Tie::SubstrHash(3pm)                            Perl Programmers Reference Guide                            Tie::SubstrHash(3pm)



NAME
       Tie::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.

       The hash does not support exists().



perl v5.12.4                                               2011-06-01                                       Tie::SubstrHash(3pm)