use Fcntl qw( :DEFAULT :flock :seek );
+sub precalc_sizes {
+ ##
+ # Precalculate index, bucket and bucket list sizes
+ ##
+ my $self = shift;
+
+ $self->{index_size} = (2**8) * $self->{long_size};
+ $self->{bucket_size} = $self->{hash_size} + $self->{long_size};
+ $self->{bucket_list_size} = $self->{max_buckets} * $self->{bucket_size};
+
+ return 1;
+}
+
+sub set_pack {
+ ##
+ # Set pack/unpack modes (see file header for more)
+ ##
+ my $self = shift;
+ my ($long_s, $long_p, $data_s, $data_p) = @_;
+
+ ##
+ # Set to 4 and 'N' for 32-bit offset tags (default). Theoretical limit of 4 GB per file.
+ # (Perl must be compiled with largefile support for files > 2 GB)
+ #
+ # Set to 8 and 'Q' for 64-bit offsets. Theoretical limit of 16 XB per file.
+ # (Perl must be compiled with largefile and 64-bit long support)
+ ##
+ $self->{long_size} = $long_s ? $long_s : 4;
+ $self->{long_pack} = $long_p ? $long_p : 'N';
+
+ ##
+ # Set to 4 and 'N' for 32-bit data length prefixes. Limit of 4 GB for each key/value.
+ # Upgrading this is possible (see above) but probably not necessary. If you need
+ # more than 4 GB for a single key or value, this module is really not for you :-)
+ ##
+ $self->{data_size} = $data_s ? $data_s : 4;
+ $self->{data_pack} = $data_p ? $data_p : 'N';
+
+ return $self->precalc_sizes();
+}
+
+sub set_digest {
+ ##
+ # Set key digest function (default is MD5)
+ ##
+ my $self = shift;
+ my ($digest_func, $hash_size) = @_;
+
+ $self->{digest} = $digest_func ? $digest_func : \&Digest::MD5::md5;
+ $self->{hash_size} = $hash_size ? $hash_size : 16;
+
+ return $self->precalc_sizes();
+}
+
+sub new {
+ my $class = shift;
+ my ($args) = @_;
+
+ my $self = bless {
+ long_size => 4,
+ long_pack => 'N',
+ data_size => 4,
+ data_pack => 'N',
+
+ digest => \&Digest::MD5::md5,
+ hash_size => 16,
+
+ ##
+ # Maximum number of buckets per list before another level of indexing is done.
+ # Increase this value for slightly greater speed, but larger database files.
+ # DO NOT decrease this value below 16, due to risk of recursive reindex overrun.
+ ##
+ max_buckets => 16,
+ }, $class;
+
+ $self->precalc_sizes;
+
+ return $self;
+}
+
+sub setup_fh {
+ my $self = shift;
+ my ($obj) = @_;
+
+ $self->open( $obj ) if !defined $obj->_fh;
+
+ #XXX Is {end} busted? Can't we just seek( $fh, 0, SEEK_END ) ?
+ unless ( $obj->_root->{inode} ) {
+ my @stats = stat($obj->_fh);
+ $obj->_root->{inode} = $stats[1];
+ $obj->_root->{end} = $stats[7];
+ }
+
+ return 1;
+}
+
sub open {
- ##
- # Open a fh to the database, create if nonexistent.
- # Make sure file signature matches DBM::Deep spec.
- ##
+ ##
+ # Open a fh to the database, create if nonexistent.
+ # Make sure file signature matches DBM::Deep spec.
