src/code/target-extensions.lisp

   1 ;;;; This file contains things for the extensions packages (SB-EXT and
   2 ;;;; also "internal extensions" SB-INT) which can't be built at
   3 ;;;; cross-compile time, and perhaps also some things which might as
   4 ;;;; well not be built at cross-compile time because they're not
   5 ;;;; needed then. Things which can't be built at cross-compile time
   6 ;;;; (e.g. because they need machinery which only exists inside SBCL's
   7 ;;;; implementation of the LISP package) do not belong in this file.
   8
   9 ;;;; This software is part of the SBCL system. See the README file for
  10 ;;;; more information.
  11 ;;;;
  12 ;;;; This software is derived from the CMU CL system, which was
  13 ;;;; written at Carnegie Mellon University and released into the
  14 ;;;; public domain. The software is in the public domain and is
  15 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  16 ;;;; files for more information.
  17
  18 (in-package "SB!IMPL")
  19 \f
  20 ;;;; variables initialization and shutdown sequences
  21
  22 ;; (Most of the save-a-core functionality is defined later, in its
  23 ;; own file, but we'd like to have these symbols declared special
  24 ;; and initialized ASAP.)
  25 (defvar *save-hooks* nil
  26   #!+sb-doc
  27   "This is a list of functions which are called in an unspecified
  28 order before creating a saved core image. Unused by SBCL itself:
  29 reserved for user and applications.")
  30
  31 (defvar *init-hooks* nil
  32   #!+sb-doc
  33   "This is a list of functions which are called in an unspecified
  34 order when a saved core image starts up, after the system itself has
  35 been initialized. Unused by SBCL itself: reserved for user and
  36 applications.")
  37
  38 \f
  39 ;;; Binary search for simple vectors
  40 (defun binary-search (value seq &key (key #'identity))
  41   (declare (simple-vector seq))
  42   (labels ((recurse (start end)
  43              (when (< start end)
  44                (let* ((i (+ start (truncate (- end start) 2)))
  45                       (elt (svref seq i))
  46                       (key-value (funcall key elt)))
  47                  (cond ((< value key-value)
  48                         (recurse start i))
  49                        ((> value key-value)
  50                         (recurse (1+ i) end))
  51                        (t
  52                         elt))))))
  53     (recurse 0 (length seq))))
  54
  55 \f
  56 ;;; like LISTEN, but any whitespace in the input stream will be flushed
  57 (defun listen-skip-whitespace (&optional (stream *standard-input*))
  58   (do ((char (read-char-no-hang stream nil nil nil)
  59              (read-char-no-hang stream nil nil nil)))
  60       ((null char) nil)
  61     (cond ((not (whitespace[1]p char))
  62            (unread-char char stream)
  63            (return t)))))
  64 \f
  65 ;;;; helpers for C library calls
  66
  67 ;;; Signal a SIMPLE-CONDITION/ERROR condition associated with an ANSI C
  68 ;;; errno problem, arranging for the condition's print representation
  69 ;;; to be similar to the ANSI C perror(3) style.
  70 (defun simple-perror (prefix-string
  71                       &key
  72                       (errno (get-errno))
  73                       (simple-error 'simple-error)
  74                       other-condition-args)
  75   (declare (type symbol simple-error))
  76   (aver (subtypep simple-error 'simple-condition))
  77   (aver (subtypep simple-error 'error))
  78   (apply #'error
  79          simple-error
  80          :format-control "~@<~A: ~2I~_~A~:>"
  81          :format-arguments (list prefix-string (strerror errno))
  82          other-condition-args))
  83
  84 ;;; Constructing shortish strings one character at a time. More efficient then
  85 ;;; a string-stream, as can directly use simple-base-strings when applicable,
  86 ;;; and if the maximum size is know doesn't need to copy the result at all --
  87 ;;; but if the result is going to be HUGE, string-streams will win.
  88 (defmacro with-push-char ((&key (element-type 'character) (initial-size 28)) &body body)
  89   (with-unique-names (string size pointer)
  90     `(let* ((,size ,initial-size)
  91             (,string (make-array ,size :element-type ',element-type))
  92             (,pointer 0))
  93        (declare (type (integer 0 ,sb!xc:array-dimension-limit) ,size)
  94                 (type (integer 0 ,(1- sb!xc:array-dimension-limit)) ,pointer)
  95                 (type (simple-array ,element-type (*)) ,string))
  96        (flet ((push-char (char)
  97                 (declare (optimize (sb!c::insert-array-bounds-checks 0)))
  98                 (when (= ,pointer ,size)
  99                   (let ((old ,string))
 100                     (setf ,size (* 2 (+ ,size 2))
 101                           ,string (make-array ,size :element-type ',element-type))
 102                     (replace ,string old)))
 103                 (setf (char ,string ,pointer) char)
 104                 (incf ,pointer))
 105               (get-pushed-string ()
 106                 (let ((string ,string)
 107                       (size ,pointer))
 108                   (setf ,size 0
 109                         ,pointer 0
 110                         ,string ,(coerce "" `(simple-array ,element-type (*))))
 111                   ;; This is really local, so we can be destructive!
 112                   (%shrink-vector string size)
 113                   string)))
 114          ,@body))))