Add lumiera_tmpbuf_strcat3 for concating up to three strings to safeclib

src/lib/safeclib.c

@@ -175,6 +175,18 @@ lumiera_tmpbuf_snprintf (size_t size, const char* fmt, ...)
 }
 
 
+char*
+lumiera_tmpbuf_strcat3 (const char* str1, size_t str1_len,
+                        const char* str2, size_t str2_len,
+                        const char* str3, size_t str3_len)
+{
+  return lumiera_tmpbuf_snprintf (SIZE_MAX, "%.*s%s%.*s%s%.*s",
+                                  str1?str1_len:0, str1?str1:"", str1?".":"",
+                                  str2?str2_len:0, str2?str2:"",
+                                  str3?".":"", str3?str3_len:0, str3?str3:"");
+}
+
+
 char*
 lumiera_tmpbuf_tr (const char* in, const char* from, const char* to, const char* def)
 {

src/lib/safeclib.h

@@ -135,6 +135,21 @@ lumiera_tmpbuf_strndup (const char* src, size_t size);
 char*
 lumiera_tmpbuf_snprintf (size_t size, const char* fmt, ...);
 
+/**
+ * Concat up to 3 strings in a tmpbuf.
+ * @param str1 first string to concat or NULL
+ * @param str1_len how much of the first string shall be used
+ * @param str2 second string to concat or NULL
+ * @param str2_len how much of the second string shall be used
+ * @param str3 third string to concat or NULL
+ * @param str3_len how much of the third string shall be used
+ * @return temporary buffer containing the constructed of the string
+ */
+char*
+lumiera_tmpbuf_strcat3 (const char* str1, size_t str1_len,
+                        const char* str2, size_t str2_len,
+                        const char* str3, size_t str3_len);
+
 /**
  * Translates characters in a string, similar to the shell 'tr' utility
  * @param in input string to  be translated