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Implemented a slower but shorter version of MathLib::isNullValue() as suggested by PKeuS. Removed not needed test cases. Improved doxygen documentation for MathLib::IsNullValue().

This commit is contained in:
orbitcowboy 2014-04-14 05:27:38 +02:00
parent 28751c8ad0
commit 3d0217b69e
2 changed files with 19 additions and 107 deletions
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109
lib/mathlib.cpp
View File

@ -645,100 +645,27 @@ bool MathLib::isLessEqual(const std::string &first, const std::string &second)
return toDoubleNumber(first) <= toDoubleNumber(second);
}
bool MathLib::isNullValue(const std::string &s)
/*! \brief Does the string represent the numerical value of 0?
* In case leading or trailing white space is provided, the function
* returns false.
* Requirement for this function:
* - This code is allowed to be slow because of simplicity of the code.
*
* \param[in] str The string to check. In case the string is empty, the function returns false.
* \return Return true in case the string represents a numerical null value.
**/
bool MathLib::isNullValue(const std::string &str)
{
enum {START, PLUSMINUS, LEADING_ZERO, BIN_OR_HEX_PREFIX, DOT, TRAILING_ZERO, TRAILING_F, ZERO, E, E_PLUSMINUS, E_DIGIT} state = START;
for (std::string::const_iterator it = s.begin(); it != s.end(); ++it) {
switch (state) {
case START:
if (*it == '+' || *it == '-')
state = PLUSMINUS;
else if (*it == '0')
state = LEADING_ZERO;
else if (*it == '.')
state = DOT;
else
return false;
break;
case PLUSMINUS:
if (*it == '0')
state = LEADING_ZERO;
else
return false;
break;
case LEADING_ZERO:
if (*it == '0')
state = LEADING_ZERO;
else if (*it == 'b' || *it == 'B')
state = BIN_OR_HEX_PREFIX;
else if (*it == 'x' || *it == 'X')
state = BIN_OR_HEX_PREFIX;
else if (*it == '.')
state = DOT;
else if (*it == 'e' || *it == 'E')
state = E;
else
return isValidSuffix(it, s.end());
break;
case BIN_OR_HEX_PREFIX:
if (*it == '0')
state = ZERO;
else
return false;
break;
case ZERO:
if (*it == '0')
state = ZERO;
else
return isValidSuffix(it, s.end());
break;
case DOT:
if (*it == '0')
state = TRAILING_ZERO;
else if (*it == 'f' || *it == 'F')
state = TRAILING_F;
else if (*it == 'e' || *it == 'E')
state = E;
else
return false;
break;
case E:
if (*it == '+' || *it == '-')
state = E_PLUSMINUS;
else if (isdigit(*it))
state = E_DIGIT;
else
return false;
break;
case E_PLUSMINUS:
if (isdigit(*it))
state = E_DIGIT;
else
return false;
break;
case E_DIGIT:
if (isdigit(*it))
state = E_DIGIT;
else if (*it == 'f' || *it == 'F')
state = TRAILING_F;
else
return false;
break;
case TRAILING_ZERO:
if (*it == '0')
state = TRAILING_ZERO;
else if (*it == 'f' || *it == 'F')
state = TRAILING_F;
else if (*it == 'e' || *it == 'E')
state = E;
else
return false;
break;
default:
if (str.empty() || (!std::isdigit(static_cast<unsigned char>(str[0])) && (str.size() < 1 || (str[0] != '.' && str[0] != '-' && str[0] != '+'))))
return false; // Has to be a number
for (size_t i = 0; i < str.size(); i++) {
if (std::isdigit(static_cast<unsigned char>(str[i])) && str[i] != '0') // May not contain digits other than 0
return false;
if (str[i] == 'E' || str[i] == 'e')
return true;
}
}
return state == LEADING_ZERO || state == ZERO || state == DOT || state == E_DIGIT || state == TRAILING_ZERO || state == TRAILING_F;
return true;
}
bool MathLib::isOctalDigit(char c)

17
test/testmathlib.cpp
View File

@ -766,25 +766,10 @@ private:
ASSERT_EQUALS(false, MathLib::isNullValue("-00.01e-12"));
ASSERT_EQUALS(false, MathLib::isNullValue("-00.01e+12"));
ASSERT_EQUALS(false, MathLib::isNullValue(""));
ASSERT_EQUALS(false, MathLib::isNullValue(" "));
ASSERT_EQUALS(false, MathLib::isNullValue("x"));
ASSERT_EQUALS(false, MathLib::isNullValue("garbage"));
ASSERT_EQUALS(false, MathLib::isNullValue("UL"));
ASSERT_EQUALS(false, MathLib::isNullValue("0x"));
ASSERT_EQUALS(false, MathLib::isNullValue("0xx"));
ASSERT_EQUALS(false, MathLib::isNullValue("0x0x"));
ASSERT_EQUALS(false, MathLib::isNullValue("0x000x"));
ASSERT_EQUALS(false, MathLib::isNullValue("0b"));
ASSERT_EQUALS(false, MathLib::isNullValue("0bx"));
ASSERT_EQUALS(false, MathLib::isNullValue("0b0x"));
ASSERT_EQUALS(false, MathLib::isNullValue("0b000x"));
ASSERT_EQUALS(false, MathLib::isNullValue("0.0Ex"));
ASSERT_EQUALS(false, MathLib::isNullValue("0.0E-x"));
ASSERT_EQUALS(false, MathLib::isNullValue("0.0E-1x"));
ASSERT_EQUALS(false, MathLib::isNullValue("0.0E-1fx"));
// suffix LUL is not allowed
ASSERT_EQUALS(false, MathLib::isNullValue("0LUL"));
ASSERT_EQUALS(false, MathLib::isNullValue("+0LUL"));
ASSERT_EQUALS(false, MathLib::isNullValue("-0LUL"));
}
};