+\f
+bool
+get_encoding_info (struct encoding_info *e, const char *name)
+{
+ const struct substring in = SS_LITERAL_INITIALIZER (
+ "\t\n\v\f\r "
+ "!\"#$%&'()*+,-./0123456789:;<=>?@"
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`"
+ "abcdefghijklmnopqrstuvwxyz{|}~");
+
+ struct substring out, cr, lf, space;
+ bool ok;
+
+ memset (e, 0, sizeof *e);
+
+ cr = recode_substring_pool (name, "UTF-8", ss_cstr ("\r"), NULL);
+ lf = recode_substring_pool (name, "UTF-8", ss_cstr ("\n"), NULL);
+ space = recode_substring_pool (name, "UTF-8", ss_cstr (" "), NULL);
+ ok = (cr.length >= 1
+ && cr.length <= MAX_UNIT
+ && cr.length == lf.length
+ && cr.length == space.length);
+ if (!ok)
+ {
+ fprintf (stderr, "warning: encoding `%s' is not supported.\n", name);
+ ss_dealloc (&cr);
+ ss_dealloc (&lf);
+ ss_dealloc (&space);
+ ss_alloc_substring (&cr, ss_cstr ("\r"));
+ ss_alloc_substring (&lf, ss_cstr ("\n"));
+ ss_alloc_substring (&space, ss_cstr (" "));
+ }
+
+ e->unit = cr.length;
+ memcpy (e->cr, cr.string, e->unit);
+ memcpy (e->lf, lf.string, e->unit);
+ memcpy (e->space, space.string, e->unit);
+
+ ss_dealloc (&cr);
+ ss_dealloc (&lf);
+ ss_dealloc (&space);
+
+ out = recode_substring_pool ("UTF-8", name, in, NULL);
+ e->is_ascii_compatible = ss_equals (in, out);
+ ss_dealloc (&out);
+
+ if (!e->is_ascii_compatible && e->unit == 1)
+ {
+ out = recode_substring_pool ("UTF-8", name, ss_cstr ("A"), NULL);
+ e->is_ebcdic_compatible = (out.length == 1
+ && (uint8_t) out.string[0] == 0xc1);
+ ss_dealloc (&out);
+ }
+ else
+ e->is_ebcdic_compatible = false;
+
+ return ok;
+}
+
+bool
+is_encoding_ascii_compatible (const char *encoding)
+{
+ struct encoding_info e;
+
+ get_encoding_info (&e, encoding);
+ return e.is_ascii_compatible;
+}
+
+bool
+is_encoding_ebcdic_compatible (const char *encoding)
+{
+ struct encoding_info e;
+
+ get_encoding_info (&e, encoding);
+ return e.is_ebcdic_compatible;
+}
+
+/* Returns true if iconv can convert ENCODING to and from UTF-8,
+ otherwise false. */
+bool
+is_encoding_supported (const char *encoding)
+{
+ return (create_iconv__ ("UTF-8", encoding)->conv != (iconv_t) -1
+ && create_iconv__ (encoding, "UTF-8")->conv != (iconv_t) -1);
+}