1 files changed, 154 insertions, 0 deletions
diff --git a/src/expr.l b/src/expr.l
new file mode 100644
index 0000000..aa6f538
--- /dev/null
+++ b/src/expr.l
@@ -0,0 +1,154 @@
+%{
+/* $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;
+}
+
+