1fileutil::magic::rt(n) file utilities fileutil::magic::rt(n)
2______________________________________________________________________________
6
8 fileutil::magic::rt - Runtime core for file type recognition engines
9 written in pure Tcl
10
12 package require Tcl 8.5
13 package require fileutil::magic::rt ?2.0?
15 ::fileutil::magic::rt::>
17 ::fileutil::magic::rt::<
19 ::fileutil::magic::rt::new chan named analyze
21 ::fileutil::magic::rt::file_start name
23 ::fileutil::magic::rt::emit msg
25 ::fileutil::magic::rt::O where
27 ::fileutil::magic::rt::R where
29 ::fileutil::magic::rt::Nv type offset compinvert comp expected
31 ::fileutil::magic::rt::N type offset testinvert compinvert mod mand
33 comp expected
34 ::fileutil::magic::rt::S type offset testinvert mod mand comp val
36 ::fileutil::magic::rt::L newlevel
38 ::fileutil::magic::rt::I offset it ioi ioo iir io
40 ::fileutil::magic::rt::R offset
42 ::fileutil::magic::rt::U fileindex name
44______________________________________________________________________________
46
48 This package provides the runtime core for file type recognition en‐
49 gines written in pure Tcl and is thus used by all other packages in
50 this module such as fileutil::magic::filetype and the two compiler
51 packages fileutil::magic::cgen and fileutil::magic::cfront.
52
54 ::fileutil::magic::rt::>
55 Increment the level and perform related housekeeping
56 ::fileutil::magic::rt::<
58 Decrement the level and perform related housekeeping
59 ::fileutil::magic::rt::new chan named analyze
61 Create a new command which returns one description of the file
62 each time it is called, and a code of break when there are no
63 more descriptions. chan is the channel containing the data to
64 describe. The channel configuration is then managed as needed.
65 named is a dictionary of named tests, as generated by fileu‐
66 til::magic::cfront::compile. test is a command prefix for a
67 routine composed of the list of commands as returned by fileu‐
68 til::magic::cfront::compile.
69 ::fileutil::magic::rt::file_start name
71 This command marks the start of a magic file when debugging. It
72 returns the empty string as its result.
73 ::fileutil::magic::rt::emit msg
75 This command adds the text msg to the result buffer. The message
76 may contain the following special character sequences. They will
77 be replaced with buffered values before the message is added to
78 the result. The command returns the empty string as its result.
79 \b This sequence is removed
81 %s Replaced with the last buffered string value.
83 %ld Replaced with the last buffered numeric value.
85 %d See above.
87 ${x:...?...}
89 Substitute one string if the file is executable, and an‐
90 other string otherwise.
91 ::fileutil::magic::rt::O where
93 Produce an offset from where, relative to the cursor one level
94 up. Produce an offset from where, relative to the offset one
95 level up.
96 ::fileutil::magic::rt::Nv type offset compinvert comp expected
98 A limited form of ::fileutile::magic::rt::N that only checks for
99 equality and can't be told to invert the test.
100 ::fileutil::magic::rt::N type offset testinvert compinvert mod mand
102 comp expected
103 Fetch the numeric value with type from the absolute location
104 offset, compare it with expected using comp as the comparision
105 operator, and returns the result.
106 The argument comp must be one of Tcl's comparison operators.
108 <comp> <fetched-and-masked-value> <comp> <expected>
111 The special comparison operator x signals that no comparison should be
114 done, or, in other words, that the fetched value will always match val.
115 ::fileutil::magic::rt::S type offset testinvert mod mand comp val
117 Like ::fileutil::magic::rt::N except that it fetches and com‐
118 pares string types , not numeric data.
119 ::fileutil::magic::rt::L newlevel
121 Sets the current level in the calling context to newlevel. The
122 command returns the empty string as its result.
123 ::fileutil::magic::rt::I offset it ioi ioo iir io
125 Calculates an offset based on an initial offset and the provided
126 modifiers.
127 ::fileutil::magic::rt::R offset
129 Given an initial offset, calculates an offset relative to the
130 cursor at the next level up. The cursor is the position in the
131 data one character after the data extracted from the file one
132 level up.
133 ::fileutil::magic::rt::U fileindex name
136 Add a level and use a named test script.
137
139 byte 8-bit integer
140 short 16-bit integer, stored in native endianess
142 beshort
144 see above, stored in big endian
145 leshort
147 see above, stored in small/little endian
148 long 32-bit integer, stored in native endianess
150 belong see above, stored in big endian
152 lelong see above, stored in small/little endian
154 All of the types above exit in an unsigned form as well. The type names
156 are the same, with the character "u" added as prefix.
157 date 32-bit integer timestamp, stored in native endianess
159 bedate see above, stored in big endian
161 ledate see above, stored in small/little endian
163 ldate 32-bit integer timestamp, stored in native endianess
165 beldate
167 see above, stored in big endian
168 leldate
170 see above, stored in small/little endian
171
173 This document, and the package it describes, will undoubtedly contain
174 bugs and other problems. Please report such in the category fileutil
175 :: magic of the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist].
176 Please also report any ideas for enhancements you may have for either
177 package and/or documentation.
178 When proposing code changes, please provide unified diffs, i.e the out‐
180 put of diff -u.
181 Note further that attachments are strongly preferred over inlined
183 patches. Attachments can be made by going to the Edit form of the
184 ticket immediately after its creation, and then using the left-most
185 button in the secondary navigation bar.
186
188 file(1), fileutil, magic(5)
189
191 file recognition, file type, file utilities, mime, type
192
194 Programming tools
195tcllib 2.0 fileutil::magic::rt(n)