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/* 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.
*
*
*/
/*
* This code is based on original Tony Tough source code
*
* Copyright (c) 1997-2003 Nayma Software
*/
#include "tony/mpal/mpal.h"
#include "tony/mpal/memory.h"
#include "tony/mpal/mpaldll.h"
#include "tony/tony.h"
/*
#include "lzo1x.h"
*/
namespace Tony {
namespace MPAL {
/**
* @defgroup Mathamatical operations
*/
//@{
#define OP_MUL ((1 << 4) | 0)
#define OP_DIV ((1 << 4) | 1)
#define OP_MODULE ((1 << 4) | 2)
#define OP_ADD ((2 << 4) | 0)
#define OP_SUB ((2 << 4) | 1)
#define OP_SHL ((3 << 4) | 0)
#define OP_SHR ((3 << 4) | 1)
#define OP_MINOR ((4 << 4) | 0)
#define OP_MAJOR ((4 << 4) | 1)
#define OP_MINEQ ((4 << 4) | 2)
#define OP_MAJEQ ((4 << 4) | 3)
#define OP_EQUAL ((5 << 4) | 0)
#define OP_NOEQUAL ((5 << 4) | 1)
#define OP_BITAND ((6 << 4) | 0)
#define OP_BITXOR ((7 << 4) | 0)
#define OP_BITOR ((8 << 4) | 0)
#define OP_AND ((9 << 4) | 0)
#define OP_OR ((10 << 4) | 0)
/**
* Object types that can be contained in an EXPRESSION structure
*/
enum ExprListTypes {
ELT_NUMBER = 1,
ELT_VAR = 2,
ELT_PARENTH = 3,
ELT_PARENTH2 = 4
};
//@}
/**
* @defgroup Structures
*/
//@{
/**
* Mathamatical framework to manage operations
*/
typedef struct {
byte type; // Tipo di oggetto (vedi enum ExprListTypes)
byte unary; // Unary operatore (NON SUPPORTATO)
union {
int num; // Numero (se type==ELT_NUMBER)
char *name; // Nome variabile (se type==ELT_VAR)
HGLOBAL son; // Handle a espressione (type==ELT_PARENTH)
byte *pson; // Handle lockato (type==ELT_PARENTH2)
} val;
byte symbol; // Simbolo matematico (vedi #define OP_*)
} EXPRESSION;
typedef EXPRESSION *LPEXPRESSION;
//@}
/**
* Duplicate a mathematical expression.
*
* @param h Handle to the original expression
* @retruns Pointer to the cloned expression
*/
static byte *duplicateExpression(HGLOBAL h) {
byte *orig, *clone;
LPEXPRESSION one, two;
orig = (byte *)globalLock(h);
int num = *(byte *)orig;
one = (LPEXPRESSION)(orig+1);
clone = (byte *)globalAlloc(GMEM_FIXED, sizeof(EXPRESSION) * num + 1);
two = (LPEXPRESSION)(clone + 1);
memcpy(clone, orig, sizeof(EXPRESSION) * num + 1);
for (int i = 0; i < num; i++) {
if (one->type == ELT_PARENTH) {
two->type = ELT_PARENTH2;
two->val.pson = duplicateExpression(two->val.son);
}
++one;
++two;
}
globalUnlock(h);
return clone;
}
static int Compute(int a, int b, byte symbol) {
switch (symbol) {
case OP_MUL:
return a * b;
case OP_DIV:
return a / b;
case OP_MODULE:
return a % b;
case OP_ADD:
return a + b;
case OP_SUB:
return a - b;
case OP_SHL:
return a << b;
case OP_SHR:
return a >> b;
case OP_MINOR:
return a < b;
case OP_MAJOR:
return a > b;
case OP_MINEQ:
return a <= b;
case OP_MAJEQ:
return a >= b;
case OP_EQUAL:
return a == b;
case OP_NOEQUAL:
return a != b;
case OP_BITAND:
return a & b;
case OP_BITXOR:
return a ^ b;
case OP_BITOR:
return a | b;
case OP_AND:
return a && b;
case OP_OR:
return a || b;
default:
GLOBALS._mpalError = 1;
break;
}
return 0;
}
static void solve(LPEXPRESSION one, int num) {
LPEXPRESSION two, three;
int j;
while (num > 1) {
two = one + 1;
if ((two->symbol == 0) || (one->symbol & 0xF0) <= (two->symbol & 0xF0)) {
two->val.num = Compute(one->val.num, two->val.num, one->symbol);
memmove(one, two, (num - 1) * sizeof(EXPRESSION));
--num;
} else {
j = 1;
three = two + 1;
while ((three->symbol != 0) && (two->symbol & 0xF0) > (three->symbol & 0xF0)) {
++two;
++three;
++j;
}
three->val.num = Compute(two->val.num, three->val.num, two->symbol);
memmove(two, three, (num - j - 1) * sizeof(EXPRESSION));
--num;
}
}
}
/**
* Calculates the result of a mathematical expression, replacing the current
* value of any variable.