+ ##
my $self = shift;
- my $obj = shift;
+ my ($obj) = @_;
+
+ if (defined($obj->_fh)) { $self->close_fh( $obj ); }
- if (defined($obj->_fh)) { $self->close( $obj ); }
-
eval {
local $SIG{'__DIE__'};
# Theoretically, adding O_BINARY should remove the need for the binmode
or $fh = undef;
$obj->_root->{fh} = $fh;
}; if ($@ ) { $obj->_throw_error( "Received error: $@\n" ); }
- if (! defined($obj->_fh)) {
- return $obj->_throw_error("Cannot sysopen file: " . $obj->_root->{file} . ": $!");
- }
+ if (! defined($obj->_fh)) {
+ return $obj->_throw_error("Cannot sysopen file: " . $obj->_root->{file} . ": $!");
+ }
my $fh = $obj->_fh;
$|=1;
select $old;
}
-
+
seek($fh, 0 + $obj->_root->{file_offset}, SEEK_SET);
my $signature;
my $bytes_read = read( $fh, $signature, length(DBM::Deep->SIG_FILE));
-
+
##
# File is empty -- write signature and master index
##
if (!$bytes_read) {
seek($fh, 0 + $obj->_root->{file_offset}, SEEK_SET);
print( $fh DBM::Deep->SIG_FILE);
- $obj->_create_tag($obj->_base_offset, $obj->_type, chr(0) x $DBM::Deep::INDEX_SIZE);
+
+ $self->create_tag($obj, $obj->_base_offset, $obj->_type, chr(0) x $self->{index_size});
my $plain_key = "[base]";
- print( $fh pack($DBM::Deep::DATA_LENGTH_PACK, length($plain_key)) . $plain_key );
+ print( $fh pack($self->{data_pack}, length($plain_key)) . $plain_key );
# Flush the filehandle
my $old_fh = select $fh;
my $old_af = $|; $| = 1; $| = $old_af;
select $old_fh;
- my @stats = stat($fh);
- $obj->_root->{inode} = $stats[1];
- $obj->_root->{end} = $stats[7];
-
return 1;
}
-
+
##
# Check signature was valid
##
unless ($signature eq DBM::Deep->SIG_FILE) {
- $self->close( $obj );
+ $self->close_fh( $obj );
return $obj->_throw_error("Signature not found -- file is not a Deep DB");
}
- my @stats = stat($fh);
- $obj->_root->{inode} = $stats[1];
- $obj->_root->{end} = $stats[7];
-
##
# Get our type from master index signature
##
- my $tag = $obj->_load_tag($obj->_base_offset);
-
-#XXX We probably also want to store the hash algorithm name and not assume anything
-#XXX The cool thing would be to allow a different hashing algorithm at every level
-
+ my $tag = $self->load_tag($obj, $obj->_base_offset);
if (!$tag) {
- return $obj->_throw_error("Corrupted file, no master index record");
+ return $obj->_throw_error("Corrupted file, no master index record");
}
+
if ($obj->{type} ne $tag->{signature}) {
- return $obj->_throw_error("File type mismatch");
+ return $obj->_throw_error("File type mismatch");
}
-
+
+#XXX We probably also want to store the hash algorithm name and not assume anything
+#XXX The cool thing would be to allow a different hashing algorithm at every level
+
return 1;
}
-sub close {
+sub close_fh {
my $self = shift;
- my $obj = shift;
+ my ($obj) = @_;
if ( my $fh = $obj->_root->{fh} ) {
close $fh;
return 1;
}
+sub create_tag {
+ ##
+ # Given offset, signature and content, create tag and write to disk
+ ##
+ my $self = shift;
+ my ($obj, $offset, $sig, $content) = @_;
+ my $size = length($content);
+
+ my $fh = $obj->_fh;
+
+ seek($fh, $offset + $obj->_root->{file_offset}, SEEK_SET);
+ print( $fh $sig . pack($self->{data_pack}, $size) . $content );
+
+ if ($offset == $obj->_root->{end}) {
+ $obj->_root->{end} += DBM::Deep->SIG_SIZE + $self->{data_size} + $size;
+ }
+
+ return {
+ signature => $sig,
+ size => $size,
+ offset => $offset + DBM::Deep->SIG_SIZE + $self->{data_size},
+ content => $content
+ };
+}
+
+sub load_tag {
+ ##
+ # Given offset, load single tag and return signature, size and data
+ ##
+ my $self = shift;
+ my ($obj, $offset) = @_;
+
+ my $fh = $obj->_fh;
+
+ seek($fh, $offset + $obj->_root->{file_offset}, SEEK_SET);
+ if (eof $fh) { return undef; }
+
+ my $b;
+ read( $fh, $b, DBM::Deep->SIG_SIZE + $self->{data_size} );
+ my ($sig, $size) = unpack( "A $self->{data_pack}", $b );
+
+ my $buffer;
+ read( $fh, $buffer, $size);
+
+ return {
+ signature => $sig,
+ size => $size,
+ offset => $offset + DBM::Deep->SIG_SIZE + $self->{data_size},
+ content => $buffer
+ };
+}
+
+sub add_bucket {
+ ##
+ # Adds one key/value pair to bucket list, given offset, MD5 digest of key,
+ # plain (undigested) key and value.
