Update H5_IS_BUFFER_OVERFLOW to account for 'size' of 0

src/H5private.h

@@ -352,12 +352,21 @@
  * For the time being, these can be suppressed with
  * H5_GCC_CLANG_DIAG_OFF("type-limits")/H5_GCC_CLANG_DIAG_ON("type-limits")
  */
+/* clang-format off */
 #define H5_IS_BUFFER_OVERFLOW(ptr, size, buffer_end) \
- (((ptr) > (buffer_end)) || /* Bad precondition */ \
- (((size_t)(size) <= PTRDIFF_MAX) && \
- ((ptrdiff_t)(size) < 0)) || /* Account for (likely unintentional) negative 'size' */ \
- ((size_t)(size) > \
- (size_t)((((const uint8_t *)buffer_end) - ((const uint8_t *)ptr)) + 1))) /* Typical overflow */
+ ( \
+ /* Trivial case */ \
+ ((size) != 0) && \
+ ( \
+ /* Bad precondition */ \
+ ((ptr) > (buffer_end)) || \
+ /* Account for (likely unintentional) negative 'size' */ \
+ (((size_t)(size) <= PTRDIFF_MAX) && ((ptrdiff_t)(size) < 0)) || \
+ /* Typical overflow */ \
+ ((size_t)(size) > (size_t)((((const uint8_t *)buffer_end) - ((const uint8_t *)ptr)) + 1)) \
+ ) \
+ )
+/* clang-format on */
 
 /* Variant of H5_IS_BUFFER_OVERFLOW, used with functions such as H5Tdecode()
  * that don't take a size parameter, where we need to skip the bounds checks.
@@ -366,7 +375,7 @@
  * the entire library.
  */
 #define H5_IS_KNOWN_BUFFER_OVERFLOW(skip, ptr, size, buffer_end) \
- (skip ? false : ((ptr) + (size)-1) > (buffer_end))
+ (skip ? false : H5_IS_BUFFER_OVERFLOW(ptr, size, buffer_end))
 
 /*
  * HDF Boolean type.