Code changes that make it easier to prove that no 32-bit integer overflows

happen during memory allocation.  No problems fixed; this change is just
to make future maintenance easier.

FossilOrigin-Name: 215650a5a1d55bdbca9c92524804a1a54456a17f42a17e53747b21a6507506f5

1 files changed, 8 insertions, 0 deletions

diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index c8ecaf857..6ebd8eb4f 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1017,6 +1017,14 @@ typedef INT16_TYPE LogEst;
 #define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
 
 /*
+** Macro SMXV(n) return the maximum value that can be held in variable n,
+** assuming n is a signed integer type.  UMXV(n) is similar for unsigned
+** integer types.
+*/
+#define SMXV(n) ((((i64)1)<<(sizeof(n)-1))-1)
+#define UMXV(n) ((((i64)1)<<(sizeof(n)))-1)
+
+/*
 ** Round up a number to the next larger multiple of 8.  This is used
 ** to force 8-byte alignment on 64-bit architectures.
 **