+ ##
+ my $self = shift;
+ my ($obj, $tag, $md5, $plain_key, $value) = @_;
+ my $keys = $tag->{content};
+ my $location = 0;
+ my $result = 2;
+
+ my $root = $obj->_root;
+
+ my $is_dbm_deep = eval { local $SIG{'__DIE__'}; $value->isa( 'DBM::Deep' ) };
+ my $internal_ref = $is_dbm_deep && ($value->_root eq $root);
+
+ my $fh = $obj->_fh;
+
+ ##
+ # Iterate through buckets, seeing if this is a new entry or a replace.
+ ##
+ for (my $i = 0; $i < $self->{max_buckets}; $i++) {
+ my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size}));
+ if (!$subloc) {
+ ##
+ # Found empty bucket (end of list). Populate and exit loop.
+ ##
+ $result = 2;
+
+ $location = $internal_ref
+ ? $value->_base_offset
+ : $root->{end};
+
+ seek($fh, $tag->{offset} + ($i * $self->{bucket_size}) + $root->{file_offset}, SEEK_SET);
+ print( $fh $md5 . pack($self->{long_pack}, $location) );
+ last;
+ }
+
+ my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size});
+ if ($md5 eq $key) {
+ ##
+ # Found existing bucket with same key. Replace with new value.
+ ##
+ $result = 1;
+
+ if ($internal_ref) {
+ $location = $value->_base_offset;
+ seek($fh, $tag->{offset} + ($i * $self->{bucket_size}) + $root->{file_offset}, SEEK_SET);
+ print( $fh $md5 . pack($self->{long_pack}, $location) );
+ return $result;
+ }
+
+ seek($fh, $subloc + DBM::Deep->SIG_SIZE + $root->{file_offset}, SEEK_SET);
+ my $size;
+ read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size);
+
+ ##
+ # If value is a hash, array, or raw value with equal or less size, we can
+ # reuse the same content area of the database. Otherwise, we have to create
+ # a new content area at the EOF.
+ ##
+ my $actual_length;
+ my $r = Scalar::Util::reftype( $value ) || '';
+ if ( $r eq 'HASH' || $r eq 'ARRAY' ) {
+ $actual_length = $self->{index_size};
+
+ # if autobless is enabled, must also take into consideration
+ # the class name, as it is stored along with key/value.
+ if ( $root->{autobless} ) {
+ my $value_class = Scalar::Util::blessed($value);
+ if ( defined $value_class && !$value->isa('DBM::Deep') ) {
+ $actual_length += length($value_class);
+ }
+ }
+ }
+ else { $actual_length = length($value); }
+
+ if ($actual_length <= $size) {
+ $location = $subloc;
+ }
+ else {
+ $location = $root->{end};
+ seek($fh, $tag->{offset} + ($i * $self->{bucket_size}) + $self->{hash_size} + $root->{file_offset}, SEEK_SET);
+ print( $fh pack($self->{long_pack}, $location) );
+ }
+
+ last;
+ }
+ }
+
+ ##
+ # If this is an internal reference, return now.
