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Commit6a02746

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Change MemSet and StrNCpy to evaluate their arguments only once.
Fix inadequate parenthesization in several other macros.
1 parentfdd7f59 commit6a02746

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+64
-65
lines changed

1 file changed

+64
-65
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‎src/include/c.h‎

Lines changed: 64 additions & 65 deletions
Original file line numberDiff line numberDiff line change
@@ -8,14 +8,14 @@
88
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
99
* Portions Copyright (c) 1994, Regents of the University of California
1010
*
11-
* $Id: c.h,v 1.64 2000/01/26 05:57:46 momjian Exp $
11+
* $Id: c.h,v 1.65 2000/03/19 22:08:51 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
1515
/*
1616
* TABLE OF CONTENTS
1717
*
18-
*When adding stuff to this file, please tryand put stuff
18+
*When adding stuff to this file, please tryto put stuff
1919
*into the relevant section, or add new sections as appropriate.
2020
*
2121
* sectiondescription
@@ -34,10 +34,6 @@
3434
*10)Berkeley-specific defs
3535
*11)system-specific hacks
3636
*
37-
* NOTES
38-
*
39-
*This file is MACHINE AND COMPILER dependent!!!(For now.)
40-
*
4137
* ----------------------------------------------------------------
4238
*/
4339
#ifndefC_H
@@ -279,8 +275,6 @@ typedef signed int Offset;
279275
*
280276
*If your machine meets these requirements, Datums should also be checked
281277
*to see if the positioning is correct.
282-
*
283-
*This file is MACHINE AND COMPILER dependent!!!
284278
*/
285279

286280
typedefunsigned longDatum;/* XXX sizeof(long) >= sizeof(void *) */
@@ -403,28 +397,28 @@ typedef Datum *DatumPtr;
403397
*Returns pointer value of a datum.
404398
*/
405399

406-
#defineDatumGetPointer(X) ((Pointer)X)
400+
#defineDatumGetPointer(X) ((Pointer)(X))
407401

408402
/*
409403
* PointerGetDatum
410404
*Returns datum representation for a pointer.
411405
*/
412406

413-
#definePointerGetDatum(X) ((Datum)X)
407+
#definePointerGetDatum(X) ((Datum)(X))
414408

415409
/*
416410
* DatumGetName
417411
*Returns name value of a datum.
418412
*/
419413

420-
#defineDatumGetName(X) ((Name) DatumGetPointer((Datum)X))
414+
#defineDatumGetName(X) ((Name) DatumGetPointer((Datum)(X)))
421415

422416
/*
423417
* NameGetDatum
424418
*Returns datum representation for a name.
425419
*/
426420

427-
#defineNameGetDatum(X) PointerGetDatum((Pointer)X)
421+
#defineNameGetDatum(X) PointerGetDatum((Pointer)(X))
428422

429423

430424
/*
@@ -433,15 +427,15 @@ typedef Datum *DatumPtr;
433427
*This is really a pointer, of course.
434428
*/
435429

436-
#defineDatumGetFloat32(X) ((float32) DatumGetPointer((Datum)X))
430+
#defineDatumGetFloat32(X) ((float32) DatumGetPointer(X))
437431

438432
/*
439433
* Float32GetDatum
440434
*Returns datum representation for a 32-bit floating point number.
441435
*This is really a pointer, of course.
442436
*/
443437

444-
#defineFloat32GetDatum(X) PointerGetDatum((Pointer)X)
438+
#defineFloat32GetDatum(X) PointerGetDatum((Pointer)(X))
445439

446440
/*
447441
* DatumGetFloat64
@@ -457,7 +451,7 @@ typedef Datum *DatumPtr;
457451
*This is really a pointer, of course.
458452
*/
459453

460-
#defineFloat64GetDatum(X) PointerGetDatum((Pointer)X)
454+
#defineFloat64GetDatum(X) PointerGetDatum((Pointer)(X))
461455

462456
/* ----------------------------------------------------------------
463457
*Section 5:IsValid macros for system types
@@ -473,18 +467,7 @@ typedef Datum *DatumPtr;
473467
* PointerIsValid
474468
*True iff pointer is valid.
475469
*/
476-
#definePointerIsValid(pointer) (bool)((void*)(pointer) != NULL)
477-
478-
/*
479-
* PointerIsInBounds
480-
*True iff pointer is within given bounds.
481-
*
482-
* Note:
483-
*Assumes the bounded interval to be [min,max),
484-
*i.e. closed on the left and open on the right.
485-
*/
486-
#definePointerIsInBounds(pointer,min,max) \
487-
((min) <= (pointer) && (pointer) < (max))
470+
#definePointerIsValid(pointer) ((void*)(pointer) != NULL)
488471

489472
/*
490473
* PointerIsAligned
@@ -560,14 +543,14 @@ typedef struct Exception
560543
*Isn't CPP fun?
561544
*/
562545
#defineTrapMacro(condition,exception) \
563-
((bool) ((! assert_enabled) ||(!condition) || \
546+
((bool) ((! assert_enabled) ||! (condition) || \
564547
(ExceptionalCondition(CppAsString(condition), \
565548
&(exception), \
566549
(char*) NULL, __FILE__, __LINE__))))
567550

