diff --git a/src/util.c b/src/util.c
index 58dfbdd..88d366f 100644
--- a/src/util.c
+++ b/src/util.c
@@ -507,6 +507,108 @@ char *iso_2_fileid(const char *src)
     return strdup(dest);
 }
 
+/**
+ * Create a file/dir name suitable for an ISO image with relaxed constraints.
+ * 
+ * @param len
+ *     Max len for the name, without taken the "." into account.
+ * @param relaxed
+ *     0 only allow d-characters, 1 allow also lowe case chars, 
+ *     2 allow all characters 
+ * @param forcedot
+ *     Whether to ensure that "." is added
+ */
+char *iso_r_id(const char *src, size_t len, int relaxed, int forcedot)
+{
+    char *dot;
+    int lname, lext, lnname, lnext, pos, i;
+    char *dest = alloca(len + 1 + 1);
+
+    if (src == NULL) {
+        return NULL;
+    }
+
+    dot = strrchr(src, '.');
+
+    /* 
+     * Since the maximum length can be divided freely over the name and
+     * extension, we need to calculate their new lengths (lnname and
+     * lnext). If the original filename is too long, we start by trimming
+     * the extension, but keep a minimum extension length of 3. 
+     */
+    if (dot == NULL || *(dot + 1) == '\0') {
+        lname = strlen(src);
+        lnname = (lname > len) ? len : lname;
+        lext = lnext = 0;
+    } else {
+        lext = strlen(dot + 1);
+        lname = strlen(src) - lext - 1;
+        lnext = (strlen(src) > len + 1 && lext > 3) ? 
+                (lname < len - 3 ? len - lname : 3)
+                : lext;
+        lnname = (strlen(src) > len + 1) ? len - lnext : lname;
+    }
+
+    if (lnname == 0 && lnext == 0) {
+        return NULL;
+    }
+
+    pos = 0;
+
+    /* Convert up to lnname characters of the filename. */
+    for (i = 0; i < lnname; i++) {
+        char c= src[i];
+        if (relaxed == 2) {
+            /* all chars are allowed */
+            dest[pos++] = c;
+        } else if (valid_d_char(c)) {
+            /* it is a valid char */
+            dest[pos++] = c;
+        } else {
+            c= toupper(src[i]);
+            if (valid_d_char(c)) {
+                if (relaxed) {
+                    /* lower chars are allowed */
+                    dest[pos++] = src[i];
+                } else {
+                    dest[pos++] = c;
+                }
+            } else {
+                dest[pos++] = '_';
+            }
+        }
+    }
+    if (lnext > 0 || forcedot) {
+        dest[pos++] = '.';
+    }
+
+    /* Convert up to lnext characters of the extension, if any. */
+    for (i = lname + 1; i < lname + 1 + lnext; i++) {
+        char c= src[i];
+        if (relaxed == 2) {
+            /* all chars are allowed */
+            dest[pos++] = c;
+        } else if (valid_d_char(c)) {
+            /* it is a valid char */
+            dest[pos++] = c;
+        } else {
+            c= toupper(src[i]);
+            if (valid_d_char(c)) {
+                if (relaxed) {
+                    /* lower chars are allowed */
+                    dest[pos++] = src[i];
+                } else {
+                    dest[pos++] = c;
+                }
+            } else {
+                dest[pos++] = '_';
+            }
+        }
+    }
+    dest[pos] = '\0';
+    return strdup(dest);
+}
+
 uint16_t *iso_j_file_id(const uint16_t *src)
 {
     uint16_t *dot;
diff --git a/src/util.h b/src/util.h
index 7967db7..4e013a4 100644
--- a/src/util.h
+++ b/src/util.h
@@ -106,6 +106,19 @@ char *iso_1_fileid(const char *src);
  */
 char *iso_2_fileid(const char *src);
 
+/**
+ * Create a file/dir name suitable for an ISO image with relaxed constraints.
+ * 
+ * @param len
+ *     Max len for the name, without taken the "." into account.
+ * @param relaxed
+ *     0 only allow d-characters, 1 allow also lowe case chars, 
+ *     2 allow all characters 
+ * @param forcedot
+ *     Whether to ensure that "." is added
+ */
+char *iso_r_id(const char *src, size_t len, int relaxed, int forcedot);
+
 /**
  * Create a Joliet file identifier that consists of name and extension. The 
  * combined name and extension length will not exceed 128 bytes, and the 
diff --git a/test/test_util.c b/test/test_util.c
index 2e030c9..398bba5 100644
--- a/test/test_util.c
+++ b/test/test_util.c
@@ -374,6 +374,140 @@ static void test_iso_2_fileid()
     free(file);
 }
 
