-/* norm_charmap.c -- map locale's encoding to MIME charset.
+/* check_charset.c -- routines for character sets
*
- * The Single Unix Specification function nl_langinfo(CODESET)
+ * This code is Copyright (c) 2002, by the authors of nmh. See the
+ * COPYRIGHT file in the root directory of the nmh distribution for
+ * complete copyright information.
+ */
+
+#include <h/mh.h>
+
+#include <string.h>
+#include <langinfo.h>
+
+static const char *norm_charmap(char *name);
+
+/*
+ * Get the current character set
+ */
+char *
+get_charset(void)
+{
+ return (char *)norm_charmap(nl_langinfo(CODESET));
+}
+
+
+/*
+ * Check if we can display a given character set natively.
+ * We are passed the length of the initial part of the
+ * string to check, since we want to allow the name of the
+ * character set to be a substring of a larger string.
+ */
+
+int
+check_charset (char *str, int len)
+{
+ static char *mm_charset = NULL;
+ static char *alt_charset = NULL;
+ static int mm_len;
+ static int alt_len;
+
+ /* Cache the name of our default character set */
+ if (!mm_charset) {
+ if (!(mm_charset = get_charset ()))
+ mm_charset = "US-ASCII";
+ mm_len = strlen (mm_charset);
+
+ /* US-ASCII is a subset of the ISO-8859-X and UTF-8 character sets */
+ if (!strncasecmp("ISO-8859-", mm_charset, 9) ||
+ !strcasecmp("UTF-8", mm_charset)) {
+ alt_charset = "US-ASCII";
+ alt_len = strlen (alt_charset);
+ }
+ }
+
+ /* Check if character set is OK */
+ if ((len == mm_len) && !strncasecmp(str, mm_charset, mm_len))
+ return 1;
+ if (alt_charset && (len == alt_len) && !strncasecmp(str, alt_charset, alt_len))
+ return 1;
+
+ return 0;
+}
+
+
+/*
+ * Return the name of the character set we are
+ * using for 8bit text.
+ */
+char *
+write_charset_8bit (void)
+{
+ static char *mm_charset = NULL;
+
+ /*
+ * Cache the name of the character set to
+ * use for 8bit text.
+ */
+ if (!mm_charset && !(mm_charset = get_charset ()))
+ mm_charset = "x-unknown";
+
+ 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.cl.cam.ac.uk/~mgk25/ucs/norm_charmap.c
*/
-#include <string.h>
+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 }
+ };
-#define digit(x) ((x) >= '0' && (x) <= '9')
+ if (!name)
+ return name;
-static char buf[16];
+ /* 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;
-char *
-norm_charmap(char *name)
-{
- char *p;
-
- if (!name)
return name;
-
- /* Many need no remapping, but they are listed here so you
- * can see what output to expect, and modify for your needs
- * as necessary. */
- if (!strcmp(name, "UTF-8"))
- return "UTF-8";
- if (!strcmp(name, "EUC-JP"))
- return "EUC-JP";
- if (!strcmp(name, "EUC-KR"))
- return "EUC-KR";
- if (!strcmp(name, "EUC-TW"))
- return "EUC-TW";
- if (!strcmp(name, "KOI8-R"))
- return "KOI8-R";
- if (!strcmp(name, "KOI8-U"))
- return "KOI8-U";
- if (!strcmp(name, "GBK"))
- return "GBK";
- if (!strcmp(name, "GB2312"))
- return "GB2312";
- if (!strcmp(name, "GB18030"))
- return "GB18030";
- if (!strcmp(name, "VSCII"))
- return "VSCII";
-
- /* ASCII comes in many names */
- if (!strcmp(name, "ASCII") ||
- !strcmp(name, "US-ASCII") ||
- !strcmp(name, "ANSI_X3.4-1968") ||
- !strcmp(name, "646") ||
- !strcmp(name, "ISO646") ||
- !strcmp(name, "ISO_646.IRV"))
- return "US-ASCII";
-
- /* ISO 8859 will be converted to "ISO-8859-x" */
- if ((p = strstr(name, "8859-"))) {
- memcpy(buf, "ISO-8859-\0\0", 12);
- p += 5;
- if (digit(*p)) {
- buf[9] = *p++;
- if (digit(*p)) buf[10] = *p++;
- return buf;
- }
- }
-
- /* Windows code pages will be converted to "WINDOWS-12xx" */
- if ((p = strstr(name, "CP12"))) {
- memcpy(buf, "WINDOWS-12\0\0", 13);
- p += 4;
- if (digit(*p)) {
- buf[10] = *p++;
- if (digit(*p)) buf[11] = *p++;
- return buf;
- }
- }
-
- /* TIS-620 comes in at least the following two forms */
- if (!strcmp(name, "TIS-620") ||
- !strcmp(name, "TIS620.2533"))
- return "ISO-8859-11";
-
- /* For some, uppercase/lowercase might differ */
- if (!strcmp(name, "Big5") || !strcmp(name, "BIG5"))
- return "Big5";
- if (!strcmp(name, "Big5HKSCS") || !strcmp(name, "BIG5HKSCS"))
- return "Big5HKSCS";
-
- /* I don't know of any implementation of nl_langinfo(CODESET) out
- * there that returns anything else (and I'm not even certain all of
- * the above occur in the wild), but just in case, as a fallback,
- * return the unmodified name. */
- return name;
}
projects / nmh / blobdiff