X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fxsize.h;h=7634c6d4d5a4047da0f1896b410b163bd4edbe40;hb=575e5c29872d9eef1940036f78c7ee202df905ff;hp=42aa68a2a90da1f77ad0e3a13be6d540b9d436e4;hpb=8224e3007771aa0ef666eb1ff1d2564208cc2c91;p=gnulib.git

diff --git a/lib/xsize.h b/lib/xsize.h
index 42aa68a2a..7634c6d4d 100644
--- a/lib/xsize.h
+++ b/lib/xsize.h
@@ -37,11 +37,11 @@
    To avoid this, the functions and macros in this file check for overflow.
    The convention is that SIZE_MAX represents overflow.
    malloc (SIZE_MAX) is not guaranteed to fail -- think of a malloc
-   implementation that uses mmap --, it's recommended to use SIZE_OVERFLOW_P
-   before invoking malloc().
+   implementation that uses mmap --, it's recommended to use size_overflow_p()
+   or size_in_bounds_p() before invoking malloc().
    The example thus becomes:
       size_t size = xsum (header_size, xtimes (n, element_size));
-      void *p = (!SIZE_OVERFLOW_P (size) ? malloc (size) : NULL);
+      void *p = (size_in_bounds_p (size) ? malloc (size) : NULL);
 */
 
 /* Convert an arbitrary value >= 0 to type size_t.  */
@@ -50,6 +50,9 @@
 
 /* Sum of two sizes, with overflow check.  */
 static inline size_t
+#if __GNUC__ >= 3
+__attribute__ ((__pure__))
+#endif
 xsum (size_t size1, size_t size2)
 {
   size_t sum = size1 + size2;
@@ -58,6 +61,9 @@ xsum (size_t size1, size_t size2)
 
 /* Sum of three sizes, with overflow check.  */
 static inline size_t
+#if __GNUC__ >= 3
+__attribute__ ((__pure__))
+#endif
 xsum3 (size_t size1, size_t size2, size_t size3)
 {
   return xsum (xsum (size1, size2), size3);
@@ -65,11 +71,26 @@ xsum3 (size_t size1, size_t size2, size_t size3)
 
 /* Sum of four sizes, with overflow check.  */
 static inline size_t
+#if __GNUC__ >= 3
+__attribute__ ((__pure__))
+#endif
 xsum4 (size_t size1, size_t size2, size_t size3, size_t size4)
 {
   return xsum (xsum (xsum (size1, size2), size3), size4);
 }
 
+/* Maximum of two sizes, with overflow check.  */
+static inline size_t
+#if __GNUC__ >= 3
+__attribute__ ((__pure__))
+#endif
+xmax (size_t size1, size_t size2)
+{
+  /* No explicit check is needed here, because for any n:
+     max (SIZE_MAX, n) == SIZE_MAX and max (n, SIZE_MAX) == SIZE_MAX.  */
+  return (size1 >= size2 ? size1 : size2);
+}
+
 /* Multiplication of a count with an element size, with overflow check.
    The count must be >= 0 and the element size must be > 0.
    This is a macro, not an inline function, so that it works correctly even