duckdb::DecimalToString Struct Reference

Public Member Functions
template<>
int	DecimalLength (hugeint_t value, uint8_t width, uint8_t scale)
template<>
string_t	Format (hugeint_t value, uint8_t width, uint8_t scale, Vector &vector)
template<>
void	FormatDecimal (hugeint_t value, uint8_t width, uint8_t scale, char *dst, idx_t len)

Static Public Member Functions
template<class SIGNED >
static int	DecimalLength (SIGNED value, uint8_t width, uint8_t scale)
template<class SIGNED >
static void	FormatDecimal (SIGNED value, uint8_t width, uint8_t scale, char *dst, idx_t len)
template<class SIGNED >
static string_t	Format (SIGNED value, uint8_t width, uint8_t scale, Vector &vector)

Member Function Documentation

DecimalLength()

template<class SIGNED >

static int duckdb::DecimalToString::DecimalLength ( SIGNED  value, uint8_t  width, uint8_t  scale  )

inlinestatic

                                                                         {
        using UNSIGNED = typename MakeUnsigned<SIGNED>::type;
        if (scale == 0) {
            // scale is 0: regular number
            return NumericHelper::SignedLength<SIGNED, UNSIGNED>(value);
        }
        // length is max of either:
        // scale + 2 OR
        // integer length + 1
        // scale + 2 happens when the number is in the range of (-1, 1)
        // in that case we print "0.XXX", which is the scale, plus "0." (2 chars)
        // integer length + 1 happens when the number is outside of that range
        // in that case we print the integer number, but with one extra character ('.')
        auto extra_characters = width > scale ? 2 : 1;
        return MaxValue(scale + extra_characters + (value < 0 ? 1 : 0),
                        NumericHelper::SignedLength<SIGNED, UNSIGNED>(value) + 1);
    }

FormatDecimal()

template<class SIGNED >

static void duckdb::DecimalToString::FormatDecimal ( SIGNED  value, uint8_t  width, uint8_t  scale, char *  dst, idx_t  len  )

inlinestatic

                                                                                                {
        using UNSIGNED = typename MakeUnsigned<SIGNED>::type;
        char *end = dst + len;
        if (value < 0) {
            value = -value;
            *dst = '-';
        }
        if (scale == 0) {
            NumericHelper::FormatUnsigned<UNSIGNED>(UnsafeNumericCast<UNSIGNED>(value), end);
            return;
        }
        // we write two numbers:
        // the numbers BEFORE the decimal (major)
        // and the numbers AFTER the decimal (minor)
        auto minor =
            UnsafeNumericCast<UNSIGNED>(value) % UnsafeNumericCast<UNSIGNED>(NumericHelper::POWERS_OF_TEN[scale]);
        auto major =
            UnsafeNumericCast<UNSIGNED>(value) / UnsafeNumericCast<UNSIGNED>(NumericHelper::POWERS_OF_TEN[scale]);
        // write the number after the decimal
        dst = NumericHelper::FormatUnsigned<UNSIGNED>(UnsafeNumericCast<UNSIGNED>(minor), end);
        // (optionally) pad with zeros and add the decimal point
        while (dst > (end - scale)) {
            *--dst = '0';
        }
        *--dst = '.';
        // now write the part before the decimal
        D_ASSERT(width > scale || major == 0);
        if (width > scale) {
            // there are numbers after the comma
            dst = NumericHelper::FormatUnsigned<UNSIGNED>(UnsafeNumericCast<UNSIGNED>(major), dst);
        }
    }

Format()

template<class SIGNED >

static string_t duckdb::DecimalToString::Format ( SIGNED  value, uint8_t  width, uint8_t  scale, Vector &  vector  )

inlinestatic

                                                                                       {
        int len = DecimalLength<SIGNED>(value, width, scale);
        string_t result = StringVector::EmptyString(vector, NumericCast<size_t>(len));
        FormatDecimal<SIGNED>(value, width, scale, result.GetDataWriteable(), UnsafeNumericCast<idx_t>(len));
        result.Finalize();
        return result;
    }

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The documentation for this struct was generated from the following file:

• external/duckdb/duckdb.cpp