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############################
package SQL::Statement::RAM;
############################
######################################################################
#
# This module is copyright (c), 2001,2005 by Jeff Zucker.
# This module is copyright (c), 2007-2020 by Jens Rehsack.
# All rights reserved.
#
# It may be freely distributed under the same terms as Perl itself.
# See below for help and copyright information (search for SYNOPSIS).
#
######################################################################
use strict;
use warnings FATAL => "all";
use vars qw($VERSION);
$VERSION = '1.414';
####################################
package SQL::Statement::RAM::Table;
####################################
use strict;
use warnings FATAL => "all";
use SQL::Eval ();
use vars qw(@ISA);
@ISA = qw(SQL::Eval::Table);
use Carp qw(croak);
sub new
{
    my ( $class, $tname, $col_names, $data_tbl ) = @_;
    my %table = (
        NAME         => $tname,
        index        => 0,
        records      => $data_tbl,
        col_names    => $col_names,
        capabilities => {
            inplace_update => 1,
            inplace_delete => 1,
        },
    );
    my $self = $class->SUPER::new( \%table );
}
##################################
# fetch_row()
##################################
sub fetch_row
{
    my ( $self, $data ) = @_;
    return $self->{row} =
        ( $self->{records} and ( $self->{index} < scalar( @{ $self->{records} } ) ) )
      ? [ @{ $self->{records}->[ $self->{index}++ ] } ]
      : undef;
}
####################################
# insert_new_row()
####################################
sub insert_new_row
{
    my ( $self, $data, $fields ) = @_;
    push @{ $self->{records} }, [ @{$fields} ];
    return 1;
}
##################################
# delete_current_row()
##################################
sub delete_current_row
{
    my ( $self, $data, $fields ) = @_;
    my $currentRow = $self->{index} - 1;
    croak "No current row" unless ( $currentRow >= 0 );
    splice @{ $self->{records} }, $currentRow, 1;
    --$self->{index};
    return 1;
}
##################################
# update_current_row()
##################################
sub update_current_row
{
    my ( $self, $data, $fields ) = @_;
    my $currentRow = $self->{index} - 1;
    croak "No current row" unless ( $currentRow >= 0 );
    $self->{records}->[$currentRow] = [ @{$fields} ];
    return 1;
}
##################################
# truncate()
##################################
sub truncate
{
    return splice @{ $_[0]->{records} }, $_[0]->{index};
}
#####################################
# push_names()
#####################################
sub push_names
{
    my ( $self, $data, $names ) = @_;
    $self->{col_names}     = $names;
    $self->{org_col_names} = [ @{$names} ];
    $self->{col_nums}      = SQL::Eval::Table::_map_colnums($names);
}
#####################################
# drop()
#####################################
sub drop
{
    my ( $self, $data ) = @_;
    my $tname = $self->{NAME};
    delete $data->{Database}->{sql_ram_tables}->{$tname};
    return 1;
}
#####################################
# seek()
#####################################
sub seek
{
    my ( $self, $data, $pos, $whence ) = @_;
    return unless defined $self->{records};
    my ($currentRow) = $self->{index};
    if ( $whence == 0 )
    {
        $currentRow = $pos;
    }
    elsif ( $whence == 1 )
    {
        $currentRow += $pos;
    }
    elsif ( $whence == 2 )
    {
        $currentRow = @{ $self->{records} } + $pos;
    }
    else
    {
        croak $self . "->seek: Illegal whence argument ($whence)";
    }
    if ( $currentRow < 0 )
    {
        croak "Illegal row number: $currentRow";
    }
    $self->{index} = $currentRow;
}
1;
HideShow 142 lines of Pod
=pod
=head1 NAME
SQL::Statement::RAM
=head1 SYNOPSIS
  SQL::Statement::RAM
=head1 DESCRIPTION
This package contains support for the internally used
SQL::Statement::RAM::Table.
=head1 INHERITANCE
  SQL::Statement::RAM
  SQL::Statement::RAM::Table
  ISA SQL::Eval::Table
=head1 SQL::Statement::RAM::Table
=head2 METHODS
=over 8
=item new
Instantiates a new C<SQL::Statement::RAM::Table> object, used for temporary
tables.
    CREATE TEMP TABLE foo ....
=item fetch_row
Fetches the next row
=item push_row
As fetch_row except for writing
=item delete_current_row
Deletes the last fetched/pushed row
=item update_current_row
Updates the last fetched/pushed row
=item truncate
Truncates the table at the current position
=item push_names
Set the column names of the table
=item drop
Discards the table
=item seek
Seek the row pointer
=back
=head2 CAPABILITIES
This table has following capabilities:
=over 8
=item update_current_row
Using provided method C<update_current_row> and capability C<inplace_update>.
=item rowwise_update
By providing capability C<update_current_row>.
=item inplace_update
By definition (appropriate flag set in constructor).
=item delete_current_row
Using provided method C<delete_current_row> and capability C<inplace_delete>.
=item rowwise_delete
By providing capability C<delete_current_row>.
=item inplace_delete
By definition (appropriate flag set in constructor).
=back
=head1 SUPPORT
You can find documentation for this module with the perldoc command.
    perldoc SQL::Statement
You can also look for information at:
=over 4
=item * RT: CPAN's request tracker
L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=SQL-Statement>
=item * AnnoCPAN: Annotated CPAN documentation
L<http://annocpan.org/dist/SQL-Statement>
=item * CPAN Ratings
L<http://cpanratings.perl.org/s/SQL-Statement>
=item * Search CPAN
L<http://search.cpan.org/dist/SQL-Statement/>
=back
=head1 AUTHOR AND COPYRIGHT
Copyright (c) 2001,2005 by Jeff Zucker: jzuckerATcpan.org
Copyright (c) 2007-2020 by Jens Rehsack: rehsackATcpan.org
All rights reserved.
You may distribute this module under the terms of either the GNU
General Public License or the Artistic License, as specified in
the Perl README file.
=cut