io.streams/zeta/buffer.lisp

   1 ;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Indent-tabs-mode: NIL -*-
   2 ;;;
   3 ;;; buffer.lisp --- Foreign memory buffers.
   4 ;;;
   5 ;;; Copyright (C) 2006-2008, Stelian Ionescu  <sionescu@common-lisp.net>
   6 ;;;
   7 ;;; This code is free software; you can redistribute it and/or
   8 ;;; modify it under the terms of the version 2.1 of
   9 ;;; the GNU Lesser General Public License as published by
  10 ;;; the Free Software Foundation, as clarified by the
  11 ;;; preamble found here:
  12 ;;;     http://opensource.franz.com/preamble.html
  13 ;;;
  14 ;;; This program is distributed in the hope that it will be useful,
  15 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;;; GNU General Public License for more details.
  18 ;;;
  19 ;;; You should have received a copy of the GNU Lesser General
  20 ;;; Public License along with this library; if not, write to the
  21 ;;; Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  22 ;;; Boston, MA 02110-1301, USA
  23
  24 (in-package :io.zeta-streams)
  25
  26 ;;;; Foreign Buffers
  27
  28 (define-constant +bytes-per-iobuf+ 4096)
  29
  30 ;;; FIXME: make this right
  31 ;;; probably not all SIMPLE-ARRAYs are admissible
  32 ;;; on all implementations
  33 (deftype compatible-lisp-array ()
  34   '(simple-array * (*)))
  35
  36 (declaim (inline allocate-iobuf iobuf-length iobuf-start-pointer
  37                  iobuf-end-pointer iobuf-end-space-length
  38                  iobuf-empty-p iobuf-full-p
  39                  iobuf-reset iobuf-copy-data-to-start
  40                  bref (setf bref) iobuf-copy
  41                  iobuf-pop-octet iobuf-push-octet))
  42
  43 (defun make-iobuf (&optional (size +bytes-per-iobuf+))
  44   (let ((b (%make-iobuf)))
  45     (setf (iobuf-data b) (foreign-alloc :uint8 :count size)
  46           (iobuf-size b) size)
  47     (values b)))
  48
  49 (defun iobuf-length (iobuf)
  50   (declare (type iobuf iobuf))
  51   (- (iobuf-end iobuf)
  52      (iobuf-start iobuf)))
  53
  54 (defun iobuf-start-pointer (iobuf data-pointer)
  55   (declare (type iobuf iobuf)
  56            (type cffi:foreign-pointer))
  57   (inc-pointer data-pointer (iobuf-start iobuf)))
  58
  59 (defun iobuf-end-pointer (iobuf data-pointer)
  60   (declare (type iobuf iobuf)
  61            (type cffi:foreign-pointer))
  62   (inc-pointer data-pointer (iobuf-end iobuf)))
  63
  64 (defun iobuf-empty-p (iobuf)
  65   (declare (type iobuf iobuf))
  66   (= (iobuf-end iobuf)
  67      (iobuf-start iobuf)))
  68
  69 (defun iobuf-full-p (iobuf)
  70   (declare (type iobuf iobuf))
  71   (= (iobuf-end iobuf)
  72      (iobuf-size iobuf)))
  73
  74 (defun iobuf-end-space-length (iobuf)
  75   (declare (type iobuf iobuf))
  76   (- (iobuf-size iobuf)
  77      (iobuf-end iobuf)))
  78
  79 (defun iobuf-reset (iobuf)
  80   (declare (type iobuf iobuf))
  81   (setf (iobuf-start iobuf) 0
  82         (iobuf-end iobuf)   0))
  83
  84 (defun iobuf-copy-data-to-start (iobuf)
  85   (declare (type iobuf iobuf))
  86   (cffi:with-pointer-to-vector-data (ptr (iobuf-data iobuf))
  87     (nix:memmove ptr (cffi:inc-pointer ptr (iobuf-start iobuf))
  88                  (iobuf-length iobuf)))
  89   (setf (iobuf-end iobuf) (iobuf-length iobuf))
  90   (setf (iobuf-start iobuf) 0))
  91
  92 ;;; BREF, (SETF BREF) and BUFFER-COPY *DO NOT* check boundaries
  93 ;;; that must be done by their callers
  94 (defun bref (iobuf index)
  95   (declare (type iobuf iobuf)
  96            (type iobuf-index index))
  97   (aref (iobuf-data iobuf) index))
  98
  99 (defun (setf bref) (octet iobuf index)
 100   (declare (type ub8 octet)
 101            (type iobuf iobuf)
 102            (type iobuf-index index))
 103   (setf (aref (iobuf-data iobuf) index) octet))
 104
 105 (defun iobuf-pop-octet (iobuf)
 106   (declare (type iobuf iobuf))
 107   (let ((start (iobuf-start iobuf)))
 108     (prog1 (bref iobuf start)
 109       (incf (iobuf-start iobuf)))))
 110
 111 (defun iobuf-push-octet (iobuf octet)
 112   (declare (type iobuf iobuf)
 113            (type (unsigned-byte 8) octet))
 114   (let ((end (iobuf-end iobuf)))
 115     (prog1 (setf (bref iobuf end) octet)
 116       (incf (iobuf-end iobuf)))))