ReactOS 0.4.15-dev-8348-gc1b9bb5
strtol.c File Reference
#include <precomp.h>
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Functions

long CDECL strtol (const char *nptr, char **endptr, int base)
 

Function Documentation

◆ strtol()

long CDECL strtol ( const char nptr,
char **  endptr,
int  base 
)

Definition at line 8 of file strtol.c.

9{
10 const char *s = nptr;
11 unsigned long acc;
12 int c;
13 unsigned long cutoff;
14 int neg = 0, any, cutlim;
15
16 /*
17 * Skip white space and pick up leading +/- sign if any.
18 * If base is 0, allow 0x for hex and 0 for octal, else
19 * assume decimal; if base is already 16, allow 0x.
20 */
21 do {
22 c = *s++;
23 } while (isspace(c));
24 if (c == '-')
25 {
26 neg = 1;
27 c = *s++;
28 }
29 else if (c == '+')
30 c = *s++;
31 if ((base == 0 || base == 16) &&
32 c == '0' && (*s == 'x' || *s == 'X'))
33 {
34 c = s[1];
35 s += 2;
36 base = 16;
37 }
38 if (base == 0)
39 base = c == '0' ? 8 : 10;
40
41 /*
42 * Compute the cutoff value between legal numbers and illegal
43 * numbers. That is the largest legal value, divided by the
44 * base. An input number that is greater than this value, if
45 * followed by a legal input character, is too big. One that
46 * is equal to this value may be valid or not; the limit
47 * between valid and invalid numbers is then based on the last
48 * digit. For instance, if the range for longs is
49 * [-2147483648..2147483647] and the input base is 10,
50 * cutoff will be set to 214748364 and cutlim to either
51 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
52 * a value > 214748364, or equal but the next digit is > 7 (or 8),
53 * the number is too big, and we will return a range error.
54 *
55 * Set any if any `digits' consumed; make it negative to indicate
56 * overflow.
57 */
58 cutoff = neg ? ((unsigned long)LONG_MAX+1) : LONG_MAX;
59 cutlim = cutoff % (unsigned long)base;
60 cutoff /= (unsigned long)base;
61 for (acc = 0, any = 0;; c = *s++)
62 {
63 if (isdigit(c))
64 c -= '0';
65 else if (isalpha(c))
66 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
67 else
68 break;
69 if (c >= base)
70 break;
71 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
72 any = -1;
73 else
74 {
75 any = 1;
76 acc *= base;
77 acc += c;
78 }
79 }
80 if (any < 0)
81 {
82 acc = neg ? LONG_MIN : LONG_MAX;
83#ifndef _LIBCNT_
85#endif
86 }
87 else if (neg)
88 acc = 0-acc;
89 if (endptr != 0)
90 *endptr = any ? (char *)((size_t)(s - 1)) : (char *)((size_t)nptr);
91 return acc;
92}
#define isspace(c)
Definition: acclib.h:69
#define isalpha(c)
Definition: acclib.h:74
#define isdigit(c)
Definition: acclib.h:68
#define ERANGE
Definition: acclib.h:92
#define isupper(c)
Definition: acclib.h:71
unsigned char
Definition: typeof.h:29
__kernel_size_t size_t
Definition: linux.h:237
GLdouble s
Definition: gl.h:2039
const GLubyte * c
Definition: glext.h:8905
#define LONG_MAX
Definition: limits.h:43
#define LONG_MIN
Definition: limits.h:42
#define c
Definition: ke_i.h:80
#define long
Definition: qsort.c:33
errno_t __cdecl _set_errno(_In_ int _Value)