libblkid-tiny/encode.c

   1 /*
   2  * encode.c - string conversion routines (mostly for compatibility with
   3  *            udev/volume_id)
   4  *
   5  * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
   6  * Copyright (C) 2009 Karel Zak <kzak@redhat.com>
   7  *
   8  * This file may be redistributed under the terms of the
   9  * GNU Lesser General Public License.
  10  */
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <stdint.h>
  14 #include <stddef.h>
  15 #include <unistd.h>
  16 #include <errno.h>
  17 #include <string.h>
  18 #include <ctype.h>
  19
  20 #include "encode.h"
  21
  22 size_t blkid_encode_to_utf8(int enc, unsigned char *dest, size_t len,
  23                                 const unsigned char *src, size_t count)
  24 {
  25         size_t i, j;
  26         uint16_t c;
  27
  28         for (j = i = 0; i < count; i++) {
  29                 if (enc == BLKID_ENC_UTF16LE) {
  30                         if (i+2 > count)
  31                                 break;
  32                         c = (src[i+1] << 8) | src[i];
  33                         i++;
  34                 } else if (enc == BLKID_ENC_UTF16BE) {
  35                         if (i+2 > count)
  36                                 break;
  37                         c = (src[i] << 8) | src[i+1];
  38                         i++;
  39                 } else if (enc == BLKID_ENC_LATIN1) {
  40                         c = src[i];
  41                 } else {
  42                         return 0;
  43                 }
  44                 if (c == 0) {
  45                         dest[j] = '\0';
  46                         break;
  47                 } else if (c < 0x80) {
  48                         if (j+1 >= len)
  49                                 break;
  50                         dest[j++] = (uint8_t) c;
  51                 } else if (c < 0x800) {
  52                         if (j+2 >= len)
  53                                 break;
  54                         dest[j++] = (uint8_t) (0xc0 | (c >> 6));
  55                         dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
  56                 } else {
  57                         if (j+3 >= len)
  58                                 break;
  59                         dest[j++] = (uint8_t) (0xe0 | (c >> 12));
  60                         dest[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
  61                         dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
  62                 }
  63         }
  64         dest[j] = '\0';
  65         return j;
  66 }