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Fix portability problems recently exposed by regression tests on Alphas.
1. Distinguish cases where a Datum representing a tuple datatype is an OID from cases where it is a pointer to TupleTableSlot, and make sure we use the right typlen in each case. 2. Make fetchatt() and related code support 8-byte by-value datatypes on machines where Datum is 8 bytes. Centralize knowledge of the available by-value datatype sizes in two macros in tupmacs.h, so that this will be easier if we ever have to do it again.
This commit is contained in:
Tom Lane
@@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: tupmacs.h,v 1.14 2000/03/17 02:36:37 tgl Exp $
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* $Id: tupmacs.h,v 1.15 2000/12/27 23:59:13 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@@ -22,50 +22,79 @@
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#define att_isnull(ATT, BITS) (!((BITS)[(ATT) >> 3] & (1 << ((ATT) & 0x07))))
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/*
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* given a Form_pg_attribute and a pointer into a tuple's data
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* area, return the correct value or pointer.
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* Given a Form_pg_attribute and a pointer into a tuple's data area,
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* return the correct value or pointer.
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*
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* We return a 4 byte (char *) value in all cases. If the attribute has
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* "byval" false or has variable length, we return the same pointer
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* into the tuple data area that we're passed. Otherwise, we return
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* the 1, 2, or 4 bytes pointed to by it, properly extended to 4
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* bytes, depending on the length of the attribute.
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* We return a Datum value in all cases. If the attribute has "byval" false,
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* we return the same pointer into the tuple data area that we're passed.
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* Otherwise, we return the correct number of bytes fetched from the data
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* area and extended to Datum form.
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*
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* note that T must already be properly LONGALIGN/SHORTALIGN'd for
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* this to work correctly.
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* On machines where Datum is 8 bytes, we support fetching 8-byte byval
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* attributes; otherwise, only 1, 2, and 4-byte values are supported.
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*
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* the double-cast is to stop gcc from (correctly) complaining about
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* casting integer types with size < sizeof(char *) to (char *).
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* sign-extension may get weird if you use an integer type that
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* isn't the same size as (char *) for the first cast. (on the other
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* hand, it's safe to use another type for the (foo *)(T).)
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*
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* attbyval seems to be fairly redundant. We have to return a pointer if
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* the value is longer than 4 bytes or has variable length; returning the
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* value would be useless. In fact, for at least the variable length case,
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* the caller assumes we return a pointer regardless of attbyval.
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* I would eliminate attbyval altogether, but I don't know how. -BRYANH.
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* Note that T must already be properly aligned for this to work correctly.
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*/
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#define fetchatt(A, T) \
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#define fetchatt(A,T) fetch_att(T, (A)->attbyval, (A)->attlen)
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/*
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* Same, but work from byval/len parameters rather than Form_pg_attribute.
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*/
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#if SIZEOF_DATUM == 8
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#define fetch_att(T,attbyval,attlen) \
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( \
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(*(A))->attbyval && (*(A))->attlen != -1 ? \
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(attbyval) ? \
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( \
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(*(A))->attlen > (int) sizeof(int16) ? \
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( \
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(char *) (long) *((int32 *)(T)) \
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) \
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(attlen) == (int) sizeof(Datum) ? \
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*((Datum *)(T)) \
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: \
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( \
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(attlen) == (int) sizeof(int32) ? \
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Int32GetDatum(*((int32 *)(T))) \
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: \
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( \
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(*(A))->attlen < (int) sizeof(int16) ? \
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(char *) (long) *((char *)(T)) \
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(attlen) == (int) sizeof(int16) ? \
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Int16GetDatum(*((int16 *)(T))) \
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: \
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(char *) (long) *((int16 *)(T))) \
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( \
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AssertMacro((attlen) == 1), \
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CharGetDatum(*((char *)(T))) \
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) \
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) \
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) \
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) \
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: \
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(char *) (T) \
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PointerGetDatum((char *) (T)) \
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)
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/* att_align aligns the given offset as needed for a datum of length attlen
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#else /* SIZEOF_DATUM != 8 */
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#define fetch_att(T,attbyval,attlen) \
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( \
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(attbyval) ? \
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( \
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(attlen) == (int) sizeof(int32) ? \
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Int32GetDatum(*((int32 *)(T))) \
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: \
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( \
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(attlen) == (int) sizeof(int16) ? \
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Int16GetDatum(*((int16 *)(T))) \
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: \
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( \
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AssertMacro((attlen) == 1), \
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CharGetDatum(*((char *)(T))) \
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) \
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) \
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) \
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: \
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PointerGetDatum((char *) (T)) \
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)
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#endif /* SIZEOF_DATUM == 8 */
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/*
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* att_align aligns the given offset as needed for a datum of length attlen
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* and alignment requirement attalign. In practice we don't need the length.
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* The attalign cases are tested in what is hopefully something like their
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* frequency of occurrence.
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@@ -81,6 +110,10 @@
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))) \
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)
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/*
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* att_addlength increments the given offset by the length of the attribute.
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* attval is only accessed if we are dealing with a varlena attribute.
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*/
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#define att_addlength(cur_offset, attlen, attval) \
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( \
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((attlen) != -1) ? \
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@@ -93,4 +126,60 @@
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) \
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)
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/*
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* store_att_byval is a partial inverse of fetch_att: store a given Datum
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* value into a tuple data area at the specified address. However, it only
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* handles the byval case, because in typical usage the caller needs to
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* distinguish by-val and by-ref cases anyway, and so a do-it-all macro
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* wouldn't be convenient.
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*/
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#if SIZEOF_DATUM == 8
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#define store_att_byval(T,newdatum,attlen) \
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do { \
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switch (attlen) \
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{ \
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case sizeof(char): \
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*(char *) (T) = DatumGetChar(newdatum); \
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break; \
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case sizeof(int16): \
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*(int16 *) (T) = DatumGetInt16(newdatum); \
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break; \
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case sizeof(int32): \
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*(int32 *) (T) = DatumGetInt32(newdatum); \
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break; \
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case sizeof(Datum): \
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*(Datum *) (T) = (newdatum); \
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break; \
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default: \
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elog(ERROR, "store_att_byval: unsupported byval length %d", \
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(int) (attlen)); \
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break; \
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} \
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} while (0)
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#else /* SIZEOF_DATUM != 8 */
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#define store_att_byval(T,newdatum,attlen) \
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do { \
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switch (attlen) \
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{ \
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case sizeof(char): \
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*(char *) (T) = DatumGetChar(newdatum); \
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break; \
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case sizeof(int16): \
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*(int16 *) (T) = DatumGetInt16(newdatum); \
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break; \
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case sizeof(int32): \
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*(int32 *) (T) = DatumGetInt32(newdatum); \
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break; \
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default: \
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elog(ERROR, "store_att_byval: unsupported byval length %d", \
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(int) (attlen)); \
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break; \
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} \
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} while (0)
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#endif /* SIZEOF_DATUM == 8 */
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#endif
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