Add memchr()

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4989 42af7a65-404d-4744-a932-0658087f49c3

3 files changed, 106 insertions, 17 deletions

diff --git a/nuttx/lib/string/Make.defs b/nuttx/lib/string/Make.defs
index 246b05381..c0a477c53 100644
--- a/nuttx/lib/string/Make.defs
+++ b/nuttx/lib/string/Make.defs
@@ -1,8 +1,8 @@
 ############################################################################
 # lib/string/Make.defs
 #
-#   Copyright (C) 2011 Gregory Nutt. All rights reserved.
-#   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+#   Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
@@ -33,11 +33,11 @@
 #
 ############################################################################
 
-STRING_SRCS	= lib_checkbase.c lib_isbasedigit.c lib_memset.c lib_memcpy.c \
-		  lib_memcmp.c lib_memmove.c lib_skipspace.c lib_strcasecmp.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 \
+STRING_SRCS	= lib_checkbase.c lib_isbasedigit.c lib_memset.c lib_memchr.c \
+		  lib_memcpy.c lib_memcmp.c lib_memmove.c lib_skipspace.c \
+		  lib_strcasecmp.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_strndup.c lib_strcasestr.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_strcasestr.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
diff --git a/nuttx/lib/string/lib_memchr.c b/nuttx/lib/string/lib_memchr.c
new file mode 100644
index 000000000..e0dec8270
--- /dev/null
+++ b/nuttx/lib/string/lib_memchr.c
@@ -0,0 +1,80 @@
+/****************************************************************************
+ * lib/string/lib_memchr.c
+ *
+ *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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>
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: memchr
+ *
+ * Description:
+ *   The memchr() function locates the first occurrence of 'c' (converted to
+ *   an unsigned char) in the initial 'n' bytes (each interpreted as
+ *   unsigned char) of the object pointed to by s.
+ *
+ * Returned Value:
+ *   The memchr() function returns a pointer to the located byte, or a null
+ *   pointer if the byte does not occur in the object.
+ *
+ ****************************************************************************/
+
+FAR void *memchr(FAR const void *s, int c, size_t n)
+{
+  FAR const unsigned char *p = (FAR const unsigned char *)s;
+
+  if (s)
+    {
+      while (n--)
+        {
+          if (*p == (unsigned char)c)
+            {
+              return (FAR void *)p;
+            }
+
+          p++;
+        }
+    }
+
+  return NULL;
+}
diff --git a/nuttx/lib/string/lib_strchr.c b/nuttx/lib/string/lib_strchr.c
index 1086f128d..ad7273862 100644
--- a/nuttx/lib/string/lib_strchr.c
+++ b/nuttx/lib/string/lib_strchr.c
@@ -1,8 +1,8 @@
 /****************************************************************************
  * lib/string/lib_strchr.c
  *
- *   Copyright (C) 2007, 2009, 2011 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *   Copyright (C) 2007, 2009, 2011-2012 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -45,11 +45,21 @@
  * Global Functions
  ****************************************************************************/
 
-/* The strchr() function returns a pointer to the first
- * occurrence of the character c in the string s.
- */
+/****************************************************************************
+ * Name: strchr
+ *
+ * Description:
+ *   The strchr() function locates the first occurrence of 'c' (converted to
+ *   a char) in the string pointed to by 's'. The terminating null byte is
+ *   considered to be part of the string.
+ *
+ * Returned Value:
+ *   Upon completion, strchr() returns a pointer to the byte, or a null
+ *   pointer if the byte was not found.
+ *
+ ****************************************************************************/
 
-char *strchr(const char *s, int c)
+FAR char *strchr(FAR const char *s, int c)
 {
   if (s)
     {
@@ -57,11 +67,10 @@ char *strchr(const char *s, int c)
         {
           if (*s == c)
             {
-              return (char*)s;
+              return (FAR char *)s;
             }
         }
     }
 
   return NULL;
 }
-