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Support INF and NAN in locale-independent dmlc::strtof
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@hcho3
hcho3 committed Mar 3, 2019
1 parent ea0f2c3 commit 8afbca6
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Showing 2 changed files with 87 additions and 8 deletions.
66 changes: 58 additions & 8 deletions include/dmlc/strtonum.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,19 @@ inline bool isdigit(char c) {
return (c >= '0' && c <= '9');
}

/*!
* \brief Inline implementation of isalpha(). Tests whether the given character
* is an alphabet letter
* \param c Character to test
* \return Result of the test
*/
inline bool isalpha(char c) {
static_assert(
static_cast<int>('A') == 65 && static_cast<int>('Z' - 'A') == 25,
"Only system with ASCII character set is supported");
return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
}

/*!
* \brief Tests whether the given character is a valid letter in the string
* representation of a floating-point value, i.e. decimal digits,
Expand All @@ -69,7 +82,7 @@ const int kStrtofMaxDigits = 19;

/*!
* \brief Common implementation for dmlc::strtof() and dmlc::strtod()
* TODO: the current version does not support INF, NAN, and hex number
* TODO: the current version does not support hex number
* \param nptr Beginning of the string that's to be converted into a
* floating-point number
* \param endptr After the conversion, this pointer will be set to point one
Expand Down Expand Up @@ -123,6 +136,43 @@ inline FloatType ParseFloat(const char* nptr, char** endptr) {
++p;
}

// Handle INF and NAN
{
int i = 0;
// case-insensitive match for INF and INFINITY
while (i < 8 && static_cast<char>((*p) | 32) == "infinity"[i]) {
++i; ++p;
}
if (i == 3 || i == 8) {
if (endptr) *endptr = (char*)p; // NOLINT(*)
return sign ? std::numeric_limits<FloatType>::infinity()
: -std::numeric_limits<FloatType>::infinity();
} else {
p -= i;
}

// case-insensitive match for NAN
i = 0;
while (i < 3 && static_cast<char>((*p) | 32) == "nan"[i]) {
++i; ++p;
}
if (i == 3) {
// Got NAN; check if the value is of form NAN(char_sequence)
if (*p == '(') {
++p;
while (isdigit(*p) || isalpha(*p) || *p == '_') ++p;
CHECK_EQ(*p, ')') << "Invalid NAN literal";
++p;
}
static_assert(std::numeric_limits<FloatType>::has_quiet_NaN,
"Only system with quiet NaN is supported");
if (endptr) *endptr = (char*)p; // NOLINT(*)
return std::numeric_limits<FloatType>::quiet_NaN();
} else {
p -= i;
}
}

