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fix(libc): preserve zero in alternate wide octal formatting #8440

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Merged
oneandonlydean merged 1 commit into from
Oct 20, 2026
+28 −0
Merged

fix(libc): preserve zero in alternate wide octal formatting #8440

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2 changes: 2 additions & 0 deletions core/libs/prx/libc/src/FormattingWide.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -167,6 +167,8 @@ std::u16string FormatWide(const char16_t* format, VaList* source, bool secure =
if (length == "h") value = static_cast<unsigned short>(value);
if (length == "hh") value = static_cast<unsigned char>(value);
} else value = args.Next<unsigned long long>();
if (conversion == u'o' && value == 0 && precision == 0 && spec.find('#') != std::string::npos)
spec = spec.substr(0, spec.find('.')) + ".1";
AppendNumber(out, spec + "ll" + static_cast<char>(conversion), value);
} else if (In(conversion, "aAeEfFgG")) {
if (length == "L") AppendNumber(out, spec + "L" + static_cast<char>(conversion), args.Next<long double>());
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26 changes: 26 additions & 0 deletions core/libs/tests/GuestWideFormatting.cpp
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Expand Up @@ -276,7 +276,33 @@ static void CheckWcsftime() {
Require(WcsftimeThrows(buffer, u"%Y", nullptr), "wcsftime null time");
}

static void CheckAlternateOctalZero() {
struct Case { const char16_t* format; const char16_t* expected; unsigned value; };
for (const auto& test : {
Case{u"%#.0o", u"0", 0}, Case{u"%#.o", u"0", 0}, Case{u"%#.00o", u"0", 0},
Case{u"[%#5.0o]", u"[ 0]", 0}, Case{u"[%-#5.0o]", u"[0 ]", 0},
Case{u"[%#05.0o]", u"[ 0]", 0}, Case{u"%.0o", u"", 0}, Case{u"%#.0x", u"", 0},
Case{u"%#.0o", u"01", 1}, Case{u"%#.1o", u"0", 0}, Case{u"%#.3o", u"000", 0},
Case{u"%#.0hho", u"0", 256}, Case{u"%#.0ho", u"0", 65536}
}) {
char16_t buffer[32];
const auto expected = std::u16string(test.expected);
Require(swprintf_nid_postfix(buffer, 32, test.format, test.value) == static_cast<int>(expected.size()) && buffer == expected, "swprintf alternate octal zero");
Require(Format(buffer, 32, test.format, test.value) == static_cast<int>(expected.size()) && buffer == expected, "vswprintf alternate octal zero");
Require(snwprintf_s_nid_postfix(buffer, 32, test.format, test.value) == static_cast<int>(expected.size()) && buffer == expected, "snwprintf_s alternate octal zero");
}
char16_t buffer[16];
Require(swprintf_nid_postfix(buffer, 16, u"%#.*o", 0, 0u) == 1 && buffer == std::u16string(u"0"), "octal zero dynamic precision");
Require(swprintf_nid_postfix(buffer, 16, u"%#.*o", -1, 0u) == 1 && buffer == std::u16string(u"0"), "octal zero omitted precision");
Require(swprintf_nid_postfix(buffer, 16, u"%2$#.*1$o", 0, 0u) == 1 && buffer == std::u16string(u"0"), "octal zero positional precision");
Require(swprintf_nid_postfix(buffer, 16, u"%#.0llo", 0ull) == 1 && buffer == std::u16string(u"0"), "octal zero long long");
buffer[0] = u'x';
buffer[1] = u'y';
Require(snwprintf_s_nid_postfix(buffer, 1, u"%#.0o", 0u) == 1 && buffer[0] == 0 && buffer[1] == u'y', "octal zero bounded output");
}

int main() {
CheckAlternateOctalZero();
CheckBounded();
CheckPositional();
CheckPointer();
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