src/common.[ch]: Rewrite the escape_slashes() function.

Cleaner and slightly more efficient (3.8% faster) version of escape_slashes().
This function is quite hot with, depending on the configuration, between 1.2%
and 2.6% of total CPU time spent here.

diff --git a/src/common.c b/src/common.c
index 161b4d6..81142fd 100644 (file)
--- a/src/common.c
+++ b/src/common.c
@@ -1,6 +1,6 @@
 /**
  * collectd - src/common.c
- * Copyright (C) 2005-2010  Florian octo Forster
+ * Copyright (C) 2005-2014  Florian octo Forster
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -418,34 +418,36 @@ size_t strstripnewline (char *buffer)
        return (buffer_len);
 } /* size_t strstripnewline */
 
-int escape_slashes (char *buf, int buf_len)
+int escape_slashes (char *buffer, size_t buffer_size)
 {
        int i;
+       size_t buffer_len;
 
-       if (strcmp (buf, "/") == 0)
-       {
-               if (buf_len < 5)
-                       return (-1);
+       buffer_len = strlen (buffer);
 
-               strncpy (buf, "root", buf_len);
+       if (buffer_len <= 1)
+       {
+               if (strcmp ("/", buffer) == 0)
+               {
+                       if (buffer_size < 5)
+                               return (-1);
+                       sstrncpy (buffer, "root", buffer_size);
+               }
                return (0);
        }
 
-       if (buf_len <= 1)
-               return (0);
-
        /* Move one to the left */
-       if (buf[0] == '/')
-               memmove (buf, buf + 1, buf_len - 1);
+       if (buffer[0] == '/')
+       {
+               memmove (buffer, buffer + 1, buffer_len);
+               buffer_len--;
+       }
 
-       for (i = 0; i < buf_len - 1; i++)
+       for (i = 0; i < buffer_len - 1; i++)
        {
-               if (buf[i] == '\0')
-                       break;
-               else if (buf[i] == '/')
-                       buf[i] = '_';
+               if (buffer[i] == '/')
+                       buffer[i] = '_';
        }
-       buf[i] = '\0';
 
        return (0);
 } /* int escape_slashes */

diff --git a/src/common.h b/src/common.h
index 317be8d..67f307c 100644 (file)
--- a/src/common.h
+++ b/src/common.h
@@ -1,6 +1,6 @@
 /**
  * collectd - src/common.h
- * Copyright (C) 2005-2010  Florian octo Forster
+ * Copyright (C) 2005-2014  Florian octo Forster
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -158,19 +158,21 @@ int strjoin (char *dst, size_t dst_len, char **fields, size_t fields_num, const
  *   escape_slashes
  *
  * DESCRIPTION
- *   Removes slashes from the string `buf' and substitutes them with something
- *   appropriate. This function should be used whenever a path is to be used as
- *   (part of) an instance.
+ *   Removes slashes ("/") from "buffer". If buffer contains a single slash,
+ *   the result will be "root". Leading slashes are removed. All other slashes
+ *   are replaced with underscores ("_").
+ *   This function is used by plugin_dispatch_values() to escape all parts of
+ *   the identifier.
  *
  * PARAMETERS
- *   `buf'         String to be escaped.
- *   `buf_len'     Length of the buffer. No more then this many bytes will be
- *   written to `buf', including the trailing null-byte.
+ *   `buffer'         String to be escaped.
+ *   `buffer_size'    Size of the buffer. No more then this many bytes will be
+ *                    written to `buffer', including the trailing null-byte.
  *
  * RETURN VALUE
  *   Returns zero upon success and a value smaller than zero upon failure.
  */
-int escape_slashes (char *buf, int buf_len);
+int escape_slashes (char *buffer, size_t buffer_size);
 
 /*
  * NAME