summary refs log tree commit diff
path: root/stdlib/strtol.c
blob: 888a94e4d7f6f0e845d0751d094082da06c90df5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
/* 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;
}