From 3ad39e9878310e5317ee73c9b353c1e2c1c5c4ee Mon Sep 17 00:00:00 2001
From: Richard Qin <richard.qin.x@gmail.com>
Date: Sat, 11 Jul 2026 22:48:30 +0800
Subject: lib: establish Zircon libc++ and KTL foundation

---
 lib/libc/include/string.h | 97 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 lib/libc/include/string.h

(limited to 'lib/libc/include/string.h')

diff --git a/lib/libc/include/string.h b/lib/libc/include/string.h
new file mode 100644
index 0000000..3b55ccb
--- /dev/null
+++ b/lib/libc/include/string.h
@@ -0,0 +1,97 @@
+// Copyright 2016 The Fuchsia Authors
+// Copyright (c) 2008 Travis Geiselbrecht
+//
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT
+
+#ifndef ZIRCON_KERNEL_LIB_LIBC_INCLUDE_STRING_H_
+#define ZIRCON_KERNEL_LIB_LIBC_INCLUDE_STRING_H_
+
+// Other libc++ headers use <cstring> but libc++'s <cstring> complains if it
+// thinks <string.h> is not its own wrapper, which we do not need.  We always
+// get the kernel's <string.h> before the libc++ with the way the include paths
+// are set up, which is necessary because of other headers where preempting
+// libc++'s header is unavoidable for the kernel environment.  So just we
+// define the macro that <cstring> checks for to keep it happy.
+#define _LIBCPP_STRING_H
+
+#include <stddef.h>
+#include <zircon/compiler.h>
+
+__BEGIN_CDECLS
+
+int memcmp(const void*, const void*, size_t) __PURE;
+void* memcpy(void*, const void*, size_t);
+void* memmove(void*, const void*, size_t);
+void* memset(void*, int, size_t);
+
+char* strcat(char*, const char*);
+int strcmp(const char*, const char*) __PURE;
+char* strcpy(char*, const char*);
+size_t strlen(const char*) __PURE;
+char* strncat(char*, const char*, size_t);
+int strncmp(const char*, const char*, size_t) __PURE;
+char* strncpy(char*, const char*, size_t);
+size_t strspn(const char*, const char*) __PURE;
+size_t strcspn(const char* s, const char*) __PURE;
+char* strtok(char*, const char*);
+int strcoll(const char* s1, const char* s2) __PURE;
+size_t strxfrm(char* dest, const char* src, size_t n) __PURE;
+
+// Not actually defined in the kernel, but <cstring> expects the declaration.
+char* strerror(int);
+
+// Nonstandard.
+size_t strlcat(char*, const char*, size_t);
+size_t strlcpy(char*, const char*, size_t);
+int strncasecmp(const char*, const char*, size_t) __PURE;
+int strnicmp(const char*, const char*, size_t) __PURE;
+size_t strnlen(const char* s, size_t count) __PURE;
+
+// Used by address sanitizer.
+__typeof(memcpy) __unsanitized_memcpy;
+__typeof(memmove) __unsanitized_memmove;
+__typeof(memset) __unsanitized_memset;
+
+__END_CDECLS
+
+// C++ wants overloads for const and non-const versions of some functions.
+#ifdef __cplusplus
+
+const char* strchr(const char*, int) __asm__("strchr") __PURE;
+inline char* strchr(char* s, int c) {
+  return const_cast<char*>(strchr(const_cast<const char*>(s), c));
+}
+
+const char* strpbrk(const char*, const char*) __asm__("strpbrk") __PURE;
+inline char* strpbrk(char* s1, const char* s2) {
+  return const_cast<char*>(strpbrk(const_cast<const char*>(s1), s2));
+}
+
+const char* strrchr(const char*, int) __asm__("strrchr") __PURE;
+inline char* strrchr(char* s, int c) {
+  return const_cast<char*>(strrchr(const_cast<const char*>(s), c));
+}
+
+const void* memchr(const void*, int, size_t) __asm__("memchr") __PURE;
+inline void* memchr(void* s, int c, size_t n) {
+  return const_cast<void*>(memchr(const_cast<const void*>(s), c, n));
+}
+
+const char* strstr(const char*, const char*) __asm__("strstr") __PURE;
+inline char* strstr(char* s1, const char* s2) {
+  return const_cast<char*>(strstr(const_cast<const char*>(s1), s2));
+}
+
+#else
+
+void* memchr(const void*, int, size_t);
+char* strchr(const char*, int) __PURE;
+char* strpbrk(const char*, const char*) __PURE;
+char* strrchr(const char*, int) __PURE;
+char* strstr(const char*, const char*) __PURE;
+
+#endif  // __cplusplus
+
+#endif  // ZIRCON_KERNEL_LIB_LIBC_INCLUDE_STRING_H_
-- 
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