Centralize definition of integer limits.

Several submitted and even committed patches have run into the problem
that C89, our baseline, does not provide minimum/maximum values for
various integer datatypes. C99's stdint.h does, but we can't rely on
it.

Several parts of the code defined limits locally, so instead centralize
the definitions to c.h.

This patch also changes the more obvious usages of literal limit values;
there's more places that could be changed, but it's less clear whether
it's beneficial to change those.

Author: Andrew Gierth
Discussion: 87619tc5wc.fsf@news-spur.riddles.org.uk

contrib/btree_gist/btree_ts.c

@@ -153,7 +153,7 @@ ts_dist(PG_FUNCTION_ARGS)
 		p->day = INT_MAX;
 		p->month = INT_MAX;
 #ifdef HAVE_INT64_TIMESTAMP
-		p->time = INT64CONST(0x7FFFFFFFFFFFFFFF);
+		p->time = INT64_MAX;
 #else
 		p->time = DBL_MAX;
 #endif
@@ -181,7 +181,7 @@ tstz_dist(PG_FUNCTION_ARGS)
 		p->day = INT_MAX;
 		p->month = INT_MAX;
 #ifdef HAVE_INT64_TIMESTAMP
-		p->time = INT64CONST(0x7FFFFFFFFFFFFFFF);
+		p->time = INT64_MAX;
 #else
 		p->time = DBL_MAX;
 #endif

contrib/intarray/_int_gist.c

@@ -3,6 +3,8 @@
  */
 #include "postgres.h"
 
+#include <limits.h>
+
 #include "access/gist.h"
 #include "access/skey.h"
 
@@ -191,7 +193,7 @@ g_int_compress(PG_FUNCTION_ARGS)
 		cand = 1;
 		while (len > MAXNUMRANGE * 2)
 		{
-			min = 0x7fffffff;
+			min = INT_MAX;
 			for (i = 2; i < len; i += 2)
 				if (min > (dr[i] - dr[i - 1]))
 				{

contrib/pgbench/pgbench.c

@@ -49,10 +49,6 @@
 #include <sys/resource.h>		/* for getrlimit */
 #endif
 
-#ifndef INT64_MAX
-#define INT64_MAX	INT64CONST(0x7FFFFFFFFFFFFFFF)
-#endif
-
 #ifndef M_PI
 #define M_PI 3.14159265358979323846
 #endif
@@ -453,7 +449,7 @@ strtoint64(const char *str)
 		 */
 		if (strncmp(ptr, "9223372036854775808", 19) == 0)
 		{
-			result = -INT64CONST(0x7fffffffffffffff) - 1;
+			result = INT64_MIN;
 			ptr += 19;
 			goto gotdigits;
 		}

src/backend/access/transam/xlog.c

@@ -1408,7 +1408,7 @@ WALInsertLockAcquireExclusive(void)
 	{
 		LWLockAcquireWithVar(&WALInsertLocks[i].l.lock,
 							 &WALInsertLocks[i].l.insertingAt,
-							 UINT64CONST(0xFFFFFFFFFFFFFFFF));
+							 UINT64_MAX);
 	}
 	LWLockAcquireWithVar(&WALInsertLocks[i].l.lock,
 						 &WALInsertLocks[i].l.insertingAt,

src/backend/tsearch/wparser_def.c

@@ -14,6 +14,8 @@
 
 #include "postgres.h"
 
+#include <limits.h>
+
 #include "catalog/pg_collation.h"
 #include "commands/defrem.h"
 #include "tsearch/ts_locale.h"
@@ -2047,7 +2049,7 @@ hlCover(HeadlineParsedText *prs, TSQuery query, int *p, int *q)
 	int			pos = *p;
 
 	*q = -1;
-	*p = 0x7fffffff;
+	*p = INT_MAX;
 
 	for (j = 0; j < query->size; j++)
 	{
@@ -2258,7 +2260,7 @@ mark_hl_fragments(HeadlineParsedText *prs, TSQuery query, int highlight,
 	for (f = 0; f < max_fragments; f++)
 	{
 		maxitems = 0;
-		minwords = 0x7fffffff;
+		minwords = INT32_MAX;
 		minI = -1;
 
