mirror of
https://github.com/postgres/postgres.git
synced 2026-04-07 18:26:06 -04:00
9181c870ba
This commit changes the definition of varlena to a typedef, so as it becomes possible to remove "struct" markers from various declarations in the code base. Historically, "struct" markers are not the project style for variable declarations, so this update simplifies the code and makes it more consistent across the board. This change has an impact on the following structures, simplifying declarations using them: - varlena - varatt_indirect - varatt_external This cleanup has come up in a different path set that played with TOAST and varatt.h, independently worth doing on its own. Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de> Reviewed-by: Andreas Karlsson <andreas@proxel.se> Reviewed-by: Shinya Kato <shinya11.kato@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Chao Li <li.evan.chao@gmail.com> Discussion: https://postgr.es/m/aW8xvVbovdhyI4yo@paquier.xyz
89 lines
2.9 KiB
C
89 lines
2.9 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* varbit.h
|
|
* Functions for the SQL datatypes BIT() and BIT VARYING().
|
|
*
|
|
* Code originally contributed by Adriaan Joubert.
|
|
*
|
|
* Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
* src/include/utils/varbit.h
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#ifndef VARBIT_H
|
|
#define VARBIT_H
|
|
|
|
#include <limits.h>
|
|
|
|
#include "fmgr.h"
|
|
|
|
/*
|
|
* Modeled on varlena from c.h, but data type is bits8.
|
|
*
|
|
* Caution: if bit_len is not a multiple of BITS_PER_BYTE, the low-order
|
|
* bits of the last byte of bit_dat[] are unused and MUST be zeroes.
|
|
* (This allows bit_cmp() to not bother masking the last byte.)
|
|
* Also, there should not be any excess bytes counted in the header length.
|
|
*/
|
|
typedef struct
|
|
{
|
|
int32 vl_len_; /* varlena header (do not touch directly!) */
|
|
int32 bit_len; /* number of valid bits */
|
|
bits8 bit_dat[FLEXIBLE_ARRAY_MEMBER]; /* bit string, most sig. byte
|
|
* first */
|
|
} VarBit;
|
|
|
|
/*
|
|
* fmgr interface macros
|
|
*
|
|
* BIT and BIT VARYING are toastable varlena types. They are the same
|
|
* as far as representation goes, so we just have one set of macros.
|
|
*/
|
|
static inline VarBit *
|
|
DatumGetVarBitP(Datum X)
|
|
{
|
|
return (VarBit *) PG_DETOAST_DATUM(X);
|
|
}
|
|
|
|
static inline VarBit *
|
|
DatumGetVarBitPCopy(Datum X)
|
|
{
|
|
return (VarBit *) PG_DETOAST_DATUM_COPY(X);
|
|
}
|
|
|
|
static inline Datum
|
|
VarBitPGetDatum(const VarBit *X)
|
|
{
|
|
return PointerGetDatum(X);
|
|
}
|
|
|
|
#define PG_GETARG_VARBIT_P(n) DatumGetVarBitP(PG_GETARG_DATUM(n))
|
|
#define PG_GETARG_VARBIT_P_COPY(n) DatumGetVarBitPCopy(PG_GETARG_DATUM(n))
|
|
#define PG_RETURN_VARBIT_P(x) return VarBitPGetDatum(x)
|
|
|
|
/* Header overhead *in addition to* VARHDRSZ */
|
|
#define VARBITHDRSZ sizeof(int32)
|
|
/* Number of bits in this bit string */
|
|
#define VARBITLEN(PTR) (((VarBit *) (PTR))->bit_len)
|
|
/* Pointer to the first byte containing bit string data */
|
|
#define VARBITS(PTR) (((VarBit *) (PTR))->bit_dat)
|
|
/* Number of bytes in the data section of a bit string */
|
|
#define VARBITBYTES(PTR) (VARSIZE(PTR) - VARHDRSZ - VARBITHDRSZ)
|
|
/* Padding of the bit string at the end (in bits) */
|
|
#define VARBITPAD(PTR) (VARBITBYTES(PTR)*BITS_PER_BYTE - VARBITLEN(PTR))
|
|
/* Number of bytes needed to store a bit string of a given length */
|
|
#define VARBITTOTALLEN(BITLEN) (((BITLEN) + BITS_PER_BYTE-1)/BITS_PER_BYTE + \
|
|
VARHDRSZ + VARBITHDRSZ)
|
|
/*
|
|
* Maximum number of bits. Several code sites assume no overflow from
|
|
* computing bitlen + X; VARBITTOTALLEN() has the largest such X.
|
|
*/
|
|
#define VARBITMAXLEN (INT_MAX - BITS_PER_BYTE + 1)
|
|
/* pointer beyond the end of the bit string (like end() in STL containers) */
|
|
#define VARBITEND(PTR) (((bits8 *) (PTR)) + VARSIZE(PTR))
|
|
/* Mask that will cover exactly one byte, i.e. BITS_PER_BYTE bits */
|
|
#define BITMASK 0xFF
|
|
|
|
#endif
|