APR::Table
TABLE(1) User Contributed Perl Documentation TABLE(1)
NAME
APR::Table -- A Perl API for manipulating opaque string-content table
SYNOPSIS
use APR::Table;
$table = make($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 => $val);
overlap($table_a, $table_b, $flags);
$new_table = overlay($table_base, $table_overlay, $pool);
$table->do(sub {print "key $_[0], value $_[1]\n"}, @valid_keys);
#Tied Interface
$value = $table->{$key};
$table->{$key} = $value;
$table->{$key} = $value;
exists $table->{$key};
foreach my $key (keys %{$table}) {
print "$key = $table->{$key}\n";
}
DESCRIPTION
"APR::Table" allows its users to manipulate opaque string-content
tables.
The table's structure is somewhat similar to the Perl's hash structure,
but allows multiply values for the same key. An access to the records
stored in the table always requires a key.
The key-value pairs are stored in the order they are added.
The keys are case-insensitive.
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.
"APR::Table" provides a TIE Interface.
See apr/include/apr_tables.h in ASF's apr project for low level
details.
API
The variables used in the API definition have the following "types":
o APR::Table
"$table_*"
o APR::Pool
$pool
o scalars: unsigned integers only (SVIV) (as C expects them)
$nelts, $flags
o scalars: (numerical (SVIV/SVNV) and strings (SVPV))
$key, $val
Function arguments (if any) and return values are shown in the func-
tion's synopsis.
o make()
$table = make($pool, $nelts);
Make a new table.
param $pool: The pool to allocate the pool out of.
param $nelts: The number of elements in the initial table.
return: a new table.
warning: This table can only store text data
o copy()
$table_copy = $table->copy($pool);
Create a new table and copy another table into it
param $pool: The pool to allocate the new table out of
param $table: The table to copy
return: A copy of the table passed in
o clear()
$table->clear();
Delete all of the elements from a table.
param $table: A copy of the table passed in
o set();
$table->set($key => $val);
Add a key/value pair to a table, if another element already exists
with the same key, this will over-write the old data.
param $table: The table to add the data to.
param $key: The key fo use.
param $val: The value to add.
o add()
$table->add($key, $val);
Add data to a table, regardless of whether there is another element
with the same key.
param $table: The table to add to
param $key: The key to use
param $val: The value to add.
o do()
$table->do(sub {[...]}, [@filter]);
Iterate over all the elements of the table, invoking provided
subroutine for each element. The subroutine gets passed as argu-
ment, a key-value pair.
The subroutine can abort the iteration by returning 0 and should
always return 1 otherwise.
param "sub": A subroutine reference or name to be called on each
item in the table
param @filter: Only keys matching one of the entries in the filter
will be processed
o get()
$val = $table->get($key);
@val = $table->get($key);
Get the value(s) associated with a given key.
After this call, the data is still in the table.
param $table: The table to search for the key
param $key: The key to search for
return: In the scalar context the first matching value returned.
(The oldest in the table, if there is more than one value.) In the
list context the whole table is traversed and all matching values
are returned. If nothing matches undef is returned.
o unset();
$table->unset($key);
Remove data from the table
param $table: The table to remove data from
param $key: The key of the data being removed
o merge()
$table->merge($key => $val);
Add data to a table by merging the value with data that has already
been stored
param $table: The table to search for the data
param $key: The key to merge data for
param $val: The data to add
remark: If the key is not found, then this function acts like add()
o overlap()
overlap($table_a, $table_b, $flags);
For each key/value pair in $table_b, add the data to $table_a. The
definition of $flags explains how $flags define the overlapping
method.
param $table_a: The table to add the data to.
param $table_b: The table to iterate over, adding its data to %ta-
ble_a.
param $flags: How to add the $table_b to $table_a.
When $flags == "APR_OVERLAP_TABLES_SET", if another element already
exists with the same key, this will over-write the old data.
When $flags == "APR_OVERLAP_TABLES_MERGE", the key/value pair from
$table_b is added, regardless of whether there is another element
with the same key in $table_a.
remark: This function is highly optimized, and uses less memory and
CPU cycles than a function that just loops through table b calling
other functions.
o overlay()
$new_table = overlay($table_base, $table_overlay, $pool);
Merge two tables into one new table. The resulting table may have
more than one value for the same key.
param $pool: The pool to use for the new table
param $table_overlay: The first table to put in the new table
param $table_base: The table to add at the end of the new table
return: A new table containing all of the data from the two passed
in
TIE Interface
"APR::Table" also implements a tied interface, so you can work with the
$table object as a hash reference.
The following tied-hash function are supported: FETCH, STORE, DELETE,
CLEAR, EXISTS, FIRSTKEY, NEXTKEY and DESTROY.
remark: "APR::Table" can hold more than one key-value pair sharing the
same key, so when using a table through the tied interface, the first
entry found with the right key will be used, completely disregarding
possible other entries with the same key. The only exception to this
is if you iterate over the list with each, then you can access all key-
value pairs that share the same key.
perl v5.8.0 2002-05-19 TABLE(1)
