;;; -*- Log: code.log; Package: Lisp -*-
;;;
;;; **********************************************************************
;;; This code was written as part of the CMU Common Lisp project at
;;; Carnegie Mellon University, and has been placed in the public domain.
;;;
(ext:file-comment
  "$Header: /home/pvaneynd/fakeroot/cvs2.cons.org/src/code/array.lisp,v 1.23 1997/04/01 19:23:31 dtc Exp $")
;;;
;;; **********************************************************************
;;;
;;; Functions to implement arrays for CMU Common Lisp.
;;; Written by Skef Wholey.
;;; Worked over for the MIPS port by William Lott.
;;;
(in-package "LISP")

(export '(array-rank-limit array-dimension-limit array-total-size-limit
	  make-array vector aref array-element-type array-rank
	  array-dimension array-dimensions array-in-bounds-p
	  array-row-major-index array-total-size svref bit sbit
	  bit-and bit-ior bit-xor bit-eqv bit-nand bit-nor bit-andc1 bit-andc2
	  bit-orc1 bit-orc2 bit-not array-has-fill-pointer-p
	  fill-pointer vector-push vector-push-extend vector-pop adjust-array
          adjustable-array-p row-major-aref array-displacement))

(in-package "KERNEL")
(export '(%with-array-data))
(in-package "LISP")

(declaim (inline fill-pointer array-has-fill-pointer-p adjustable-array-p
		 array-displacement))

(defconstant array-rank-limit 65529
  "The exclusive upper bound on the rank of an array.")

(defconstant array-dimension-limit most-positive-fixnum
  "The exclusive upper bound any given dimension of an array.")

(defconstant array-total-size-limit most-positive-fixnum
  "The exclusive upper bound on the total number of elements in an array.")



;;;; Random accessor functions.

;;; These functions are needed by the interpreter, 'cause the compiler inlines
;;; them.

(macrolet ((frob (name)
	     `(progn
		(defun ,name (array)
		  (,name array))
		(defun (setf ,name) (value array)
		  (setf (,name array) value)))))
  (frob %array-fill-pointer)
  (frob %array-fill-pointer-p)
  (frob %array-available-elements)
  (frob %array-data-vector)
  (frob %array-displacement)
  (frob %array-displaced-p))

(defun %array-rank (array)
  (%array-rank array))

(defun %array-dimension (array axis)
  (%array-dimension array axis))

(defun %set-array-dimension (array axis value)
  (%set-array-dimension array axis value))

(defun %check-bound (array bound index)
  (declare (type index bound)
	   (fixnum index))
  (%check-bound array bound index))

;;; %WITH-ARRAY-DATA  --  Interface
;;;
;;;    The guts of the WITH-ARRAY-DATA macro (in sysmacs).  Note that this
;;; function is only called if we have an array header or an error, so it
;;; doesn't have to be too tense.
;;;
(defun %with-array-data (array start end)
  (declare (array array) (type index start) (type (or index null) end)
	   (values (simple-array * (*)) index index index))
  (let* ((size (array-total-size array))
	 (end (cond (end
		     (unless (<= end size)
		       (error "End ~D is greater than total size ~D."
			      end size))
		     end)
		    (t size))))
    (when (> start end)
      (error "Start ~D is greater than end ~D." start end))
    (do ((data array (%array-data-vector data))
	 (cumulative-offset 0
			    (+ cumulative-offset
			       (%array-displacement data))))
	((not (array-header-p data))
	 (values data
		 (+ cumulative-offset start)
		 (+ cumulative-offset end)
		 cumulative-offset))
      (declare (type index cumulative-offset)))))


;;;; MAKE-ARRAY

(eval-when (compile eval)

(defmacro pick-type (type &rest specs)
  `(cond ,@(mapcar #'(lambda (spec)
		       `(,(if (eq (car spec) t)
			      t
			      `(subtypep ,type ',(car spec)))
			 ,@(cdr spec)))
		   specs)))

