xstrtol.c

gnu tar 源码包。 tar 软件是 Unix 系统下的一个打包软件

/* A more useful interface to strtol.

   Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2003, 2004, 2005,
   2006, 2007 Free Software Foundation, Inc.

   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 3 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.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Written by Jim Meyering. */

#ifndef __strtol
# define __strtol strtol
# define __strtol_t long int
# define __xstrtol xstrtol
# define STRTOL_T_MINIMUM LONG_MIN
# define STRTOL_T_MAXIMUM LONG_MAX
#endif

#include <config.h>

#include "xstrtol.h"

/* Some pre-ANSI implementations (e.g. SunOS 4)
   need stderr defined if assertion checking is enabled.  */
#include <stdio.h>

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>

#include "intprops.h"

static strtol_error
bkm_scale (__strtol_t *x, int scale_factor)
{
  if (TYPE_SIGNED (__strtol_t) && *x < STRTOL_T_MINIMUM / scale_factor)
    {
      *x = STRTOL_T_MINIMUM;
      return LONGINT_OVERFLOW;
    }
  if (STRTOL_T_MAXIMUM / scale_factor < *x)
    {
      *x = STRTOL_T_MAXIMUM;
      return LONGINT_OVERFLOW;
    }
  *x *= scale_factor;
  return LONGINT_OK;
}

static strtol_error
bkm_scale_by_power (__strtol_t *x, int base, int power)
{
  strtol_error err = LONGINT_OK;
  while (power--)
    err |= bkm_scale (x, base);
  return err;
}

/* FIXME: comment.  */

strtol_error
__xstrtol (const char *s, char **ptr, int strtol_base,
	   __strtol_t *val, const char *valid_suffixes)
{
  char *t_ptr;
  char **p;
  __strtol_t tmp;
  strtol_error err = LONGINT_OK;

  assert (0 <= strtol_base && strtol_base <= 36);

  p = (ptr ? ptr : &t_ptr);

  if (! TYPE_SIGNED (__strtol_t))
    {
      const char *q = s;
      unsigned char ch = *q;
      while (isspace (ch))
	ch = *++q;
      if (ch == '-')
	return LONGINT_INVALID;
    }

  errno = 0;
  tmp = __strtol (s, p, strtol_base);

  if (*p == s)
    {
      /* If there is no number but there is a valid suffix, assume the
	 number is 1.  The string is invalid otherwise.  */
      if (valid_suffixes && **p && strchr (valid_suffixes, **p))
	tmp = 1;
      else
	return LONGINT_INVALID;
    }
  else if (errno != 0)
    {
      if (errno != ERANGE)
	return LONGINT_INVALID;
      err = LONGINT_OVERFLOW;
    }

  /* Let valid_suffixes == NULL mean `allow any suffix'.  */
  /* FIXME: update all callers except the ones that allow suffixes
     after the number, changing last parameter NULL to `""'.  */
  if (!valid_suffixes)
    {
      *val = tmp;
      return err;
    }

  if (**p != '\0')
    {
      int base = 1024;
      int suffixes = 1;
      strtol_error overflow;

      if (!strchr (valid_suffixes, **p))
	{
	  *val = tmp;
	  return err | LONGINT_INVALID_SUFFIX_CHAR;
	}

      if (strchr (valid_suffixes, '0'))
	{
	  /* The ``valid suffix'' '0' is a special flag meaning that
	     an optional second suffix is allowed, which can change
	     the base.  A suffix "B" (e.g. "100MB") stands for a power
	     of 1000, whereas a suffix "iB" (e.g. "100MiB") stands for
	     a power of 1024.  If no suffix (e.g. "100M"), assume
	     power-of-1024.  */

	  switch (p[0][1])
	    {
	    case 'i':
	      if (p[0][2] == 'B')
		suffixes += 2;
	      break;

	    case 'B':
	    case 'D': /* 'D' is obsolescent */
	      base = 1000;
	      suffixes++;
	      break;
	    }
	}

      switch (**p)
	{
	case 'b':
	  overflow = bkm_scale (&tmp, 512);
	  break;

	case 'B':
	  overflow = bkm_scale (&tmp, 1024);
	  break;

	case 'c':
	  overflow = 0;
	  break;

	case 'E': /* exa or exbi */
	  overflow = bkm_scale_by_power (&tmp, base, 6);
	  break;

	case 'G': /* giga or gibi */
	case 'g': /* 'g' is undocumented; for compatibility only */
	  overflow = bkm_scale_by_power (&tmp, base, 3);
	  break;

	case 'k': /* kilo */
	case 'K': /* kibi */
	  overflow = bkm_scale_by_power (&tmp, base, 1);
	  break;

	case 'M': /* mega or mebi */
	case 'm': /* 'm' is undocumented; for compatibility only */
	  overflow = bkm_scale_by_power (&tmp, base, 2);
	  break;

	case 'P': /* peta or pebi */
	  overflow = bkm_scale_by_power (&tmp, base, 5);
	  break;

	case 'T': /* tera or tebi */
	case 't': /* 't' is undocumented; for compatibility only */
	  overflow = bkm_scale_by_power (&tmp, base, 4);
	  break;

	case 'w':
	  overflow = bkm_scale (&tmp, 2);
	  break;

	case 'Y': /* yotta or 2**80 */
	  overflow = bkm_scale_by_power (&tmp, base, 8);
	  break;

	case 'Z': /* zetta or 2**70 */
	  overflow = bkm_scale_by_power (&tmp, base, 7);
	  break;

	default:
	  *val = tmp;
	  return err | LONGINT_INVALID_SUFFIX_CHAR;
	}

      err |= overflow;
      *p += suffixes;
      if (**p)
	err |= LONGINT_INVALID_SUFFIX_CHAR;
    }

  *val = tmp;
  return err;
}