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fix(NumberParser): Rounds very large negative numbers to the incorrect values #3580

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This commit is contained in:
Alex Fabijanic
2022-06-22 12:12:30 +02:00
parent 47f2c3573c
commit 5cbe30e199
2 changed files with 20 additions and 34 deletions
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41
Foundation/include/Poco/NumericString.h
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@@ -33,7 +33,8 @@
#if !defined(POCO_NO_LOCALE)
#include <locale>
#endif
#include <iostream>
#include <iomanip>
#if defined(POCO_NOINTMAX)
typedef Poco::UInt64 uintmax_t;
typedef Poco::Int64 intmax_t;
@@ -188,26 +189,10 @@ bool strToInt(const char* pStr, I& outResult, short base, char thSep = ',')
}
else if (*pStr == '+') ++pStr;
// all numbers are parsed as positive; the sign
// for negative numbers is adjusted after parsing
uintmax_t limitCheck = std::numeric_limits<I>::max();
if (negative)
{
poco_assert_dbg(std::numeric_limits<I>::is_signed);
// to cover the entire range, (-min > max) has to be
// taken into account;
// to avoid overflow for the largest int size,
// we resort to FPEnvironment::copySign() (ie. floating-point)
if (sizeof(I) == sizeof(intmax_t))
limitCheck = static_cast<uintmax_t>(FPEnvironment::copySign(static_cast<double>(std::numeric_limits<I>::min()), 1));
else
{
intmax_t i = std::numeric_limits<I>::min();
limitCheck = -i;
}
}
uintmax_t result = 0;
// numbers are parsed as unsigned, for negative numbers the sign is applied after parsing
// overflow is checked in every parse step
uintmax_t limitCheck = negative ? -std::numeric_limits<I>::min() : std::numeric_limits<I>::max();
I result = 0;
for (; *pStr != '\0'; ++pStr)
{
if (result > (limitCheck / base)) return false;
@@ -268,21 +253,9 @@ bool strToInt(const char* pStr, I& outResult, short base, char thSep = ',')
}
if (negative && (base == 10))
{
poco_assert_dbg(std::numeric_limits<I>::is_signed);
intmax_t i;
if (sizeof(I) == sizeof(intmax_t))
i = static_cast<intmax_t>(FPEnvironment::copySign(static_cast<double>(result), -1));
outResult = static_cast<I>(-result);
else
i = static_cast<intmax_t>(-result);
if (isIntOverflow<I>(i)) return false;
outResult = static_cast<I>(i);
}
else
{
if (isIntOverflow<I>(result)) return false;
outResult = static_cast<I>(result);
}
return true;
}

13
Foundation/testsuite/src/NumberParserTest.cpp
View File

@@ -188,6 +188,19 @@ void NumberParserTest::testLimits()
assertTrue (testLowerLimit64<Int64>());
assertTrue (testUpperLimit64<UInt64>());
#endif
Poco::Int64 val1, val2;
// smallest 64-bit int is actually -9223372036854775808
// but the sign and number are parsed as two tokens,
// resulting in compiler warning, for explanation see
// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52661
NumberParser::tryParse64("-9223372036854775807", val1);
NumberParser::tryParse64("9223372036854775807", val2);
assertTrue (val1 == -9223372036854775807LL);
assertTrue (val2 == 9223372036854775807LL);
int i;
assertFalse (NumberParser::tryParse("-9223372036854775807", i));
assertFalse (NumberParser::tryParse("9223372036854775807", i));
}