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AK: Add formatting for infinity and NaN

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Without this patch, we would end up printing garbage values when we
encountered floating point infinity or NaN values, and also triggered
UBSAN with Clang. This added code models `std::format`'s behavior: the
sign is added the same way as with normal values and the strings 'nan'
and 'inf' are printed.
This commit is contained in:
Daniel Bertalan 2021-08-06 21:47:49 +02:00 • committed by Andreas Kling
parent 12dc2c2079
commit 1472f6d986
1 changed files with 33 additions and 0 deletions
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33
AK/Format.cpp
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@ -19,6 +19,7 @@
# include <Kernel/Process.h>
# include <Kernel/Thread.h>
#else
# include <math.h>
# include <stdio.h>
# include <string.h>
#endif
@ -344,6 +345,22 @@ void FormatBuilder::put_f64(
StringBuilder string_builder;
FormatBuilder format_builder { string_builder };
if (isnan(value) || isinf(value)) [[unlikely]] {
if (value < 0.0)
string_builder.append('-');
else if (sign_mode == SignMode::Always)
string_builder.append('+');
else
string_builder.append(' ');
if (isnan(value))
string_builder.append(upper_case ? "NAN"sv : "nan"sv);
else
string_builder.append(upper_case ? "INF"sv : "inf"sv);
format_builder.put_string(string_builder.string_view(), align, min_width, NumericLimits<size_t>::max(), fill);
return;
}
bool is_negative = value < 0.0;
if (is_negative)
value = -value;
@ -394,6 +411,22 @@ void FormatBuilder::put_f80(
StringBuilder string_builder;
FormatBuilder format_builder { string_builder };
if (isnan(value) || isinf(value)) [[unlikely]] {
if (value < 0.0l)
string_builder.append('-');
else if (sign_mode == SignMode::Always)
string_builder.append('+');
else
string_builder.append(' ');
if (isnan(value))
string_builder.append(upper_case ? "NAN"sv : "nan"sv);
else
string_builder.append(upper_case ? "INF"sv : "inf"sv);
format_builder.put_string(string_builder.string_view(), align, min_width, NumericLimits<size_t>::max(), fill);
return;
}
bool is_negative = value < 0.0l;
if (is_negative)
value = -value;