X-Git-Url: https://diplodocus.org/git/nmh/blobdiff_plain/adc954633908e3fc97dfa94c08f964e1bbb94086..c576ad2674c37a1c63f004c71049998f38854c64:/sbr/check_charset.c

diff --git a/sbr/check_charset.c b/sbr/check_charset.c
index d6b8ca34..71129fef 100644
--- a/sbr/check_charset.c
+++ b/sbr/check_charset.c
@@ -1,8 +1,4 @@
-
-/*
- * check_charset.c -- routines for character sets
- *
- * $Id$
+/* check_charset.c -- routines for character sets
  *
  * This code is Copyright (c) 2002, by the authors of nmh.  See the
  * COPYRIGHT file in the root directory of the nmh distribution for
@@ -10,23 +6,19 @@
  */
 
 #include <h/mh.h>
-#ifdef HAVE_LANGINFO_H
-# include <langinfo.h>
-#endif
 
+#include <string.h>
+#include <langinfo.h>
+
+static const char *norm_charmap(char *name);
 
 /*
  * Get the current character set
  */
 char *
-get_charset ()
+get_charset(void)
 {
-    char *charset = getenv ("MM_CHARSET");
-#if defined(HAVE_NL_LANGINFO) && defined(CODESET)
-    if (!charset)
-	charset = norm_charmap(nl_langinfo (CODESET));
-#endif
-    return charset;
+    return (char *)norm_charmap(nl_langinfo(CODESET));
 }
 
 
@@ -87,3 +79,106 @@ write_charset_8bit (void)
 
     return mm_charset;
 }
+
+/* The Single Unix Specification function nl_langinfo(CODESET)
+ * returns the name of the encoding used by the currently selected
+ * locale:
+ *
+ *   http://www.opengroup.org/onlinepubs/7908799/xsh/langinfo.h.html
+ *
+ * Unfortunately the encoding names are not yet standardized.
+ * This function knows about the encoding names used on many
+ * different systems and converts them where possible into
+ * the corresponding MIME charset name registered in
+ *
+ *   http://www.iana.org/assignments/character-sets
+ *
+ * Please extend it as needed and suggest improvements to the author.
+ *
+ * Markus.Kuhn@cl.cam.ac.uk -- 2002-03-11
+ * Permission to use, copy, modify, and distribute this software
+ * for any purpose and without fee is hereby granted. The author
+ * disclaims all warranties with regard to this software.
+ *
+ * Latest version:
+ *
+ *   http://www.cl.cam.ac.uk/~mgk25/ucs/norm_charmap.c
+ */
+
+static const char *norm_charmap(char *name)
+{
+    static const char *correct[] = {
+        "UTF-8",
+        "US-ASCII",
+        NULL
+    }, **cor;
+    static struct {
+        const char *alias;
+        const char *name;
+    } *ali, aliases[] = {
+        /* Names for US-ASCII. */
+        { "ANSI_X3.4-1968", "US-ASCII" }, /* LC_ALL=C. */
+        { "ASCII", "US-ASCII" },
+        { "646", "US-ASCII" },
+        { "ISO646", "US-ASCII" },
+        { "ISO_646.IRV", "US-ASCII" },
+        /* Case differs. */
+        { "BIG5", "Big5" },
+        { "BIG5HKSCS", "Big5HKSCS" },
+        /* Names for ISO-8859-11. */
+        { "TIS-620", "ISO-8859-11" },
+        { "TIS620.2533", "ISO-8859-11" },
+        { NULL, NULL }
+    };
+    static struct {
+        const char *substr;
+        const char *name;
+    } *sub, substrs[] = {
+        { "8859-1", "ISO-8859-1" },
+        { "8859-2", "ISO-8859-2" },
+        { "8859-3", "ISO-8859-3" },
+        { "8859-4", "ISO-8859-4" },
+        { "8859-5", "ISO-8859-5" },
+        { "8859-6", "ISO-8859-6" },
+        { "8859-7", "ISO-8859-7" },
+        { "8859-8", "ISO-8859-8" },
+        { "8859-9", "ISO-8859-9" },
+        { "8859-10", "ISO-8859-10" },
+        { "8859-11", "ISO-8859-11" },
+        /* 12, Latin/Devanagari, not completed. */
+        { "8859-13", "ISO-8859-13" },
+        { "8859-14", "ISO-8859-14" },
+        { "8859-15", "ISO-8859-15" },
+        { "8859-16", "ISO-8859-16" },
+        { "CP1200", "WINDOWS-1200" },
+        { "CP1201", "WINDOWS-1201" },
+        { "CP1250", "WINDOWS-1250" },
+        { "CP1251", "WINDOWS-1251" },
+        { "CP1252", "WINDOWS-1252" },
+        { "CP1253", "WINDOWS-1253" },
+        { "CP1254", "WINDOWS-1254" },
+        { "CP1255", "WINDOWS-1255" },
+        { "CP1256", "WINDOWS-1256" },
+        { "CP1257", "WINDOWS-1257" },
+        { "CP1258", "WINDOWS-1258" },
+        { NULL, NULL }
+    };
+
+    if (!name)
+        return name;
+
+    /* Avoid lots of tests for common correct names. */
+    for (cor = correct; *cor; cor++)
+        if (!strcmp(name, *cor))
+            return name;
+
+    for (ali = aliases; ali->alias; ali++)
+        if (!strcmp(name, ali->alias))
+            return ali->name;
+
+    for (sub = substrs; sub->substr; sub++)
+        if (strstr(name, sub->substr))
+            return sub->name;
+
+    return name;
+}