream &reader) {
+	Common::Stack<uint16> stk;
+	mathExpressionObject obj;
+
+	// Read in initial math object
+	obj = (mathExpressionObject)reader.readUint16LE();
+
+	uint16 value;
+	while (1) {
+		if (obj == kMathEnd) {
+			// Check whether the expression was evaluated correctly
+			// The stack should contain only one value after the evaluation
+			// i.e. the result of the expression
+			assert(stk.size() == 1 && "Mathematical expression error");	
+			break;
+		}
+
+		switch (obj) {
+
+		// If the object type is not known, assume that it's a number
+		default:
+		case kMathNumber:
+			value = reader.readUint16LE();
+			stk.push(value);
+			debugC(3, kDraciBytecodeDebugLevel, "\t\t-number %hu", value);
+			break;
+
+		case kMathOperator:
+			value = reader.readUint16LE();
+			stk.pop();
+			stk.pop();
+
+			// FIXME: Pushing dummy value for now, but should push return value
+			stk.push(0);
+
+			debugC(3, kDraciBytecodeDebugLevel, "\t\t-operator %s",
+				operators[value-1].c_str());
+			break;
+
+		case kMathVariable:
+			value = reader.readUint16LE();
+			stk.push(value);
+			debugC(3, kDraciBytecodeDebugLevel, "\t\t-variable %hu", value);
+			break;
+
+		case kMathFunctionCall:
+			value = reader.readUint16LE();
+						
+			stk.pop();
+
+			// FIXME: Pushing dummy value for now, but should push return value
+			stk.push(0);
+
+			debugC(3, kDraciBytecodeDebugLevel, "\t\t-functioncall %s",
+				functions[value-1].c_str());
+			break;
+		}
+
+		obj = (mathExpressionObject) reader.readUint16LE();
+	}
+
+	return;
+}
+
+/**
+ * @brief Find the current command in the internal table
+ *
+ * @param num 		Command number
+ * @param subnum 	Command subnumer
+ *
+ * @return NULL if command is not found. Otherwise, a pointer to a GPL2Command
+ *         struct representing the command.
+ */
+GPL2Command *findCommand(byte num, byte subnum) {
+	unsigned int i = 0;
+	while (1) {
+
+		// Command not found
+		if (i >= kNumCommands) {
+			break;
+		}
+
+		// Return found command
+		if (gplCommands[i]._number == num &&
+			gplCommands[i]._subNumber == subnum) {
+			return &gplCommands[i];
+		}
+
+		++i;
+	}
+
+	return NULL;
+}
+
+/**
+ * @brief GPL2 bytecode disassembler
+ * @param gplcode A pointer to the bytecode
+ * @param len Length of the bytecode
+ *
+ * GPL2 is short for Game Programming Language 2 which is the script language
+ * used by Draci Historie. This is a simple disassembler for the language.
+ *
+ * A compiled GPL2 program consists of a stream of bytes representing commands
+ * and their parameters. The syntax is as follows:
+ *
+ * Syntax of a command:
+ *	<name of the command> <number> <sub-number> <list of parameters...>
+ *
+ *	Syntax of a parameter:
+ *	- 1: integer number literally passed to the program
+ *	- 2-1: string stored in the reservouir of game strings (i.e. something to be
+ *	  displayed) and stored as an index in this list
+ *	- 2-2: string resolved by the compiler (i.e., a path to another file) and
+ *	  replaced by an integer index of this entity in the appropriate namespace
+ *	  (e.g., the index of the palette, location, ...)
+ *	- 3-0: relative jump to a label defined in this code.  Each label must be
+ *	  first declared in the beginning of the program.
+ *	- 3-1 .. 3-9: index of an entity in several namespaces, defined in file ident
+ *	- 4: mathematical expression compiled into a postfix format
+ *
+ * 	In the compiled program, parameters of type 1..3 are represented by a single
+ *	16-bit integer.  The called command knows by its definition what namespace the
+ *	value comes from.
+ */
+
+int gpldisasm(byte *gplcode, uint16 len) {
+	Common::MemoryReadStream reader(gplcode, len);
+
+	while (!reader.eos()) {
+		// read in command pair
+		uint16 cmdpair = reader.readUint16BE();
+
+		// extract high byte, i.e. the command number
+		byte num = (cmdpair >> 8) & 0xFF;
+
+		// extract low byte, i.e. the command subnumber
+		byte subnum = cmdpair & 0xFF;
+
+		GPL2Command *cmd;
+		if ((cmd = findCommand(num, subnum))) {
+
+			// Print command name
+			debugC(2, kDraciBytecodeDebugLevel, "%s", cmd->_name.c_str());
+
+			for (uint16 i = 0; i < cmd->_numParams; ++i) {
+				if (cmd->_paramTypes[i] == 4) {
+					debugC(3, kDraciBytecodeDebugLevel, "\t<MATHEXPR>");
+					handleMathExpression(reader);
+				}
+				else {
+					debugC(3, kDraciBytecodeDebugLevel, "\t%hu", reader.readUint16LE());
+				}
+			}
+		}
+		else {
+			debugC(2, kDraciBytecodeDebugLevel, "Unknown opcode %hu, %hu",
+				num, subnum);
+		}
+
+
+	}
+
+	return 0;
+}
+
+}
+