scsh-0.5/scsh/ndbm.scm

;;; Very vanilla DBM processing code

;;; Copyright (c) 1995 by David Albertz (dalbertz@clark.lcs.mit.edu).

;;; This code is freely available for use by anyone for any purpose,
;;; so long as you don't charge money for it, remove this notice, or
;;; hold us liable for any results of its use.  --enjoy.

;;; This is just a straight translation of the UNIX freebie NDBM code.

;;; Usage:	(dbm-open name flags mode)
;;;                 name  := name of database file (no extension)
;;;                 flags := file access flags (open/create etc.)
;;;                 mode  := file access modes (privileges)

;;; Return:	Alien value pointer to the open DBM structure

;;; Usage:      (dbm-close db)
;;;                 db := The pointer returned by dbm-open

;;; Return:     Always returns 0

;;; Usage:      (dbm-fetch db key)
;;;                 db  := The pointer returned by dbm-open
;;;                 key := The key value of data to be retrieved

;;; Return:     String containing data associated with key

;;; Usage:      (dbm-store db key data flag)
;;;                 db   := The pointer returned by dbm-open
;;;                 key  := The key value to be associated with data
;;;                 data := The data to be stored with the key
;;;                 flag := 0 for insert, 1 for replace

;;; Return:     Integer returned by UNIX dbm_store routine

;;; Usage:      (dbm-delete db key)
;;;                 db  := The pointer returned by dbm-open
;;;                 key := The key value of data to be deleted

;;; Return:     Integer returned by UNIX dbm_delete routine

;;; Usage:      (dbm-firstkey db)
;;;                 db   := The pointer returned by dbm-open

;;; Return:     First key value stored in database hash table.

;;; Usage:      (dbm-nextkey db)
;;;                 db   := The pointer returned by dbm-open

;;; Return:     Next key value stored in database hash table.

;;; Usage:      (dbm-error db)
;;;                 db   := The pointer returned by dbm-open

;;; Return:     Error number returned by UNIX dbm_error routine

;;; Usage:      (dbm-clearerr db)
;;;                 db   := The pointer returned by dbm-open

;;; Return:     Clears any database error condition and returns the 
;;;             integer from the UNIX dbm_clearerr routine

;;; ***NOTE:  All key and data elements must be strings

;;; Scheme48 implementation.

(foreign-source
  "#include <ndbm.h>"
  ""
  "extern int errno;"
  ""
  "#define errno_or_false(x) (((x) == -1) ? ENTER_FIXNUM(errno) : SCHFALSE)"
  "" "")

(define-foreign %dbm-open (database_open (string file)
					 (integer flags)
					 (integer mode))
  (to-scheme integer errno_or_false) ; error flag
  (C DBM**)) ; DBM structure

(define (dbm-open file flags mode)
  (receive (err dbm) (%dbm-open file flags mode)
	   (if err
	       (errno-error err dbm-open file flags mode)
	       dbm)))

(define-foreign dbm-close (database_close ((C DBM*) dbm))
  integer);

(define-foreign dbm-error (database_error ((C DBM*) dbm))
  integer)

(define-foreign dbm-clearerr (database_clearerr ((C DBM*) dbm))
  integer)

(define-foreign dbm-delete (database_delete ((C DBM*) dbm)
					    (string key))
  integer)

(define-foreign dbm-fetch (database_fetch ((C DBM*) dbm)
					  (string key))
  string)

(define-foreign dbm-store (database_store ((C DBM*) dbm)
					  (string key)
					  (string data)
					  (integer flags))
  integer)

(define-foreign dbm-firstkey (database_first ((C DBM*) dbm))
  string)

(define-foreign dbm-nextkey (database_next ((C DBM*) dbm
))
  string)