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74 lines
1.4 KiB
C
74 lines
1.4 KiB
C
#include <precomp.h>
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/*
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* Convert a unicode string to an unsigned long integer.
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*
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* Ignores `locale' stuff. Assumes that the upper and lower case
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* alphabets and digits are each contiguous.
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*
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* @implemented
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*/
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unsigned long
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CDECL
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wcstoul(const wchar_t *nptr, wchar_t **endptr, int base)
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{
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const wchar_t *s = nptr;
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unsigned long acc;
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int c;
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unsigned long cutoff;
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int neg = 0, any, cutlim;
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/*
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* See strtol for comments as to the logic used.
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*/
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do {
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c = *s++;
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} while (iswctype(c, _SPACE));
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if (c == L'-')
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{
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neg = 1;
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c = *s++;
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}
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else if (c == L'+')
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c = *s++;
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if ((base == 0 || base == 16) &&
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c == L'0' && (*s == L'x' || *s == L'X'))
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{
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c = s[1];
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s += 2;
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base = 16;
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}
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if (base == 0)
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base = c == L'0' ? 8 : 10;
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cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
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cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
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for (acc = 0, any = 0;; c = *s++)
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{
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if (iswctype(c, _DIGIT))
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c -= L'0';
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else if (iswctype(c, _ALPHA))
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c -= iswctype(c, _UPPER) ? L'A' - 10 : L'a' - 10;
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else
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break;
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if (c >= base)
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break;
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if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
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any = -1;
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else {
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any = 1;
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acc *= base;
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acc += c;
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}
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}
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if (any < 0)
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{
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acc = ULONG_MAX;
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}
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else if (neg)
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acc = 0-acc;
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if (endptr != 0)
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*endptr = any ? (wchar_t *)((size_t)(s - 1)) : (wchar_t *)((size_t)nptr);
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return acc;
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}
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