1 /*-------------------------------------------------------------------------
4 * Tuple macros used by both index tuples and heap tuples.
7 * Copyright (c) 1994, Regents of the University of California
9 * $Id: tupmacs.h,v 1.10 1999/05/25 16:13:36 momjian Exp $
11 *-------------------------------------------------------------------------
17 * check to see if the ATT'th bit of an array of 8-bit bytes is set.
19 #define att_isnull(ATT, BITS) (!((BITS)[(ATT) >> 3] & (1 << ((ATT) & 0x07))))
22 * given a Form_pg_attribute and a pointer into a tuple's data
23 * area, return the correct value or pointer.
25 * We return a 4 byte (char *) value in all cases. If the attribute has
26 * "byval" false or has variable length, we return the same pointer
27 * into the tuple data area that we're passed. Otherwise, we return
28 * the 1, 2, or 4 bytes pointed to by it, properly extended to 4
29 * bytes, depending on the length of the attribute.
31 * note that T must already be properly LONGALIGN/SHORTALIGN'd for
32 * this to work correctly.
34 * the double-cast is to stop gcc from (correctly) complaining about
35 * casting integer types with size < sizeof(char *) to (char *).
36 * sign-extension may get weird if you use an integer type that
37 * isn't the same size as (char *) for the first cast. (on the other
38 * hand, it's safe to use another type for the (foo *)(T).)
40 * attbyval seems to be fairly redundant. We have to return a pointer if
41 * the value is longer than 4 bytes or has variable length; returning the
42 * value would be useless. In fact, for at least the variable length case,
43 * the caller assumes we return a pointer regardless of attbyval.
44 * I would eliminate attbyval altogether, but I don't know how. -BRYANH.
46 #define fetchatt(A, T) \
48 (*(A))->attbyval && (*(A))->attlen != -1 ? \
50 (*(A))->attlen > sizeof(int16) ? \
52 (char *) (long) *((int32 *)(T)) \
56 (*(A))->attlen < sizeof(int16) ? \
57 (char *) (long) *((char *)(T)) \
59 (char *) (long) *((int16 *)(T))) \
65 /* att_align aligns the given offset as needed for a datum of length attlen
66 * and alignment requirement attalign. In practice we don't need the length.
67 * The attalign cases are tested in what is hopefully something like their
68 * frequency of occurrence.
70 #define att_align(cur_offset, attlen, attalign) \
72 ((attalign) == 'i') ? INTALIGN(cur_offset) : \
73 (((attalign) == 'c') ? ((long)(cur_offset)) : \
74 (((attalign) == 'd') ? DOUBLEALIGN(cur_offset) : \
76 AssertMacro((attalign) == 's'), \
77 SHORTALIGN(cur_offset) \
81 #define att_addlength(cur_offset, attlen, attval) \
85 (cur_offset) + (attlen) \
89 (cur_offset) + VARSIZE(DatumGetPointer(attval)) \