Tie::SubstrHash(3Perl Programmers Reference GuiTie::SubstrHash(3)NAMETie::SubstrHash - Fixed-table-size, fixed-key-length
hashing
SYNOPSIS
require Tie::SubstrHash;
tie %myhash, 'Tie::SubstrHash', $key_len, $value_len, $table_size;
DESCRIPTION
The Tie::SubstrHash package provides a hash-table-like
interface to an array of determinate size, with constant
key size and record size.
Upon tying a new hash to this package, the developer must
specify the size of the keys that will be used, the size
of the value fields that the keys will index, and the size
of the overall table (in terms of key-value pairs, not
size in hard memory). These values will not change for the
duration of the tied hash. The newly-allocated hash table
may now have data stored and retrieved. Efforts to store
more than $table_size elements will result in a fatal
error, as will efforts to store a value not exactly
$value_len characters in length, or reference through a
key not exactly $key_len characters in length. While these
constraints may seem excessive, the result is a hash table
using much less internal memory than an equivalent freely-
allocated hash table.
CAVEATS
Because the current implementation uses the table and key
sizes for the hashing algorithm, there is no means by
which to dynamically change the value of any of the
initialization parameters.
16/Sep/1999 perl 5.005, patch 03 1
