mirror of
https://github.com/libretro/scummvm.git
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391 lines
8.6 KiB
C++
391 lines
8.6 KiB
C++
/* ScummVM - Scumm Interpreter
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* Copyright (C) 2004 The ScummVM project
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*
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* The ReInherit Engine is (C)2000-2003 by Daniel Balsom.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* $Header$
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*
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*/
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// Expression parsing module, and string handling functions
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// EXPR_ParseArgs() lifted wholesale from SDL win32 initialization code by Sam Lantinga
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#include "saga/saga.h"
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#include "saga/cvar_mod.h"
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#include "saga/expr.h"
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namespace Saga {
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static const char *EXPR_ErrMsg[] = {
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"Invalid error state.",
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"No Error",
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"Memory allocation failed",
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"Illegal variable name",
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"Expected \'=\' or \'(\' in expression",
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"Expected \'(\' in function call",
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"Illegal \'(\', identifier is not function",
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"Expected a value to assign",
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"Unterminated string literal",
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"Unmatched parenthesis in function call",
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"Error reading value string",
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"Expected a number or boolean",
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"Unknown variable or function"
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};
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enum EXPR_Errors {
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EXERR_ASSERT,
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EXERR_NONE,
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EXERR_MEM,
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EXERR_ILLEGAL,
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EXERR_EXPR,
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EXERR_FUNC,
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EXERR_NOTFUNC,
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EXERR_RVALUE,
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EXERR_LITERAL,
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EXERR_PAREN,
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EXERR_STRING,
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EXERR_NUMBER,
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EXERR_NOTFOUND
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};
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static enum EXPR_Errors EXPR_ErrorState;
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// Returns the appropriate expression parser error string given an error code.
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int EXPR_GetError(const char **err_str) {
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*err_str = EXPR_ErrMsg[EXPR_ErrorState];
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return EXPR_ErrorState;
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}
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// Parses an interactive expression.
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// Sets 'expr_cvar' to the cvar/cfunction identifier input by the user, and
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// 'rvalue' to the corresponding rvalue ( in an expression ) or argument string
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// ( in a function call ).
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//
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// Memory pointed to by rvalue after return must be explicitly freed by the
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// caller.
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int EXPR_Parse(const char **exp_pp, int *len, R_CVAR_P *expr_cvar, char **rvalue) {
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int i;
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int in_char;
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int equ_offset = 0;
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int rvalue_offset;
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char *lvalue_str;
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int lvalue_len;
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char *rvalue_str;
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int rvalue_len;
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const char *scan_p;
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int scan_len;
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const char *expr_p;
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int expr_len;
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int test_char = '\0';
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int have_func = 0;
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R_CVAR_P lvalue_cvar;
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expr_p = *exp_pp;
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expr_len = strlen(*exp_pp);
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scan_p = *exp_pp;
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scan_len = expr_len;
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//*lvalue = NULL;
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*rvalue = NULL;
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EXPR_ErrorState = EXERR_ASSERT;
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for (i = 0; i <= scan_len; i++, scan_p++) {
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in_char = *scan_p;
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if ((i == 0) && isdigit(in_char)) {
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// First character of a valid identifier cannot be a digit
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EXPR_ErrorState = EXERR_ILLEGAL;
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return R_FAILURE;
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}
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// If we reach a character that isn't valid in an identifier...
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if ((!isalnum(in_char)) && ((in_char != '_'))) {
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// then eat remaining whitespace, if any
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equ_offset = strspn(scan_p, R_EXPR_WHITESPACE);
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test_char = scan_p[equ_offset];
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// and test for the only valid characters after an identifier
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if ((test_char != '=') && (test_char != '\0') && (test_char != '(')) {
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if ((equ_offset == 0) && ((scan_p - expr_p) != expr_len)) {
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EXPR_ErrorState = EXERR_ILLEGAL;
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} else {
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EXPR_ErrorState = EXERR_EXPR;
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}
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return R_FAILURE;
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}
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break;
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}
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}
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lvalue_len = (scan_p - expr_p);
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lvalue_str = (char *)malloc(lvalue_len + 1);
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if (lvalue_str == NULL) {
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EXPR_ErrorState = EXERR_MEM;
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return R_FAILURE;
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}
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strncpy(lvalue_str, expr_p, lvalue_len);
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lvalue_str[lvalue_len] = 0;
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// We now have the lvalue, so attempt to find it
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lvalue_cvar = CVAR_Find(lvalue_str);
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if (lvalue_cvar == NULL) {
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EXPR_ErrorState = EXERR_NOTFOUND;
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return R_FAILURE;
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}
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if (lvalue_str) {
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free(lvalue_str);
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lvalue_str = NULL;
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}
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// Skip parsed character, if any
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scan_p += equ_offset + 1;
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scan_len = (scan_p - expr_p);
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// Check if the 'cvar' is really a function
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have_func = CVAR_IsFunc(lvalue_cvar);
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if (test_char == '(') {
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if (have_func) {
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rvalue_str = EXPR_ReadString(&scan_p, &rvalue_len, ')');
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if (rvalue_str != NULL) {
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// Successfully read string
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//CON_Print("Read function parameters \"%s\".", rvalue_str);
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*expr_cvar = lvalue_cvar;
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*rvalue = rvalue_str;
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scan_len = (scan_p - expr_p);
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*exp_pp = scan_p;
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*len -= scan_len;
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EXPR_ErrorState = EXERR_NONE;
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return R_SUCCESS;
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} else {
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EXPR_ErrorState = EXERR_PAREN;
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return R_FAILURE;
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}
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} else {
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EXPR_ErrorState = EXERR_NOTFUNC;
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return R_FAILURE;
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}
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}
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// Eat more whitespace
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rvalue_offset = strspn(scan_p, R_EXPR_WHITESPACE);
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if (rvalue_offset + i == expr_len) {
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// Only found single lvalue
