Move cntrl_to_mnemonic() to util.c from regcomp.c

This is in preparation for it being used elsewhere, to reduce
duplication of code.

1 files changed, 20 insertions, 0 deletions

diff --git a/util.c b/util.c
index 88752653c9..f3acdfe862 100644
--- a/util.c
+++ b/util.c
@@ -1035,6 +1035,26 @@ Perl_fbm_instr(pTHX_ unsigned char *big, unsigned char *bigend, SV *littlestr, U
     }
 }
 
+const char *
+Perl_cntrl_to_mnemonic(const U8 c)
+{
+    /* Returns the mnemonic string that represents character 'c', if one
+     * exists; NULL otherwise.  The only ones that exist for the purposes of
+     * this routine are a few control characters */
+
+    switch (c) {
+        case '\a':       return "\\a";
+        case '\b':       return "\\b";
+        case ESC_NATIVE: return "\\e";
+        case '\f':       return "\\f";
+        case '\n':       return "\\n";
+        case '\r':       return "\\r";
+        case '\t':       return "\\t";
+    }
+
+    return NULL;
+}
+
 /* copy a string to a safe spot */
 
 /*