568551
#ifndefUSE_ASSERT_CHECKING
569552
#defineAssert(condition)
570-
#defineAssertMacro(condition)(void)true
553+
#defineAssertMacro(condition)((void)true)
571554
#defineAssertArg(condition)
572555
#defineAssertState(condition)
573556
#defineassert_enabled 0
@@ -576,7 +559,7 @@ typedef struct Exception
576559
Trap(!(condition), FailedAssertion)
577560

578561
#defineAssertMacro(condition) \
579-
(void)TrapMacro(!(condition), FailedAssertion)
562+
((void)TrapMacro(!(condition), FailedAssertion))
580563

581564
#defineAssertArg(condition) \
582565
Trap(!(condition), BadArg)
@@ -604,7 +587,7 @@ extern intassert_enabled;
604587
*#define foo(x) (LogAssertMacro(x != 0, "yow!") && bar(x))
605588
*/
606589
#defineLogTrapMacro(condition,exception,printArgs) \
607-
((bool) ((! assert_enabled) ||(!condition) || \
590+
((bool) ((! assert_enabled) ||! (condition) || \
608591
(ExceptionalCondition(CppAsString(condition), \
609592
&(exception), \
610593
vararg_format printArgs, __FILE__, __LINE__))))
@@ -659,46 +642,62 @@ extern intassertTest(int val);
659642

660643
/*
661644
* StrNCpy
662-
*Does string copy, and forces terminating NULL
663-
*/
664-
/* we do this so if the macro is used in an if action, it will work */
665-
#defineStrNCpy(dst,src,len)\
666-
( \
667-
((len) > 0) ? \
668-
( \
669-
strncpy((dst),(src),(len)-1), \
670-
*((dst)+(len)-1)='\0' \
671-
) \
672-
: \
673-
(dummyret)NULL,(void)(dst) \
674-
)
645+
*Like standard library function strncpy(), except that result string
646+
*is guaranteed to be null-terminated --- that is, at most N-1 bytes
647+
*of the source string will be kept.
648+
*Also, the macro returns no result (too hard to do that without
649+
*evaluating the arguments multiple times, which seems worse).
650+
*/
651+
#defineStrNCpy(dst,src,len) \
652+
do \
653+
{ \
654+
char * _dst = (dst); \
655+
Size _len = (len); \
656+
\
657+
if (_len > 0) \
658+
{ \
659+
strncpy(_dst, (src), _len); \
660+
_dst[_len-1] = '\0'; \
661+
} \
662+
} while (0)
663+
675664

676665
/* Get a bit mask of the bits set in non-int32 aligned addresses */
677666
#defineINT_ALIGN_MASK (sizeof(int32) - 1)
678667

679668
/*
680-
*This function gets call too often, so we inline it if we can.
681-
*Are we aligned for int32?
682-
*We have to cast the pointer to int so we can do the AND
669+
* MemSet
670+
*Exactly the same as standard library function memset(), but considerably
671+
*faster for zeroing small word-aligned structures (such as parsetree nodes).
672+
*This has to be a macro because the main point is to avoid function-call
673+
*overhead.
674+
*
683675
*We got the 64 number by testing this against the stock memset() on
684-
*BSD/OS 3.0. Larger values were slower.
685-
*/
686-
#defineMemSet(start,val,len) do \
687-
{ \
688-
if (((long)(start) & INT_ALIGN_MASK) == 0 && \
689-
((len) & INT_ALIGN_MASK) == 0 && \
690-
(val) == 0 && \
691-
(len) <= 64) \
692-
{ \
693-
int32 *_i = (int32 *)(start); \
694-
int32 *_stop = (int32 *)((char *)(start) + (len)); \
695-
\
696-
while (_i < _stop) \
697-
*_i++ = 0; \
698-
} \
699-
else \
700-
memset((start), (val), (len)); \
701-
} while (0)
676+
*BSD/OS 3.0. Larger values were slower. (I think the crossover point
677+
*could be a good deal higher for most platforms, actually --- tgl)
678+
*/
679+
#defineMemSet(start,val,len) \
680+
do \
681+
{ \
682+
int32 * _start = (int32 *) (start); \
683+
int_val = (val); \
684+
Size_len = (len); \
685+
\
686+
if ((((long) _start) & INT_ALIGN_MASK) == 0 && \
687+
(_len & INT_ALIGN_MASK) == 0 && \
688+
_val == 0 && \
689+
_len <= MEMSET_LOOP_LIMIT) \
690+
{ \
691+
int32 * _stop = (int32 *) ((char *) _start + _len); \
692+
while (_start < _stop) \
693+
*_start++ = 0; \
694+
} \
695+
else \
696+
memset((char *) _start, _val, _len); \
697+
} while (0)
698+
699+
#defineMEMSET_LOOP_LIMIT 64
700+
702701

703702
/* ----------------------------------------------------------------
704703
*Section 9: externs

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