Tie::SubstrHash(3Perl Programmers Reference GuTie::SubstrHash(3p)
Tie::SubstrHash - Fixed-table-size, fixed-key-length hashing
require Tie::SubstrHash;
tie %myhash, 'Tie::SubstrHash', $key_len, $value_len, $table_size;
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 inter-
nal memory than an equivalent freely-allocated hash table.
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.
The hash does not support exists().
perl v5.8.8 2005-02-05 1
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