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Diffstat (limited to 'src/include/access/tupmacs.h')
-rw-r--r-- | src/include/access/tupmacs.h | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/src/include/access/tupmacs.h b/src/include/access/tupmacs.h new file mode 100644 index 00000000000..23e8ea1686a --- /dev/null +++ b/src/include/access/tupmacs.h @@ -0,0 +1,55 @@ +/*------------------------------------------------------------------------- + * + * tupmacs.h-- + * Tuple macros used by both index tuples and heap tuples. + * + * + * Copyright (c) 1994, Regents of the University of California + * + * $Id: tupmacs.h,v 1.1 1996/08/27 21:50:27 scrappy Exp $ + * + *------------------------------------------------------------------------- + */ +#ifndef TUPMACS_H +#define TUPMACS_H + +/* + * check to see if the ATT'th bit of an array of 8-bit bytes is set. + */ +#define att_isnull(ATT, BITS) (!((BITS)[(ATT) >> 3] & (1 << ((ATT) & 0x07)))) + +/* + * given a AttributeTupleForm and a pointer into a tuple's data + * area, return the correct value or pointer. + * + * We return a 4 byte (char *) value in all cases. If the attribute has + * "byval" false or has variable length, we return the same pointer + * into the tuple data area that we're passed. Otherwise, we return + * the 1, 2, or 4 bytes pointed to by it, properly extended to 4 + * bytes, depending on the length of the attribute. + * + * note that T must already be properly LONGALIGN/SHORTALIGN'd for + * this to work correctly. + * + * the double-cast is to stop gcc from (correctly) complaining about + * casting integer types with size < sizeof(char *) to (char *). + * sign-extension may get weird if you use an integer type that + * isn't the same size as (char *) for the first cast. (on the other + * hand, it's safe to use another type for the (foo *)(T).) + * + * attbyval seems to be fairly redundant. We have to return a pointer if + * the value is longer than 4 bytes or has variable length; returning the + * value would be useless. In fact, for at least the variable length case, + * the caller assumes we return a pointer regardless of attbyval. + * I would eliminate attbyval altogether, but I don't know how. -BRYANH. + */ +#define fetchatt(A, T) \ + ((*(A))->attbyval && (*(A))->attlen != -1 \ + ? ((*(A))->attlen > sizeof(int16) \ + ? (char *) (long) *((int32 *)(T)) \ + : ((*(A))->attlen < sizeof(int16) \ + ? (char *) (long) *((char *)(T)) \ + : (char *) (long) *((int16 *)(T)))) \ + : (char *) (T)) + +#endif |