WIP for arbitrary widget positions. See

http://wiki.scummvm.org/index.php/GUI_Themes
Code is not yet used.

svn-id: r21115

gui/eval.cpp

@@ -0,0 +1,292 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2006 The ScummVM project
+ *
+ * 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/stdafx.h"
+#include "common/system.h"
+#include "gui/eval.h"
+#include "gui/widget.h"
+#include "gui/newgui.h"
+
+namespace GUI {
+
+static bool isdelim(char c) {
+	if (strchr(" ;,+-<>/*%^=()", c) || c == 9 || c == '\n' || !c)
+		return true;
+
+	return false;
+}
+
+Eval::Eval() {
+}
+
+Eval::~Eval() {
+	reset();
+}
+
+int Eval::eval(const String &input, const String &section, const String &name, int startpos) {
+	int result;
+
+	debug(3, "<%s>", input.c_str());
+
+	strncpy(_input, input.c_str(), 256);
+	_section = section;
+	_name = name;
+	_startpos = startpos;
+
+	_pos = 0;
+
+	getToken();
+
+	if (!*_token)
+		exprError(eBadExpr);
+
+	level2(&result);
+
+	debug(3, "Result: %d", result);
+
+	return result;
+}
+
+void Eval::level2(int *result) {
+	char op;
+	int hold;
+
+	level3(result);
+
+	while ((op = *_token) == '+' || op == '-') {
+		getToken();
+		level3(&hold);
+		arith(op, result, &hold);
+	}
+}
+
+void Eval::level3(int *result) {
+	char op;
+	int hold;
+
+	level4(result);
+
+	while ((op = *_token) == '*' || op == '/' || op == '%') {
+		getToken();
+		level4(&hold);
+		arith(op, result, &hold);
+	}
+}
+
+void Eval::level4(int *result) {
+	char op;
+
+	op = 0;
+	if ((_tokenType == tDelimiter) && *_token == '+' || *_token == '-') {
+		op = *_token;
+		getToken();
+	}
+
+	level5(result);
+
+	if (op)
+		unary(op, result);
+}
+
+void Eval::level5(int *result) {
+	if ((*_token == '(') && (_tokenType == tDelimiter)) {
+		getToken();
+
+		level2(result);
+
+		if (*_token != ')')
+			exprError(eUnclosedBracket);
+		getToken();
+	} else {
+		primitive(result);
+	}
+}
+
+void Eval::primitive(int *result) {
+	if (*_token == ')')
+		exprError(eExtraBracket);
+
+	switch (_tokenType) {
+	case tVariable:
+		*result = lookupVar(_token);
+		if (*result == EVAL_UNDEF_VAR)
+			exprError(eUndefVar);
+		getToken();
+		return;
+	case tNumber:
+		*result = atoi(_token);
+		getToken();
+		return;
+	default:
+		exprError(eSyntaxError);
+	}
+}
+
+void Eval::arith(char op, int *r, int *h) {
+	int t;
+
+	switch (op) {
+	case '-':
+		*r = *r - *h;
+		break;
+	case '+':
+		*r = *r + *h;
+		break;
+	case '*':
+		*r = *r * *h;
+		break;
+	case '/':
+		*r = (*r) / (*h);
+		break;
+	case '%':
+		t = (*r) / (*h);
+		*r = *r - (t * (*h));
+		break;
+	}
+}
+
+void Eval::unary(char op, int *r) {
+	if (op == '-')
+		*r = -(*r);
+}
+
+void Eval::getToken() {
+	char *temp;
+
+	_tokenType = 0;
+	temp = _token;
+
+	if (_input[_pos] == 0) {
+		*_token = 0;
+		_tokenType = tDelimiter;
+		return;
+	}
+	while (isspace(_input[_pos]))
+		_pos++;
+
+	if (isdigit(_input[_pos])) {
+		while (!isdelim(_input[_pos]))
+			*temp++ = _input[_pos++];
+		*temp = 0;
+
+		_tokenType = tNumber;
+		return;
+	}
+
+	if (isalpha(_input[_pos])) {
+		while (!isdelim(_input[_pos]))
+			*temp++ = _input[_pos++];
+		*temp = 0;
+		_tokenType = tVariable;
+		return;
+	}
+
+	
+	if (!_tokenType && isdelim(_input[_pos])) {
+		*temp++ = _input[_pos++];
+		*temp = 0;                                                      
+		_tokenType = tDelimiter;                                
+	}
+}
+
+void Eval::exprError(int err) {
+	static const char *errors[] = {
+		"Syntax error",
+		"Extra ')'",
+		"Missing ')'",
+		"Bad expression",
+		"Undefined variable"
+	};
+
+	error("%s in section [%s] expression: \"%s\" start is at: %d near token '%s'",
+		  errors[err], _section.c_str(), _name.c_str(), _pos + _startpos, _token);
+}
+
+struct BuiltinConsts {
+	const char *name;
+	int value;
+};
+
+static const BuiltinConsts builtinConsts[] = {
+	{"kButtonWidth", GUI::kButtonWidth},
+	{"kButtonHeight", GUI::kButtonHeight},
+	{"kSliderWidth", GUI::kSliderWidth},
+	{"kSliderHeight", GUI::kSliderHeight},
+
+	{"kBigButtonWidth", GUI::kBigButtonWidth},
+	{"kBigButtonHeight", GUI::kBigButtonHeight},
+	{"kBigSliderWidth", GUI::kBigSliderWidth},
+	{"kBigSliderHeight", GUI::kBigSliderHeight},
+	{NULL, 0}
+};
+
+int Eval::getBuiltinVar(const char *s) {
+	if (!strcmp(s, "w"))
+		return g_system->getOverlayWidth();
+
+	if (!strcmp(s, "h"))
+		return g_system->getOverlayHeight();
+
+	return EVAL_UNDEF_VAR;
+}
+
+int Eval::lookupVar(const char *s, bool includeAliases) {
+	int i;
+	int val;
+
+	for (i = 0; builtinConsts[i].name; i++)
+		if (!scumm_stricmp(s, builtinConsts[i].name))
+			return builtinConsts[i].value;
+
+	val = getBuiltinVar(s);
+
+	if (val != EVAL_UNDEF_VAR)
+		return val;
+
+	String var = String(s);
+	if (includeAliases && _aliases.contains(var))
+		var = _aliases[var];
+
+	if (_vars.contains(var))
+		return _vars[var];
+
+	return EVAL_UNDEF_VAR;
+}
+
+void Eval::setAlias(const String &section, const String name, const String value) {
+	String var = String(&(name.c_str()[4]));
+
+	_aliases[var] = value;
+}
+
+void Eval::setVariable(const String &section, const String name, const String value) {
+	String var = String(&(name.c_str()[4]));
+
+	_vars[var] = eval(value, section, name, 0);
+}
+
+void Eval::reset() {
+	_vars.clear();
+	_aliases.clear();
+}
+
+} // end of namespace GUI