+ # No need to write value or plain key
+ ##
+ if ($internal_ref) {
+ return $result;
+ }
+
+ ##
+ # If bucket didn't fit into list, split into a new index level
+ ##
+ if (!$location) {
+ seek($fh, $tag->{ref_loc} + $root->{file_offset}, SEEK_SET);
+ print( $fh pack($self->{long_pack}, $root->{end}) );
+
+ my $index_tag = $self->create_tag($obj, $root->{end}, DBM::Deep->SIG_INDEX, chr(0) x $self->{index_size});
+ my @offsets = ();
+
+ $keys .= $md5 . pack($self->{long_pack}, 0);
+
+ for (my $i=0; $i<=$self->{max_buckets}; $i++) {
+ my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size});
+ if ($key) {
+ my $old_subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) +
+ $self->{hash_size}, $self->{long_size}));
+ my $num = ord(substr($key, $tag->{ch} + 1, 1));
+
+ if ($offsets[$num]) {
+ my $offset = $offsets[$num] + DBM::Deep->SIG_SIZE + $self->{data_size};
+ seek($fh, $offset + $root->{file_offset}, SEEK_SET);
+ my $subkeys;
+ read( $fh, $subkeys, $self->{bucket_list_size});
+
+ for (my $k=0; $k<$self->{max_buckets}; $k++) {
+ my $subloc = unpack($self->{long_pack}, substr($subkeys, ($k * $self->{bucket_size}) +
+ $self->{hash_size}, $self->{long_size}));
+ if (!$subloc) {
+ seek($fh, $offset + ($k * $self->{bucket_size}) + $root->{file_offset}, SEEK_SET);
+ print( $fh $key . pack($self->{long_pack}, $old_subloc || $root->{end}) );
+ last;
+ }
+ } # k loop
+ }
+ else {
+ $offsets[$num] = $root->{end};
+ seek($fh, $index_tag->{offset} + ($num * $self->{long_size}) + $root->{file_offset}, SEEK_SET);
+ print( $fh pack($self->{long_pack}, $root->{end}) );
+
+ my $blist_tag = $self->create_tag($obj, $root->{end}, DBM::Deep->SIG_BLIST, chr(0) x $self->{bucket_list_size});
+
+ seek($fh, $blist_tag->{offset} + $root->{file_offset}, SEEK_SET);
+ print( $fh $key . pack($self->{long_pack}, $old_subloc || $root->{end}) );
+ }
+ } # key is real
+ } # i loop
+
+ $location ||= $root->{end};
+ } # re-index bucket list
+
+ ##
+ # Seek to content area and store signature, value and plaintext key
+ ##
+ if ($location) {
+ my $content_length;
+ seek($fh, $location + $root->{file_offset}, SEEK_SET);
+
+ ##
+ # Write signature based on content type, set content length and write actual value.
+ ##
+ my $r = Scalar::Util::reftype($value) || '';
+ if ($r eq 'HASH') {
+ print( $fh DBM::Deep->TYPE_HASH );
+ print( $fh pack($self->{data_pack}, $self->{index_size}) . chr(0) x $self->{index_size} );
+ $content_length = $self->{index_size};
+ }
+ elsif ($r eq 'ARRAY') {
+ print( $fh DBM::Deep->TYPE_ARRAY );
+ print( $fh pack($self->{data_pack}, $self->{index_size}) . chr(0) x $self->{index_size} );
+ $content_length = $self->{index_size};
+ }
+ elsif (!defined($value)) {
+ print( $fh DBM::Deep->SIG_NULL );
+ print( $fh pack($self->{data_pack}, 0) );
+ $content_length = 0;
+ }
+ else {
+ print( $fh DBM::Deep->SIG_DATA );
+ print( $fh pack($self->{data_pack}, length($value)) . $value );
+ $content_length = length($value);
+ }
+
+ ##
+ # Plain key is stored AFTER value, as keys are typically fetched less often.