// Get digits before decimal point or exponent, if any.
uint64_t predec; // to store digits before decimal point
for (predec = 0; isdigit(*p); ++p) {
Expand Down Expand Up @@ -206,7 +256,7 @@ inline FloatType ParseFloat(const char* nptr, char** endptr) {
* \brief A faster implementation of strtof(). See documentation of
* std::strtof() for more information. Note that this function does not
* check for overflow. Use strtof_check_range() to check for overflow.
* TODO: the current version does not support INF, NAN, and hex number
* TODO: the current version does not support hex number
* TODO: the current version does not handle long decimals: you may only have
* up to 19 digits after the decimal point, and you cannot have too many
* digits before the decimal point either.
Expand All @@ -224,7 +274,7 @@ inline float strtof(const char* nptr, char** endptr) {
* std::strtof() for more information. This function will check for
* overflow. If the converted value is outside the range for the float
* type, errno is set to ERANGE and HUGE_VALF is returned.
* TODO: the current version does not support INF, NAN, and hex number
* TODO: the current version does not support hex number
* TODO: the current version does not handle long decimals: you may only have
* up to 19 digits after the decimal point, and you cannot have too many
* digits before the decimal point either.
Expand All @@ -241,7 +291,7 @@ inline float strtof_check_range(const char* nptr, char** endptr) {
* \brief A faster implementation of strtod(). See documentation of
* std::strtof() for more information. Note that this function does not
* check for overflow. Use strtod_check_range() to check for overflow.
* TODO: the current version does not support INF, NAN, and hex number
* TODO: the current version does not support hex number
* TODO: the current version does not handle long decimals: you may only have
* up to 19 digits after the decimal point, and you cannot have too many
* digits before the decimal point either.
Expand All @@ -259,7 +309,7 @@ inline double strtod(const char* nptr, char** endptr) {
* std::strtod() for more information. This function will check for
* overflow. If the converted value is outside the range for the double
* type, errno is set to ERANGE and HUGE_VAL is returned.
* TODO: the current version does not support INF, NAN, and hex number
* TODO: the current version does not support hex number
* TODO: the current version does not handle long decimals: you may only have
* up to 19 digits after the decimal point, and you cannot have too many
* digits before the decimal point either.
Expand Down Expand Up @@ -388,7 +438,7 @@ inline long atol(const char* p) { // NOLINT(*)
/*!
* \brief A faster implementation of atof(). Unlike std::atof(), this function
* returns float type. Note that this function does not check for overflow.
* TODO: the current version does not support INF, NAN, and hex number
* TODO: the current version does not support hex number
* TODO: the current version does not handle long decimals: you may only have
* up to 19 digits after the decimal point, and you cannot have too many
* digits before the decimal point either.
Expand All @@ -403,7 +453,7 @@ inline float atof(const char* nptr) {
* \brief A faster implementation of stof(). See documentation of std::stof()
* for more information. This function will test for overflow and
* invalid arguments.
* TODO: the current version does not support INF, NAN, and hex number
* TODO: the current version does not support hex number
* TODO: the current version does not handle long decimals: you may only have
* up to 19 digits after the decimal point, and you cannot have too many
* digits before the decimal point either.
Expand Down Expand Up @@ -433,7 +483,7 @@ inline float stof(const std::string& value, size_t* pos = nullptr) {
* \brief A faster implementation of stod(). See documentation of std::stod()
* for more information. This function will test for overflow and
* invalid arguments.
* TODO: the current version does not support INF, NAN, and hex number
* TODO: the current version does not support hex number
* TODO: the current version does not handle long decimals: you may only have
* up to 19 digits after the decimal point, and you cannot have too many
* digits before the decimal point either.
Expand Down
29 changes: 29 additions & 0 deletions test/unittest/unittest_param.cc
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,8 @@
#include <gtest/gtest.h>
#include <dmlc/parameter.h>
#include <vector>
#include <string>
#include <cmath>

struct LearningParam : public dmlc::Parameter<LearningParam> {
float float_param;
Expand Down Expand Up @@ -121,4 +124,30 @@ TEST(Parameter, parsing_float) {
ASSERT_THROW(param.Init(kwargs), dmlc::ParamError);
kwargs["double_param"] = "1.2e-2 foo";
ASSERT_THROW(param.Init(kwargs), dmlc::ParamError);

// INF and NAN
kwargs = std::map<std::string, std::string>();
errno = 0; // clear errno, to clear previous range error
for (const char* s : {
"inf", "+inf", "-inf", "INF", "+INF", "-INF", "infinity", "+infinity",
"-infinity", "INFINITY", "+INFINITY", "-INFINITY"}) {
kwargs["float_param"] = s;
ASSERT_NO_THROW(param.Init(kwargs));
ASSERT_TRUE(std::isinf(param.float_param));
kwargs["double_param"] = s;
ASSERT_NO_THROW(param.Init(kwargs));
ASSERT_TRUE(std::isinf(param.double_param));
}
for (const char* s : {
"nan", "NAN", "nan(foobar)", "NAN(FooBar)", "NaN", "NaN(foo_bar_12)",
"+nan", "+NAN", "+nan(foobar)", "+NAN(FooBar)", "+NaN", "+NaN(foo_bar_12)",
"-nan", "-NAN", "-nan(foobar)", "-NAN(FooBar)", "-NaN",
"-NaN(foo_bar_12)"}) {
kwargs["float_param"] = s;
ASSERT_NO_THROW(param.Init(kwargs));
ASSERT_TRUE(std::isnan(param.float_param));
kwargs["double_param"] = s;
ASSERT_NO_THROW(param.Init(kwargs));
ASSERT_TRUE(std::isnan(param.double_param));
}
}

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