atokenbuffer.cpp

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/* ANTLRTokenBuffer.C
 *
 * SOFTWARE RIGHTS
 *
 * We reserve no LEGAL rights to the Purdue Compiler Construction Tool
 * Set (PCCTS) -- PCCTS is in the public domain.  An individual or
 * company may do whatever they wish with source code distributed with
 * PCCTS or the code generated by PCCTS, including the incorporation of
 * PCCTS, or its output, into commerical software.
 *
 * We encourage users to develop software with PCCTS.  However, we do ask
 * that credit is given to us for developing PCCTS.  By "credit",
 * we mean that if you incorporate our source code into one of your
 * programs (commercial product, research project, or otherwise) that you
 * acknowledge this fact somewhere in the documentation, research report,
 * etc...  If you like PCCTS and have developed a nice tool with the
 * output, please mention that you developed it using PCCTS.  In
 * addition, we ask that this header remain intact in our source code.
 * As long as these guidelines are kept, we expect to continue enhancing
 * this system and expect to make other tools available as they are
 * completed.
 *
 * ANTLR 1.33
 * Terence Parr
 * Parr Research Corporation
 * with Purdue University and AHPCRC, University of Minnesota
 * 1989-1998
 */

typedef int ANTLRTokenType;  // fool AToken.h into compiling

class ANTLRParser;          /* MR1 */

#define ANTLR_SUPPORT_CODE

#include "pcctscfg.h"

#include ATOKENBUFFER_H
typedef ANTLRAbstractToken *_ANTLRTokenPtr;

#if defined(DBG_TBUF)||defined(DBG_TBUF_MARK_REW)
static unsigned char test[1000];
#endif

#ifdef DBG_REFCOUNTTOKEN
int ANTLRCommonToken::ctor = 0;
int ANTLRCommonToken::dtor = 0;
#endif

ANTLRTokenBuffer::
ANTLRTokenBuffer(ANTLRTokenStream *_input, int _k, int _chunk_size_formal) /* MR14 */
{
  this->input = _input;
  this->k = _k;
  buffer_size = chunk_size = _chunk_size_formal;
  buffer = (_ANTLRTokenPtr *)
       calloc(chunk_size+1,sizeof(_ANTLRTokenPtr ));
  if ( buffer == NULL ) {
    panic("cannot alloc token buffer");
  }
  buffer++;        // leave the first elem empty so tp-1 is valid ptr

  tp = &buffer[0];
  last = tp-1;
  next = &buffer[0];
  num_markers = 0;
  end_of_buffer = &buffer[buffer_size-1];
  // BUGBUG -- threshold = &buffer[(int)(buffer_size*(1.0/2.0))];
  threshold = &buffer[(int)(buffer_size / 2)];
  _deleteTokens = 1;   // assume we delete tokens
  parser=NULL;        // MR5 - uninitialized reference
}

static void f() {;}
ANTLRTokenBuffer::
~ANTLRTokenBuffer()
{
  f();
  // Delete all remaining tokens (from 0..last inclusive)
  if ( _deleteTokens )
  {
    _ANTLRTokenPtr *z;
    for (z=buffer; z<=last; z++)
    {
      (*z)->deref();
//      z->deref();
#ifdef DBG_REFCOUNTTOKEN
          fprintf(stderr, "##########dtor: deleting token '%s' (ref %d)\n",
              ((ANTLRCommonToken *)*z)->getText(), (*z)->nref());
#endif
      if ( (*z)->nref()==0 )
      {
        delete (*z);
      }
    }
  }

  if ( buffer!=NULL ) free((char *)(buffer-1));
}

#if defined(DBG_TBUF)||defined(DBG_TBUF_MARK_REW)
#include "pccts_stdio.h"
PCCTS_NAMESPACE_STD
#endif

