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%{
/* $Id: expr.l,v 1.4 2006-11-05 04:42:43 ganzhorn Exp $
* This file is part of lfhex.
* Copyright (C) 2006 Salem Ganzhorn <eyekode@yahoo.com>
*
* 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 version 2.
*
* 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.
*/
#include <math.h>
#include <string>
#include <stdexcept>
#include <iostream>
using namespace std;
#include "expr.h"
#include "expr_yacc.h"
int exprparse();
extern off_t expr_value;
static off_t hex2l( const string &str );
#define yylval exprlval
%}
%option noyywrap
hexnum [0-9a-fA-F]+
%%
[1-9][0-9]* {
yylval = atol(yytext);
return NUMBER;
}
{hexnum} |
0x{hexnum} {
string hexnum = yytext;
if( hexnum.substr(0,2) == "0x" ) {
hexnum = hexnum.substr(2);
}
yylval = hex2l(hexnum);
return NUMBER;
}
[-+*()] { return yytext[0]; }
[ \r\n\t] {/*nop*/}
. { return yytext[0]; }
%%
static off_t
hex2l(
const string &str
)
{
//
off_t ret = 0;
size_t scale = 1;
int i = str.size()-1;
while( i > -1 ) {
switch( str[i] ) {
case '0':
break;
case '1':
ret += 1*scale;
break;
case '2':
ret += 2*scale;
break;
case '3':
ret += 3*scale;
break;
case '4':
ret += 4*scale;
break;
case '5':
ret += 5*scale;
break;
case '6':
ret += 6*scale;
break;
case '7':
ret += 7*scale;
break;
case '8':
ret += 8*scale;
break;
case '9':
ret += 9*scale;
break;
case 'a':
case 'A':
ret += 10*scale;
break;
case 'b':
case 'B':
ret += 11*scale;
break;
case 'c':
case 'C':
ret += 12*scale;
break;
case 'd':
case 'D':
ret += 13*scale;
break;
case 'e':
case 'E':
ret += 14*scale;
break;
case 'f':
case 'F':
ret += 15*scale;
break;
default:
char buf[1024];
sprintf(buf,"Unknown hex char: \"%s\"[%d]",str.c_str(),i);
throw runtime_error(buf);
}
--i;
scale *= 16;
}
return ret;
}
bool
expr_eval(
const string &str,
off_t &retval
)
{
// exprrestart(NULL);
expr_scan_string(str.c_str());
expr_value = 0;
bool status = !exprparse();
retval = expr_value;
return status;
}
|