+ ##
+ print( $fh pack($self->{data_pack}, length($plain_key)) . $plain_key );
+
+ ##
+ # If value is blessed, preserve class name
+ ##
+ if ( $root->{autobless} ) {
+ my $value_class = Scalar::Util::blessed($value);
+ if ( defined $value_class && $value_class ne 'DBM::Deep' ) {
+ ##
+ # Blessed ref -- will restore later
+ ##
+ print( $fh chr(1) );
+ print( $fh pack($self->{data_pack}, length($value_class)) . $value_class );
+ $content_length += 1;
+ $content_length += $self->{data_size} + length($value_class);
+ }
+ else {
+ print( $fh chr(0) );
+ $content_length += 1;
+ }
+ }
+
+ ##
+ # If this is a new content area, advance EOF counter
+ ##
+ if ($location == $root->{end}) {
+ $root->{end} += DBM::Deep->SIG_SIZE;
+ $root->{end} += $self->{data_size} + $content_length;
+ $root->{end} += $self->{data_size} + length($plain_key);
+ }
+
+ ##
+ # If content is a hash or array, create new child DBM::Deep object and
+ # pass each key or element to it.
+ ##
+ if ($r eq 'HASH') {
+ my $branch = DBM::Deep->new(
+ type => DBM::Deep->TYPE_HASH,
+ base_offset => $location,
+ root => $root,
+ );
+ foreach my $key (keys %{$value}) {
+ $branch->STORE( $key, $value->{$key} );
+ }
+ }
+ elsif ($r eq 'ARRAY') {
+ my $branch = DBM::Deep->new(
+ type => DBM::Deep->TYPE_ARRAY,
+ base_offset => $location,
+ root => $root,
+ );
+ my $index = 0;
+ foreach my $element (@{$value}) {
+ $branch->STORE( $index, $element );
+ $index++;
+ }
+ }
+
+ return $result;
+ }
+
+ return $obj->_throw_error("Fatal error: indexing failed -- possibly due to corruption in file");
+}
+
+sub get_bucket_value {
+ ##
+ # Fetch single value given tag and MD5 digested key.
+ ##
+ my $self = shift;
+ my ($obj, $tag, $md5) = @_;
+ my $keys = $tag->{content};
+
+ my $fh = $obj->_fh;
+
+ ##
+ # Iterate through buckets, looking for a key match
+ ##
+ BUCKET:
+ for (my $i=0; $i<$self->{max_buckets}; $i++) {
+ my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size});
+ my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size}));
+
+ if (!$subloc) {
+ ##
+ # Hit end of list, no match
+ ##
+ return;
+ }
+
+ if ( $md5 ne $key ) {
+ next BUCKET;
+ }
+
+ ##
+ # Found match -- seek to offset and read signature
+ ##
+ my $signature;
+ seek($fh, $subloc + $obj->_root->{file_offset}, SEEK_SET);
+ read( $fh, $signature, DBM::Deep->SIG_SIZE);
+
+ ##
+ # If value is a hash or array, return new DBM::Deep object with correct offset
+ ##
+ if (($signature eq DBM::Deep->TYPE_HASH) || ($signature eq DBM::Deep->TYPE_ARRAY)) {
+ my $obj = DBM::Deep->new(
+ type => $signature,
+ base_offset => $subloc,
+ root => $obj->_root,
+ );
+
+ if ($obj->_root->{autobless}) {
+ ##
+ # Skip over value and plain key to see if object needs
+ # to be re-blessed
+ ##
+ seek($fh, $self->{data_size} + $self->{index_size}, SEEK_CUR);
+
+ my $size;
+ read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size);
+ if ($size) { seek($fh, $size, SEEK_CUR); }
+
+ my $bless_bit;
+ read( $fh, $bless_bit, 1);
+ if (ord($bless_bit)) {
+ ##
+ # Yes, object needs to be re-blessed
+ ##
+ my $class_name;
+ read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size);
+ if ($size) { read( $fh, $class_name, $size); }
+ if ($class_name) { $obj = bless( $obj, $class_name ); }
+ }
+ }
+
+ return $obj;
+ }
+
+ ##
+ # Otherwise return actual value
+ ##
+ elsif ($signature eq DBM::Deep->SIG_DATA) {
+ my $size;
+ my $value = '';
+ read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size);
+ if ($size) { read( $fh, $value, $size); }
+ return $value;
+ }
+
+ ##
+ # Key exists, but content is null
+ ##
+ else { return; }
+ } # i loop
+
+ return;
+}
+
+sub delete_bucket {
+ ##
+ # Delete single key/value pair given tag and MD5 digested key.
