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Genezzo::Block::RDBlkAUser Contributed Perl DocumentaGenezzo::Block::RDBlkA(3) NAME Genezzo::Block::RDBlkA.pm - Row Directory Block Adjunct tied hash class. This class adds array-like splice capabilities to Genezzo::Block::RDBlock. Genezzo::Block::RDBArray uses this class as the basis of a tied array. Note: Like its parent RDBlock, this class is almost, but not quite, a pushhash. SYNOPSIS use Genezzo::Block::RDBlkA; use Genezzo::Block::Std; local $Genezzo::Block::Std::DEFBLOCKSIZE = 500; my $buff = "\0" x 500; # construct an empty byte buffer my %tied_hash = (); my $tie_val = tie %tied_hash, 'Genezzo::Block::RDBlkA', (refbufstr => \$buff); # pushhash style # (note that the "PUSH" pseudo key is not supported)... my $newkey = $tie_val->HPush("this is a test"); # or array style, your choice my $pushcount = $tie_val->PUSH(qw(push lots of data)); $tied_hash{$newkey} = "update this entry"; # a hash that supports array style FETCHSIZE my $getcount = $tie_val->FETCHSIZE(); # Note: not HCount # splice it my $err_str; my @a1 = $tie_val->HeSplice(\$err_str, 5, 3, qw(more stuff to splice)); DESCRIPTION RDBlkA adds array-like splice capabilities to RDBlock, violating the standard hash abstraction. Splicing values resets hash keys, treating them more like array offsets. If you want to use a hash, use RDBlock or "Genezzo::Row::RSBlock". If you want to use an array, use "Genezzo::Block::RDBArray". FUNCTIONS RDBlkA support all standard hash operations, with the exception that you cannot create or insert a user key -- you must push new entries and use the generated key or basic iteration to retrieve your data. In addition to the RDBlock standard public methods, RDBlkA adds HSplice and HeSplice. HSplice this, offset, length, LIST Perform the equivalent of "splice" on the array. offset is optional and defaults to zero, negative values count back from the end of the array. length is optional and defaults to rest of the array. LIST may be empty. Returns a list of the original length elements at offset. HeSplice this, error_ref, offset, length, LIST error_ref is a string ref. Normally set to undef, set to error string on failure. LIMITATIONS The effort to convert a set of potentially sparse hash keys to array indexes is O(n), which ain't cheap. See Genezzo::Block::RDBlk_NN as an alternative -- imposing certain restrictions on the array contents and usage makes it possible to perform this conversion at O(1). EXPORT none TODO HSplice: offset calculation must match offset2hkey in RDBlock. Special handling needed if inherited by RDBlk_NN? AUTHOR Jeffrey I. Cohen, jcohen@genezzo.com SEE ALSO perl(1). Copyright (c) 2003, 2004 Jeffrey I Cohen. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Address bug reports and comments to: jcohen@genezzo.com For more information, please visit the Genezzo homepage at <http://www.genezzo.com> perl v5.32.0 2005-07-19 Genezzo::Block::RDBlkA(3)
NAME | SYNOPSIS | DESCRIPTION | FUNCTIONS | LIMITATIONS | TODO | AUTHOR | SEE ALSO
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