xref: /freebsd/contrib/mandoc/mchars_alloc.3 (revision 2008043f386721d58158e37e0d7e50df8095942d) 
1.\"	$Id: mchars_alloc.3,v 1.4 2016/07/07 19:19:01 schwarze Exp $
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3.\" Copyright (c) 2014 Ingo Schwarze <schwarze@openbsd.org>
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17.Dd $Mdocdate: July 7 2016 $
18.Dt MCHARS_ALLOC 3
19.Os
20.Sh NAME
21.Nm mchars_alloc ,
22.Nm mchars_free ,
23.Nm mchars_num2char ,
24.Nm mchars_num2uc ,
25.Nm mchars_spec2cp ,
26.Nm mchars_spec2str ,
27.Nm mchars_uc2str
28.Nd character table for mandoc
29.Sh SYNOPSIS
30.In sys/types.h
31.In mandoc.h
32.Ft void
33.Fn mchars_alloc void
34.Ft void
35.Fn mchars_free void
36.Ft char
37.Fo mchars_num2char
38.Fa "const char *decimal"
39.Fa "size_t sz"
40.Fc
41.Ft int
42.Fo mchars_num2uc
43.Fa "const char *hexadecimal"
44.Fa "size_t sz"
45.Fc
46.Ft int
47.Fo mchars_spec2cp
48.Fa "const char *name"
49.Fa "size_t sz"
50.Fc
51.Ft "const char *"
52.Fo mchars_spec2str
53.Fa "const char *name"
54.Fa "size_t sz"
55.Fa "size_t *rsz"
56.Fc
57.Ft "const char *"
58.Fn mchars_uc2str "int codepoint"
59.Sh DESCRIPTION
60These functions translate Unicode character numbers and
61.Xr roff 7
62character names into glyphs.
63See
64.Xr mandoc_char 7
65for a list of
66.Xr roff 7
67special characters.
68These functions are intended for external use by programs formatting
69.Xr mdoc 7
70and
71.Xr man 7
72pages for output, for example the
73.Xr mandoc 1
74output formatter modules and
75.Xr makewhatis 8 .
76The
77.Fa decimal ,
78.Fa hexadecimal ,
79.Fa name ,
80and
81.Fa size
82input arguments are usually obtained from the
83.Xr mandoc_escape 3
84parser function.
85.Pp
86The function
87.Fn mchars_num2char
88converts a
89.Fa decimal
90string representation of a character number consisting of
91.Fa sz
92digits into a printable ASCII character.
93If the input string is non-numeric or does not represent a printable
94ASCII character, the NUL character
95.Pq Sq \e0
96is returned.
97For example, the
98.Xr mandoc 1
99.Fl Tascii ,
100.Fl Tutf8 ,
101and
102.Fl Thtml
103output modules use this function to render
104.Xr roff 7
105.Ic \eN
106escape sequences.
107.Pp
108The function
109.Fn mchars_num2uc
110converts a
111.Fa hexadecimal
112string representation of a Unicode codepoint consisting of
113.Fa sz
114digits into an integer representation.
115If the input string is non-numeric or represents an ASCII character,
116the NUL character
117.Pq Sq \e0
118is returned.
119For example, the
120.Xr mandoc 1
121.Fl Tutf8
122and
123.Fl Thtml
124output modules use this function to render
125.Xr roff 7
126.Ic \e[u Ns Ar XXXX Ns Ic \&]
127and
128.Ic \eC\(aqu Ns Ar XXXX Ns Ic \(aq
129escape sequences.
130.Pp
131The function
132.Fn mchars_alloc
133initializes a static
134.Vt "struct ohash"
135object for subsequent use by the following two lookup functions.
136When no longer needed, this object can be destroyed with
137.Fn mchars_free .
138.Pp
139The function
140.Fn mchars_spec2cp
141looks up a
142.Xr roff 7
143special character
144.Fa name
145consisting of
146.Fa sz
147characters and returns the corresponding Unicode codepoint.
148If the
149.Ar name
150is not recognized, \-1 is returned.
151For example, the
152.Xr mandoc 1
153.Fl Tutf8
154and
155.Fl Thtml
156output modules use this function to render
157.Xr roff 7
158.Ic \e[ Ns Ar name Ns Ic \&]
159and
160.Ic \eC\(aq Ns Ar name Ns Ic \(aq
161escape sequences.
162.Pp
163The function
164.Fn mchars_spec2str
165looks up a
166.Xr roff 7
167special character
168.Fa name
169consisting of
170.Fa sz
171characters and returns an ASCII string representation.
172The length of the representation is returned in
173.Fa rsz .
174In many cases, the meaning of such ASCII representations
175is not quite obvious, so using
176.Xr roff 7
177special characters in documents intended for ASCII rendering
178is usually a bad idea.
179If the
180.Ar name
181is not recognized,
182.Dv NULL
183is returned.
184For example,
185.Xr makewhatis 8
186and the
187.Xr mandoc 1
188.Fl Tascii
189output module use this function to render
190.Xr roff 7
191.Ic \e[ Ns Ar name Ns Ic \&]
192and
193.Ic \eC\(aq Ns Ar name Ns Ic \(aq
194escape sequences.
195.Pp
196The function
197.Fn mchars_uc2str
198performs a reverse lookup of the Unicode
199.Fa codepoint
200and returns an ASCII string representation, or the string
201.Qq <?>
202if none is available.
203.Sh FILES
204These funtions are implemented in the file
205.Pa chars.c .
206.Sh SEE ALSO
207.Xr mandoc 1 ,
208.Xr mandoc_escape 3 ,
209.Xr ohash_init 3 ,
210.Xr mandoc_char 7 ,
211.Xr roff 7
212.Sh HISTORY
213These functions and their predecessors have been available since the
214following mandoc versions:
215.Bl -column "mchars_num2char()" "1.11.3" "chars_num2char()" "1.10.10"
216.It Sy function Ta since Ta Sy predecessor Ta since
217.It Fn mchars_alloc Ta 1.11.3 Ta Fn ascii2htab Ta 1.5.3
218.It Fn mchars_free Ta 1.11.2 Ta Fn asciifree Ta 1.6.0
219.It Fn mchars_num2char Ta 1.11.2 Ta Fn chars_num2char Ta 1.10.10
220.It Fn mchars_num2uc Ta 1.11.3 Ta \(em Ta \(em
221.It Fn mchars_spec2cp Ta 1.11.2 Ta Fn chars_spec2cp Ta 1.10.5
222.It Fn mchars_spec2str Ta 1.11.2 Ta Fn a2ascii Ta 1.5.3
223.It Fn mchars_uc2str Ta 1.13.2 Ta \(em Ta \(em
224.El
225.Sh AUTHORS
226.An Kristaps Dzonsons Aq Mt kristaps@bsd.lv
227.An Ingo Schwarze Aq Mt schwarze@openbsd.org
228