+ ##
+ my $self = shift;
+ my ($obj, $tag, $md5) = @_;
+ my $keys = $tag->{content};
+
+ my $fh = $obj->_fh;
+
+ ##
+ # Iterate through buckets, looking for a key match
+ ##
+ BUCKET:
+ for (my $i=0; $i<$self->{max_buckets}; $i++) {
+ my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size});
+ my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size}));
+
+ if (!$subloc) {
+ ##
+ # Hit end of list, no match
+ ##
+ return;
+ }
+
+ if ( $md5 ne $key ) {
+ next BUCKET;
+ }
+
+ ##
+ # Matched key -- delete bucket and return
+ ##
+ seek($fh, $tag->{offset} + ($i * $self->{bucket_size}) + $obj->_root->{file_offset}, SEEK_SET);
+ print( $fh substr($keys, ($i+1) * $self->{bucket_size} ) );
+ print( $fh chr(0) x $self->{bucket_size} );
+
+ return 1;
+ } # i loop
+
+ return;
+}
+
+sub bucket_exists {
+ ##
+ # Check existence of single key given tag and MD5 digested key.
+ ##
+ my $self = shift;
+ my ($obj, $tag, $md5) = @_;
+ my $keys = $tag->{content};
+
+ ##
+ # Iterate through buckets, looking for a key match
+ ##
+ BUCKET:
+ for (my $i=0; $i<$self->{max_buckets}; $i++) {
+ my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size});
+ my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size}));
+
+ if (!$subloc) {
+ ##
+ # Hit end of list, no match
+ ##
+ return;
+ }
+
+ if ( $md5 ne $key ) {
+ next BUCKET;
+ }
+
+ ##
+ # Matched key -- return true
+ ##
+ return 1;
+ } # i loop
+
+ return;
+}
+
+sub find_bucket_list {
+ ##
+ # Locate offset for bucket list, given digested key
+ ##
+ my $self = shift;
+ my ($obj, $md5, $args) = @_;
+ $args = {} unless $args;
+
+ ##
+ # Locate offset for bucket list using digest index system
+ ##
+ my $ch = 0;
+ my $tag = $self->load_tag($obj, $obj->_base_offset);
+ if (!$tag) {
+ return $self->_throw_error( "INTERNAL ERROR - Cannot find tag" );
+ }
+
+ while ($tag->{signature} ne DBM::Deep->SIG_BLIST) {
+ my $num = ord substr($md5, $ch, 1);
+
+ my $ref_loc = $tag->{offset} + ($num * $self->{long_size});
+ $tag = $self->index_lookup( $obj, $tag, $num );
+
+ if (!$tag) {
+ if ( $args->{create} ) {
+ my $fh = $obj->_fh;
+ seek($fh, $ref_loc + $obj->_root->{file_offset}, SEEK_SET);
+ print( $fh pack($self->{long_pack}, $obj->_root->{end}) );
+
+ $tag = $self->create_tag(
+ $obj, $obj->_root->{end},
+ DBM::Deep->SIG_BLIST,
+ chr(0) x $self->{bucket_list_size},
+ );
+
+ $tag->{ref_loc} = $ref_loc;
+ $tag->{ch} = $ch;
+
+ last;
+ }
+ else {
+ return;
+ }
+ }
+
+ $tag->{ch} = $ch;
+ $tag->{ref_loc} = $ref_loc;
+
+ $ch++;
+ }
+
+ return $tag;
+}
+
+sub index_lookup {
+ ##
+ # Given index tag, lookup single entry in index and return .
