apr::table.3

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

.\" Automatically generated by Pod::Man 2.16 (Pod::Simple 3.05)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sh \" Subsection heading
.br
.if t .Sp
.ne 5
.PP
\fB\\$1\fR
.PP
..
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.ie \nF \{\
.    de IX
.    tm Index:\\$1\t\\n%\t"\\$2"
..
.    nr % 0
.    rr F
.\}
.el \{\
.    de IX
..
.\}
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "mod_perl-2.0.2::docs::api::APR::Table 3"
.TH mod_perl-2.0.2::docs::api::APR::Table 3 "2005-10-21" "perl v5.10.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
APR::Table \- Perl API for manipulating APR opaque string\-content tables
.SH "Synopsis"
.IX Header "Synopsis"
.Vb 1
\&  use APR::Table ();
\&  
\&  $table = APR::Table::make($pool, $nelts);
\&  $table_copy = $table\->copy($pool);
\&  
\&  $table\->clear();
\&  
\&  $table\->set($key => $val);
\&  $table\->unset($key);
\&  $table\->add($key, $val);
\&  
\&  $val = $table\->get($key);
\&  @val = $table\->get($key);
\&  
\&  $table\->merge($key => $val);
\&  
\&  use APR::Const \-compile qw(:table);
\&  $table_overlay = $table_base\->overlay($table_overlay, $pool);
\&  $table_overlay\->compress(APR::Const::OVERLAP_TABLES_MERGE);
\&  
\&  $table_a\->overlap($table_b, APR::Const::OVERLAP_TABLES_SET);
\&  
\&  $table\->do(sub {print "key $_[0], value $_[1]\en"}, @valid_keys);
\&  
\&  #Tied Interface
\&  $value = $table\->{$key};
\&  $table\->{$key} = $value;
\&  print "got it" if exists $table\->{$key};
\&  
\&  foreach my $key (keys %{$table}) {
\&      print "$key = $table\->{$key}\en";
\&  }
.Ve
.SH "Description"
.IX Header "Description"
\&\f(CW\*(C`APR::Table\*(C'\fR allows its users to manipulate opaque string-content
tables.
.PP
On the C level the \*(L"opaque string-content\*(R" means: you can put in
\&'\e0'\-terminated strings and whatever you put in your get out.
.PP
On the Perl level that means that we convert scalars into strings and
store those strings. Any special information that was in the Perl
scalar is not stored. So for example if a scalar was marked as utf8,
tainted or tied, that information is not stored. When you get the data
back as a Perl scalar you get only the string.
.PP
The table's structure is somewhat similar to the Perl's hash
structure, but allows multiple values for the same key.  An access to
the records stored in the table always requires a key.
.PP
The key-value pairs are stored in the order they are added.
.PP
The keys are case-insensitive.
.PP
However as of the current implementation if more than value for the
same key is requested, the whole table is lineary searched, which is
very inefficient unless the table is very small.
.PP
\&\f(CW\*(C`APR::Table\*(C'\fR provides a \s-1TIE\s0 Interface.
.PP
See \fIapr/include/apr_tables.h\fR in \s-1ASF\s0's \fIapr\fR project for low level
details.
.SH "API"
.IX Header "API"
\&\f(CW\*(C`APR::Table\*(C'\fR provides the following functions and/or methods:
.ie n .Sh """add"""
.el .Sh "\f(CWadd\fP"
.IX Subsection "add"
Add data to a table, regardless of whether there is another element
with the same key.
.PP
.Vb 1
\&  $table\->add($key, $val);
.Ve
.ie n .IP "obj: $table\fR ( \f(CW""APR::Table object"" )" 4
.el .IP "obj: \f(CW$table\fR ( \f(CWAPR::Table object\fR )" 4
.IX Item "obj: $table ( APR::Table object )"
The table to add to.
.ie n .IP "arg1: $key ( string )" 4
.el .IP "arg1: \f(CW$key\fR ( string )" 4
.IX Item "arg1: $key ( string )"
The key to use.
.ie n .IP "arg2: $val ( string )" 4
.el .IP "arg2: \f(CW$val\fR ( string )" 4
.IX Item "arg2: $val ( string )"
The value to add.
.IP "ret: no return value" 4
.IX Item "ret: no return value"
.PD 0
.IP "since: 2.0.00" 4
.IX Item "since: 2.0.00"
.PD
.PP
When adding data, this function makes a copy of both the key and the
value.
.ie n .Sh """clear"""
.el .Sh "\f(CWclear\fP"
.IX Subsection "clear"
Delete all of the elements from a table.
