Add strndup()

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3649 42af7a65-404d-4744-a932-0658087f49c3
2026-06-07 17:33:08 +08:00 · 2011-05-29 16:07:13 +00:00
parent ae8cfb1bf1
commit a201aecd89
6 changed files with 101 additions and 6 deletions
@@ -38,6 +38,6 @@ STRING_SRCS	= lib_checkbase.c lib_isbasedigit.c lib_memset.c lib_memcpy.c \
 		  lib_strcat.c lib_strchr.c lib_strcpy.c lib_strcmp.c lib_strcspn.c \
 		  lib_strdup.c lib_strerror.c lib_strlen.c lib_strnlen.c \
 		  lib_strncasecmp.c lib_strncat.c lib_strncmp.c lib_strncpy.c \
-		  lib_strpbrk.c lib_strrchr.c  lib_strspn.c lib_strstr.c lib_strtok.c \
-		  lib_strtokr.c lib_strtol.c lib_strtoll.c lib_strtoul.c \
-		  lib_strtoull.c lib_strtod.c
+		  lib_strndup.c lib_strpbrk.c lib_strrchr.c  lib_strspn.c \
+		  lib_strstr.c lib_strtok.c lib_strtokr.c lib_strtol.c lib_strtoll.c \
+		  lib_strtoul.c lib_strtoull.c lib_strtod.c
@@ -0,0 +1,93 @@
+/************************************************************************
+ * lib/string//lib_strndup.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************************/
+
+/************************************************************************
+ * Included Files
+ ************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <string.h>
+
+#include "lib_internal.h"
+
+/************************************************************************
+ * Global Functions
+ ************************************************************************/
+/************************************************************************
+ * Name: strndup
+ *
+ * Description:
+ *   The strndup() function is equivalent to the strdup() function,
+ *   duplicating the provided 's' in a new block of memory allocated as
+ *   if by using malloc(), with the exception being that strndup() copies
+ *   at most 'size' plus one bytes into the newly allocated memory,
+ *   terminating the new string with a NUL character. If the length of 's'
+ *   is larger than 'size', only 'size' bytes will be duplicated. If
+ *   'size' is larger than the length of 's', all bytes in s will be
+ *   copied into the new memory buffer, including the terminating NUL
+ *   character. The newly created string will always be properly
+ *   terminated.
+ *
+ ************************************************************************/
+
+FAR char *strndup(FAR const char *s, size_t size)
+{
+  FAR char *news = NULL;
+  if (s)
+    {
+      /* Get the size of the new string = MIN(strlen(s), size) */
+
+      size_t allocsize = strlen(s);
+      if (allocsize > size)
+        {
+          allocsize = size;
+        }
+
+      /* Allocate the new string, adding 1 for the NUL terminator */
+
+      news = (FAR char*)lib_malloc(allocsize + 1);
+      if (news)
+        {
+          /* Copy the string into the allocated memory and add a NUL
+           * terminator in any case.
+           */
+
+          memcpy(news, s, allocsize);
+          news[allocsize] = '\0';
+        }
+    }
+  return news;
+}