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LibC: New implementation of strtol (NIH) (#263)

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Fixes #189.
This commit is contained in:
Christopher Dumas 2019-06-30 21:07:10 -07:00 • committed by Andreas Kling
parent c70fbca23a
commit df34de369b
1 changed files with 35 additions and 49 deletions
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82
LibC/stdlib.cpp
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@ -331,58 +331,44 @@ size_t mbstowcs(wchar_t*, const char*, size_t)
long strtol(const char* str, char** endptr, int base)
{
const char* s = str;
unsigned long acc;
int c;
unsigned long cutoff;
int neg = 0;
int any;
int cutlim;
do {
c = *s++;
} while (isspace(c));
if (c == '-') {
neg = 1;
c = *s++;
} else if (c == '+')
c = *s++;
if ((base == 0 || base == 16) && c == '0' && (*s == 'x' || *s == 'X')) {
c = s[1];
s += 2;
base = 16;
int sign = 1;
while (isspace(*str))
str++;
if (*str == '-' || *str == '+') {
if (*str == '-')
sign = -1;
str++;
}
if (base == 0 || base == 16) {
if (base == 0)
base = c == '0' ? 8 : 10;
cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
cutlim = cutoff % (unsigned long)base;
cutoff /= (unsigned long)base;
for (acc = 0, any = 0;; c = *s++) {
if (isdigit(c))
c -= '0';
else if (isalpha(c))
c -= isupper(c) ? 'A' - 10 : 'a' - 10;
else
break;
if (c >= base)
break;
if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
any = -1;
else {
any = 1;
acc *= base;
acc += c;
base = 10;
if (*str == '0') {
str++;
if (*str == 'X' || *str == 'x') {
str++;
base = 16;
} else if (base != 16) {
base = 8;
}
}
if (any < 0) {
acc = neg ? LONG_MIN : LONG_MAX;
errno = ERANGE;
} else if (neg)
acc = -acc;
if (endptr)
*endptr = const_cast<char*>((any ? s - 1 : str));
return acc;
}
const char* estr = str + strlen(str) - 1;
long track = 1;
long num = 0;
while (estr >= str) {
if ((*estr >= '0' && *estr <= '9') || (base > 10 && (*estr >= 'A' && *estr <= 'Z'))) {
int digit_value = *estr - '0';
if (*estr >= 'A' && *estr <= 'Z')
digit_value = 10 + (*estr - 'A');
num += (track *= base) / base * digit_value;
} else {
if (endptr != NULL)
*endptr = estr;
return 0;
};
estr--;
}
return num * sign;
}
unsigned long strtoul(const char* str, char** endptr, int base)