LibC: Implement floating point parsing to *scanf functions
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@ -3,6 +3,7 @@
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#include <BAN/Traits.h>
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#include <ctype.h>
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#include <math.h>
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#include <scanf_impl.h>
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#include <stddef.h>
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#include <stdint.h>
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@ -261,6 +262,181 @@ int scanf_impl(const char* format, va_list arguments, int (*__getc_fun)(void*),
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}
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};
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auto parse_floating_point_internal =
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[&parse_integer_internal, &get_input, &in]<int BASE, typename T>(BASE_TYPE<BASE>, bool negative, int width, T* out, bool require_start = true) -> ConversionResult
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{
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constexpr auto is_base_digit =
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[](char c) -> bool
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{
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c = tolower(c);
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if ('0' <= c && c <= '9')
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return c - '0' < BASE;
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if ('a' <= c && c <= 'z')
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return c - 'a' + 10 < BASE;
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return false;
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};
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constexpr auto get_base_digit = [](char c) -> T { if (c <= '9') return T(c - '0'); return T(tolower(c) - 'a' + 10); };
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if (require_start && !is_base_digit(in))
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return ConversionResult::MATCH_FAILURE;
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*out = T(0);
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// Parse whole part
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while (width > 0 && is_base_digit(in))
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{
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*out = (*out * BASE) + get_base_digit(in);
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get_input(true);
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width--;
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}
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if (width == 0)
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goto done;
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// Parse fractional part
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if (in == '.')
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{
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get_input(true);
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width--;
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T multiplier = T(1) / T(BASE);
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while (width > 0 && is_base_digit(in))
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{
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*out += get_base_digit(in) * multiplier;
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multiplier /= T(BASE);
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get_input(true);
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width--;
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}
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}
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if (width == 0)
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goto done;
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// Parse exponent
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static_assert(BASE == 10 || BASE == 16);
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if ((BASE == 10 && tolower(in) == 'e') || (BASE == 16 && tolower(in) == 'p'))
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{
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get_input(true);
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width--;
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bool exp_negative = (in == '-');
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if (in == '+' || in == '-')
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{
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get_input(true);
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if (--width == 0)
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goto done;
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}
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int exp;
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if (parse_integer_internal(BASE_TYPE<10>{}, exp_negative, width, &exp) == ConversionResult::SUCCESS)
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*out *= BAN::Math::pow<T>(BASE == 10 ? T(10) : T(2), T(exp));
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}
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done:
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if (negative)
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*out = -*out;
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return ConversionResult::SUCCESS;
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};
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auto parse_floating_point_typed =
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[&parse_floating_point_internal, &arguments, &get_input, &in]<typename T>(bool suppress, int width, T*) -> ConversionResult
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{
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T dummy;
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T* out = suppress ? &dummy : va_arg(arguments, T*);
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get_input(false);
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while (isspace(in))
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get_input(true);
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if (in == DONE)
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return ConversionResult::INPUT_FAILURE;
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bool negative = (in == '-');
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if (in == '-' || in == '+')
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{
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get_input(true);
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if (--width == 0)
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return ConversionResult::MATCH_FAILURE;
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}
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if (tolower(in) == 'i')
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{
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get_input(true);
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if (--width == 0)
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return ConversionResult::MATCH_FAILURE;
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if (tolower(in) != 'n')
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return ConversionResult::MATCH_FAILURE;
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get_input(true);
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if (--width == 0)
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return ConversionResult::MATCH_FAILURE;
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if (tolower(in) != 'f')
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return ConversionResult::MATCH_FAILURE;
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if constexpr(sizeof(T) == sizeof(float))
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*out = HUGE_VALF;
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else if constexpr(sizeof(T) == sizeof(double))
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*out = HUGE_VAL;
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else if constexpr(sizeof(T) == sizeof(long double))
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*out = HUGE_VALL;
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else
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[]<bool flag = false>() { static_assert(flag); };
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if (negative)
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*out = -*out;
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return ConversionResult::SUCCESS;
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}
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if (tolower(in) == 'n')
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{
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get_input(true);
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if (--width == 0)
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return ConversionResult::MATCH_FAILURE;
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if (tolower(in) != 'a')
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return ConversionResult::MATCH_FAILURE;
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get_input(true);
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if (--width == 0)
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return ConversionResult::MATCH_FAILURE;
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if (tolower(in) != 'n')
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return ConversionResult::MATCH_FAILURE;
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if constexpr(sizeof(T) == sizeof(float))
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*out = nanf("");
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else if constexpr(sizeof(T) == sizeof(double))
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*out = nan("");
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else if constexpr(sizeof(T) == sizeof(long double))
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*out = nanl("");
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else
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[]<bool flag = false>() { static_assert(flag); };
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return ConversionResult::SUCCESS;
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}
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if (in == '0' && width > 2)
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{
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get_input(true);
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width--;
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if (tolower(in) == 'x')
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{
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get_input(true);
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width--;
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return parse_floating_point_internal(BASE_TYPE<16>{}, negative, width, out);
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}
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return parse_floating_point_internal(BASE_TYPE<10>{}, negative, width, out, false);
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}
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return parse_floating_point_internal(BASE_TYPE<10>{}, negative, width, out);
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};
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auto parse_floating_point =
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[&parse_floating_point_typed](bool suppress, int width, LengthModifier length) -> ConversionResult
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{
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if (width == -1)
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width = __INT_MAX__;
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switch (length)
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{
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case LengthModifier::none: return parse_floating_point_typed(suppress, width, static_cast<float*> (nullptr));
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case LengthModifier::l: return parse_floating_point_typed(suppress, width, static_cast<double*> (nullptr));
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case LengthModifier::L: return parse_floating_point_typed(suppress, width, static_cast<long double*> (nullptr));
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default:
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return ConversionResult::MATCH_FAILURE;
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}
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};
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auto parse_string =
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[&arguments, &get_input, &in](uint8_t* mask, bool exclude, bool suppress, bool allocate, int min_len, int max_len, bool terminate) -> ConversionResult
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{
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@ -344,6 +520,9 @@ int scanf_impl(const char* format, va_list arguments, int (*__getc_fun)(void*),
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case 'x': result = parse_integer(BASE_TYPE<16>{}, IS_UNSIGNED<true> {}, conversion.suppress, conversion.field_width, conversion.length); break;
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case 'X': result = parse_integer(BASE_TYPE<16>{}, IS_UNSIGNED<true> {}, conversion.suppress, conversion.field_width, conversion.length); break;
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case 'p': result = parse_integer(BASE_TYPE<16>{}, IS_UNSIGNED<true> {}, conversion.suppress, conversion.field_width, LengthModifier::j); break;
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case 'a': case 'e': case 'f': case 'g':
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result = parse_floating_point(conversion.suppress, conversion.field_width, conversion.length);
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break;
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case 'S':
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conversion.length = LengthModifier::l;
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// fall through
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