Age         Owner                  TLA  Line data    Source code

                                  1                 : /*-------------------------------------------------------------------------
                                  2                 :  *
                                  3                 :  * varbit.h
                                  4                 :  *    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 Group
                                  9                 :  * Portions Copyright (c) 1994, Regents of the University of California
                                 10                 :  *
                                 11                 :  * src/include/utils/varbit.h
                                 12                 :  *
                                 13                 :  *-------------------------------------------------------------------------
                                 14                 :  */
                                 15                 : #ifndef VARBIT_H
                                 16                 : #define VARBIT_H
                                 17                 : 
                                 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-order
                                 26                 :  * 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                 :  */
                                 30                 : typedef struct
                                 31                 : {
                                 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. byte
                                 35                 :                                                  * first */
                                 36                 : } VarBit;
                                 37                 : 
                                 38                 : /*
                                 39                 :  * fmgr interface macros
                                 40                 :  *
                                 41                 :  * BIT and BIT VARYING are toastable varlena types.  They are the same
                                 42                 :  * as far as representation goes, so we just have one set of macros.
                                 43                 :  */
                                 44                 : static inline VarBit *
  194 peter                      45 GNC       51865 : DatumGetVarBitP(Datum X)
                                 46                 : {
                                 47           51865 :     return (VarBit *) PG_DETOAST_DATUM(X);
                                 48                 : }
                                 49                 : 
                                 50                 : static inline VarBit *
                                 51                 : DatumGetVarBitPCopy(Datum X)
                                 52                 : {
                                 53                 :     return (VarBit *) PG_DETOAST_DATUM_COPY(X);
                                 54                 : }
                                 55                 : 
                                 56                 : static inline Datum
                                 57            8142 : VarBitPGetDatum(const VarBit *X)
                                 58                 : {
                                 59            8142 :     return PointerGetDatum(X);
                                 60                 : }
                                 61                 : 
 8053 bruce                      62 ECB             : #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)
lockhart                   72                 : /* Number of bytes in the data section of a bit string */
                                 73                 : #define VARBITBYTES(PTR)    (VARSIZE(PTR) - VARHDRSZ - VARBITHDRSZ)
tgl                        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 from
                                 81                 :  * 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 0xFF
                                 88                 : 
                                 89                 : #endif