src/code/sysmacs.lisp

   1 ;;;; miscellaneous system hacking macros
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!IMPL")
  13 \f
  14
  15 #!-sb-thread
  16 (defmacro atomic-incf (symbol-name &optional (delta 1))
  17   `(incf ,symbol-name ,delta))
  18
  19 (defmacro atomic-decf (place &optional (delta 1))
  20   `(atomic-incf ,place ,(- delta)))
  21
  22
  23 (defmacro without-gcing (&rest body)
  24   #!+sb-doc
  25   "Executes the forms in the body without doing a garbage collection."
  26   `(unwind-protect
  27     (progn
  28       (atomic-incf *gc-inhibit*)
  29       ,@body)
  30     (atomic-decf *gc-inhibit*)
  31     (when (and *need-to-collect-garbage* (zerop *gc-inhibit*))
  32       (maybe-gc nil))))
  33
  34 \f
  35 ;;; EOF-OR-LOSE is a useful macro that handles EOF.
  36 (defmacro eof-or-lose (stream eof-error-p eof-value)
  37   `(if ,eof-error-p
  38        (error 'end-of-file :stream ,stream)
  39        ,eof-value))
  40
  41 ;;; These macros handle the special cases of T and NIL for input and
  42 ;;; output streams.
  43 ;;;
  44 ;;; FIXME: Shouldn't these be functions instead of macros?
  45 (defmacro in-synonym-of (stream &optional check-type)
  46   (let ((svar (gensym)))
  47     `(let ((,svar ,stream))
  48        (cond ((null ,svar) *standard-input*)
  49              ((eq ,svar t) *terminal-io*)
  50              (T ,@(when check-type `((enforce-type ,svar ,check-type)))
  51                 #!+high-security
  52                 (unless (input-stream-p ,svar)
  53                   (error 'simple-type-error
  54                          :datum ,svar
  55                          :expected-type '(satisfies input-stream-p)
  56                          :format-control "~S isn't an input stream"
  57                          :format-arguments ,(list  svar)))
  58                 ,svar)))))
  59 (defmacro out-synonym-of (stream &optional check-type)
  60   (let ((svar (gensym)))
  61     `(let ((,svar ,stream))
  62        (cond ((null ,svar) *standard-output*)
  63              ((eq ,svar t) *terminal-io*)
  64              (T ,@(when check-type `((check-type ,svar ,check-type)))
  65                 #!+high-security
  66                 (unless (output-stream-p ,svar)
  67                   (error 'simple-type-error
  68                          :datum ,svar
  69                          :expected-type '(satisfies output-stream-p)
  70                          :format-control "~S isn't an output stream."
  71                          :format-arguments ,(list  svar)))
  72                 ,svar)))))
  73
  74 ;;; WITH-mumble-STREAM calls the function in the given SLOT of the
  75 ;;; STREAM with the ARGS for ANSI-STREAMs, or the FUNCTION with the
  76 ;;; ARGS for FUNDAMENTAL-STREAMs.
  77 (defmacro with-in-stream (stream (slot &rest args) &optional stream-dispatch)
  78   `(let ((stream (in-synonym-of ,stream)))
  79     ,(if stream-dispatch
  80          `(if (ansi-stream-p stream)
  81               (funcall (,slot stream) stream ,@args)
  82               ,@(when stream-dispatch
  83                   `(,(destructuring-bind (function &rest args) stream-dispatch
  84                        `(,function stream ,@args)))))
  85          `(funcall (,slot stream) stream ,@args))))
  86
  87 (defmacro with-out-stream (stream (slot &rest args) &optional stream-dispatch)
  88   `(let ((stream (out-synonym-of ,stream)))
  89     ,(if stream-dispatch
  90          `(if (ansi-stream-p stream)
  91               (funcall (,slot stream) stream ,@args)
  92               ,@(when stream-dispatch
  93                   `(,(destructuring-bind (function &rest args) stream-dispatch
  94                                          `(,function stream ,@args)))))
  95          `(funcall (,slot stream) stream ,@args))))
  96 \f
  97 ;;;; These are hacks to make the reader win.
  98
  99 ;;; This macro sets up some local vars for use by the
 100 ;;; FAST-READ-CHAR macro within the enclosed lexical scope. The stream
 101 ;;; is assumed to be a ANSI-STREAM.
