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Diffstat (limited to 'engines/tony/mpal/expr.cpp')
-rw-r--r-- | engines/tony/mpal/expr.cpp | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/engines/tony/mpal/expr.cpp b/engines/tony/mpal/expr.cpp new file mode 100644 index 0000000000..7923d263c0 --- /dev/null +++ b/engines/tony/mpal/expr.cpp @@ -0,0 +1,433 @@ +/* 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" + +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) + MpalHandle _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(MpalHandle 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) Substitutions of variables + 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) Replacement of brackets (using recursive calls) + 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) algebraic resolution + 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, MpalHandle *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(MpalHandle 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(MpalHandle h1, MpalHandle 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(MpalHandle 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 |