diff lib/bitrotate.h @ 40214:452ab00796c7

Fix undefined behaviour. * lib/bitrotate.h (rotl16, rotr16, rotl8, rotr8): Case x to 'unsigned int', to avoid shift operations on 'int'. * lib/xmemdup0.c (xmemdup0): Don't invoke memcpy with a zero size. * tests/test-count-leading-zeros.c (main): Use a random number that has as many bits as TYPE, not only 2*15 or 2*31 bits. * tests/test-count-trailing-zeros.c (main): Likewise. * tests/test-count-one-bits.c (main): Likewise. * tests/test-memmem.c: Don't include "null-ptr.h". (main): Use zerosize_ptr() instead of null_ptr(). * modules/memmem-tests (Files): Remove tests/null-ptr.h.
author Bruno Haible <bruno@clisp.org>
date Sat, 09 Mar 2019 20:32:25 +0100
parents b06060465f09
children
line wrap: on
line diff
--- a/lib/bitrotate.h	Sat Mar 09 00:27:19 2019 +0100
+++ b/lib/bitrotate.h	Sat Mar 09 20:32:25 2019 +0100
@@ -95,7 +95,8 @@
 BITROTATE_INLINE uint16_t
 rotl16 (uint16_t x, int n)
 {
-  return ((x << n) | (x >> (16 - n))) & UINT16_MAX;
+  return (((unsigned int) x << n) | ((unsigned int) x >> (16 - n)))
+         & UINT16_MAX;
 }
 
 /* Given an unsigned 16-bit argument X, return the value corresponding
@@ -106,7 +107,8 @@
 BITROTATE_INLINE uint16_t
 rotr16 (uint16_t x, int n)
 {
-  return ((x >> n) | (x << (16 - n))) & UINT16_MAX;
+  return (((unsigned int) x >> n) | ((unsigned int) x << (16 - n)))
+         & UINT16_MAX;
 }
 
 /* Given an unsigned 8-bit argument X, return the value corresponding
@@ -117,7 +119,7 @@
 BITROTATE_INLINE uint8_t
 rotl8 (uint8_t x, int n)
 {
-  return ((x << n) | (x >> (8 - n))) & UINT8_MAX;
+  return (((unsigned int) x << n) | ((unsigned int) x >> (8 - n))) & UINT8_MAX;
 }
 
 /* Given an unsigned 8-bit argument X, return the value corresponding
@@ -128,7 +130,7 @@
 BITROTATE_INLINE uint8_t
 rotr8 (uint8_t x, int n)
 {
-  return ((x >> n) | (x << (8 - n))) & UINT8_MAX;
+  return (((unsigned int) x >> n) | ((unsigned int) x << (8 - n))) & UINT8_MAX;
 }
 
 _GL_INLINE_HEADER_END