Ensure SIZE_MAX can be used throughout our code.

Pre-C99 platforms may lack  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 2b5d84e53f1992fc8830d9f5ad645d0c6e5db56d..fad895204b7fef99cf5eab005e7d7fd5af14ab09 100644 (file)
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -288,6 +288,10 @@ typedef unsigned long long int uint64;
 #define UINT64CONST(x) ((uint64) x)
 #endif
 
+/* Max value of size_t might be missing if we don't have stdint.h */
+#ifndef SIZE_MAX
+#define SIZE_MAX ((size_t) -1)
+#endif
 
 /* Select timestamp representation (float8 or int64) */
 #ifdef USE_INTEGER_DATETIMES

diff --git a/src/include/utils/memutils.h b/src/include/utils/memutils.h
index 9f499d118042cd33e97af09a9022c47539cc6bb1..a0c755daf3734f1f30c5ac5560002e9209f19458 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 f031b17b7eff0ecab9c55ad04a962679f8c072c3..f78053660e8dc1dafd8d72270a79fc11bea8fd87 100644 (file)
--- a/src/timezone/private.h
+++ b/src/timezone/private.h
@@ -48,10 +48,6 @@
 /* Unlike '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.
  */