This file is indexed.

/usr/share/tcltk/tcllib1.16/clock/rfc2822.tcl is in tcllib 1.16-dfsg-2.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
## -*- tcl -*-
# # ## ### ##### ######## ############# #####################
## Copyright (c) 2004 Kevin Kenny
## Origin http://wiki.tcl.tk/24074

# # ## ### ##### ######## ############# #####################
## Requisites

package require Tcl 8.5
package provide clock::rfc2822 0.1
namespace eval ::clock::rfc2822 {}

# # ## ### ##### ######## ############# #####################
## API

# ::clock::rfc2822::parse_date --
#
#       Parses a date expressed in RFC2822 format
#
# Parameters:
#       date - The date to parse
#
# Results:
#       Returns the date expressed in seconds from the Epoch, or throws
#       an error if the date could not be parsed.

proc ::clock::rfc2822::parse_date { date } {
    variable datepats

    # Strip comments and excess whitespace from the date field

    regsub -all -expanded {
        \(              # open parenthesis
        (:?
	 [^()[.\.]]     # character other than ()\
	     |\\.       # or backslash escape
	 )*             # any number of times
        \)              # close paren
    } $date {} date
    set date [string trim $date]

    # Match the patterns in order of preference, returning the first success

    foreach {regexp pat} $datepats {
        if { [regexp -nocase $regexp $date] } {
            return [clock scan $date -format $pat]
        }
    }

    return -code error -errorcode {CLOCK RFC2822 BADDATE} \
        "expected an RFC2822 date, got \"$date\""
}


# # ## ### ##### ######## ############# #####################
## Internals, transient, removed after initialization.

# AddDatePat --
#
#       Internal procedure that adds a date pattern to the pattern list
#
# Parameters:
#       wpat - Regexp pattern that matches the weekday
#       wgrp - Format group that matches the weekday
#       ypat - Regexp pattern that matches the year
#       ygrp - Format group that matches the year
#       mdpat - Regexp pattern that matches month and day
#       mdgrp - Format group that matches month and day
#       spat - Regexp pattern that matches the seconds of the minute
#       sgrp - Format group that matches the seconds of the minute
#       zpat - Regexp pattern that matches the time zone
#       zgrp - Format group that matches the time zone
#
# Results:
#       None
#
# Side effects:
#       Adds a complete regexp and a complete [clock scan] pattern to
#       'datepats'

proc ::clock::rfc2822::AddDatePat { wpat wgrp ypat ygrp mdpat mdgrp
				    spat sgrp zpat zgrp } {
    variable datepats

    set regexp {^[[:space:]]*}
    set pat {}
    append regexp $wpat $mdpat {[[:space:]]+} $ypat
    append pat $wgrp $mdgrp $ygrp
    append regexp {[[:space:]]+\d\d?:\d\d} $spat
    append pat { %H:%M} $sgrp
    append regexp $zpat
    append pat $zgrp
    append regexp {[[:space:]]*$}
    lappend datepats $regexp $pat
    return
}

# InitDatePats --
#
#       Internal procedure that initializes the set of date patterns
# 	allowed in an RFC2822 date
#
# Parameters:
#       permissible - 1 if erroneous (but common) time zones are to be
#                     allowed, 0 if they are to be rejected
#
# Results:
#       None.
#
# Side effects:

proc ::clock::rfc2822::InitDatePats { permissible } {
    # Produce formats for the observed variants of ISO2822 dates.
    # Permissible variants come first in the list; impermissible ones
    # come later.

    # The month and day may be "%b %d" or "%d %b"

    foreach mdpat {{[[:alpha:]]+[[:space:]]+\d\d?}
        {\d\d?[[:space:]]+[[:alpha:]]+}} \
        mdgrp {{%b %d} {%d %b}} \
        mdperm {0 1} {
            # The year may be two digits, or four. Four digit year is
            # done first.

            foreach ypat {{\d\d\d\d} {\d\d}} ygrp {%Y %y} {
                # The seconds of the minute may be provided, or
                # omitted.

                foreach spat {{:\d\d} {}} sgrp {:%S {}} {
                    # The weekday may be provided or omitted. It is
                    # common but impermissible to omit the comma after
                    # the weekday name.

                    foreach wpat {
                        {(?:Mon|T(?:ue|hu)|Wed|Fri|S(?:at|un)),[[:space:]]+}
                        {(?:Mon|T(?:ue|hu)|Wed|Fri|S(?:at|un))[[:space:]]+}
                        {}
                    } wgrp {
                        {%a, }
                        {%a }
                        {}
                    } wperm {
                        1
                        0
                        1
                    } {
                        # Time zone is defined as +/- hhmm, or as a
                        # named time zone.  Other common but buggy
                        # formats are GMT+-hh:mm, a time zone name in
                        # quotation marks, and complete omission of
                        # the time zone.

                        foreach zpat {
                            {[[:space:]]+(?:[-+]\d\d\d\d|[[:alpha:]]+)}
                            {[[:space:]]+GMT[-+]\d\d:?\d\d}
                            {[[:space:]]+"[[:alpha:]]+"}
                            {}
                        } zgrp {
                            { %Z}
                            { GMT%Z}
                            { "%Z"}
                            {}
                        } zperm {
                            1
                            0
                            0
                            0
                        } {
                            if { ($zperm && $wperm && $mdperm)
                                 == $permissible } {
                                AddDatePat $wpat $wgrp $ypat $ygrp \
                                    $mdpat $mdgrp \
                                    $spat $sgrp $zpat $zgrp
                            }
                        }
                    }
                }
            }
        }
    return
}

# # ## ### ##### ######## ############# #####################
## State

namespace eval ::clock::rfc2822 {
    namespace export parse_date
    namespace ensemble create

    variable datepats {}
}

# # ## ### ##### ######## ############# #####################
# Initialize the date patterns

namespace eval ::clock::rfc2822 {
    InitDatePats 1
    InitDatePats 0
    rename AddDatePat {}
    rename InitDatePats {}
    #puts [join $datepats \n]
}

# # ## ### ##### ######## ############# #####################

return
# Usage example, disabled

if {![info exists ::argv0] || [info script] ne $::argv0} return
puts [clock format \
          [::clock::rfc2822::parse_date {Mon(day), 23 Aug(ust) 2004 01:23:45 UT}]]
puts [clock format \
          [::clock::rfc2822::parse_date "Tue, Jul 21 2009 19:37:47 GMT-0400"]]