); eval-when


(defun %vector-type-code (type)
  (pick-type type
    (base-char (values #.vm:simple-string-type #.vm:byte-bits))
    (bit (values #.vm:simple-bit-vector-type 1))
    ((unsigned-byte 2) (values #.vm:simple-array-unsigned-byte-2-type 2))
    ((unsigned-byte 4) (values #.vm:simple-array-unsigned-byte-4-type 4))
    ((unsigned-byte 8) (values #.vm:simple-array-unsigned-byte-8-type 8))
    ((unsigned-byte 16) (values #.vm:simple-array-unsigned-byte-16-type 16))
    ((unsigned-byte 32) (values #.vm:simple-array-unsigned-byte-32-type 32))
    #+signed-array ((signed-byte 8)
		    (values #.vm:simple-array-signed-byte-8-type 8))
    #+signed-array ((signed-byte 16)
		    (values #.vm:simple-array-signed-byte-16-type 16))
    #+signed-array ((signed-byte 30)
		    (values #.vm:simple-array-signed-byte-30-type 32))
    #+signed-array ((signed-byte 32)
		    (values #.vm:simple-array-signed-byte-32-type 32))
    (single-float (values #.vm:simple-array-single-float-type 32))
    (double-float (values #.vm:simple-array-double-float-type 64))
    (t (values #.vm:simple-vector-type #.vm:word-bits))))

(defun %complex-vector-type-code (type)
  (pick-type type
    (base-char #.vm:complex-string-type)
    (bit #.vm:complex-bit-vector-type)
    (t #.vm:complex-vector-type)))

(defun make-array (dimensions &key
			      (element-type t)
			      (initial-element nil initial-element-p)
			      initial-contents adjustable fill-pointer
			      displaced-to displaced-index-offset)
  "Creates an array of the specified Dimensions.  See manual for details."
  (let* ((dimensions (if (listp dimensions) dimensions (list dimensions)))
	 (array-rank (length (the list dimensions)))
	 (simple (and (null fill-pointer)
		      (not adjustable)
		      (null displaced-to))))
    (declare (fixnum array-rank))
    (when (and displaced-index-offset (null displaced-to))
      (error "Can't specify :displaced-index-offset without :displaced-to"))
    (if (and simple (= array-rank 1))
	;; Its a (simple-array * (*))
	(multiple-value-bind (type bits)
			     (%vector-type-code element-type)
	  (declare (type (unsigned-byte 8) type)
		   (type (integer 1 64) bits))
	  (let* ((length (car dimensions))
		 (array (allocate-vector
			 type
			 length
			 (ceiling (* (if (= type vm:simple-string-type)
					 (1+ length)
					 length)
				     bits)
				  vm:word-bits))))
	    (declare (type index length))
	    (when initial-element-p
	      (fill array initial-element))
	    (when initial-contents
	      (when initial-element
		(error "Cannot specify both :initial-element and ~
		:initial-contents"))
	      (unless (= length (length initial-contents))
		(error "~D elements in the initial-contents, but the ~
		vector length is ~D."
		       (length initial-contents)
		       length))
	      (replace array initial-contents))
	    array))
	;; It's either a complex array or a multidimensional array.
	(let* ((total-size (reduce #'* dimensions))
	       (data (or displaced-to
			 (data-vector-from-inits
			  dimensions total-size element-type
			  initial-contents initial-element initial-element-p)))
	       (array (make-array-header
		       (cond ((= array-rank 1)
			      (%complex-vector-type-code element-type))
			     (simple vm:simple-array-type)
			     (t vm:complex-array-type))
		       array-rank)))
	  (cond (fill-pointer
		 (unless (= array-rank 1)
		   (error "Only vectors can have fill pointers."))
		 (let ((length (car dimensions)))
		   (declare (fixnum length))
		   (setf (%array-fill-pointer array)
		     (cond ((eq fill-pointer t)
			    length)
			   (t
			    (unless (and (fixnump fill-pointer)
					 (>= fill-pointer 0)
					 (<= fill-pointer length))
				    (error "Invalid fill-pointer ~D"
					   fill-pointer))
			    fill-pointer))))
		 (setf (%array-fill-pointer-p array) t))
		(t
		 (setf (%array-fill-pointer array) total-size)
		 (setf (%array-fill-pointer-p array) nil)))
	  (setf (%array-available-elements array) total-size)
	  (setf (%array-data-vector array) data)
	  (cond (displaced-to
		 (when (or initial-element-p initial-contents)
		   (error "Neither :initial-element nor :initial-contents ~
		   can be specified along with :displaced-to"))
		 (let ((offset (or displaced-index-offset 0)))
		   (when (> (+ offset total-size)
			    (array-total-size displaced-to))
		     (error "~S doesn't have enough elements." displaced-to))
		   (setf (%array-displacement array) offset)
		   (setf (%array-displaced-p array) t)))
		(t
		 (setf (%array-displaced-p array) nil)))
	  (let ((axis 0))
	    (dolist (dim dimensions)
	      (setf (%array-dimension array axis) dim)
	      (incf axis)))
	  array))))
	
