libc: Introduce cdefs.h, assert.h and strlen.c

Change-Id: I76091d52571f1950111c4b1670d5fc3883607715
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

include/lib/libc/assert.h

+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef ASSERT_H
+#define ASSERT_H
+
+#include <cdefs.h>
+#include <debug.h>
+#include <platform_def.h>
+
+#ifndef PLAT_LOG_LEVEL_ASSERT
+#define PLAT_LOG_LEVEL_ASSERT	LOG_LEVEL
+#endif
+
+#if ENABLE_ASSERTIONS
+# if PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_VERBOSE
+#  define assert(e)	((e) ? (void)0 : __assert(__FILE__, __LINE__, #e))
+# elif PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_INFO
+#  define assert(e)	((e) ? (void)0 : __assert(__FILE__, __LINE__))
+# else
+#  define assert(e)	((e) ? (void)0 : __assert())
+# endif
+#else
+#define assert(e)	((void)0)
+#endif /* ENABLE_ASSERTIONS */
+
+#if PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_VERBOSE
+__dead2 void __assert(const char *file, unsigned int line,
+		      const char *assertion);
+#elif PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_INFO
+__dead2 void __assert(const char *file, unsigned int line);
+#else
+__dead2 void __assert(void);
+#endif
+
+#endif /* ASSERT_H */

include/lib/libc/cdefs.h

+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef CDEFS_H
+#define CDEFS_H
+
+#define __dead2		__attribute__((__noreturn__))
+#define __deprecated	__attribute__((__deprecated__))
+#define __packed	__attribute__((__packed__))
+#define __used		__attribute__((__used__))
+#define __unused	__attribute__((__unused__))
+#define __aligned(x)	__attribute__((__aligned__(x)))
+#define __section(x)	__attribute__((__section__(x)))
+
+#define __printflike(fmtarg, firstvararg) \
+		__attribute__((__format__ (__printf__, fmtarg, firstvararg)))
+
+#define __weak_reference(sym, alias)	\
+	__asm__(".weak alias");		\
+	__asm__(".equ alias, sym")
+
+#define __STRING(x)	#x
+#define __XSTRING(x)	__STRING(x)
+
+#endif /* CDEFS_H */

lib/libc/strlen.c

+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <string.h>
+
+size_t strlen(const char *s)
+{
+	const char *cursor = s;
+
+	while (*cursor)
+		cursor++;
+
+	return cursor - s;
+}