+static void test_iso_r_id()
+{
+    char *file;
+    
+    /* force dot */
+    file = iso_r_id("file1", 30, 0, 1);
+    CU_ASSERT_STRING_EQUAL(file, "FILE1.");
+    free(file);
+    
+    /* and not */
+    file = iso_r_id("file1", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "FILE1");
+    free(file);
+    
+    /* allow lowercase */
+    file = iso_r_id("file1", 30, 1, 0);
+    CU_ASSERT_STRING_EQUAL(file, "file1");
+    free(file);
+    file = iso_r_id("file1", 30, 2, 0);
+    CU_ASSERT_STRING_EQUAL(file, "file1");
+    free(file);
+    
+    /* force d-char and dot */
+    file = iso_r_id("fILe1", 30, 0, 1);
+    CU_ASSERT_STRING_EQUAL(file, "FILE1.");
+    free(file);
+    /* force d-char but not dot */
+    file = iso_r_id("fILe1", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "FILE1");
+    free(file);
+    /* allow lower case but force dot */
+    file = iso_r_id("fILe1", 30, 1, 1);
+    CU_ASSERT_STRING_EQUAL(file, "fILe1.");
+    free(file);
+    
+    file = iso_r_id("FILE1", 30, 0, 1);
+    CU_ASSERT_STRING_EQUAL(file, "FILE1.");
+    free(file);
+    file = iso_r_id(".EXT", 30, 0, 1);
+    CU_ASSERT_STRING_EQUAL(file, ".EXT");
+    free(file);
+    file = iso_r_id(".EXT", 30, 1, 0);
+    CU_ASSERT_STRING_EQUAL(file, ".EXT");
+    free(file);
+    
+    file = iso_r_id("file.ext", 30, 0, 1);
+    CU_ASSERT_STRING_EQUAL(file, "FILE.EXT");
+    free(file);
+    
+    /* not force dot is the same in this case */
+    file = iso_r_id("fiLE.ext", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "FILE.EXT");
+    free(file);
+    file = iso_r_id("fiLE.ext", 30, 2, 0);
+    CU_ASSERT_STRING_EQUAL(file, "fiLE.ext");
+    free(file);
+
+    file = iso_r_id("file.EXt", 30, 0, 1);
+    CU_ASSERT_STRING_EQUAL(file, "FILE.EXT");
+    free(file);
+    file = iso_r_id("FILE.EXT", 30, 0, 1);
+    CU_ASSERT_STRING_EQUAL(file, "FILE.EXT");
+    free(file);
+    
+    file = iso_r_id("31 characters filename.extensio", 30, 0, 1);
+    CU_ASSERT_STRING_EQUAL(file, "31_CHARACTERS_FILENAME.EXTENSIO");
+    free(file);
+    file = iso_r_id("32 characters filename.extension", 30, 0, 1);
+    CU_ASSERT_STRING_EQUAL(file, "32_CHARACTERS_FILENAME.EXTENSIO");
+    free(file);
+    
+    /* allow lowercase */
+    file = iso_r_id("31 characters filename.extensio", 30, 1, 1);
+    CU_ASSERT_STRING_EQUAL(file, "31_characters_filename.extensio");
+    free(file);
+    
+    /* and all characters */
+    file = iso_r_id("31 characters filename.extensio", 30, 2, 1);
+    CU_ASSERT_STRING_EQUAL(file, "31 characters filename.extensio");
+    free(file);
+    
+    file = iso_r_id("more than 30 characters filename.extension", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "MORE_THAN_30_CHARACTERS_FIL.EXT");
+    
+    /* incrementing the size... */
+    file = iso_r_id("more than 30 characters filename.extension", 35, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "MORE_THAN_30_CHARACTERS_FILENAME.EXT");
+    file = iso_r_id("more than 30 characters filename.extension", 36, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "MORE_THAN_30_CHARACTERS_FILENAME.EXTE");
+    
+    free(file);
+    file = iso_r_id("file.bigext", 30, 1, 0);
+    CU_ASSERT_STRING_EQUAL(file, "file.bigext");
+    free(file);
+    file = iso_r_id(".bigext", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, ".BIGEXT");
+    
+    /* "strange" characters */
+    file = iso_r_id("file<:a.ext", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "FILE__A.EXT");
+    free(file);
+    file = iso_r_id("file<:a.ext", 30, 1, 0);
+    CU_ASSERT_STRING_EQUAL(file, "file__a.ext");
+    free(file);
+    file = iso_r_id("file<:a.ext", 30, 2, 0);
+    CU_ASSERT_STRING_EQUAL(file, "file<:a.ext");
+    free(file);
+    
+    /* multiple dots */
+    file = iso_r_id("fi.le.a.ext", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "FI_LE_A.EXT");
+    free(file);
+    file = iso_r_id("fi.le.a.ext", 30, 1, 0);
+    CU_ASSERT_STRING_EQUAL(file, "fi_le_a.ext");
+    free(file);
+    file = iso_r_id("fi.le.a.ext", 30, 2, 0);
+    CU_ASSERT_STRING_EQUAL(file, "fi.le.a.ext");
+    
+    file = iso_r_id("file.<:a", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "FILE.__A");
+    free(file);
+    file = iso_r_id("file<:a.--a", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "FILE__A.__A");
+    free(file);
+
+    file = iso_r_id(".file.bigext", 30, 0, 0);
+    CU_ASSERT_STRING_EQUAL(file, "_FILE.BIGEXT");
+    free(file);
+
+    file = iso_r_id(".file.bigext", 30, 2, 0);
+    CU_ASSERT_STRING_EQUAL(file, ".file.bigext");
+    free(file);
+}
+
 static void test_iso_rbtree_insert()
 {
     int res;
@@ -509,6 +643,7 @@ void add_util_suite()
     CU_add_test(pSuite, "iso_2_dirid()", test_iso_2_dirid);
     CU_add_test(pSuite, "iso_1_fileid()", test_iso_1_fileid);
     CU_add_test(pSuite, "iso_2_fileid()", test_iso_2_fileid);
+    CU_add_test(pSuite, "iso_r_id()", test_iso_r_id);
     CU_add_test(pSuite, "iso_rbtree_insert()", test_iso_rbtree_insert);
     CU_add_test(pSuite, "iso_htable_put/get()", test_iso_htable_put_get);
 }