 		/*

src/backend/utils/adt/int8.c

@@ -78,7 +78,7 @@ scanint8(const char *str, bool errorOK, int64 *result)
 		 */
 		if (strncmp(ptr, "9223372036854775808", 19) == 0)
 		{
-			tmp = -INT64CONST(0x7fffffffffffffff) - 1;
+			tmp = INT64_MIN;
 			ptr += 19;
 			goto gotdigits;
 		}

src/backend/utils/adt/numutils.c

@@ -190,7 +190,7 @@ pg_lltoa(int64 value, char *a)
 	 * Avoid problems with the most negative integer not being representable
 	 * as a positive integer.
 	 */
-	if (value == (-INT64CONST(0x7FFFFFFFFFFFFFFF) - 1))
+	if (value == INT64_MIN)
 	{
 		memcpy(a, "-9223372036854775808", 21);
 		return;

src/backend/utils/adt/timestamp.c

@@ -44,14 +44,6 @@
 
 #define SAMESIGN(a,b)	(((a) < 0) == ((b) < 0))
 
-#ifndef INT64_MAX
-#define INT64_MAX	INT64CONST(0x7FFFFFFFFFFFFFFF)
-#endif
-
-#ifndef INT64_MIN
-#define INT64_MIN	(-INT64CONST(0x7FFFFFFFFFFFFFFF) - 1)
-#endif
-
 /* Set at postmaster start */
 TimestampTz PgStartTime;
 

src/backend/utils/adt/tsrank.c

@@ -13,6 +13,7 @@
  */
 #include "postgres.h"
 
+#include <limits.h>
 #include <math.h>
 
 #include "tsearch/ts_utils.h"
@@ -555,7 +556,7 @@ Cover(DocRepresentation *doc, int len, QueryRepresentation *qr, CoverExt *ext)
 
 	memset(qr->operandexist, 0, sizeof(bool) * qr->query->size);
 
-	ext->p = 0x7fffffff;
+	ext->p = INT_MAX;
 	ext->q = 0;
 	ptr = doc + ext->pos;
 

src/backend/utils/adt/txid.c

@@ -34,7 +34,7 @@
 
 
 /* txid will be signed int8 in database, so must limit to 63 bits */
-#define MAX_TXID   UINT64CONST(0x7FFFFFFFFFFFFFFF)
+#define MAX_TXID   ((uint64) INT64_MAX)
 
 /* Use unsigned variant internally */
 typedef uint64 txid;

src/include/c.h

@@ -249,6 +249,36 @@ typedef uint8 bits8;			/* >= 8 bits */
 typedef uint16 bits16;			/* >= 16 bits */
 typedef uint32 bits32;			/* >= 32 bits */
 
+/* should be defined in stdint.h, but we guarantee them here */
+#ifndef INT8_MIN
+#define INT8_MIN	(-0x7F-1)
+#endif
+#ifndef INT8_MAX
+#define INT8_MAX	(0x7F)
+#endif
+#ifndef INT16_MIN
+#define INT16_MIN	(-0x7FFF-1)
+#endif
+#ifndef INT16_MAX
+#define INT16_MAX	(0x7FFF)
+#endif
+#ifndef INT32_MIN
+#define INT32_MIN	(-0x7FFFFFFF-1)
+#endif
+#ifndef INT32_MAX
+#define INT32_MAX	(0x7FFFFFFF)
+#endif
+
+#ifndef UINT8_MAX
+#define UINT8_MAX	(0xFF)
+#endif
+#ifndef UINT16_MAX
+#define UINT16_MAX	(0xFFFF)
+#endif
+#ifndef UINT32_MAX
+#define UINT32_MAX	(0xFFFFFFFF)
+#endif
+
 /*
  * 64-bit integers
  */
@@ -284,6 +314,17 @@ typedef unsigned long long int uint64;
 #define UINT64CONST(x) ((uint64) x)
 #endif
 
+/* should be defined in stdint.h, but we guarantee them here */
+#ifndef INT64_MIN
+#define INT64_MIN	(-INT64CONST(0x7FFFFFFFFFFFFFFF) - 1)
+#endif
+#ifndef INT64_MAX
+#define INT64_MAX	INT64CONST(0x7FFFFFFFFFFFFFFF)
+#endif
+#ifndef UINT64_MAX
+#define UINT64_MAX	UINT64CONST(0xFFFFFFFFFFFFFFFF)
+#endif
+
 /* snprintf format strings to use for 64-bit integers */
 #define INT64_FORMAT "%" INT64_MODIFIER "d"
 #define UINT64_FORMAT "%" INT64_MODIFIER "u"

src/include/datatype/timestamp.h

@@ -119,8 +119,8 @@ typedef struct
  * DT_NOBEGIN represents timestamp -infinity; DT_NOEND represents +infinity
  */
 #ifdef HAVE_INT64_TIMESTAMP
-#define DT_NOBEGIN		(-INT64CONST(0x7fffffffffffffff) - 1)
-#define DT_NOEND		(INT64CONST(0x7fffffffffffffff))
+#define DT_NOBEGIN		INT64_MIN
+#define DT_NOEND		INT64_MAX
 #else							/* !HAVE_INT64_TIMESTAMP */
 #ifdef HUGE_VAL
 #define DT_NOBEGIN		(-HUGE_VAL)

