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https://github.com/SerenityOS/serenity
synced 2024-09-06 08:56:40 +00:00
LibC: Do not write value when scanf assignment value is suppressed
This change has the positive side-effect of causing scanf to *segfault* when a NULL pointer argument is passed to scanf. e.g. sscanf(str, "%d", NULL);
This commit is contained in:
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31079a56d7
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5b32b46ebc
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@ -179,6 +179,7 @@ const TestSuite test_suites[] {
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{ "%n", "", 0, 1, { intarg0 }, { to_value_t(0) } },
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{ "%d %n", "1 a", 1, 2, { intarg0, intarg1 }, { to_value_t(1), to_value_t(2) } },
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{ "%*d", " 42", 0, 0, {}, {} },
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{ "%d%*1[:/]%d", "24/7", 2, 2, { intarg0, intarg1 }, { to_value_t(24), to_value_t(7) } },
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};
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bool g_any_failed = false;
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@ -60,11 +60,10 @@ struct ReadElementConcrete {
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template<typename ApT, ReadKind kind>
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struct ReadElementConcrete<int, ApT, kind> {
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bool operator()(GenericLexer& lexer, va_list* ap)
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bool operator()(GenericLexer& lexer, va_list* ap, bool suppress_assignment)
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{
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lexer.ignore_while(isspace);
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auto* ptr = ap ? va_arg(*ap, ApT*) : nullptr;
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long value = 0;
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char* endptr = nullptr;
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auto nptr = lexer.remaining().characters_without_null_termination();
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@ -87,37 +86,38 @@ struct ReadElementConcrete<int, ApT, kind> {
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VERIFY(diff > 0);
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lexer.ignore((size_t)diff);
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if (ptr)
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if (!suppress_assignment) {
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auto* ptr = va_arg(*ap, ApT*);
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*ptr = value;
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}
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return true;
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}
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};
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template<typename ApT, ReadKind kind>
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struct ReadElementConcrete<char, ApT, kind> {
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bool operator()(GenericLexer& lexer, va_list* ap)
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bool operator()(GenericLexer& lexer, va_list* ap, bool suppress_assignment)
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{
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static_assert(kind == ReadKind::Normal, "Can't read a non-normal character");
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auto* ptr = ap ? va_arg(*ap, ApT*) : nullptr;
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if (lexer.is_eof())
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return false;
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auto ch = lexer.consume();
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if (ptr)
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if (!suppress_assignment) {
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auto* ptr = va_arg(*ap, ApT*);
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*ptr = ch;
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}
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return true;
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}
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};
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template<typename ApT, ReadKind kind>
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struct ReadElementConcrete<unsigned, ApT, kind> {
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bool operator()(GenericLexer& lexer, va_list* ap)
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bool operator()(GenericLexer& lexer, va_list* ap, bool suppress_assignment)
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{
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lexer.ignore_while(isspace);
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auto* ptr = ap ? va_arg(*ap, ApT*) : nullptr;
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unsigned long value = 0;
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char* endptr = nullptr;
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auto nptr = lexer.remaining().characters_without_null_termination();
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@ -140,19 +140,20 @@ struct ReadElementConcrete<unsigned, ApT, kind> {
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VERIFY(diff > 0);
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lexer.ignore((size_t)diff);
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if (ptr)
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if (!suppress_assignment) {
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auto* ptr = va_arg(*ap, ApT*);
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*ptr = value;
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}
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return true;
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}
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};
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template<typename ApT, ReadKind kind>
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struct ReadElementConcrete<long long, ApT, kind> {
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bool operator()(GenericLexer& lexer, va_list* ap)
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bool operator()(GenericLexer& lexer, va_list* ap, bool suppress_assignment)
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{
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lexer.ignore_while(isspace);
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auto* ptr = ap ? va_arg(*ap, ApT*) : nullptr;
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long long value = 0;
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char* endptr = nullptr;
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auto nptr = lexer.remaining().characters_without_null_termination();
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@ -175,19 +176,20 @@ struct ReadElementConcrete<long long, ApT, kind> {
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VERIFY(diff > 0);
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lexer.ignore((size_t)diff);
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if (ptr)
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if (!suppress_assignment) {
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auto* ptr = va_arg(*ap, ApT*);
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*ptr = value;
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}
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return true;
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}
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};
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template<typename ApT, ReadKind kind>
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struct ReadElementConcrete<unsigned long long, ApT, kind> {
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bool operator()(GenericLexer& lexer, va_list* ap)
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bool operator()(GenericLexer& lexer, va_list* ap, bool suppress_assignment)
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{
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lexer.ignore_while(isspace);
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auto* ptr = ap ? va_arg(*ap, ApT*) : nullptr;
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unsigned long long value = 0;
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char* endptr = nullptr;
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auto nptr = lexer.remaining().characters_without_null_termination();
