/tags/Release_1_4_beta/Supermon/src/common/sexpr_0.3.0/io.c

/**
This software and ancillary information (herein called "SOFTWARE")
called Supermon is made available under the terms described
here.  The SOFTWARE has been approved for release with associated
LA-CC Number LA-CC 99-51.

Unless otherwise indicated, this SOFTWARE has been authored by an
employee or employees of the University of California, operator of the
Los Alamos National Laboratory under Contract No.  W-7405-ENG-36 with
the U.S. Department of Energy.  The U.S. Government has rights to use,
reproduce, and distribute this SOFTWARE, and to allow others to do so.
The public may copy, distribute, prepare derivative works and publicly
display this SOFTWARE without charge, provided that this Notice and
any statement of authorship are reproduced on all copies.  Neither the
Government nor the University makes any warranty, express or implied,
or assumes any liability or responsibility for the use of this
SOFTWARE.

If SOFTWARE is modified to produce derivative works, such modified
SOFTWARE should be clearly marked, so as not to confuse it with the
version available from LANL.
**/
/** NOTE: This library is part of the supermon project, hence the name
          supermon above. **/
/***
 * Matt's smaller s-expression parsing library
 *
 * Written by Matt Sottile (matt@lanl.gov), January 2002.
 ***/

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "sexp.h"
#include <assert.h>

/**
 * read_sexp :: same as fread_sexp, except with read vs fgetch.  NOTE:
 * assumes that the expression has at least one pair of outer parens.
 * So it will not read an atom in properly.
 */
int
read_sexp (char *buf, int size, int f)
{
  signed char ch = 0;
  char *sexp;
  int i = 0, depth = 0;
  int numread;
  int sawQuote = 0;
  
  sexp = (char *) malloc (sizeof (char) * size);
  assert(sexp != NULL);
  
  /* read until a '(' */
  do
    {
      numread = read (f, &ch, 1);
    }
  while (ch != '(' && numread == 1);
  
  if (numread < 1) {
    free(sexp);
    return 0;			/* bail! - no sexp here. */
  }

  sexp[i] = ch;
  i++;
  depth++;			/* inc depth since we know we have a '(' */

  while (depth > 0)
    {
      numread = read (f, &ch, 1);
      
      /* if we see an escape character, store it and the character it
         is escaping, and move on. */
      if (ch == '\\') {
        sexp[i] = ch;
        i++;
        
        if (i == size) {
          fprintf(stderr,"read_sexp overran buffer.  %d bytes is too small.\n",
                  size);
          free(sexp);
          return -1;
        }
        
        numread = read(f,&ch,1);
        if (numread < 1) {
          free(sexp);
          return 0;
        } else {
          sexp[i] = ch;
          i++;

          if (i == size) {
            fprintf(stderr,"read_sexp overran buffer.  %d bytes is too small.\n",
                    size);
            free(sexp);
            return -1;
          }

          numread = read(f,&ch,1);
        }
      }

      if (numread < 1) {
        free(sexp);             /* fix leak - thanks smj */
	return 0;		/* bail! */
      }
      
      if (ch == '\"') {
        if (sawQuote == 0)
          sawQuote = 1;
        else
          sawQuote = 0;
      }

      if (ch == ')' && sawQuote == 0)
	depth--;
      else if (ch == '(' && sawQuote == 0)
	depth++;

      /* strip out CR and LF -- I hate them. */
      if (ch != '\n' && ch != '\r')
	{
	  sexp[i] = ch;
	  i++;
	}

      if (i == size) {
        fprintf(stderr,"read_sexp overran buffer.  %d bytes is too small.\n",
                size);
        free(sexp);
        return -1;
      }
    }

  /* null terminate the string */
  sexp[i] = '\0';

  if (i > size)
    {
      strncpy (buf, sexp, size);
      fprintf (stderr, "Warning: read_sexp over buffer size - truncating.\n");
    }
  else
    strncpy (buf, sexp, i + 1);

  free (sexp);

  return 1;
}

/*
 * fread_sexp :: given a FD, read until ( and return the string including the
 * ( to the corresponding ).  return 1 if OK, 0 otherwise.  this is useful,
 * since now we work by sexps, not lines.  So if someone asks for a variable
 * the expression might span multiple lines.  Not hard to deal with.
 * Use this if you're reading from a file or socket and know that the
 * matchine parens for the s-expr might not be on the same line.
 *
 * Return value of 0 = fail, 1 = succeed.
 */
int
fread_sexp (char *buf, int size, FILE * fd)
{
  signed char ch = 0;
  char *sexp;
  int i = 0, depth = 0;
  int sawQuote = 0;

  sexp = (char *) malloc (sizeof (char) * size);
  assert(sexp != NULL);

  /* read until a '(' */
  do
    {
      ch = fgetc (fd);
    }
  while (ch != '(' && ch != EOF);

  if (ch == EOF) { 
    free(sexp);
    return 0;			/* bail! - no sexp here. */
  }

  sexp[i] = ch;
  i++;
  depth++;			/* inc depth since we know we have a '(' */

  while (depth > 0)
    {
      ch = fgetc (fd);

      if (ch == '\"') {
        if (sawQuote == 0)
          sawQuote = 1;
        else
          sawQuote = 0;
      }

      if (ch == '\\') {
        sexp[i] = ch;
        i++;

        if (i == size) {
          fprintf(stderr,"fread_sexp overran buffer.  %d bytes is too small.\n",
                  size);
          free(sexp);             /* fix leak - thanks smj */
          return -1;
        }
        
        ch = fgetc(fd);
        if (ch == EOF) {
          free(sexp);
          return 0;
        } else {
          sexp[i] = ch;
          i++;

          if (i == size) {
            fprintf(stderr,"fread_sexp overran buffer.  %d bytes is too small.\n",
                    size);
            free(sexp);             /* fix leak - thanks smj */
            return -1;
          }
          
          ch = fgetc(fd);
        }
      }

      if (ch == EOF) {
	free(sexp);             /* fix leak - thanks smj */
	return 0;		/* bail! */
      }
      
      if (ch == ')' && sawQuote == 0)
	depth--;
      else if (ch == '(' && sawQuote == 0)
	depth++;

      /* strip out CR and LF -- I hate them. */
      if (ch != '\n' && ch != '\r')
	{
	  sexp[i] = ch;
	  i++;
	}

      if (i == size) {
        fprintf(stderr,"fread_sexp overran buffer.  %d bytes is too small.\n",
                size);
	free(sexp);             /* fix leak - thanks smj */
        return -1;
      }
    }

  /* null terminate the string */
  sexp[i] = '\0';

  if (i > size)
    {
      strncpy (buf, sexp, size);
      fprintf (stderr, "Warning: read_sexp over buffer size - truncating.\n");
    }
  else
    strncpy (buf, sexp, i + 1);

  free (sexp);

  return 1;
}

/**
 * Function that can parse directly from a file descriptor 
 */