fs/nls/nls_koi8-ru.c

   1 /*
   2  * linux/fs/nls/nls_koi8-ru.c
   3  *
   4  * Charset koi8-ru translation based on charset koi8-u.
   5  * The Unicode to charset table has only exact mappings.
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/kernel.h>
  10 #include <linux/string.h>
  11 #include <linux/nls.h>
  12 #include <linux/errno.h>
  13
  14 static struct nls_table *p_nls;
  15
  16 static int uni2char(const wchar_t uni,
  17                     unsigned char *out, int boundlen)
  18 {
  19         if (boundlen <= 0)
  20                 return -ENAMETOOLONG;
  21
  22         if ((uni & 0xffaf) == 0x040e || (uni & 0xffce) == 0x254c) {
  23                 /* koi8-ru and koi8-u differ only on two characters */
  24                 if (uni == 0x040e)
  25                         out[0] = 0xbe;
  26                 else if (uni == 0x045e)
  27                         out[0] = 0xae;
  28                 else if (uni == 0x255d || uni == 0x256c)
  29                         return 0;
  30                 else
  31                         return p_nls->uni2char(uni, out, boundlen);
  32                 return 1;
  33         }
  34         else
  35                 /* fast path */
  36                 return p_nls->uni2char(uni, out, boundlen);
  37 }
  38
  39 static int char2uni(const unsigned char *rawstring, int boundlen,
  40                     wchar_t *uni)
  41 {
  42         int n;
  43
  44         if ((*rawstring & 0xef) != 0xae) {
  45                 /* koi8-ru and koi8-u differ only on two characters */
  46                 *uni = (*rawstring & 0x10) ? 0x040e : 0x045e;
  47                 return 1;
  48         }
  49
  50         n = p_nls->char2uni(rawstring, boundlen, uni);
  51         return n;
  52 }
  53
  54 static struct nls_table table = {
  55         .charset        = "koi8-ru",
  56         .uni2char       = uni2char,
  57         .char2uni       = char2uni,
  58 };
  59
  60 static int __init init_nls_koi8_ru(void)
  61 {
  62         p_nls = load_nls("koi8-u");
  63
  64         if (p_nls) {
  65                 table.charset2upper = p_nls->charset2upper;
  66                 table.charset2lower = p_nls->charset2lower;
  67                 return register_nls(&table);
  68         }
  69
  70         return -EINVAL;
  71 }
  72
  73 static void __exit exit_nls_koi8_ru(void)
  74 {
  75         unregister_nls(&table);
  76         unload_nls(p_nls);
  77 }
  78
  79 module_init(init_nls_koi8_ru)
  80 module_exit(exit_nls_koi8_ru)
  81
  82 MODULE_LICENSE("Dual BSD/GPL");