codekingpro/portable-devtools

1/*-------------------------------------------------------------------------2 *3 * varbit.h4 *	  Functions for the SQL datatypes BIT() and BIT VARYING().5 *6 * Code originally contributed by Adriaan Joubert.7 *8 * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group9 * Portions Copyright (c) 1994, Regents of the University of California10 *11 * src/include/utils/varbit.h12 *13 *-------------------------------------------------------------------------14 */15#ifndef VARBIT_H16#define VARBIT_H17 18#include <limits.h>19 20#include "fmgr.h"21 22/*23 * Modeled on struct varlena from postgres.h, but data type is bits8.24 *25 * Caution: if bit_len is not a multiple of BITS_PER_BYTE, the low-order26 * bits of the last byte of bit_dat[] are unused and MUST be zeroes.27 * (This allows bit_cmp() to not bother masking the last byte.)28 * Also, there should not be any excess bytes counted in the header length.29 */30typedef struct31{32	int32		vl_len_;		/* varlena header (do not touch directly!) */33	int32		bit_len;		/* number of valid bits */34	bits8		bit_dat[FLEXIBLE_ARRAY_MEMBER]; /* bit string, most sig. byte35												 * first */36} VarBit;37 38/*39 * fmgr interface macros40 *41 * BIT and BIT VARYING are toastable varlena types.  They are the same42 * as far as representation goes, so we just have one set of macros.43 */44static inline VarBit *45DatumGetVarBitP(Datum X)46{47	return (VarBit *) PG_DETOAST_DATUM(X);48}49 50static inline VarBit *51DatumGetVarBitPCopy(Datum X)52{53	return (VarBit *) PG_DETOAST_DATUM_COPY(X);54}55 56static inline Datum57VarBitPGetDatum(const VarBit *X)58{59	return PointerGetDatum(X);60}61 62#define PG_GETARG_VARBIT_P(n)	   DatumGetVarBitP(PG_GETARG_DATUM(n))63#define PG_GETARG_VARBIT_P_COPY(n) DatumGetVarBitPCopy(PG_GETARG_DATUM(n))64#define PG_RETURN_VARBIT_P(x)	   return VarBitPGetDatum(x)65 66/* Header overhead *in addition to* VARHDRSZ */67#define VARBITHDRSZ			sizeof(int32)68/* Number of bits in this bit string */69#define VARBITLEN(PTR)		(((VarBit *) (PTR))->bit_len)70/* Pointer to the first byte containing bit string data */71#define VARBITS(PTR)		(((VarBit *) (PTR))->bit_dat)72/* Number of bytes in the data section of a bit string */73#define VARBITBYTES(PTR)	(VARSIZE(PTR) - VARHDRSZ - VARBITHDRSZ)74/* Padding of the bit string at the end (in bits) */75#define VARBITPAD(PTR)		(VARBITBYTES(PTR)*BITS_PER_BYTE - VARBITLEN(PTR))76/* Number of bytes needed to store a bit string of a given length */77#define VARBITTOTALLEN(BITLEN)	(((BITLEN) + BITS_PER_BYTE-1)/BITS_PER_BYTE + \78								 VARHDRSZ + VARBITHDRSZ)79/*80 * Maximum number of bits.  Several code sites assume no overflow from81 * computing bitlen + X; VARBITTOTALLEN() has the largest such X.82 */83#define VARBITMAXLEN		(INT_MAX - BITS_PER_BYTE + 1)84/* pointer beyond the end of the bit string (like end() in STL containers) */85#define VARBITEND(PTR)		(((bits8 *) (PTR)) + VARSIZE(PTR))86/* Mask that will cover exactly one byte, i.e. BITS_PER_BYTE bits */87#define BITMASK 0xFF88 89#endif90