X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fmem%2Fmem.h;h=19f69c038c67efe1e11ac8ab5cec036123aa3b95;hb=870b63169c782ef0cc52687397e5b9a7125a61b0;hp=99c34c0a39719ec0a262add21e74bab5b99a8e56;hpb=8f6126000bfebc71f566ce56387f86fcd567e2c7;p=ccan

diff --git a/ccan/mem/mem.h b/ccan/mem/mem.h
index 99c34c0a..19f69c03 100644
--- a/ccan/mem/mem.h
+++ b/ccan/mem/mem.h
@@ -149,6 +149,19 @@ static inline bool memeqstr(const void *data, size_t length, const char *string)
 	return memeq(data, length, string, strlen(string));
 }
 
+/**
+ * memeqzero - Is a byte array all zeroes?
+ * @data: byte array
+ * @length: length of @data in bytes
+ *
+ * Example:
+ *	if (memeqzero(somebytes, bytes_len)) {
+ *		printf("somebytes == 0!\n");
+ *	}
+ */
+PURE_FUNCTION
+bool memeqzero(const void *data, size_t length);
+
 /**
  * memstarts_str - Does this byte array start with a string prefix?
  * @a: byte array
@@ -217,4 +230,66 @@ static inline bool memoverlaps(const void *a_, size_t al,
 	return (a < (b + bl)) && (b < (a + al));
 }
 
+/*
+ * memswap - Exchange two memory regions
+ * @a: first region
+ * @b: second region
+ * @n: length of the regions
+ *
+ * Undefined results if the two memory regions overlap.
+ */
+void memswap(void *a, void *b, size_t n);
+
+#if HAVE_VALGRIND_MEMCHECK_H
+#include <valgrind/memcheck.h>
+static inline void *memcheck_(const void *data, size_t len)
+{
+	VALGRIND_CHECK_MEM_IS_DEFINED(data, len);
+	return (void *)data;
+}
+#else
+static inline void *memcheck_(const void *data, size_t len)
+{
+	(void)len;
+	return (void *)data;
+}
+#endif
+
+#if HAVE_TYPEOF
+/**
+ * memcheck - check that a memory region is initialized
+ * @data: start of region
+ * @len: length in bytes
+ *
+ * When running under valgrind, this causes an error to be printed
+ * if the entire region is not defined.  Otherwise valgrind only
+ * reports an error when an undefined value is used for a branch, or
+ * written out.
+ *
+ * Example:
+ *	// Search for space, but make sure it's all initialized.
+ *	if (memchr(memcheck(somebytes, bytes_len), ' ', bytes_len)) {
+ *		printf("space was found!\n");
+ *	}
+ */
+#define memcheck(data, len) ((__typeof__((data)+0))memcheck_((data), (len)))
+#else
+#define memcheck(data, len) memcheck_((data), (len))
+#endif
+
+/**
+ * memtaint - mark a memory region unused
+ * @data: start of region
+ * @len: length in bytes
+ *
+ * This writes an "0xdeadbeef" eyecatcher repeatedly to the memory.
+ * When running under valgrind, it also tells valgrind that the memory is
+ * uninitialized, triggering valgrind errors if it is used for branches
+ * or written out (or passed to memcheck!) in future.
+ *
+ * Example:
+ *	// We'll reuse this buffer later, but be sure we don't access it.
+ *	memtaint(somebytes, bytes_len);
+ */
+void memtaint(void *data, size_t len);
 #endif /* CCAN_MEM_H */