duckdb::Bit Class Reference

The Bit class is a static class that holds helper functions for the BIT type. More...

Static Public Member Functions
static DUCKDB_API idx_t	BitLength (bitstring_t bits)
	Returns the number of bits in the bit string.
static DUCKDB_API idx_t	BitCount (bitstring_t bits)
	Returns the number of set bits in the bit string.
static DUCKDB_API idx_t	OctetLength (bitstring_t bits)
	Returns the number of bytes in the bit string.
static DUCKDB_API idx_t	GetBit (bitstring_t bit_string, idx_t n)
	Extracts the nth bit from bit string; the first (leftmost) bit is indexed 0.
static DUCKDB_API void	SetBit (bitstring_t &bit_string, idx_t n, idx_t new_value)
	Sets the nth bit in bit string to newvalue; the first (leftmost) bit is indexed 0.
static DUCKDB_API idx_t	BitPosition (bitstring_t substring, bitstring_t bits)
	Returns first starting index of the specified substring within bits, or zero if it's not present.
static DUCKDB_API void	ToString (bitstring_t bits, char *output)
static DUCKDB_API string	ToString (bitstring_t bits)
static DUCKDB_API bool	TryGetBitStringSize (string_t str, idx_t &result_size, string *error_message)
	Returns the bit size of a string -> bit conversion.
static DUCKDB_API void	ToBit (string_t str, bitstring_t &output)
static DUCKDB_API string	ToBit (string_t str)
static DUCKDB_API void	BlobToBit (string_t blob, bitstring_t &output)
	output needs to have enough space allocated before calling this function (blob size + 1)
static DUCKDB_API string	BlobToBit (string_t blob)
template<class T >
static void	NumericToBit (T numeric, bitstring_t &output_str)
	output_str needs to have enough space allocated before calling this function (sizeof(T) + 1)
template<class T >
static string	NumericToBit (T numeric)
template<class T >
static void	BitToNumeric (bitstring_t bit, T &output_num)
	bit is expected to fit inside of output num (bit size <= sizeof(T) + 1)
template<class T >
static T	BitToNumeric (bitstring_t bit)
static void	BitToBlob (bitstring_t bit, string_t &output_blob)
	bit is expected to fit inside of output_blob (bit size = output_blob + 1)
static string	BitToBlob (bitstring_t bit)
static DUCKDB_API void	BitString (const string_t &input, idx_t len, bitstring_t &result)
	Creates a new bitstring of determined length.
static DUCKDB_API void	ExtendBitString (const bitstring_t &input, idx_t bit_length, bitstring_t &result)
static DUCKDB_API void	SetEmptyBitString (bitstring_t &target, string_t &input)
static DUCKDB_API void	SetEmptyBitString (bitstring_t &target, idx_t len)
static DUCKDB_API idx_t	ComputeBitstringLen (idx_t len)
static DUCKDB_API void	RightShift (const bitstring_t &bit_string, idx_t shift, bitstring_t &result)
static DUCKDB_API void	LeftShift (const bitstring_t &bit_string, idx_t shift, bitstring_t &result)
static DUCKDB_API void	BitwiseAnd (const bitstring_t &rhs, const bitstring_t &lhs, bitstring_t &result)
static DUCKDB_API void	BitwiseOr (const bitstring_t &rhs, const bitstring_t &lhs, bitstring_t &result)
static DUCKDB_API void	BitwiseXor (const bitstring_t &rhs, const bitstring_t &lhs, bitstring_t &result)
static DUCKDB_API void	BitwiseNot (const bitstring_t &rhs, bitstring_t &result)
static DUCKDB_API void	Verify (const bitstring_t &input)

Static Private Member Functions
static void	Finalize (bitstring_t &str)
static idx_t	GetBitInternal (bitstring_t bit_string, idx_t n)
static void	SetBitInternal (bitstring_t &bit_string, idx_t n, idx_t new_value)
static idx_t	GetBitIndex (idx_t n)
static uint8_t	GetFirstByte (const bitstring_t &str)

Detailed Description

The Bit class is a static class that holds helper functions for the BIT type.

Member Function Documentation

ToString()

static DUCKDB_API void duckdb::Bit::ToString ( bitstring_t  bits, char *  output  )

static

Converts bits to a string, writing the output to the designated output string. The string needs to have space for at least GetStringSize(bits) bytes.

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ToBit()

static DUCKDB_API void duckdb::Bit::ToBit ( string_t  str, bitstring_t &  output  )

static

Convert a string to a bit. This function should ONLY be called after calling GetBitSize, since it does NOT perform data validation.

NumericToBit() [1/2]

template<class T >

void duckdb::Bit::NumericToBit ( T  numeric, bitstring_t &  output_str  )

static

output_str needs to have enough space allocated before calling this function (sizeof(T) + 1)

                                                         {
    D_ASSERT(output_str.GetSize() >= sizeof(T) + 1);
 
    auto le_numeric = BSwapIfBE(numeric);
    auto output = output_str.GetDataWriteable();
    auto data = const_data_ptr_cast(&le_numeric);
 
    *output = 0; // set padding to 0
    ++output;
    for (idx_t idx = 0; idx < sizeof(T); ++idx) {
        output[idx] = static_cast<char>(data[sizeof(T) - idx - 1]);
    }
    Bit::Finalize(output_str);
}

NumericToBit() [2/2]

template<class T >

string duckdb::Bit::NumericToBit ( T  numeric )

static

                                  {
    auto bit_len = sizeof(T) + 1;
    auto buffer = make_unsafe_uniq_array_uninitialized<char>(bit_len);
    bitstring_t output_str(buffer.get(), UnsafeNumericCast<uint32_t>(bit_len));
    Bit::NumericToBit(numeric, output_str);
    return output_str.GetString();
}

BitToNumeric() [1/2]

template<class T >

void duckdb::Bit::BitToNumeric ( bitstring_t  bit, T &  output_num  )

static

bit is expected to fit inside of output num (bit size <= sizeof(T) + 1)

                                                     {
    D_ASSERT(bit.GetSize() <= sizeof(T) + 1);
 
    output_num = 0;
    auto data = const_data_ptr_cast(bit.GetData());
    auto output = data_ptr_cast(&output_num);
 
    idx_t padded_byte_idx = sizeof(T) - bit.GetSize() + 1;
    output[sizeof(T) - 1 - padded_byte_idx] = GetFirstByte(bit);
    for (idx_t idx = padded_byte_idx + 1; idx < sizeof(T); ++idx) {
        output[sizeof(T) - 1 - idx] = data[1 + idx - padded_byte_idx];
    }
    output_num = BSwapIfBE(output_num);
}

BitToNumeric() [2/2]

template<class T >

T duckdb::Bit::BitToNumeric ( bitstring_t  bit )

static

                                   {
    T output;
    Bit::BitToNumeric(bit, output);
    return (output);
}

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

• external/duckdb/duckdb.cpp