libc/str:add strlcat to libc

Signed-off-by: anjiahao <anjiahao@xiaomi.com>

include/string.h

@@ -63,6 +63,7 @@ int        strerror_r(int, FAR char *, size_t);
 size_t     strlen(FAR const char *);
 size_t     strnlen(FAR const char *, size_t);
 FAR char  *strcat(FAR char *, FAR const char *);
+size_t     strlcat(FAR char *, FAR const char *, size_t);
 FAR char  *strncat(FAR char *, FAR const char *, size_t);
 int        strcmp(FAR const char *, FAR const char *);
 int        strncmp(FAR const char *, FAR const char *, size_t);

libs/libc/machine/Kconfig

@@ -80,6 +80,10 @@ config LIBC_ARCH_STRCPY
 	bool
 	default n
 
+config LIBC_ARCH_STRLCAT
+	bool
+	default n
+
 config LIBC_ARCH_STRLCPY
 	bool
 	default n

libs/libc/string/Make.defs

@@ -69,6 +69,10 @@ ifneq ($(CONFIG_LIBC_ARCH_STRCPY),y)
 CSRCS += lib_strcpy.c
 endif
 
+ifneq ($(CONFIG_LIBC_ARCH_STRLCAT),y)
+CSRCS += lib_strlcat.c
+endif
+
 ifneq ($(CONFIG_LIBC_ARCH_STRLCPY),y)
 CSRCS += lib_strlcpy.c
 endif

libs/libc/string/lib_strlcat.c

@@ -0,0 +1,87 @@
+/****************************************************************************
+ * libs/libc/string/lib_strlcat.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <string.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: strlcat
+ *
+ * Description:
+ *   The strlcat() function appends at most (dstsize-strlen(dst)-1)
+ *   characters of src to dst (dstsize being the size of the string buffer
+ *   dst).
+ *
+ * Returned Value:
+ *   Returns min{dstsize,strlen(dst)} + strlen(src).
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_LIBC_ARCH_STRLCAT
+size_t strlcat(FAR char *dst, FAR const char *src, size_t dsize)
+{
+  FAR const char *odst = dst;
+  FAR const char *osrc = src;
+  size_t n = dsize;
+  size_t dlen;
+
+  /* Find the end of dst and adjust bytes left but don't go past end. */
+
+  while (n-- != 0 && *dst != '\0')
+    {
+      dst++;
+    }
+
+  dlen = dst - odst;
+  n = dsize - dlen;
+
+  if (n-- == 0)
+    {
+      return dlen + strlen(src);
+    }
+
+  while (*src != '\0')
+    {
+      if (n != 0)
+        {
+          *dst++ = *src;
+          n--;
+        }
+
+      src++;
+    }
+
+  *dst = '\0';
+
+  /* Count does not include NUL */
+
+  return dlen + (src - osrc);
+}
+#endif