;;; DATA-VECTOR-FROM-INITS returns a simple vector that has the specified array
;;; characteristics.  Dimensions is only used to pass to FILL-DATA-VECTOR
;;; for error checking on the structure of initial-contents.
;;;
(defun data-vector-from-inits (dimensions total-size element-type
			       initial-contents initial-element
			       initial-element-p)
  (when (and initial-contents initial-element-p)
    (error "Cannot supply both :initial-contents and :initial-element to
            either make-array or adjust-array."))
  (let ((data (if initial-element-p
		  (make-array total-size
			      :element-type element-type
			      :initial-element initial-element)
		  (make-array total-size
			      :element-type element-type))))
    (cond (initial-element-p
	   (unless (simple-vector-p data)
	     (unless (typep initial-element element-type)
	       (error "~S cannot be used to initialize an array of type ~S."
		      initial-element element-type))
	     (fill (the vector data) initial-element)))
	  (initial-contents
	   (fill-data-vector data dimensions initial-contents)))
    data))


(defun fill-data-vector (vector dimensions initial-contents)
  (let ((index 0))
    (labels ((frob (axis dims contents)
	       (cond ((null dims)
		      (setf (aref vector index) contents)
		      (incf index))
		     (t
		      (unless (typep contents 'sequence)
			(error "Malformed :initial-contents.  ~S is not a ~
			        sequence, but ~D more layer~:P needed."
			       contents
			       (- (length dimensions) axis)))
		      (unless (= (length contents) (car dims))
			(error "Malformed :initial-contents.  Dimension of ~
			        axis ~D is ~D, but ~S is ~D long."
			       axis (car dims) contents (length contents)))
		      (if (listp contents)
			  (dolist (content contents)
			    (frob (1+ axis) (cdr dims) content))
			  (dotimes (i (length contents))
			    (frob (1+ axis) (cdr dims) (aref contents i))))))))
      (frob 0 dimensions initial-contents))))


;;; Some people out there are still calling MAKE-VECTOR:
;;;
(setf (symbol-function 'make-vector) #'make-array)


(defun vector (&rest objects)
  "Constructs a simple-vector from the given objects."
  (coerce (the list objects) 'simple-vector))



;;;; Accessor/Setter functions.

(defun data-vector-ref (array index)
  (with-array-data ((vector array) (index index) (end))
    (declare (ignore end) (optimize (safety 3)))
    (macrolet ((dispatch (&rest stuff)
		 `(etypecase vector
		    ,@(mapcar #'(lambda (type)
				  (let ((atype `(simple-array ,type (*))))
				    `(,atype
				      (data-vector-ref (the ,atype vector)
						       index))))
			      stuff))))
      (dispatch
       t
       bit
       character
       (unsigned-byte 2)
       (unsigned-byte 4)
       (unsigned-byte 8)
       (unsigned-byte 16)
       (unsigned-byte 32)
       #+signed-array (signed-byte 8)
       #+signed-array (signed-byte 16)
       #+signed-array (signed-byte 30)
       #+signed-array (signed-byte 32)
       single-float
       double-float))))

(defun data-vector-set (array index new-value)
  (with-array-data ((vector array) (index index) (end))
    (declare (ignore end) (optimize (safety 3)))
    (macrolet ((dispatch (&rest stuff)
		 `(etypecase vector
		    ,@(mapcar #'(lambda (type)
				  (let ((atype `(simple-array ,type (*))))
				    `(,atype
				      (data-vector-set (the ,atype vector)
						       index
						       (the ,type new-value)))))
			      stuff))))
      (dispatch
       t
       bit
       character
       (unsigned-byte 2)
       (unsigned-byte 4)
       (unsigned-byte 8)
       (unsigned-byte 16)
       (unsigned-byte 32)
       #+signed-array (signed-byte 8)
       #+signed-array (signed-byte 16)
       #+signed-array (signed-byte 30)
       #+signed-array (signed-byte 32)
       single-float
       double-float))))



