strscan.diff

diff --git a/ext/strscan/strscan.c b/ext/strscan/strscan.c
index b81e1f1..2475ba5 100644
--- a/ext/strscan/strscan.c
+++ b/ext/strscan/strscan.c
@@ -38,6 +38,9 @@ struct strscanner
 
     /* the regexp register; legal only when MATCHED_P(s) */
     struct re_registers regs;
+
+    /* regexp used for last scan */
+    VALUE regex;
 };
 
 #define MATCHED_P(s)          ((s)->flags & FLAG_MATCHED)
@@ -445,17 +448,36 @@ strscan_do_scan(VALUE self, VALUE regex, int succptr, int getstr, int headonly)
 {
     regex_t *rb_reg_prepare_re(VALUE re, VALUE str);
     struct strscanner *p;
-    regex_t *re;
+    regex_t *re, *oldre;
     long ret;
-    int tmpreg;
+    int tmpreg, oldtmpreg;
 
     Check_Type(regex, T_REGEXP);
     GET_SCANNER(self, p);
 
+    // THIS SEGFAULTS
+    // if (p->regex) {
+    //     oldre = rb_reg_prepare_re(regex, p->str);
+    //     oldtmpreg = oldre != RREGEXP(p->regex)->ptr;
+    //     if (oldtmpreg) {
+    //         if (RREGEXP(p->regex)->usecnt) {
+    //             onig_free(oldre);
+    //         }
+    //         else {
+    //             onig_free(RREGEXP(p->regex)->ptr);
+    //             RREGEXP(p->regex)->ptr = oldre;
+    //         }
+    //     } else {
+    //         RREGEXP(p->regex)->usecnt--;
+    //     }
+    // }
+
     CLEAR_MATCH_STATUS(p);
     if (S_RESTLEN(p) < 0) {
         return Qnil;
     }
+
+    p->regex = regex;
     re = rb_reg_prepare_re(regex, p->str);
     tmpreg = re != RREGEXP(regex)->ptr;
     if (!tmpreg) RREGEXP(regex)->usecnt++;
@@ -471,16 +493,6 @@ strscan_do_scan(VALUE self, VALUE regex, int succptr, int getstr, int headonly)
                           (UChar* )CURPTR(p), (UChar* )(CURPTR(p) + S_RESTLEN(p)),
                           &(p->regs), ONIG_OPTION_NONE);
     }
-    if (!tmpreg) RREGEXP(regex)->usecnt--;
-    if (tmpreg) {
-        if (RREGEXP(regex)->usecnt) {
-            onig_free(re);
-        }
-        else {
-            onig_free(RREGEXP(regex)->ptr);
-            RREGEXP(regex)->ptr = re;
-        }
-    }
 
     if (ret == -2) rb_raise(ScanError, "regexp buffer overflow");
     if (ret < 0) {
@@ -976,11 +988,14 @@ strscan_matched_size(VALUE self)
  * Return the n-th subgroup in the most recent match.
  *
  *   s = StringScanner.new("Fri Dec 12 1975 14:39")
- *   s.scan(/(\w+) (\w+) (\d+) /)       # -> "Fri Dec 12 "
+ *   s.scan(/(?<wday>\w+) (?<month>\w+) (?<day>\d+) /)       # -> "Fri Dec 12 "
  *   s[0]                               # -> "Fri Dec 12 "
  *   s[1]                               # -> "Fri"
  *   s[2]                               # -> "Dec"
  *   s[3]                               # -> "12"
+ *   s[:wday]                           # -> "Fri"
+ *   s[:month]                          # -> "Dec"
+ *   s[:day]                            # -> "12"
  *   s.post_match                       # -> "1975 14:39"
  *   s.pre_match                        # -> ""
  */
@@ -993,7 +1008,16 @@ strscan_aref(VALUE self, VALUE idx)
     GET_SCANNER(self, p);
     if (! MATCHED_P(p))        return Qnil;
 
-    i = NUM2LONG(idx);
+    if (TYPE(idx) == T_SYMBOL) {
+        const char *name, *name_end;
+        name = rb_id2name(SYM2ID(idx));
+        name_end = name + strlen(name);
+        i = onig_name_to_backref_number(RREGEXP(p->regex)->ptr,
+            (const unsigned char* )name, (const unsigned char* )name_end, &(p->regs));
+    } else {
+        i = NUM2LONG(idx);
+    }
+
     if (i < 0)
         i += p->regs.num_regs;
     if (i < 0)                 return Qnil;
diff --git a/test/strscan/test_stringscanner.rb b/test/strscan/test_stringscanner.rb
index 2c4cf90..c1c356e 100644
--- a/test/strscan/test_stringscanner.rb
+++ b/test/strscan/test_stringscanner.rb
@@ -457,6 +457,14 @@ class TestStringScanner < Test::Unit::TestCase
     assert_equal true, s[2].tainted?
     assert_equal true, s[3].tainted?
     assert_equal true, s[4].tainted?
+
+    s = StringScanner.new("foo bar")
+    s.scan /(?<a>(\w+)) (?<b>(\w+))/
+    assert_equal 'foo', s[1]
+    assert_equal 'bar', s[2]
+    assert_equal 'foo', s[:a]
+    assert_equal 'bar', s[:b]
+    assert_equal nil,   s[:c]
   end
 
   def test_pre_match