database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-08 11:42:09 +03:00
Code Activity

Revise memutils.h to use alignment information gathered by

Browse Source 
configure, instead of having a bunch of crufty platform-specific guesses.
This commit is contained in:
Tom Lane
1999-03-25 19:05:19 +00:00
parent 235a569aaa
commit 1e117923aa
4 changed files with 370 additions and 96 deletions
Download Patch File Download Diff File Expand all files Collapse all files

51
src/include/utils/memutils.h
View File

@ -15,7 +15,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: memutils.h,v 1.22 1999/03/25 03:49:34 tgl Exp $
* $Id: memutils.h,v 1.23 1999/03/25 19:05:19 tgl Exp $
*
* NOTES
* some of the information in this file will be moved to
@ -30,50 +30,21 @@
/* ----------------
* Alignment macros: align a length or address appropriately for a given type.
*
* It'd be best to use offsetof to check how the compiler aligns stuff,
* but not all compilers support that (still true)? So we make the
* conservative assumption that a type must be aligned on a boundary equal
* to its own size, except on a few architectures where we know better.
* There used to be some incredibly crufty platform-dependent hackery here,
* but now we rely on the configure script to get the info for us. Much nicer.
*
* CAUTION: for the system tables, the struct declarations found in
* src/include/pg_*.h had better be interpreted by the compiler in a way
* that agrees with the workings of these macros. In practice that means
* being careful to lay out the columns of a system table in a way that avoids
* wasted pad space.
*
* CAUTION: _ALIGN will not work if sizeof(TYPE) is not a power of 2.
* There are machines where sizeof(double) is not, for example.
* But such a size is almost certainly not an alignment boundary anyway.
* NOTE: _ALIGN will not work if ALIGNVAL is not a power of 2.
* That case seems extremely unlikely to occur in practice, however.
* ----------------
*/
#define _ALIGN(TYPE,LEN) \
(((long)(LEN) + (sizeof(TYPE) - 1)) & ~(sizeof(TYPE) - 1))
#define _ALIGN(ALIGNVAL,LEN) (((long)(LEN) + (ALIGNVAL-1)) & ~(ALIGNVAL-1))
#define SHORTALIGN(LEN) _ALIGN(short, (LEN))
#if defined(m68k)
#define INTALIGN(LEN) _ALIGN(short, (LEN))
#else
#define INTALIGN(LEN) _ALIGN(int, (LEN))
#endif
#if (defined(sun) && ! defined(sparc)) || defined(m68k)
#define LONGALIGN(LEN) _ALIGN(short, (LEN))
#else
#define LONGALIGN(LEN) _ALIGN(long, (LEN))
#endif
#if defined(m68k)
#define DOUBLEALIGN(LEN) _ALIGN(short, (LEN))
#define MAXALIGN(LEN) _ALIGN(short, (LEN))
#elif defined(sco)
#define DOUBLEALIGN(LEN) _ALIGN(int, (LEN))
#define MAXALIGN(LEN) _ALIGN(int, (LEN))
#else
#define DOUBLEALIGN(LEN) _ALIGN(double, (LEN))
#define MAXALIGN(LEN) _ALIGN(double, (LEN))
#endif
#define SHORTALIGN(LEN) _ALIGN(ALIGNOF_SHORT, (LEN))
#define INTALIGN(LEN) _ALIGN(ALIGNOF_INT, (LEN))
#define LONGALIGN(LEN) _ALIGN(ALIGNOF_LONG, (LEN))
#define DOUBLEALIGN(LEN) _ALIGN(ALIGNOF_DOUBLE, (LEN))
#define MAXALIGN(LEN) _ALIGN(MAXIMUM_ALIGNOF, (LEN))
/*****************************************************************************
* oset.h -- Fixed format ordered set definitions. *