_ANTLRTokenPtr ANTLRTokenBuffer::
getToken()
{
  if ( tp <= last )  // is there any buffered lookahead still to be read?
  {
    return *tp++;  // read buffered lookahead
  }
  // out of buffered lookahead, get some more "real"
  // input from getANTLRToken()
  if ( num_markers==0 )
  {
    if( next > threshold )
    {
#ifdef DBG_TBUF
fprintf(stderr,"getToken: next > threshold (high water is %d)\n", threshold-buffer);
#endif
      makeRoom();
    }
  }
  else {
    if ( next > end_of_buffer )
    {
#ifdef DBG_TBUF
fprintf(stderr,"getToken: next > end_of_buffer (size is %d)\n", buffer_size);
#endif
      extendBuffer();
    }
  }
  *next = getANTLRToken();
  (*next)->ref();        // say we have a copy of this pointer in buffer
  last = next;
  next++;
  tp = last;
  return *tp++;
}

void ANTLRTokenBuffer::
rewind(int pos)
{
#if defined(DBG_TBUF)||defined(DBG_TBUF_MARK_REW)
  fprintf(stderr, "rewind(%d)[nm=%d,from=%d,%d.n=%d]\n", pos, num_markers, tp-buffer,pos,test[pos]);
  test[pos]--;
#endif
  tp = &buffer[pos];
  num_markers--;
}

/*
 * This function is used to specify that the token pointers read
 * by the ANTLRTokenBuffer should be buffered up (to be reused later).
 */
int ANTLRTokenBuffer::
mark()
{
#if defined(DBG_TBUF)||defined(DBG_TBUF_MARK_REW)
  test[tp-buffer]++;
  fprintf(stderr,"mark(%d)[nm=%d,%d.n=%d]\n",tp-buffer,num_markers+1,tp-buffer,test[tp-buffer]);
#endif
  num_markers++;
  return tp - buffer;
}

/*
 * returns the token pointer n positions ahead.
 * This implies that bufferedToken(1) gets the NEXT symbol of lookahead.
 * This is used in conjunction with the ANTLRParser lookahead buffer.
 *
 * No markers are set or anything.  A bunch of input is buffered--that's all.
 * The tp pointer is left alone as the lookahead has not been advanced
 * with getToken().  The next call to getToken() will find a token
 * in the buffer and won't have to call getANTLRToken().
 *
 * If this is called before a consume() is done, how_many_more_i_need is
 * set to 'n'.
 */
_ANTLRTokenPtr ANTLRTokenBuffer::
bufferedToken(int n)
{
//  int how_many_more_i_need = (last-tp < 0) ? n : n-(last-tp)-1;
  int how_many_more_i_need = (tp > last) ? n : n-(last-tp)-1;
  // Make sure that at least n tokens are available in the buffer
#ifdef DBG_TBUF
  fprintf(stderr, "bufferedToken(%d)\n", n);
#endif
  for (int i=1; i<=how_many_more_i_need; i++)
  {
    if ( next > end_of_buffer )  // buffer overflow?
    {
      extendBuffer();
    }
    *next = getANTLRToken();
    (*next)->ref();    // say we have a copy of this pointer in buffer
    last = next;
    next++;
  }
  return tp[n - 1];
}

/* If no markers are set, the none of the input needs to be saved (except
 * for the lookahead Token pointers).  We save only k-1 token pointers as
 * we are guaranteed to do a getANTLRToken() right after this because otherwise
 * we wouldn't have needed to extend the buffer.
 *
 * If there are markers in the buffer, we need to save things and so
 * extendBuffer() is called.
 */
void ANTLRTokenBuffer::
makeRoom()
{
#ifdef DBG_TBUF
  fprintf(stderr, "in makeRoom.................\n");
  fprintf(stderr, "num_markers==%d\n", num_markers);
#endif
/*
  if ( num_markers == 0 )
  {
*/
#ifdef DBG_TBUF
    fprintf(stderr, "moving lookahead and resetting next\n");

    _ANTLRTokenPtr *r;
    fprintf(stderr, "tbuf = [");
    for (r=buffer; r<=last; r++)
    {
      if ( *r==NULL ) fprintf(stderr, " xxx");
      else fprintf(stderr, " '%s'", ((ANTLRCommonToken *)*r)->getText());
    }
    fprintf(stderr, " ]\n");

    fprintf(stderr,
    "before: tp=%d, last=%d, next=%d, threshold=%d\n",tp-buffer,last-buffer,next-buffer,threshold-buffer);
#endif

