Ensure SIZE_MAX can be used throughout our code.

Pre-C99 platforms may lack <stdint.h> and thereby SIZE_MAX.  We have
a couple of places using the hack "(size_t) -1" as a fallback, but
it wasn't universally available; which means the code added in commit
2e70d6b5e fails to compile everywhere.  Move that hack to c.h so that
we can rely on having SIZE_MAX everywhere.

Per discussion, it'd be a good idea to make the macro's value safe
for use in #if-tests, but that will take a bit more work.  This is
just a quick expedient to get the buildfarm green again.

Back-patch to all supported branches, like the previous commit.

Discussion: https://postgr.es/m/15883.1504278595@sss.pgh.pa.us

diff --git a/src/include/c.h b/src/include/c.h
index af799dc1dfb3f849f18aa7c43c7120d12fc73001..4f8bbfcd621fcb96f7efa60f9645f506d851c3aa 100644 (file)
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -343,6 +343,11 @@ typedef unsigned PG_INT128_TYPE uint128;
 #define PG_INT64_MAX   INT64CONST(0x7FFFFFFFFFFFFFFF)
 #define PG_UINT64_MAX  UINT64CONST(0xFFFFFFFFFFFFFFFF)
 
+/* Max value of size_t might also be missing if we don't have stdint.h */
+#ifndef SIZE_MAX
+#define SIZE_MAX ((size_t) -1)
+#endif
+
 /*
  * We now always use int64 timestamps, but keep this symbol defined for the
  * benefit of external code that might test it.

diff --git a/src/include/utils/memutils.h b/src/include/utils/memutils.h
index c55334906689bd35752f3bd5babf67cca0a64af5..869c59dc8535bd47641b69499bab556bd780f36c 100644 (file)
--- a/src/include/utils/memutils.h
+++ b/src/include/utils/memutils.h
@@ -41,7 +41,7 @@
 
 #define AllocSizeIsValid(size) ((Size) (size) <= MaxAllocSize)
 
-#define MaxAllocHugeSize   ((Size) -1 >> 1)    /* SIZE_MAX / 2 */
+#define MaxAllocHugeSize   (SIZE_MAX / 2)
 
 #define AllocHugeSizeIsValid(size) ((Size) (size) <= MaxAllocHugeSize)
 

diff --git a/src/timezone/private.h b/src/timezone/private.h
index c141fb61314501629ddbfd17c2f48ab2e7ba617e..e65cd1bb4ecd29a91afddd9239319da3e40917d2 100644 (file)
--- a/src/timezone/private.h
+++ b/src/timezone/private.h
@@ -48,10 +48,6 @@
 /* Unlike <ctype.h>'s isdigit, this also works if c < 0 | c > UCHAR_MAX. */
 #define is_digit(c) ((unsigned)(c) - '0' <= 9)
 
-#ifndef SIZE_MAX
-#define SIZE_MAX ((size_t) -1)
-#endif
-
 /*
  * SunOS 4.1.1 libraries lack remove.
  */