*
* @param expr Pointer to an expression duplicated by DuplicateExpression
* @returns Value
*/
static int evaluateAndFreeExpression(byte *expr) {
LPEXPRESSION one, cur;
int num = *expr;
one = (LPEXPRESSION)(expr + 1);
// 1) Sostituzioni delle variabili
cur = one;
for (int i = 0; i < num; i++, cur++) {
if (cur->type == ELT_VAR) {
cur->type = ELT_NUMBER;
cur->val.num = varGetValue(cur->val.name);
}
}
// 2) Sostituzioni delle parentesi (tramite ricorsione)
cur = one;
for (int i = 0; i < num; i++, cur++) {
if (cur->type == ELT_PARENTH2) {
cur->type = ELT_NUMBER;
cur->val.num = evaluateAndFreeExpression(cur->val.pson);
}
}
// 3) Risoluzione algebrica
solve(one, num);
int val = one->val.num;
globalDestroy(expr);
return val;
}
/**
* Parses a mathematical expression from the MPC file
*
* @param buf Buffer containing the expression to evaluate
* @param h Pointer to a handle that, at the end of execution,
* will point to the area of memory containing the parsed expression
* @returns Pointer to the buffer immediately after the expression, or NULL if error.
*/
const byte *parseExpression(const byte *lpBuf, HGLOBAL *h) {
LPEXPRESSION cur;
byte *start;
uint32 num = *lpBuf;
lpBuf++;
if (num == 0)
return NULL;
*h = globalAllocate(GMEM_MOVEABLE | GMEM_ZEROINIT, num * sizeof(EXPRESSION) + 1);
if (*h == NULL)
return NULL;
start = (byte *)globalLock(*h);
*start = (byte)num;
cur = (LPEXPRESSION)(start + 1);
for (uint32 i = 0;i < num; i++) {
cur->type = *(lpBuf);
cur->unary = *(lpBuf + 1);
lpBuf += 2;
switch (cur->type) {
case ELT_NUMBER:
cur->val.num = (int32)READ_LE_UINT32(lpBuf);
lpBuf += 4;
break;
case ELT_VAR:
cur->val.name = (char *)globalAlloc(GMEM_FIXED | GMEM_ZEROINIT, (*lpBuf) + 1);
if (cur->val.name == NULL)
return NULL;
memcpy(cur->val.name, lpBuf + 1, *lpBuf);
lpBuf += *lpBuf + 1;
break;
case ELT_PARENTH:
lpBuf = parseExpression(lpBuf, &cur->val.son);
if (lpBuf == NULL)
return NULL;
break;
default:
return NULL;
}
cur->symbol = *lpBuf;
lpBuf++;
cur++;
}
if (*lpBuf != 0)
return NULL;
lpBuf++;
return lpBuf;
}
/**
* Calculate the value of a mathamatical expression
*
* @param h Handle to the expression
* @returns Numeric value
*/
int evaluateExpression(HGLOBAL h) {
int ret;
lockVar();
ret = evaluateAndFreeExpression(duplicateExpression(h));
unlockVar();
return ret;
}
/**
* Compare two mathematical expressions together
*
* @param h1 Expression to be compared
* @param h2 Expression to be compared
*/
bool compareExpressions(HGLOBAL h1, HGLOBAL h2) {
byte *e1, *e2;
LPEXPRESSION one, two;
e1 = (byte *)globalLock(h1);
e2 = (byte *)globalLock(h2);
int num1 = *(byte *)e1;
int num2 = *(byte *)e2;
if (num1 != num2) {
globalUnlock(h1);
globalUnlock(h2);
return false;
}
one = (LPEXPRESSION)(e1 + 1);
two = (LPEXPRESSION)(e2 + 1);
for (int i = 0; i < num1; i++) {
if (one->type != two->type || (i != num1 - 1 && one->symbol != two->symbol)) {
globalUnlock(h1);
globalUnlock(h2);
return false;
}
switch (one->type) {
case ELT_NUMBER:
if (one->val.num != two->val.num) {
globalUnlock(h1);
globalUnlock(h2);
return false;
}
break;
case ELT_VAR:
if (strcmp(one->val.name, two->val.name) != 0) {
globalUnlock(h1);
globalUnlock(h2);
return false;
}
break;
case ELT_PARENTH:
if (!compareExpressions(one->val.son, two->val.son)) {
globalUnlock(h1);
globalUnlock(h2);
return false;
}
break;
}
++one;
++two;
}
globalUnlock(h1);
globalUnlock(h2);
return true;
}
/**
* Frees an expression that was previously parsed
*
* @param h Handle for the expression
*/
void freeExpression(HGLOBAL h) {
byte *data = (byte *)globalLock(h);
int num = *data;
LPEXPRESSION cur = (LPEXPRESSION)(data + 1);
for (int i = 0; i < num; ++i, ++cur) {
switch (cur->type) {
case ELT_VAR:
globalDestroy(cur->val.name);
break;
case ELT_PARENTH:
freeExpression(cur->val.son);
break;
default:
break;
}
}
globalUnlock(h);
globalFree(h);
}
} // end of namespace MPAL
} // end of namespace Tony
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