glibc/stdlib/strtol.c
1995-02-18 01:27:10 +00:00

190 lines
4.3 KiB
C

/* Copyright (C) 1991, 1992, 1994, 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ctype.h>
#include <limits.h>
#include <stddef.h>
#include <stdlib.h>
#include <errno.h>
/* Nonzero if we are defining `strtoul' or `strtouq', operating on unsigned
integers. */
#ifndef UNSIGNED
#define UNSIGNED 0
#endif
/* If QUAD is defined, we are defining `strtoq' or `strtouq',
operating on `long long int's. */
#ifdef QUAD
#if UNSIGNED
#define strtoul strtouq
#else
#define strtol strtoq
#endif
#define LONG long long
#undef LONG_MIN
#define LONG_MIN LONG_LONG_MIN
#undef LONG_MAX
#define LONG_MAX LONG_LONG_MAX
#undef ULONG_MAX
#define ULONG_MAX ULONG_LONG_MAX
#if __GNUC__ == 2 && __GNUC_MINOR__ < 7
/* Work around gcc bug with using this constant. */
static const unsigned long long int maxquad = ULONG_LONG_MAX;
#undef ULONG_MAX
#define ULONG_MAX maxquad
#endif
#else
#define LONG long
#endif
/* Convert NPTR to an `unsigned long int' or `long int' in base BASE.
If BASE is 0 the base is determined by the presence of a leading
zero, indicating octal or a leading "0x" or "0X", indicating hexadecimal.
If BASE is < 2 or > 36, it is reset to 10.
If ENDPTR is not NULL, a pointer to the character after the last
one converted is stored in *ENDPTR. */
#if UNSIGNED
unsigned LONG int
#define strtol strtoul
#else
LONG int
#endif
strtol (nptr, endptr, base)
const char *nptr;
char **endptr;
int base;
{
int negative;
register unsigned LONG int cutoff;
register unsigned int cutlim;
register unsigned LONG int i;
register const char *s;
register unsigned char c;
const char *save;
int overflow;
if (base < 0 || base == 1 || base > 36)
base = 10;
s = nptr;
/* Skip white space. */
while (isspace (*s))
++s;
if (*s == '\0')
goto noconv;
/* Check for a sign. */
if (*s == '-')
{
negative = 1;
++s;
}
else if (*s == '+')
{
negative = 0;
++s;
}
else
negative = 0;
if (base == 16 && s[0] == '0' && toupper (s[1]) == 'X')
s += 2;
/* If BASE is zero, figure it out ourselves. */
if (base == 0)
if (*s == '0')
{
if (toupper (s[1]) == 'X')
{
s += 2;
base = 16;
}
else
base = 8;
}
else
base = 10;
/* Save the pointer so we can check later if anything happened. */
save = s;
cutoff = ULONG_MAX / (unsigned LONG int) base;
cutlim = ULONG_MAX % (unsigned LONG int) base;
overflow = 0;
i = 0;
for (c = *s; c != '\0'; c = *++s)
{
if (isdigit (c))
c -= '0';
else if (isalpha (c))
c = toupper (c) - 'A' + 10;
else
break;
if (c >= base)
break;
/* Check for overflow. */
if (i > cutoff || (i == cutoff && c > cutlim))
overflow = 1;
else
{
i *= (unsigned LONG int) base;
i += c;
}
}
/* Check if anything actually happened. */
if (s == save)
goto noconv;
/* Store in ENDPTR the address of one character
past the last character we converted. */
if (endptr != NULL)
*endptr = (char *) s;
#if !UNSIGNED
/* Check for a value that is within the range of
`unsigned LONG int', but outside the range of `LONG int'. */
if (i > (negative ?
-(unsigned LONG int) LONG_MIN : (unsigned LONG int) LONG_MAX))
overflow = 1;
#endif
if (overflow)
{
errno = ERANGE;
#if UNSIGNED
return ULONG_MAX;
#else
return negative ? LONG_MIN : LONG_MAX;
#endif
}
/* Return the result of the appropriate sign. */
return (negative ? -i : i);
noconv:
/* There was no number to convert. */
if (endptr != NULL)
*endptr = (char *) nptr;
return 0L;
}