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scan.c

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/*
** LCLint - annotation-assisted static program checker
** Copyright (C) 1994-2000 University of Virginia,
**         Massachusetts Institute of Technology
**
** 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.
** 
** The GNU General Public License is available from http://www.gnu.org/ or
** the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
** MA 02111-1307, USA.
**
** For information on lclint: lclint-request@cs.virginia.edu
** To report a bug: lclint-bug@cs.virginia.edu
** For more information: http://lclint.cs.virginia.edu
*/
/*
** scan.c
**
** Deliver tokens one at a time
**
**      METHOD:
**      The input arrives via LSLScanFreshToken ().
**      The output is reported via LSLScanNextToken ().
**
**      The tokens are built in module ScanLine.
**      The tokens are delivered from this module.
**      Meantimes, they are saved in a static array.
**
**      The tokenizing is split off from the delivery of tokens
**      to facilitate incremental scanning at a later date.
**      The essential is that scanline () can be called or not
**      if the input text is dirty or not.  Clean lines cause
**      tokens to be played out from the saved token list (not
**      yet implemented in this version).
*/

# include "lclintMacros.nf"
# include "llbasic.h"
# include "signature.h"
# include "signature2.h"
# include "scan.h"
# include "scanline.h"

extern /*@external@*/ /*@unused@*/ YYSTYPE lsllval;

static /*@exposed@*/ ltoken LSLScanLookAhead (void);
static tsource *scanFile;         /* file to scan */
static o_ltoken TokenList[MAXLINE]; /* available tokens */
static int nextToken;             /* next available token */
static int lastToken;             /* next available slot */

static /*@dependent@*/ /*@null@*/ char *line;   /* input text */
static unsigned int lineNumber; /* current line number */

unsigned int lsllex (YYSTYPE *lval)
{
  /* This is important!  Bison expects this */
  lval->ltok = LSLScanNextToken ();
  return (ltoken_getCode (lval->ltok));
}

ltoken LSLScanNextToken (void)
{
  
  if (nextToken < lastToken)
    {   
      /*@-retalias@*/
            return TokenList[nextToken++];
      /*@=retalias@*/
    }
  else
    {
      lastToken = 0;            
      lineNumber++;

      line = tsource_nextLine (scanFile);       
      
      if (line != (char *) 0)
        {
                  lscanLine (line);     /* tokenize */
          nextToken = 0;
          return LSLScanNextToken ();   
        }
      else
        {
                  return LSLScanEofToken ();
        }
    }
}

static /*@exposed@*/ ltoken
LSLScanLookAhead (void)
{
  if (nextToken < lastToken)
    {           
      return TokenList[nextToken];
    }
  else
    {
      lastToken = 0;            
      line = tsource_nextLine (scanFile);

      if (line != (char *) 0)
        {
          lscanLine (line);     
          nextToken = 0;        
          return LSLScanLookAhead ();   
        }
      else
        {
          /* 
          ** This is a real memory leak.  Its only a few bytes
          ** per file though, and lsl files are hardly ever used.
          */

          /*@-onlytrans@*/ 
          return LSLScanEofToken ();
          /*@=onlytrans@*/
        }
    }
}

void
LSLScanFreshToken (ltoken tok)
{
  if (lastToken < MAXLINE)
    {                           
      TokenList[lastToken++] = ltoken_copy (tok);       
    }
  else
    {
      llfatalbug (message ("LSLScanFreshToken: out of range: %s", 
                           cstring_fromChars (lsymbol_toChars (ltoken_getText (tok)))));
    }
}

/*@exposed@*/ tsource *LSLScanSource (void)
{
  return scanFile;
}


void
LSLScanInit (void)
{
}

void
LSLScanReset (tsource *s)
{
  scanFile = s;
  lastToken = 0;
  nextToken = lastToken + 1;    /* force call to scanline   */
  lineNumber = 0;
}

void
LSLScanCleanup (void)
{
}

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