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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
commit46651ce6fe013220ed397add242004d764fc0153 (patch)
tree6e5299f990f88e60174a1d3ae6e48eedd2688b2b /src/include/utils/varbit.h
parentInitial commit. (diff)
downloadpostgresql-14-46651ce6fe013220ed397add242004d764fc0153.tar.xz
postgresql-14-46651ce6fe013220ed397add242004d764fc0153.zip
Adding upstream version 14.5.upstream/14.5upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/include/utils/varbit.h')
-rw-r--r--src/include/utils/varbit.h74
1 files changed, 74 insertions, 0 deletions
diff --git a/src/include/utils/varbit.h b/src/include/utils/varbit.h
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+/*-------------------------------------------------------------------------
+ *
+ * varbit.h
+ * Functions for the SQL datatypes BIT() and BIT VARYING().
+ *
+ * Code originally contributed by Adriaan Joubert.
+ *
+ * Portions Copyright (c) 1996-2021, 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 struct varlena from postgres.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.
+ */
+#define DatumGetVarBitP(X) ((VarBit *) PG_DETOAST_DATUM(X))
+#define DatumGetVarBitPCopy(X) ((VarBit *) PG_DETOAST_DATUM_COPY(X))
+#define VarBitPGetDatum(X) 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