utils_subst: Added a module providing functions for string substitution.

Currently, the functions subst() and asubst() are available which may be used
to replace parts of a string with a specified replacement text. The latter
automatically allocates the memory required for the return value while the
former writes to a user specified buffer.

diff --git a/src/Makefile.am b/src/Makefile.am
index e9d53e5..cd50eea 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -38,6 +38,7 @@ collectd_SOURCES = collectd.c collectd.h \
                   utils_tail_match.c utils_tail_match.h \
                   utils_match.c utils_match.h \
                   utils_mount.c utils_mount.h \
+                  utils_subst.c utils_subst.h \
                   utils_tail.c utils_tail.h \
                   utils_threshold.c utils_threshold.h \
                   types_list.c types_list.h

diff --git a/src/utils_subst.c b/src/utils_subst.c
new file mode 100644 (file)
index 0000000..05dc844
--- /dev/null
+++ b/src/utils_subst.c
@@ -0,0 +1,82 @@
+/**
+ * collectd - src/utils_subst.c
+ * Copyright (C) 2008  Sebastian Harl
+ *
+ * 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
+ * Free Software Foundation; only version 2 of the License is applicable.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ * Authors:
+ *   Sebastian "tokkee" Harl <sh at tokkee.org>
+ **/
+
+/*
+ * This module provides functions for string substitution.
+ */
+
+#include "collectd.h"
+#include "common.h"
+
+char *subst (char *buf, size_t buflen, const char *string, int off1, int off2,
+               const char *replacement)
+{
+       char  *buf_ptr = buf;
+       size_t len     = buflen;
+
+       if ((NULL == buf) || (0 >= buflen) || (NULL == string)
+                       || (0 > off1) || (0 > off2) || (off1 > off2)
+                       || (NULL == replacement))
+               return NULL;
+
+       sstrncpy (buf_ptr, string, (off1 + 1 > buflen) ? buflen : off1 + 1);
+       buf_ptr += off1;
+       len     -= off1;
+
+       if (0 >= len)
+               return buf;
+
+       sstrncpy (buf_ptr, replacement, len);
+       buf_ptr += strlen (replacement);
+       len     -= strlen (replacement);
+
+       if (0 >= len)
+               return buf;
+
+       sstrncpy (buf_ptr, string + off2, len);
+       return buf;
+} /* subst */
+
+char *asubst (const char *string, int off1, int off2, const char *replacement)
+{
+       char *buf;
+       int   len;
+
+       char *ret;
+
+       if ((NULL == string) || (0 > off1) || (0 > off2) || (off1 > off2)
+                       || (NULL ==replacement))
+               return NULL;
+
+       len = off1 + strlen (replacement) + strlen (string) - off2 + 1;
+
+       buf = (char *)malloc (len);
+       if (NULL == buf)
+               return NULL;
+
+       ret = subst (buf, len, string, off1, off2, replacement);
+       if (NULL == ret)
+               free (buf);
+       return ret;
+} /* asubst */
+
+/* vim: set sw=4 ts=4 tw=78 noexpandtab : */
+

diff --git a/src/utils_subst.h b/src/utils_subst.h
new file mode 100644 (file)
index 0000000..bba33af
--- /dev/null
+++ b/src/utils_subst.h
@@ -0,0 +1,81 @@
+/**
+ * collectd - src/utils_subst.h
+ * Copyright (C) 2008  Sebastian Harl
+ *
+ * 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
+ * Free Software Foundation; only version 2 of the License is applicable.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ * Authors:
+ *   Sebastian "tokkee" Harl <sh at tokkee.org>
+ **/
+
+/*
+ * This module provides functions for string substitution.
+ */
+
+#ifndef UTILS_SUBST_H
+#define UTILS_SUBST_H 1
+
+#include <stddef.h>
+
+/*
+ * subst:
+ *
+ * Replace a substring of a string with the specified replacement text. The
+ * resulting string is stored in the buffer pointed to by 'buf' of length
+ * 'buflen'. Upon success, the buffer will always be null-terminated. The
+ * result may be truncated if the buffer is too small.
+ *
+ * The substring to be replaces is identified by the two offsets 'off1' and
+ * 'off2' where 'off1' specifies the offset to the beginning of the substring
+ * and 'off2' specifies the offset to the first byte after the substring.
+ *
+ * The minimum buffer size to store the complete return value (including the
+ * terminating '\0' character) thus has to be:
+ * off1 + strlen(replacement) + strlen(string) - off2 + 1
+ *
+ * Example:
+ *
+ *             01234567890
+ *   string = "foo_____bar"
+ *                ^    ^
+ *                |    |
+ *              off1  off2
+ *
+ *   off1 = 3
+ *   off2 = 8
+ *
+ *   replacement = " - "
+ *
+ *   -> "foo - bar"
+ *
+ * The function returns 'buf' on success, NULL else.
+ */
+char *subst (char *buf, size_t buflen, const char *string, int off1, int off2,
+               const char *replacement);
+
+/*
+ * asubst:
+ *
+ * This function is very similar to subst(). It differs in that it
+ * automatically allocates the memory required for the return value which the
+ * user then has to free himself.
+ *
+ * Returns the newly allocated result string on success, NULL else.
+ */
+char *asubst (const char *string, int off1, int off2, const char *replacement);
+
+#endif /* UTILS_SUBST_H */
+
+/* vim: set sw=4 ts=4 tw=78 noexpandtab : */
+