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@ -210,20 +212,20 @@ struct ReadElementConcrete<unsigned long long, ApT, kind> {
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VERIFY(diff > 0);
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lexer.ignore((size_t)diff);
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if (ptr)
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if (!suppress_assignment) {
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auto* ptr = va_arg(*ap, ApT*);
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*ptr = value;
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}
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return true;
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}
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};
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template<typename ApT, ReadKind kind>
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struct ReadElementConcrete<float, ApT, kind> {
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bool operator()(GenericLexer& lexer, va_list* ap)
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bool operator()(GenericLexer& lexer, va_list* ap, bool suppress_assignment)
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{
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lexer.ignore_while(isspace);
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auto* ptr = ap ? va_arg(*ap, ApT*) : nullptr;
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double value = 0;
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char* endptr = nullptr;
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auto nptr = lexer.remaining().characters_without_null_termination();
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@ -242,50 +244,52 @@ struct ReadElementConcrete<float, ApT, kind> {
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VERIFY(diff > 0);
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lexer.ignore((size_t)diff);
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if (ptr)
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if (!suppress_assignment) {
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auto* ptr = va_arg(*ap, ApT*);
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*ptr = value;
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}
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return true;
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}
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};
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template<typename T, ReadKind kind>
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struct ReadElement {
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bool operator()(LengthModifier length_modifier, GenericLexer& input_lexer, va_list* ap)
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bool operator()(LengthModifier length_modifier, GenericLexer& input_lexer, va_list* ap, bool suppress_assignment)
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{
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switch (length_modifier) {
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default:
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case LengthModifier::None:
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VERIFY_NOT_REACHED();
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case LengthModifier::Default:
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return ReadElementConcrete<T, T, kind> {}(input_lexer, ap);
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return ReadElementConcrete<T, T, kind> {}(input_lexer, ap, suppress_assignment);
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case LengthModifier::Char:
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return ReadElementConcrete<T, char, kind> {}(input_lexer, ap);
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return ReadElementConcrete<T, char, kind> {}(input_lexer, ap, suppress_assignment);
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case LengthModifier::Short:
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return ReadElementConcrete<T, short, kind> {}(input_lexer, ap);
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return ReadElementConcrete<T, short, kind> {}(input_lexer, ap, suppress_assignment);
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case LengthModifier::Long:
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if constexpr (IsSame<T, int>)
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return ReadElementConcrete<T, long, kind> {}(input_lexer, ap);
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return ReadElementConcrete<T, long, kind> {}(input_lexer, ap, suppress_assignment);
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if constexpr (IsSame<T, unsigned>)
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return ReadElementConcrete<T, unsigned, kind> {}(input_lexer, ap);
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return ReadElementConcrete<T, unsigned, kind> {}(input_lexer, ap, suppress_assignment);
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if constexpr (IsSame<T, float>)
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return ReadElementConcrete<int, double, kind> {}(input_lexer, ap);
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return ReadElementConcrete<int, double, kind> {}(input_lexer, ap, suppress_assignment);
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return false;
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case LengthModifier::LongLong:
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if constexpr (IsSame<T, int>)
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return ReadElementConcrete<long long, long long, kind> {}(input_lexer, ap);
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return ReadElementConcrete<long long, long long, kind> {}(input_lexer, ap, suppress_assignment);
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if constexpr (IsSame<T, unsigned>)
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return ReadElementConcrete<unsigned long long, unsigned long long, kind> {}(input_lexer, ap);
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return ReadElementConcrete<unsigned long long, unsigned long long, kind> {}(input_lexer, ap, suppress_assignment);
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if constexpr (IsSame<T, float>)
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return ReadElementConcrete<long long, double, kind> {}(input_lexer, ap);
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return ReadElementConcrete<long long, double, kind> {}(input_lexer, ap, suppress_assignment);
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return false;
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case LengthModifier::IntMax:
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return ReadElementConcrete<T, intmax_t, kind> {}(input_lexer, ap);
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return ReadElementConcrete<T, intmax_t, kind> {}(input_lexer, ap, suppress_assignment);
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case LengthModifier::Size:
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return ReadElementConcrete<T, size_t, kind> {}(input_lexer, ap);
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return ReadElementConcrete<T, size_t, kind> {}(input_lexer, ap, suppress_assignment);
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case LengthModifier::PtrDiff:
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return ReadElementConcrete<T, ptrdiff_t, kind> {}(input_lexer, ap);
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return ReadElementConcrete<T, ptrdiff_t, kind> {}(input_lexer, ap, suppress_assignment);
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case LengthModifier::LongDouble:
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return ReadElementConcrete<T, long double, kind> {}(input_lexer, ap);
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return ReadElementConcrete<T, long double, kind> {}(input_lexer, ap, suppress_assignment);
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}
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}
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};
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@ -299,7 +303,7 @@ struct ReadElement<char*, ReadKind::Normal> {
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{
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}
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bool operator()(LengthModifier length_modifier, GenericLexer& input_lexer, va_list* ap)
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bool operator()(LengthModifier length_modifier, GenericLexer& input_lexer, va_list* ap, bool suppress_assignment)
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{
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// FIXME: Implement wide strings and such.