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*expr_cvar = lvalue_cvar;
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*exp_pp = scan_p;
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*len -= scan_len;
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return R_SUCCESS;
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}
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scan_p += rvalue_offset;
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scan_len = (scan_p - expr_p) + 1;
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in_char = *scan_p;
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in_char = toupper(in_char);
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switch (in_char) {
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case '\"':
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scan_p++;
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scan_len--;
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rvalue_str = EXPR_ReadString(&scan_p, &rvalue_len, '\"');
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if (rvalue_str != NULL) {
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// Successfully read string
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break;
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} else {
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EXPR_ErrorState = EXERR_LITERAL;
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return R_FAILURE;
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}
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break;
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#if 0
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case 'Y': // Y[es]
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case 'T': // T[rue]
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break;
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case 'N': // N[o]
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case 'F': // F[alse]
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break;
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#endif
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default:
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if (isdigit(in_char) || (in_char == '-') || (in_char == '+')) {
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rvalue_str = EXPR_ReadString(&scan_p, &rvalue_len, 0);
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if (rvalue_str != NULL) {
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// Successfully read string
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break;
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} else {
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EXPR_ErrorState = EXERR_STRING;
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return R_FAILURE;
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}
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} else {
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EXPR_ErrorState = EXERR_NUMBER;
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return R_FAILURE;
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}
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break;
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}
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*expr_cvar = lvalue_cvar;
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*rvalue = rvalue_str;
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scan_len = (scan_p - expr_p);
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*exp_pp = scan_p;
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*len -= scan_len;
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EXPR_ErrorState = EXERR_NONE;
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return R_SUCCESS;
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}
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// Reads in a string of characters from '*string_p' until 'term_char' is
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// encountered. If 'term_char' == 0, the function reads characters until
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// whitespace is encountered.
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// Upon reading a string, the function modifies *string_p and len based on
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// the number of characters read.
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char *EXPR_ReadString(const char **string_p, int *len, int term_char) {
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int string_len;
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char *str_p = NULL;
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char *term_p;
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const char *scan_p;
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int in_char;
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if (term_char > 0) {
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term_p = (char *)strchr(*string_p, term_char);
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if (term_p == NULL) {
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return NULL;
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}
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string_len = (int)(term_p - *string_p);
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str_p = (char *)malloc(string_len + 1);
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if (str_p == NULL) {
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return NULL;
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}
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strncpy(str_p, *string_p, string_len);
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str_p[string_len] = 0;
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*string_p += (string_len + 1); /* Add 1 for terminating char */
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*len -= (string_len + 1);
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} else {
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scan_p = *string_p;
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string_len = 0;
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while (scan_p) {
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in_char = *scan_p++;
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if (!isspace(in_char)) {
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string_len++;
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} else if (string_len) {
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str_p = (char *)malloc(string_len + 1);
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if (str_p == NULL) {
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return NULL;
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}
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strncpy(str_p, *string_p, string_len);
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str_p[string_len] = 0;
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*string_p += string_len;
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*len -= string_len;
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break;
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} else {
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return NULL;
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}
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}
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}
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return str_p;
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}
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// Parses the string 'cmd_str' into argc/argv format, returning argc.
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// The resulting argv pointers point into the 'cmd_str' string, so any argv
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// entries should not be used after cmd_str is deallocated.
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//
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// Memory pointed to by expr_argv must be explicitly freed by the caller.
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int EXPR_GetArgs(char *cmd_str, char ***expr_argv) {
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int expr_argc;
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expr_argc = EXPR_ParseArgs(cmd_str, NULL);
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*expr_argv = (char **)malloc((expr_argc + 1) * sizeof(**expr_argv));
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if (expr_argv == NULL) {
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return R_FAILURE;
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}
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EXPR_ParseArgs(cmd_str, *expr_argv);
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return expr_argc;
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}
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int EXPR_ParseArgs(char *cmd_str, char **argv) {
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char *bufp;
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int argc;
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argc = 0;
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for (bufp = cmd_str; *bufp;) {
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// Skip leading whitespace
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while (isspace(*bufp)) {
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++bufp;
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}
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// Skip over argument
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if (*bufp == '"') {
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++bufp;
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if (*bufp) {
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if (argv) {
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argv[argc] = bufp;
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}
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++argc;
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}
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// Skip over word
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while (*bufp && (*bufp != '"')) {
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++bufp;
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}
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} else {
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if (*bufp) {
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if (argv) {
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argv[argc] = bufp;
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}
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++argc;
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}
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// Skip over word
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while (*bufp && !isspace(*bufp)) {
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++bufp;
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}
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}
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if (*bufp) {
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if (argv) {
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*bufp = '\0';
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}
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++bufp;
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}
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}
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if (argv) {
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argv[argc] = NULL;
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}
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return (argc);
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}
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} // End of namespace Saga
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