From e76b1a11ca8eace6ee592722255195e2fe02ecd5 Mon Sep 17 00:00:00 2001
From: usa <usa@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 26 Sep 2008 02:07:19 +0000
Subject: [PATCH] 	* transcode.c, include/ruby/encoding.c
 (rb_transcode_convertible): 	  new function. checking the existance of
 converter.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@19565 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog               |  5 +++++
 include/ruby/encoding.h |  1 +
 transcode.c             | 14 ++++++++++++++
 3 files changed, 20 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index b6b1f219e0..ff7ca9c1cf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Sep 26 11:05:41 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* transcode.c, include/ruby/encoding.c (rb_transcode_convertible):
+	  new function. checking the existance of converter.
+
 Fri Sep 26 10:35:50 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* variable.c (global_variable, struct trace_var): made function
diff --git a/include/ruby/encoding.h b/include/ruby/encoding.h
index 2c7f105ec3..b6ac57418c 100644
--- a/include/ruby/encoding.h
+++ b/include/ruby/encoding.h
@@ -209,6 +209,7 @@ typedef enum {
 typedef struct rb_econv_t rb_econv_t;
 
 VALUE rb_str_transcode(VALUE str, VALUE to, int ecflags, VALUE ecopts);
+int rb_transcode_convertible(const char* from_encoding, const char* to_encoding);
 
 int rb_econv_prepare_opts(VALUE opthash, VALUE *ecopts);
 
diff --git a/transcode.c b/transcode.c
index 26c57d039d..1f0909cd3f 100644
--- a/transcode.c
+++ b/transcode.c
@@ -2839,6 +2839,20 @@ econv_s_search_convpath(int argc, VALUE *argv, VALUE klass)
     return convpath;
 }
 
+/*
+ * check the existance of converter.
+ * returns the count of the converting paths.
+ * result: >=0:success -1:failure
+ */
+int
+rb_transcode_convertible(const char* from_encoding, const char* to_encoding)
+{
+    VALUE convpath = Qnil;
+    transcode_search_path(from_encoding, to_encoding, search_convpath_i,
+			  &convpath);
+    return RTEST(convpath);
+}
+
 struct rb_econv_init_by_convpath_t {
     rb_econv_t *ec;
     int index;