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LibC: Implement strtoull correctly

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This fixes the behavior for several inputs:
- '-0' (shouldn't work but was accepted)
- '+3' (shouldn't work but was accepted)
- '13835058055282163712' (should work but returned 9223372036854775807 with errno=ERANGE)
This commit is contained in:
Ben Wiederhake 2020-05-10 23:45:58 +02:00 • committed by Andreas Kling
parent 4bff3defa8
commit 71fd752289
1 changed files with 68 additions and 6 deletions
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74
Libraries/LibC/stdlib.cpp
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@ -107,7 +107,7 @@ public:
else
return -1;
if (digit >= m_base)
if (static_cast<T>(digit) >= m_base)
return -1;
return digit;
@ -161,6 +161,7 @@ private:
typedef NumParser<int, INT_MIN, INT_MAX> IntParser;
typedef NumParser<long long, LONG_LONG_MIN, LONG_LONG_MAX> LongLongParser;
typedef NumParser<unsigned long long, 0ULL, ULONG_LONG_MAX> ULongLongParser;
static bool is_either(char* str, int offset, char lower, char upper)
{
@ -942,11 +943,72 @@ long long strtoll(const char* str, char** endptr, int base)
unsigned long long strtoull(const char* str, char** endptr, int base)
{
auto value = strtoll(str, endptr, base);
// TODO: strtoull should not accept a sign character at all,
// not in `-0` and not even `+3`.
ASSERT(value >= 0);
return value;
// Parse spaces and sign
char* parse_ptr = const_cast<char*>(str);
strtons(parse_ptr, &parse_ptr);
// Parse base
if (base == 0) {
if (*parse_ptr == '0') {
parse_ptr += 1;
if (*parse_ptr == 'x' || *parse_ptr == 'X') {
base = 16;
parse_ptr += 2;
} else {
base = 8;
}
} else {
base = 10;
}
}
// Parse actual digits.
ULongLongParser digits { Sign::Positive, base };
bool digits_usable = false;
bool should_continue = true;
bool overflow = false;
do {
bool is_a_digit;
if (overflow) {
is_a_digit = digits.parse_digit(*parse_ptr) >= 0;
} else {
DigitConsumeDecision decision = digits.consume(*parse_ptr);
switch (decision) {
case DigitConsumeDecision::Consumed:
is_a_digit = true;
// The very first actual digit must pass here:
digits_usable = true;
break;
case DigitConsumeDecision::PosOverflow: // fall-through
case DigitConsumeDecision::NegOverflow:
is_a_digit = true;
overflow = true;
break;
case DigitConsumeDecision::Invalid:
is_a_digit = false;
break;
default:
ASSERT_NOT_REACHED();
}
}
should_continue = is_a_digit;
parse_ptr += should_continue;
} while (should_continue);
if (!digits_usable) {
// No actual number value available.
if (endptr)
*endptr = const_cast<char*>(str);
return 0;
}
if (overflow) {
errno = ERANGE;
return LONG_LONG_MAX;
}
return digits.number();
}
// Serenity's PRNG is not cryptographically secure. Do not rely on this for