1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
<!--
This is a document type declaration (DTD) for the mapping
of a character set encoding to Unicode. Documents of this type are
used by the perl module XML::Parser to register character encodings.
This dtd is provided for informational purposes only. XML::Parser
doesn't read it.
Author: Clark Cooper <coopercc@netheaven.com>
Date: $Date: 1998/12/15 01:55:45 $
Revision: $Revision: 1.1.1.1 $
-->
<!--
encmap
The expat attribute must be set to 'yes' in order for XML::Parser
to load the encoding. When this is set, it implies the following
restrictions on the encoding, which are required by the expat
library.
================
I quote these restrictions from the xmlparse.h file in the
expat distribution:
1. Every ASCII character that can appear in a well-formed XML
document other than the characters
$@\^`{}~
must be represented by a single byte, and that byte must be
the same byte that represents that character in ASCII.
2. No character may require more than 4 bytes to encode.
3. All characters encoded must have Unicode scalar values <= 0xFFFF,
(ie characters that would be encoded by surrogates in UTF-16
are not allowed). Note that this restriction doesn't apply to
the built-in support for UTF-8 and UTF-16.
4. No Unicode character may be encoded by more than one distinct
sequence of bytes.
In addition, the number of bytes in mult-byte encodings must be
determined from the 1st byte. The encoding of the 1st byte is
assumed to be ASCII for byte values < 128, although this assumed
value may be overridden for the set of characters mentioned above.
Trying to override any other character in the ASCII set is an error.
The 1st requirement implies that a uniform 2-byte encoding can't be
mapped using this mechanism.
================
In XML::Parser, the string provided by the name attribute is used
to refer to this encoding.
-->
<!ELEMENT encmap ((prefix|range|ch)+)>
<!ATTLIST encmap
name CDATA #REQUIRED
expat (yes|no) 'no'
>
<!--
prefix
Groups together encodings that have the same prefix. The
actual prefix is a concatenation of all the containing prefix
elements. So the following:
<prefix byte="x9A">
<prefix byte="x23">
<ch byte="x77" uni="x2375"/>
</prefix>
</prefix>
Maps the byte sequence '9A 23 77' to U+2375. Note that in
expat mode, all encodings under a given prefix must have
the same length. This implies that sibling prefixes below
top level must have parallel structure.
-->
<!ELEMENT prefix ((prefix|range|ch)+)>
<!ATTLIST prefix
byte CDATA #REQUIRED
>
<!--
range
Maps a range of characters in the encoding that have
have the same relative positions in the Unicode scalar value
as they do in their final encoding bytes. A range may not
cross a byte boundary.
All three attributes take numeric values expressed either
in decimal (just the digits 0-9) or hex (x followed by hex
digits 0-9a-f, case ignored).
The start attribute is the value of the final byte of the
starting character in the range.
The length attribute is the size of the range. This value
plus the start value must be less than 256.
The uni attribute is the scalar value of the Unicode
character that corresponds to the start character. This value
must be 0xFFFF or less, and the sum of the uni and len attributes
must also be 0xFFFF or less.
-->
<!ELEMENT range EMPTY>
<!ATTLIST range
byte CDATA #REQUIRED
uni CDATA #REQUIRED
len CDATA #REQUIRED
>
<!--
ch
Maps the byte, with the current prefix, to the given Unicode scalar
value. Both attributes are constrained the same way as the
corresponding attribues of the range element.
-->
<!ELEMENT ch EMPTY>
<!ATTLIST ch
byte CDATA #REQUIRED
uni CDATA #REQUIRED
>
|