src/include/executor/instrument.h

@@ -38,7 +38,7 @@ typedef enum InstrumentOption
 	INSTRUMENT_TIMER = 1 << 0,	/* needs timer (and row counts) */
 	INSTRUMENT_BUFFERS = 1 << 1,	/* needs buffer usage */
 	INSTRUMENT_ROWS = 1 << 2,	/* needs row count */
-	INSTRUMENT_ALL = 0x7FFFFFFF
+	INSTRUMENT_ALL = INT32_MAX
 } InstrumentOption;
 
 typedef struct Instrumentation

src/include/nodes/parsenodes.h

@@ -587,7 +587,7 @@ typedef enum TableLikeOption
 	CREATE_TABLE_LIKE_INDEXES = 1 << 2,
 	CREATE_TABLE_LIKE_STORAGE = 1 << 3,
 	CREATE_TABLE_LIKE_COMMENTS = 1 << 4,
-	CREATE_TABLE_LIKE_ALL = 0x7FFFFFFF
+	CREATE_TABLE_LIKE_ALL = INT32_MAX
 } TableLikeOption;
 
 /*

src/include/pg_config_manual.h

@@ -48,7 +48,7 @@
 /*
  * Set the upper and lower bounds of sequence values.
  */
-#define SEQ_MAXVALUE	INT64CONST(0x7FFFFFFFFFFFFFFF)
+#define SEQ_MAXVALUE	INT64_MAX
 #define SEQ_MINVALUE	(-SEQ_MAXVALUE)
 
 /*
@@ -185,7 +185,7 @@
  * the older rand() function, which is often different from --- and
  * considerably inferior to --- random().
  */
-#define MAX_RANDOM_VALUE  (0x7FFFFFFF)
+#define MAX_RANDOM_VALUE  INT32_MAX
 
 /*
  * On PPC machines, decide whether to use the mutex hint bit in LWARX

src/include/port/atomics.h

@@ -489,7 +489,7 @@ STATIC_IF_INLINE uint64
 pg_atomic_fetch_sub_u64(volatile pg_atomic_uint64 *ptr, int64 sub_)
 {
 	AssertPointerAlignment(ptr, 8);
-	Assert(sub_ != -INT64CONST(0x7FFFFFFFFFFFFFFF) - 1);
+	Assert(sub_ != INT64_MIN);
 	return pg_atomic_fetch_sub_u64_impl(ptr, sub_);
 }
 
@@ -518,7 +518,7 @@ STATIC_IF_INLINE uint64
 pg_atomic_sub_fetch_u64(volatile pg_atomic_uint64 *ptr, int64 sub_)
 {
 	AssertPointerAlignment(ptr, 8);
-	Assert(sub_ != -INT64CONST(0x7FFFFFFFFFFFFFFF) - 1);
+	Assert(sub_ != INT64_MIN);
 	return pg_atomic_sub_fetch_u64_impl(ptr, sub_);
 }
 

src/include/storage/predicate_internals.h

@@ -33,7 +33,7 @@ typedef uint64 SerCommitSeqNo;
  *	  at that point.  It's earlier than all normal sequence numbers,
  *	  and is only used by recovered prepared transactions
  */
-#define InvalidSerCommitSeqNo		((SerCommitSeqNo) UINT64CONST(0xFFFFFFFFFFFFFFFF))
+#define InvalidSerCommitSeqNo		((SerCommitSeqNo) UINT64_MAX)
 #define RecoverySerCommitSeqNo		((SerCommitSeqNo) 1)
 #define FirstNormalSerCommitSeqNo	((SerCommitSeqNo) 2)
 

src/include/utils/date.h

@@ -35,11 +35,9 @@ typedef struct
 
 /*
  * Infinity and minus infinity must be the max and min values of DateADT.
- * We could use INT_MIN and INT_MAX here, but seems better to not assume that
- * int32 == int.
  */
-#define DATEVAL_NOBEGIN		((DateADT) (-0x7fffffff - 1))
-#define DATEVAL_NOEND		((DateADT) 0x7fffffff)
+#define DATEVAL_NOBEGIN		((DateADT) INT32_MIN)
+#define DATEVAL_NOEND		((DateADT) INT32_MAX)
 
 #define DATE_NOBEGIN(j)		((j) = DATEVAL_NOBEGIN)
 #define DATE_IS_NOBEGIN(j)	((j) == DATEVAL_NOBEGIN)