package IO::Uncompress::Base ;

use strict ;
use warnings;
use bytes;

our (@ISA, $VERSION, @EXPORT_OK, %EXPORT_TAGS);
@ISA    = qw(Exporter IO::File);


$VERSION = '2.015';

use constant G_EOF => 0 ;
use constant G_ERR => -1 ;

use IO::Compress::Base::Common 2.015 ;
#use Parse::Parameters ;

use IO::File ;
use Symbol;
use Scalar::Util qw(readonly);
use List::Util qw(min);
use Carp ;

%EXPORT_TAGS = ( );
push @{ $EXPORT_TAGS{all} }, @EXPORT_OK ;
#Exporter::export_ok_tags('all') ;



sub smartRead
{
    my $self = $_[0];
    my $out = $_[1];
    my $size = $_[2];
    $$out = "" ;

    my $offset = 0 ;


    if (defined *$self->{InputLength}) {
        return 0
            if *$self->{InputLengthRemaining} <= 0 ;
        $size = min($size, *$self->{InputLengthRemaining});
    }

    if ( length *$self->{Prime} ) {
        #$$out = substr(*$self->{Prime}, 0, $size, '') ;
        $$out = substr(*$self->{Prime}, 0, $size) ;
        substr(*$self->{Prime}, 0, $size) =  '' ;
        if (length $$out == $size) {
            *$self->{InputLengthRemaining} -= length $$out
                if defined *$self->{InputLength};

            return length $$out ;
        }
        $offset = length $$out ;
    }

    my $get_size = $size - $offset ;

    if (defined *$self->{FH}) {
        if ($offset) {
            # Not using this 
            #
            #  *$self->{FH}->read($$out, $get_size, $offset);
            #
            # because the filehandle may not support the offset parameter
            # An example is Net::FTP
            my $tmp = '';
            *$self->{FH}->read($tmp, $get_size) > 0 &&
                (substr($$out, $offset) = $tmp);
        }
        else
          { *$self->{FH}->read($$out, $get_size) }
    }
    elsif (defined *$self->{InputEvent}) {
        my $got = 1 ;
        while (length $$out < $size) {
            last 
                if ($got = *$self->{InputEvent}->($$out, $get_size)) <= 0;
        }

        if (length $$out > $size ) {
            #*$self->{Prime} = substr($$out, $size, length($$out), '');
            *$self->{Prime} = substr($$out, $size, length($$out));
            substr($$out, $size, length($$out)) =  '';
        }

       *$self->{EventEof} = 1 if $got <= 0 ;
    }
    else {
       no warnings 'uninitialized';
       my $buf = *$self->{Buffer} ;
       $$buf = '' unless defined $$buf ;
       #$$out = '' unless defined $$out ;
       substr($$out, $offset) = substr($$buf, *$self->{BufferOffset}, $get_size);
       if (*$self->{ConsumeInput})
         { substr($$buf, 0, $get_size) = '' }