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
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
|
#-*- perl -*-
#
# Copyright (C) 2001 Ken'ichi Fukamachi
# All rights reserved. This program is free software; you can
# redistribute it and/or modify it under the same terms as Perl itself.
#
# $Id$
# $FML$
#
package File::LogStructuredData;
use strict;
use vars qw(@ISA @EXPORT @EXPORT_OK $AUTOLOAD);
use Carp;
=head1 NAME
File::LogStructuredData - hash emulation for a log structered file
=head1 SYNOPSIS
use File::LogStructuredData;
$db = new File::LogStructuredData { file => 'cache.txt' };
# add value for the key 'rudo'
$db->append('rudo', 'is pretty');
# get all entries with the key = 'rudo'
$values = $db->find( 'rudo' );
where $values->[0] is "is pretty'.
If you want to use C<tie()> style, you can use it like this:
use File::LogStructuredData;
tie %db, 'File::LogStructuredData', { file => 'cache.txt' };
print $db{ rudo }, "\n";
where the format of "cache.txt" is "key value" for each line.
For example
rudo teddy bear
kenken north fox
.....
By default, FETCH() returns the first value with the key.
use File::LogStructuredData;
tie %db, 'File::LogStructuredData', { first_match => 1, file => 'cache.txt' };
print $db{ rudo }, "\n";
If you print out the latest value (so at the later line somewhere in
the file) for the specified C<$key>
use File::LogStructuredData;
tie %db, 'File::LogStructuredData', { last_match => 1, file => 'cache.txt' };
print $db{ rudo }, "\n";
=head1 METHODS
=head2 TIEHASH, FETCH, STORE, FIRSTKEY, NEXTKEY
standard hash functions.
=cut
# Descriptions: constructor
# Arguments: $self $args
# Side Effects: import _match_style into $self
# Return Value: object
sub new
{
my ($self, $args) = @_;
my ($type) = ref($self) || $self;
my $me = {};
$me->{ _file } = $args->{ file };
if ($args->{ first_match }) {
$me->{ _match_style } = 'first';
}
elsif ($args->{ last_match }) {
$me->{ _match_style } = 'last';
}
else {
$me->{ _match_style } = 'first';
}
return bless $me, $type;
}
sub TIEHASH
{
my ($self, $args) = @_;
my ($type) = ref($self) || $self;
new($self, $args);
}
sub FETCH
{
my ($self, $key) = @_;
$self->_fetch($key, 'scalar');
}
sub STORE
{
my ($self, $key, $value) = @_;
}
sub FIRSTKEY
{
my ($self) = @_;
use IO::File;
my $fh = new IO::File;
$fh->open( $self->{ _file }, "r");
$self->{ _fh } = $fh;
my $r = <$fh>;
my @r = split(/\s+/, $r);
return $r[0];
}
sub NEXTKEY
{
my ($self) = @_;
my $fh = $self->{ _fh };
my $r = <$fh>;
my @r = split(/\s+/, $r);
return $r[0];
}
=head2 C<find(key)>
return the line with the C<key>.
The line is either first or last mached line.
It is determined by C<last_match> or C<first_match> parameter at
C<new()> method.
C<first_match> by default.
=cut
sub find
{
my ($self, $key) = @_;
return $self->_fetch($key, 'array');
}
=head2 C<get_value(key)>
get the latest value for the C<key>.
=cut
sub get_value
{
my ($self, $key) = @_;
my $ra = $self->_fetch($key, 'array');
my $x;
for (@$ra) { $x = $_;}
return $x;
}
# Descriptions: real function to search $key.
# This routine is used at find() and FETCH() methods.
# return the value with the $key
# $self->{ _match_style } conrolls the matching algorithm
# is either of the fist or last match.
# Arguments: $self $key $mode
# $key is the string to search.
# $mode selects the return value style, scalar or array.
# Side Effects: none
# Return Value: SCALAR or ARRAY with the key
sub _fetch
{
my ($self, $key, $mode) = @_;
my $prekey = $key;
# the first 1 byte of the key
if ($key =~ /^(.)/) { $prekey = $1;}
use IO::File;
my $fh = new IO::File;
$fh->open( $self->{ _file }, "r");
my ($xkey, $xvalue) = ();
my (@values) = ();
SEARCH:
while (<$fh>) {
next SEARCH if /^\#*$/;
next SEARCH if /^\s*$/;
next SEARCH unless /^$prekey/i;
next SEARCH unless /^$key/i;
chop;
($xkey, $xvalue) = split(/\s+/, $_, 2);
if ($xkey eq $key) {
if ($mode eq 'array') {
push(@values, $xvalue);
}
if ($mode eq 'scalar') {
# firstmatch: exit loop ASAP if the $key is found.
if ($self->{ _match_style } eq 'first') {
last SEARCH;
}
}
}
}
close($fh);
if ($mode eq 'scalar') {
return( $xvalue || undef );
}
if ($mode eq 'array') {
return \@values;
}
}
=head2 C<append($key, $value)>
append C<$key> and C<$value> to the database.
=cut
sub append
{
my ($self, $key, $value) = @_;
use IO::File;
my $fh = new IO::File;
$fh->open( $self->{ _file }, "a");
$fh->autoflush(1);
print $fh $key, " ", $value, "\n";
$fh->close;
}
=head1 AUTHOR
Ken'ichi Fukamachi
=head1 COPYRIGHT
Copyright (C) 2001 Ken'ichi Fukamachi
All rights reserved. This program is free software; you can
redistribute it and/or modify it under the same terms as Perl itself.
=head1 HISTORY
File::LogStructuredData appeared in fml5 mailing list driver package.
See C<http://www.fml.org/> for more details.
=cut
1;
|
