100 lines
2.2 KiB
C
100 lines
2.2 KiB
C
/* Erik van der Kouwe, 8 December 2009, based on lib/ansi/strtol.c */
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#include <ctype.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdint.h>
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#include <stdlib.h>
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#ifdef __LONG_LONG_SUPPORTED
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static unsigned long long string2long(const char *nptr, char **endptr,
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int base, int is_signed);
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long long strtoll(const char *nptr, char **endptr, int base)
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{
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return (long long) string2long(nptr, endptr, base, 1);
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}
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unsigned long long strtoull(const char *nptr, char **endptr, int base)
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{
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return (unsigned long long) string2long(nptr, endptr, base, 0);
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}
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#define between(a, c, z) \
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((unsigned long) ((c) - (a)) <= (unsigned long) ((z) - (a)))
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static unsigned long long string2long(const char *nptr, char **const endptr,
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int base, int is_signed)
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{
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unsigned int v;
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unsigned long long val = 0;
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int c;
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int ovfl = 0, sign = 1;
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const char *startnptr = nptr, *nrstart;
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if (endptr) *endptr = (char *)nptr;
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while (isspace(*nptr)) nptr++;
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c = *nptr;
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if (c == '-' || c == '+') {
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if (c == '-') sign = -1;
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nptr++;
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}
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nrstart = nptr; /* start of the number */
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/* When base is 0, the syntax determines the actual base */
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if (base == 0)
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if (*nptr == '0')
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if (*++nptr == 'x' || *nptr == 'X') {
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base = 16;
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nptr++;
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}
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else base = 8;
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else base = 10;
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else if (base==16 && *nptr=='0' && (*++nptr =='x' || *nptr =='X'))
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nptr++;
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for (;;) {
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c = *nptr;
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if (between('0', c, '9')) {
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v = c - '0';
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} else
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if (between('a', c, 'z')) {
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v = c - 'a' + 0xa;
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} else
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if (between('A', c, 'Z')) {
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v = c - 'A' + 0xA;
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} else {
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break;
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}
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if (v >= base) break;
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if (val > (ULLONG_MAX - v) / base) ovfl++;
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val = (val * base) + v;
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nptr++;
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}
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if (endptr) {
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if (nrstart == nptr) *endptr = (char *)startnptr;
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else *endptr = (char *)nptr;
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}
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if (!ovfl) {
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/* Overflow is only possible when converting a signed long. */
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if (is_signed
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&& ((sign < 0 && val > -(unsigned long long)LLONG_MIN)
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|| (sign > 0 && val > LLONG_MAX)))
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ovfl++;
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}
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if (ovfl) {
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errno = ERANGE;
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if (is_signed)
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if (sign < 0) return LLONG_MIN;
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else return LLONG_MAX;
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else return ULLONG_MAX;
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}
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return (long) sign * val;
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}
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#endif /* defined(__LONG_LONG_SUPPORTED) */
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