+ ##
+ my $self = shift;
+ my ($obj, $tag, $index) = @_;
+
+ my $location = unpack(
+ $self->{long_pack},
+ substr(
+ $tag->{content},
+ $index * $self->{long_size},
+ $self->{long_size},
+ ),
+ );
+
+ if (!$location) { return; }
+
+ return $self->load_tag( $obj, $location );
+}
+
+sub traverse_index {
+ ##
+ # Scan index and recursively step into deeper levels, looking for next key.
+ ##
+ my $self = shift;
+ my ($obj, $offset, $ch, $force_return_next) = @_;
+ $force_return_next = undef unless $force_return_next;
+
+ my $tag = $self->load_tag($obj, $offset );
+
+ my $fh = $obj->_fh;
+
+ if ($tag->{signature} ne DBM::Deep->SIG_BLIST) {
+ my $content = $tag->{content};
+ my $start;
+ if ($obj->{return_next}) { $start = 0; }
+ else { $start = ord(substr($obj->{prev_md5}, $ch, 1)); }
+
+ for (my $index = $start; $index < 256; $index++) {
+ my $subloc = unpack($self->{long_pack}, substr($content, $index * $self->{long_size}, $self->{long_size}) );
+ if ($subloc) {
+ my $result = $self->traverse_index( $obj, $subloc, $ch + 1, $force_return_next );
+ if (defined($result)) { return $result; }
+ }
+ } # index loop
+
+ $obj->{return_next} = 1;
+ } # tag is an index
+
+ elsif ($tag->{signature} eq DBM::Deep->SIG_BLIST) {
+ my $keys = $tag->{content};
+ if ($force_return_next) { $obj->{return_next} = 1; }
+
+ ##
+ # Iterate through buckets, looking for a key match
+ ##
+ for (my $i=0; $i<$self->{max_buckets}; $i++) {
+ my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size});
+ my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size}));
+
+ if (!$subloc) {
+ ##
+ # End of bucket list -- return to outer loop
+ ##
+ $obj->{return_next} = 1;
+ last;
+ }
+ elsif ($key eq $obj->{prev_md5}) {
+ ##
+ # Located previous key -- return next one found
+ ##
+ $obj->{return_next} = 1;
+ next;
+ }
+ elsif ($obj->{return_next}) {
+ ##
+ # Seek to bucket location and skip over signature
+ ##
+ seek($fh, $subloc + DBM::Deep->SIG_SIZE + $obj->_root->{file_offset}, SEEK_SET);
+
+ ##
+ # Skip over value to get to plain key
+ ##
+ my $size;
+ read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size);
+ if ($size) { seek($fh, $size, SEEK_CUR); }
+
+ ##
+ # Read in plain key and return as scalar
+ ##
+ my $plain_key;
+ read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size);
+ if ($size) { read( $fh, $plain_key, $size); }
+
+ return $plain_key;
+ }
+ } # bucket loop
+
+ $obj->{return_next} = 1;
+ } # tag is a bucket list
+
+ return;
+}
+
+sub get_next_key {
+ ##
+ # Locate next key, given digested previous one
+ ##
+ my $self = shift;
+ my ($obj) = @_;
+
+ $obj->{prev_md5} = $_[1] ? $_[1] : undef;
+ $obj->{return_next} = 0;
+
+ ##
+ # If the previous key was not specifed, start at the top and
+ # return the first one found.
+ ##
+ if (!$obj->{prev_md5}) {
+ $obj->{prev_md5} = chr(0) x $self->{hash_size};
+ $obj->{return_next} = 1;
+ }
+
+ return $self->traverse_index( $obj, $obj->_base_offset, 0 );
+}
+
1;
__END__
projects / dbsrgits/DBM-Deep.git / blobdiff