nuttx/lib/lib_sscanf.c

/************************************************************
 * lib_sscanf.c
 *
 *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name Gregory Nutt nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ************************************************************/

/************************************************************
 * Included Files
 ************************************************************/

#include <sys/types.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <debug.h>

/************************************************************
 * Definitions
 ************************************************************/

#define MAXLN 128

/************************************************************
 * Private Type Declarations
 ************************************************************/

/************************************************************
 * Private Function Prototypes
 ************************************************************/

/************************************************************
 * Global Function Prototypes
 ************************************************************/

int vsscanf(char *buf, const char *s, va_list ap);

/**********************************************************
 * Global Constant Data
 **********************************************************/

/************************************************************
 * Global Variables
 ************************************************************/

/**********************************************************
 * Private Constant Data
 **********************************************************/

static const char spaces[] = " \t\n\r\f\v";

/************************************************************
 * Private Variables
 ************************************************************/

/************************************************************
 * Function:  sscanf
 *
 * Description:
 *    ANSI standard sscanf implementation.
 *
 ************************************************************/

int sscanf(const char *buf, const char *fmt, ...)
{
  va_list ap;
  int     count;

  va_start(ap, fmt);
  count = vsscanf((char*)buf, fmt, ap);
  va_end(ap);
  return count;

} /* end sscanf */

/************************************************************
 * Function:  vsscanf
 *
 * Description:
 *    ANSI standard vsscanf implementation.
 *
 ************************************************************/
int vsscanf(char *buf, const char *s, va_list ap)
{
  int             count;
  int             noassign;
  int             width;
  int             base = 10;
  int             lflag;
  char           *tv;
  const char     *tc;
  char            tmp[MAXLN];

  vdbg("vsscanf: buf=\"%s\" fmt=\"%s\"\n", buf, s);

  count = noassign = width = lflag = 0;
  while (*s && *buf)
    {
      /* Skip over white space */

      while (isspace(*s))
	s++;

      /* Check for a conversion specifier */

      if (*s == '%')
	{
	  vdbg("vsscanf: Specifier found\n");

	  /* Check for qualifiers on the conversion specifier */
	  s++;
	  for (; *s; s++)
	    {
	      vdbg("vsscanf: Processing %c\n", *s);

	      if (strchr("dibouxcsefg%", *s))
		break;
	      if (*s == '*')
		noassign = 1;
	      else if (*s == 'l' || *s == 'L')
		lflag = 1;
	      else if (*s >= '1' && *s <= '9') {
		for (tc = s; isdigit(*s); s++);
		strncpy(tmp, tc, s - tc);
		tmp[s - tc] = '\0';
		width = atoi(tmp);
		/* atob(&width, tmp, 10); */
		s--;
	      }
	    }

	  /* Process %s:  String conversion */

	  if (*s == 's')
	    {
	      vdbg("vsscanf: Performing string conversion\n");

	      while (isspace(*buf))
		buf++;
	      if (!width)
		{
		  width = strcspn(buf, spaces);
		}
	      if (!noassign)
		{
		  tv = va_arg(ap, char*);
		  strncpy(tv, buf, width);
		  tv[width] = '\0';
		}
	      buf += width;
	    }

	  /* Process %c:  Character conversion */

	  else if (*s == 'c')
	    {
	      vdbg("vsscanf: Performing character conversion\n");

	      if (!width)
		width = 1;
	      if (!noassign)
		{
		  tv = va_arg(ap, char*);
		  strncpy(tv, buf, width);
		  tv[width] = '\0';
		}
	      buf += width;
	    }

	  /* Process %d, %o, %b, %x, %u:  Various integer conversions */

	  else if (strchr("dobxu", *s))
	    {
	      vdbg("vsscanf: Performing integer conversion\n");

	      /* Skip over any white space before the integer string */

	      while (isspace(*buf))
		buf++;

	      /* The base of the integer conversion depends on the specific
	       * conversion specification.
	       */

	      if (*s == 'd' || *s == 'u')
		base = 10;
	      else if (*s == 'x')
		base = 16;
	      else if (*s == 'o')
		base = 8;
	      else if (*s == 'b')
		base = 2;

	      /* Copy the integer string into a temporary working buffer. */

	      if (!width)
		{
		  if (isspace(*(s + 1)) || *(s + 1) == 0)
		    {
		      width = strcspn(buf, spaces);
		    }
		  else
		    {
		      width = strchr(buf, *(s + 1)) - buf;
		    }
		}
	      strncpy(tmp, buf, width);
	      tmp[width] = '\0';

	      vdbg("vsscanf: tmp[]=\"%s\"\n", tmp);

	      /* Perform the integer conversion */

	      buf += width;
	      if (!noassign)
		{
		  int *pint = va_arg(ap, int*);
		  int tmpint = strtol(tmp, NULL, base);
		  vdbg("vsscanf: Return %d to 0x%p\n", tmpint, pint);
		  *pint = tmpint;
		}
	    }

	  /* Process %f:  Floating point conversion */

	  else if (*s == 'f')
	    {
	      vdbg("vsscanf: Performing floating point conversion\n");

	      /* Skip over any white space before the real string */

	      while (isspace(*buf))
		buf++;

	      /* Copy the real string into a temporary working buffer. */

	      if (!width)
		{
		  if (isspace(*(s + 1)) || *(s + 1) == 0)
		    {
		      width = strcspn(buf, spaces);
		    }
		  else
		    {
		      width = strchr(buf, *(s + 1)) - buf;
		    }
		}
	      strncpy(tmp, buf, width);
	      tmp[width] = '\0';
	      buf += width;

	      vdbg("vsscanf: tmp[]=\"%s\"\n", tmp);

	      /* Perform the floating point conversion */

	      if (!noassign)
		{
		  /* strtod always returns a double */

		  double dvalue = strtod(tmp, NULL);
		  void *pv = va_arg(ap, void*);

		  vdbg("vsscanf: Return %f to 0x%p\n", dvalue, pv);

		  /* But we have to check whether we need to return a
		   * float or a double.
		   */

		  if (lflag)
		    {
		      *((double*)pv) = dvalue;
		    }
		  else
		    {
		      *((float*)pv) = (float)dvalue;
		    }
		}
	    }

	  if (!noassign)
	    count++;
	  width = noassign = lflag = 0;
	  s++;
	}

    /* Its is not a conversion specifier */

      else
	{
	  while (isspace(*buf))
	    buf++;
	  if (*s != *buf)
	    break;
	  else
	    s++, buf++;
	}
    }
  return count;
}