.PP
.Vb 1
\&  $table\->clear();
.Ve
.ie n .IP "obj: $table\fR ( \f(CW""APR::Table object"" )" 4
.el .IP "obj: \f(CW$table\fR ( \f(CWAPR::Table object\fR )" 4
.IX Item "obj: $table ( APR::Table object )"
The table to clear.
.IP "ret: no return value" 4
.IX Item "ret: no return value"
.PD 0
.IP "since: 2.0.00" 4
.IX Item "since: 2.0.00"
.PD
.ie n .Sh """compress"""
.el .Sh "\f(CWcompress\fP"
.IX Subsection "compress"
Eliminate redundant entries in a table by either overwriting or
merging duplicates:
.PP
.Vb 1
\&  $table\->compress($flags);
.Ve
.ie n .IP "obj: $table\fR ( \f(CW""APR::Table object"" )" 4
.el .IP "obj: \f(CW$table\fR ( \f(CWAPR::Table object\fR )" 4
.IX Item "obj: $table ( APR::Table object )"
The table to compress.
.ie n .IP "arg1: $flags\fR (\f(CW""APR::Const constant"")" 4
.el .IP "arg1: \f(CW$flags\fR (\f(CWAPR::Const constant\fR)" 4
.IX Item "arg1: $flags (APR::Const constant)"
.Vb 2
\&  APR::Const::OVERLAP_TABLES_MERGE \-\- to merge
\&  APR::Const::OVERLAP_TABLES_SET   \-\- to overwrite
.Ve
.IP "ret: no return value" 4
.IX Item "ret: no return value"
.PD 0
.IP "since: 2.0.00" 4
.IX Item "since: 2.0.00"
.PD
.PP
Converts multi-valued keys in \f(CW$table\fR into single-valued keys.  This
function takes duplicate table entries and flattens them into a single
entry.  The flattening behavior is controlled by the (mandatory)
\&\f(CW$flags\fR argument.
.PP
When \f(CW$flags\fR == \f(CW\*(C`APR::Const::OVERLAP_TABLES_SET\*(C'\fR, each key will be set to
the last value seen for that key.  For example, given key/value pairs
\&'foo => bar' and 'foo => baz', 'foo' would have a final value
of 'baz' after compression \*(-- the 'bar' value would be lost.
.PP
When \f(CW$flags\fR == \f(CW\*(C`APR::Const::OVERLAP_TABLES_MERGE\*(C'\fR, multiple values for
the same key are flattened into a comma-separated list.  Given
key/value pairs 'foo => bar' and 'foo => baz', 'foo' would
have a final value of 'bar, baz' after compression.
.PP
Access the constants via:
.PP
.Vb 1
\&  use APR::Const \-compile qw(:table);
.Ve
.PP
or an explicit:
.PP
.Vb 1
\&  use APR::Const \-compile qw(OVERLAP_TABLES_SET OVERLAP_TABLES_MERGE);
.Ve
.PP
\&\f(CW\*(C`compress()\*(C'\fR combined with \f(CW\*(C`overlay()\*(C'\fR does the same
thing as \f(CW\*(C`overlap()\*(C'\fR.
.PP
Examples:
.IP "\(bu" 4
\&\f(CW\*(C`APR::Const::OVERLAP_TABLES_SET\*(C'\fR
.Sp
Start with table \f(CW$table\fR:
.Sp
.Vb 4
\&  foo => "one"
\&  foo => "two"
\&  foo => "three"
\&  bar => "beer"
.Ve
.Sp
which is done by:
.Sp
.Vb 2
\&  use APR::Const    \-compile => \*(Aq:table\*(Aq;
\&  my $table = APR::Table::make($r\->pool, TABLE_SIZE);
\&  
\&  $table\->set(bar => \*(Aqbeer\*(Aq);
\&  $table\->set(foo => \*(Aqone\*(Aq);
\&  $table\->add(foo => \*(Aqtwo\*(Aq);
\&  $table\->add(foo => \*(Aqthree\*(Aq);
.Ve
.Sp
Now compress it using \f(CW\*(C`APR::Const::OVERLAP_TABLES_SET\*(C'\fR:
.Sp
.Vb 1
\&  $table\->compress(APR::Const::OVERLAP_TABLES_SET);
.Ve
.Sp
Now table \f(CW$table\fR contains:
.Sp
.Vb 2
\&  foo => "three"
\&  bar => "beer"
.Ve
.Sp
The value \fIthree\fR for the key \fIfoo\fR, that was added last, took over
the other values.