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if (length_modifier != LengthModifier::Default)
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@ -308,13 +312,15 @@ struct ReadElement<char*, ReadKind::Normal> {
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if (was_null)
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input_lexer.ignore_while(isspace);
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auto* ptr = ap ? va_arg(*ap, char*) : nullptr;
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auto str = input_lexer.consume_while([this](auto c) { return this->matches(c); });
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if (str.is_empty())
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return false;
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memcpy(ptr, str.characters_without_null_termination(), str.length());
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ptr[str.length()] = 0;
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if (!suppress_assignment) {
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auto* ptr = va_arg(*ap, char*);
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memcpy(ptr, str.characters_without_null_termination(), str.length());
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ptr[str.length()] = 0;
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}
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return true;
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}
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@ -332,14 +338,13 @@ private:
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template<>
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struct ReadElement<void*, ReadKind::Normal> {
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bool operator()(LengthModifier length_modifier, GenericLexer& input_lexer, va_list* ap)
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bool operator()(LengthModifier length_modifier, GenericLexer& input_lexer, va_list* ap, bool suppress_assignment)
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{
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if (length_modifier != LengthModifier::Default)
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return false;
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input_lexer.ignore_while(isspace);
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auto* ptr = ap ? va_arg(*ap, void**) : nullptr;
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auto str = input_lexer.consume_while([this](auto c) { return this->should_consume(c); });
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if (count != 8) {
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@ -358,7 +363,10 @@ struct ReadElement<void*, ReadKind::Normal> {
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if (endptr != &buf[8])
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goto fail;
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memcpy(ptr, &value, sizeof(value));
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if (!suppress_assignment) {
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auto* ptr = va_arg(*ap, void**);
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memcpy(ptr, &value, sizeof(value));
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}
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return true;
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}
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@ -542,8 +550,6 @@ extern "C" int vsscanf(const char* input, const char* format, va_list ap)
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}
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}
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auto* ap_or_null = !suppress_assignment ? (va_list*)© : nullptr;
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// Now try to read.
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switch (conversion_specifier) {
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case ConversionSpecifier::Invalid:
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@ -553,61 +559,61 @@ extern "C" int vsscanf(const char* input, const char* format, va_list ap)
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dbgln("Invalid conversion specifier {} in scanf!", (int)conversion_specifier);
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VERIFY_NOT_REACHED();
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case ConversionSpecifier::Decimal:
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if (!ReadElement<int, ReadKind::Normal> {}(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<int, ReadKind::Normal> {}(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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break;
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case ConversionSpecifier::Integer:
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if (!ReadElement<int, ReadKind::Infer> {}(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<int, ReadKind::Infer> {}(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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break;
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case ConversionSpecifier::Octal:
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if (!ReadElement<unsigned, ReadKind::Octal> {}(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<unsigned, ReadKind::Octal> {}(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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break;
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case ConversionSpecifier::Unsigned:
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if (!ReadElement<unsigned, ReadKind::Normal> {}(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<unsigned, ReadKind::Normal> {}(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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break;
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case ConversionSpecifier::Hex:
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if (!ReadElement<unsigned, ReadKind::Hex> {}(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<unsigned, ReadKind::Hex> {}(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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break;
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case ConversionSpecifier::Floating:
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if (!ReadElement<float, ReadKind::Normal> {}(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<float, ReadKind::Normal> {}(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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break;
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case ConversionSpecifier::String:
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if (!ReadElement<char*, ReadKind::Normal> {}(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<char*, ReadKind::Normal> {}(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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break;
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case ConversionSpecifier::UseScanList:
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if (!ReadElement<char*, ReadKind::Normal> { scanlist, invert_scanlist }(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<char*, ReadKind::Normal> { scanlist, invert_scanlist }(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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break;
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case ConversionSpecifier::Character:
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if (!ReadElement<char, ReadKind::Normal> {}(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<char, ReadKind::Normal> {}(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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break;
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case ConversionSpecifier::Pointer:
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if (!ReadElement<void*, ReadKind::Normal> {}(length_modifier, input_lexer, ap_or_null))
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if (!ReadElement<void*, ReadKind::Normal> {}(length_modifier, input_lexer, ©, suppress_assignment))
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format_lexer.consume_all();
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else if (!suppress_assignment)
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++elements_matched;
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