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

7 files changed, 10 insertions, 15 deletions

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2c6ae12b8d6..751253ba03c 100644
--- a/src/backend/access/transam/xlog.c
+++ b/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,
diff --git a/src/backend/tsearch/wparser_def.c b/src/backend/tsearch/wparser_def.c
index ca5b54358ac..d95fdb1fabc 100644
--- a/src/backend/tsearch/wparser_def.c
+++ b/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;
 
 		/*
diff --git a/src/backend/utils/adt/int8.c b/src/backend/utils/adt/int8.c
index 56d909a4f65..b3a11918870 100644
--- a/src/backend/utils/adt/int8.c
+++ b/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;
 		}
diff --git a/src/backend/utils/adt/numutils.c b/src/backend/utils/adt/numutils.c
index d77799acfe3..585da1e7322 100644
--- a/src/backend/utils/adt/numutils.c
+++ b/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;
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 723c67087e5..33e859d35e1 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/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;
 
diff --git a/src/backend/utils/adt/tsrank.c b/src/backend/utils/adt/tsrank.c
index 733203ec7b5..a3066fa7948 100644
--- a/src/backend/utils/adt/tsrank.c
+++ b/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;
 
diff --git a/src/backend/utils/adt/txid.c b/src/backend/utils/adt/txid.c
index f973ef936c5..31f8033ae48 100644
--- a/src/backend/utils/adt/txid.c
+++ b/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;