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-rw-r--r--lib/stdlib/mem.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/lib/stdlib/mem.c b/lib/stdlib/mem.c
new file mode 100644
index 000000000..ec9dc2dea
--- /dev/null
+++ b/lib/stdlib/mem.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stddef.h> /* size_t */
+
+/*
+ * Fill @count bytes of memory pointed to by @dst with @val
+ */
+void *memset(void *dst, int val, size_t count)
+{
+ char *ptr = dst;
+
+ while (count--)
+ *ptr++ = val;
+
+ return dst;
+}
+
+/*
+ * Compare @len bytes of @s1 and @s2
+ */
+int memcmp(const void *s1, const void *s2, size_t len)
+{
+ const char *s = s1;
+ const char *d = s2;
+ char dc;
+ char sc;
+
+ while (len--) {
+ sc = *s++;
+ dc = *d++;
+ if (sc - dc)
+ return (sc - dc);
+ }
+
+ return 0;
+}
+
+/*
+ * Copy @len bytes from @src to @dst
+ */
+void *memcpy(void *dst, const void *src, size_t len)
+{
+ const char *s = src;
+ char *d = dst;
+
+ while (len--)
+ *d++ = *s++;
+
+ return dst;
+}
+
+/*
+ * Move @len bytes from @src to @dst
+ */
+void *memmove(void *dst, const void *src, size_t len)
+{
+ /*
+ * The following test makes use of unsigned arithmetic overflow to
+ * more efficiently test the condition !(src <= dst && dst < str+len).
+ * It also avoids the situation where the more explicit test would give
+ * incorrect results were the calculation str+len to overflow (though
+ * that issue is probably moot as such usage is probably undefined
+ * behaviour and a bug anyway.
+ */
+ if ((size_t)dst - (size_t)src >= len) {
+ /* destination not in source data, so can safely use memcpy */
+ return memcpy(dst, src, len);
+ } else {
+ /* copy backwards... */
+ const char *end = dst;
+ const char *s = (const char *)src + len;
+ char *d = (char *)dst + len;
+ while (d != end)
+ *--d = *--s;
+ }
+ return dst;
+}
+
+/*
+ * Scan @len bytes of @src for value @c
+ */
+void *memchr(const void *src, int c, size_t len)
+{
+ const char *s = src;
+
+ while (len--) {
+ if (*s == c)
+ return (void *) s;
+ s++;
+ }
+
+ return NULL;
+}