gdbm.h

/* gdbm.h  -  The include file for dbm users.  */

/*  This file is part of GDBM, the GNU data base manager, by Philip A. Nelson.
    Copyright (C) 1990, 1991, 1993  Free Software Foundation, Inc.

    GDBM 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, or (at your option)
    any later version.

    GDBM 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 GDBM; see the file COPYING.  If not, write to
    the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

    You may contact the author by:
       e-mail:  phil@cs.wwu.edu
      us-mail:  Philip A. Nelson
                Computer Science Department
                Western Washington University
                Bellingham, WA 98226
       
*************************************************************************/

/* Protection for multiple includes. */
#ifndef _GDBM_H_
#define _GDBM_H_

/* Parameters to gdbm_open for READERS, WRITERS, and WRITERS who
   can create the database. */
#define  GDBM_READER  0		/* A reader. */
#define  GDBM_WRITER  1		/* A writer. */
#define  GDBM_WRCREAT 2		/* A writer.  Create the db if needed. */
#define  GDBM_NEWDB   3		/* A writer.  Always create a new db. */
#define  GDBM_FAST    0x10	/* Write fast! => No fsyncs.  OBSOLETE. */
#define  GDBM_SYNC    0x20	/* Sync operations to the disk. */
#define  GDBM_NOLOCK  0x40	/* Don't do file locking operations. */

/* Parameters to gdbm_store for simple insertion or replacement in the
   case that the key is already in the database. */
#define  GDBM_INSERT  0		/* Never replace old data with new. */
#define  GDBM_REPLACE 1		/* Always replace old data with new. */

/* Parameters to gdbm_setopt, specifing the type of operation to perform. */
#define  GDBM_CACHESIZE 1       /* Set the cache size. */
#define  GDBM_FASTMODE  2       /* Toggle fast mode.  OBSOLETE. */
#define  GDBM_SYNCMODE	3	/* Turn on or off sync operations. */
#define  GDBM_CENTFREE  4	/* Keep all free blocks in the header. */
#define  GDBM_COALESCEBLKS 5	/* Attempt to coalesce free blocks. */

/* The data and key structure.  This structure is defined for compatibility. */
typedef struct {
	char *dptr;
	int   dsize;
      } datum;


/* The file information header. This is good enough for most applications. */
typedef struct {int dummy[10];} *GDBM_FILE;

/* Determine if the C(++) compiler requires complete function prototype  */
#ifndef __P
#if defined(__STDC__) || defined(__cplusplus) || defined(c_plusplus)
#define __P(x) x
#else
#define __P(x) ()
#endif
#endif

/* External variable, the gdbm build release string. */
extern char *gdbm_version;	


/* GDBM C++ support */
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

/* These are the routines! */

extern GDBM_FILE gdbm_open __P((char *, int, int, int, void (*)()));
extern void gdbm_close __P((GDBM_FILE));
extern int gdbm_store __P((GDBM_FILE, datum, datum, int));
extern datum gdbm_fetch __P((GDBM_FILE, datum));
extern int gdbm_delete __P((GDBM_FILE, datum));
extern datum gdbm_firstkey __P((GDBM_FILE));
extern datum gdbm_nextkey __P((GDBM_FILE, datum));
extern int gdbm_reorganize __P((GDBM_FILE));
extern void gdbm_sync __P((GDBM_FILE));
extern int gdbm_exists __P((GDBM_FILE, datum));
extern int gdbm_setopt __P((GDBM_FILE, int, int *, int));
extern int gdbm_fdesc __P((GDBM_FILE));

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

#define	GDBM_NO_ERROR		0
#define	GDBM_MALLOC_ERROR	1
#define	GDBM_BLOCK_SIZE_ERROR	2
#define	GDBM_FILE_OPEN_ERROR	3
#define	GDBM_FILE_WRITE_ERROR	4
#define	GDBM_FILE_SEEK_ERROR	5
#define	GDBM_FILE_READ_ERROR	6
#define	GDBM_BAD_MAGIC_NUMBER	7
#define	GDBM_EMPTY_DATABASE	8
#define	GDBM_CANT_BE_READER	9
#define	GDBM_CANT_BE_WRITER	10
#define	GDBM_READER_CANT_DELETE	11
#define	GDBM_READER_CANT_STORE	12
#define	GDBM_READER_CANT_REORGANIZE	13
#define	GDBM_UNKNOWN_UPDATE	14
#define	GDBM_ITEM_NOT_FOUND	15
#define	GDBM_REORGANIZE_FAILED	16
#define	GDBM_CANNOT_REPLACE	17
#define	GDBM_ILLEGAL_DATA	18
#define	GDBM_OPT_ALREADY_SET	19
#define	GDBM_OPT_ILLEGAL	20
typedef int gdbm_error;		/* For compatibilities sake. */
extern gdbm_error gdbm_errno;

/* extra prototypes */

/* GDBM C++ support */
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

extern char *gdbm_strerror __P((gdbm_error));

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

#endif

gdbm.p6

#!/usr/bin/env perl6

use v6;
use lib '.';

use DBM::GDBM;

my $gdbm = DBM::GDBM.new('foo.gdbm', 0, 0o666);

my $value = $gdbm.fetch('foo');
$value.say;
$value.perl.say;

gdbm.p6.output

DBM::GDBM::GDBM_FILE.new
DBM::GDBM::datum.new(dptr => "foo", dsize => 3)
foo
3
DBM::GDBM::datum
(datum)
DBM::GDBM::datum

GDBM.pm6

use v6;

class DBM::GDBM {

  use NativeCall;

  constant GDBM_BLOCKSIZE = 0;
  constant GDBM_WRCREAT   = 2;
  constant GDBM_REPLACE   = 1;

  class datum is repr<CStruct> is rw {
    has str   $.dptr;
    has int32 $.dsize;
  }

  class GDBM_FILE is repr<CStruct> {}

  sub gdbm_open(
    Str           $name,
    int32         $block_size,
    int32         $flags,
    int32         $mode,
    Pointer[void] $fatal_func
  )
    returns GDBM_FILE is native<libgdbm.so.3> { * }

  sub gdbm_fetch(
    GDBM_FILE $dbf,
    datum     $key,
  )
    returns datum is native<libgdbm.so.3> { * }

  # attributes #################################################################

  has GDBM_FILE $.dbf;
  has Str $.gdbm_file_name;
  has Int $.open_flags;
  has Int $.mode;

  # methods ####################################################################

  method new($gdbm_file_name, $open_flags, $mode) {
    my GDBM_FILE $dbf =
      gdbm_open($gdbm_file_name, GDBM_BLOCKSIZE, GDBM_WRCREAT, $mode, Nil);

    return self.bless(:$dbf, :$gdbm_file_name, :$open_flags, :$mode);
  }

  method fetch(str $key is copy) {
    my datum $key_datum = datum.new(dptr => $key, dsize => $key.chars);

$!dbf.perl.say;
$key_datum.say;
$key_datum.dptr.say;
$key_datum.dsize.say;
    my datum $content_datum = gdbm_fetch($!dbf, $key_datum);
$content_datum.perl.say;

    return $content_datum
  }

}