    // Delete all tokens from 0..last-(k-1) inclusive
    if ( _deleteTokens )
    {
      _ANTLRTokenPtr *z;
      for (z=buffer; z<=last-(k-1); z++)
      {
        (*z)->deref();
//        z->deref();
#ifdef DBG_REFCOUNTTOKEN
          fprintf(stderr, "##########makeRoom: deleting token '%s' (ref %d)\n",
              ((ANTLRCommonToken *)*z)->getText(), (*z)->nref());
#endif
        if ( (*z)->nref()==0 )
        {
          delete (*z);
        }
      }
    }

    // reset the buffer to initial conditions, but move k-1 symbols
    // to the beginning of buffer and put new input symbol at k
    _ANTLRTokenPtr *p = buffer, *q = last-(k-1)+1;
//    ANTLRAbstractToken **p = buffer, **q = end_of_buffer-(k-1)+1;
#ifdef DBG_TBUF
    fprintf(stderr, "lookahead buffer = [");
#endif
    for (int i=1; i<=(k-1); i++)
    {
      *p++ = *q++;
#ifdef DBG_TBUF
      fprintf(stderr,
      " '%s'", ((ANTLRCommonToken *)buffer[i-1])->getText());
#endif
    }
#ifdef DBG_TBUF
    fprintf(stderr, " ]\n");
#endif
    next = &buffer[k-1];
    tp = &buffer[k-1];  // tp points to what will be filled in next
    last = tp-1;
#ifdef DBG_TBUF
    fprintf(stderr,
    "after: tp=%d, last=%d, next=%d\n",
    tp-buffer, last-buffer, next-buffer);
#endif
/*
  }
  else {
    extendBuffer();
  }
*/
}

/* This function extends 'buffer' by chunk_size and returns with all
 * pointers at the same relative positions in the buffer (the buffer base
 * address could have changed in realloc()) except that 'next' comes
 * back set to where the next token should be stored.  All other pointers
 * are untouched.
 */
void
ANTLRTokenBuffer::
extendBuffer()
{
  int save_last = last-buffer, save_tp = tp-buffer, save_next = next-buffer;
#ifdef DBG_TBUF
  fprintf(stderr, "extending physical buffer\n");
#endif
  buffer_size += chunk_size;
  buffer = (_ANTLRTokenPtr *)
    realloc((char *)(buffer-1),
        (buffer_size+1)*sizeof(_ANTLRTokenPtr ));
  if ( buffer == NULL ) {
    panic("cannot alloc token buffer");
  }
  buffer++;        // leave the first elem empty so tp-1 is valid ptr

  tp = buffer + save_tp;  // put the pointers back to same relative position
  last = buffer + save_last;
  next = buffer + save_next;
  end_of_buffer = &buffer[buffer_size-1];
  // BUGBUG -- threshold = &buffer[(int)(buffer_size*(1.0/2.0))];
  threshold = &buffer[(int)(buffer_size / 2)];

/*
  // zero out new token ptrs so we'll know if something to delete in buffer
  ANTLRAbstractToken **p = end_of_buffer-chunk_size+1;
  for (; p<=end_of_buffer; p++) *p = NULL;
*/
}

ANTLRParser * ANTLRTokenBuffer::        // MR1
setParser(ANTLRParser *p) {          // MR1
  ANTLRParser  *old=parser;          // MR1
  parser=p;              // MR1
  input->setParser(p);            // MR1
  return old;              // MR1
}                // MR1
                // MR1
ANTLRParser * ANTLRTokenBuffer::        // MR1
getParser() {              // MR1
  return parser;            // MR1
}                // MR1

/* to avoid having to link in another file just for the smart token ptr
 * stuff, we include it here.  Ugh.
 */
#include ATOKPTR_C