 102 (defmacro prepare-for-fast-read-char (stream &body forms)
 103   `(let* ((%frc-stream% ,stream)
 104           (%frc-method% (ansi-stream-in %frc-stream%))
 105           (%frc-buffer% (ansi-stream-in-buffer %frc-stream%))
 106           (%frc-index% (ansi-stream-in-index %frc-stream%)))
 107      (declare (type index %frc-index%)
 108               (type ansi-stream %frc-stream%))
 109      ,@forms))
 110
 111 ;;; This macro must be called after one is done with FAST-READ-CHAR
 112 ;;; inside its scope to decache the ANSI-STREAM-IN-INDEX.
 113 (defmacro done-with-fast-read-char ()
 114   `(setf (ansi-stream-in-index %frc-stream%) %frc-index%))
 115
 116 ;;; a macro with the same calling convention as READ-CHAR, to be used
 117 ;;; within the scope of a PREPARE-FOR-FAST-READ-CHAR
 118 (defmacro fast-read-char (&optional (eof-error-p t) (eof-value ()))
 119   `(cond
 120     ((not %frc-buffer%)
 121      (funcall %frc-method% %frc-stream% ,eof-error-p ,eof-value))
 122     ((= %frc-index% +ansi-stream-in-buffer-length+)
 123      (prog1 (fast-read-char-refill %frc-stream% ,eof-error-p ,eof-value)
 124             (setq %frc-index% (ansi-stream-in-index %frc-stream%))))
 125     (t
 126      (prog1 (code-char (aref %frc-buffer% %frc-index%))
 127             (incf %frc-index%)))))
 128
 129 ;;;; And these for the fasloader...
 130
 131 ;;; Just like PREPARE-FOR-FAST-READ-CHAR except that we get the BIN
 132 ;;; method. The stream is assumed to be a ANSI-STREAM.
 133 ;;;
 134 ;;; KLUDGE: It seems weird to have to remember to explicitly call
 135 ;;; DONE-WITH-FAST-READ-BYTE at the end of this, given that we're
 136 ;;; already wrapping the stuff inside in a block. Why not rename this
 137 ;;; macro to WITH-FAST-READ-BYTE, do the DONE-WITH-FAST-READ-BYTE stuff
 138 ;;; automatically at the end of the block, and eliminate
 139 ;;; DONE-WITH-FAST-READ-BYTE as a separate entity? (and similarly
 140 ;;; for the FAST-READ-CHAR stuff) -- WHN 19990825
 141 (defmacro prepare-for-fast-read-byte (stream &body forms)
 142   `(let* ((%frc-stream% ,stream)
 143           (%frc-method% (ansi-stream-bin %frc-stream%))
 144           (%frc-buffer% (ansi-stream-in-buffer %frc-stream%))
 145           (%frc-index% (ansi-stream-in-index %frc-stream%)))
 146      (declare (type index %frc-index%)
 147               (type ansi-stream %frc-stream%))
 148      ,@forms))
 149
 150 ;;; Similar to fast-read-char, but we use a different refill routine & don't
 151 ;;; convert to characters. If ANY-TYPE is true, then this can be used on any
 152 ;;; integer streams, and we don't assert the result type.
 153 (defmacro fast-read-byte (&optional (eof-error-p t) (eof-value ()) any-type)
 154   ;; KLUDGE: should use ONCE-ONLY on EOF-ERROR-P and EOF-VALUE -- WHN 19990825
 155   `(truly-the
 156     ,(if (and (eq eof-error-p t) (not any-type)) '(unsigned-byte 8) t)
 157     (cond
 158      ((not %frc-buffer%)
 159       (funcall %frc-method% %frc-stream% ,eof-error-p ,eof-value))
 160      ((= %frc-index% +ansi-stream-in-buffer-length+)
 161       (prog1 (fast-read-byte-refill %frc-stream% ,eof-error-p ,eof-value)
 162         (setq %frc-index% (ansi-stream-in-index %frc-stream%))))
 163      (t
 164       (prog1 (aref %frc-buffer% %frc-index%)
 165         (incf %frc-index%))))))
 166 (defmacro done-with-fast-read-byte ()
 167   `(done-with-fast-read-char))