lib/core/codecs/iso8859_1.nit

   1 # This file is part of NIT (http://www.nitlanguage.org).
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #        http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14
  15 # Codec for ISO8859-1 I/O
  16 module iso8859_1
  17
  18 import codec_base
  19 intrude import bytes
  20
  21 private class ISO88591Codec
  22         super Codec
  23
  24         redef fun char_max_size do return 1
  25
  26         redef fun codet_size do return 1
  27
  28         redef fun max_lookahead do return 1
  29
  30         redef fun encode_char(c) do
  31                 var ns = new NativeString(c.u8char_len)
  32                 add_char_to(c, ns)
  33                 return ns
  34         end
  35
  36         redef fun add_char_to(c, stream) do
  37                 var cp = if c.code_point <= 255 then c else '?'
  38                 stream[0] = cp.ascii
  39                 return 1
  40         end
  41
  42         redef fun encode_string(s) do
  43                 var ns = new Bytes.with_capacity(s.byte_length)
  44                 add_string_to(s, ns)
  45                 return ns
  46         end
  47
  48         redef fun add_string_to(s, b) do
  49                 var pos = 0
  50                 for i in s.chars do
  51                         var cp = i.code_point
  52                         if cp <= 255 then
  53                                 b[pos] = cp.to_b
  54                         else
  55                                 b[pos] = 0x3Fu8
  56                         end
  57                         pos += 1
  58                 end
  59                 return pos
  60         end
  61
  62         redef fun is_valid_char(ns, len) do
  63                 return 0
  64         end
  65
  66         redef fun decode_char(b) do
  67                 return b[0].to_i.code_point
  68         end
  69
  70         redef fun decode_string(b, len) do
  71                 var buf = new Bytes.with_capacity(len)
  72                 for i in [0 .. len[ do buf.add_char(b[i].to_i.code_point)
  73                 return buf.to_s
  74         end
  75 end
  76
  77 # Returns the instance of a ISO8859-1 Codec
  78 fun iso88591_codec: Codec do return once new ISO88591Codec