libmojave/util/lm_listbuf.ml

   1 (*
   2    Simple imperative list buffer utility (used for instruction buffers)
   3    Copyright (C) 2002,2001 Justin David Smith, Caltech
   4
   5    This library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation,
   8    version 2.1 of the License.
   9
  10    This library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with this library; if not, write to the Free Software
  17    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  18
  19    Additional permission is given to link this library with the
  20    OpenSSL project's "OpenSSL" library, and with the OCaml runtime,
  21    and you may distribute the linked executables.  See the file
  22    LICENSE.libmojave for more details.
  23  *)
  24
  25
  26 (***  Type definitions  ***)
  27
  28 type 'a t =
  29    Empty
  30  | FwdList of 'a list
  31  | RevList of 'a list
  32
  33
  34 (***  Functions  ***)
  35
  36 let empty = Empty
  37
  38 let of_elt elt = RevList [elt]
  39
  40 let of_list ls = FwdList ls
  41
  42 let to_list buf =
  43    match buf with
  44       Empty ->
  45          []
  46     | FwdList buf ->
  47          buf
  48     | RevList buf ->
  49          List.rev buf
  50
  51 let add buf elt =
  52    match buf with
  53       Empty ->
  54          RevList [elt]
  55     | FwdList buf ->
  56          RevList (elt :: List.rev buf)
  57     | RevList buf ->
  58          RevList (elt :: buf)
  59
  60 let add_list buf ls =
  61    let rec add_list buf = function
  62       elt :: ls ->
  63          add_list (elt :: buf) ls
  64     | [] ->
  65          RevList buf
  66    in
  67       match buf with
  68          Empty ->
  69             FwdList ls
  70        | FwdList buf ->
  71             add_list (List.rev buf) ls
  72        | RevList buf ->
  73             add_list buf ls
  74
  75 let add_rev_list buf ls =
  76    let rec add_rev_list buf = function
  77       elt :: ls ->
  78          elt :: (add_rev_list buf ls)
  79     | [] ->
  80          buf
  81    in
  82       match buf with
  83          Empty ->
  84             RevList ls
  85        | FwdList buf ->
  86             RevList (add_rev_list (List.rev buf) ls)
  87        | RevList buf ->
  88             RevList (add_rev_list buf ls)
  89
  90 let add_listbuf buf ls =
  91    let rec add_listbuf_rev buf = function
  92       elt :: ls ->
  93          elt :: (add_listbuf_rev buf ls)
  94     | [] ->
  95          buf
  96    in
  97    let add_listbuf_rev buf ls = RevList (add_listbuf_rev buf ls) in
  98       match buf, ls with
  99          Empty, _ ->
 100             ls
 101        | _, Empty ->
 102             buf
 103        | _, FwdList ls ->
 104             add_list buf ls
 105        | FwdList buf, RevList ls ->
 106             add_listbuf_rev (List.rev buf) ls
 107        | RevList buf, RevList ls ->
 108             add_listbuf_rev buf ls