(defun %array-row-major-index (array subscripts
				     &optional (invalid-index-error-p t))
  (declare (array array)
	   (list subscripts))
  (let ((rank (array-rank array)))
    (unless (= rank (length subscripts))
      (error "Wrong number of subscripts, ~D, for array of rank ~D"
	     (length subscripts) rank))
    (if (array-header-p array)
	(do ((subs (nreverse subscripts) (cdr subs))
	     (axis (1- (array-rank array)) (1- axis))
	     (chunk-size 1)
	     (result 0))
	    ((null subs) result)
	  (declare (list subs) (fixnum axis chunk-size result))
	  (let ((index (car subs))
		(dim (%array-dimension array axis)))
	    (declare (fixnum index dim))
	    (unless (< -1 index dim)
	      (if invalid-index-error-p
		  (error "Invalid index ~D~[~;~:; on axis ~:*~D~] in ~S"
			 index axis array)
		  (return-from %array-row-major-index nil)))
	    (incf result (* chunk-size index))
	    (setf chunk-size (* chunk-size dim))))
	(let ((index (first subscripts)))
	  (unless (< -1 index (length (the (simple-array * (*)) array)))
	    (if invalid-index-error-p
		(error "Invalid index ~D in ~S" index array)
		(return-from %array-row-major-index nil)))
	  index))))

(defun array-in-bounds-p (array &rest subscripts)
  "Returns T if the Subscipts are in bounds for the Array, Nil otherwise."
  (if (%array-row-major-index array subscripts nil)
      t))

(defun array-row-major-index (array &rest subscripts)
  (%array-row-major-index array subscripts))

(defun aref (array &rest subscripts)
  "Returns the element of the Array specified by the Subscripts."
  (row-major-aref array (%array-row-major-index array subscripts)))

(defun %aset (array &rest stuff)
  (let ((subscripts (butlast stuff))
	(new-value (car (last stuff))))
    (setf (row-major-aref array (%array-row-major-index array subscripts))
	  new-value)))

(declaim (inline (setf aref)))
(defun (setf aref) (new-value array &rest subscripts)
  (declare (type array array))
  (setf (row-major-aref array (%array-row-major-index array subscripts))
	new-value))

(defun row-major-aref (array index)
  "Returns the element of array corressponding to the row-major index.  This is
   SETF'able."
  (declare (optimize (safety 1)))
  (row-major-aref array index))


(defun %set-row-major-aref (array index new-value)
  (declare (optimize (safety 1)))
  (setf (row-major-aref array index) new-value))

(defun svref (simple-vector index)
  "Returns the Index'th element of the given Simple-Vector."
  (declare (optimize (safety 1)))
  (aref simple-vector index))

(defun %svset (simple-vector index new)
  (declare (optimize (safety 1)))
  (setf (aref simple-vector index) new))


(defun bit (bit-array &rest subscripts)
  "Returns the bit from the Bit-Array at the specified Subscripts."
  (declare (type (array bit) bit-array) (optimize (safety 1)))
  (row-major-aref bit-array (%array-row-major-index bit-array subscripts)))


(defun %bitset (bit-array &rest stuff)
  (declare (type (array bit) bit-array) (optimize (safety 1)))
  (let ((subscripts (butlast stuff))
	(new-value (car (last stuff))))
    (setf (row-major-aref bit-array
			  (%array-row-major-index bit-array subscripts))
	  new-value)))

(declaim (inline (setf bit)))
(defun (setf bit) (new-value bit-array &rest subscripts)
  (declare (type (array bit) bit-array) (optimize (safety 1)))
  (setf (row-major-aref bit-array
			(%array-row-major-index bit-array subscripts))
	new-value))

(defun sbit (simple-bit-array &rest subscripts)
  "Returns the bit from the Simple-Bit-Array at the specified Subscripts."
  (declare (type (simple-array bit) simple-bit-array) (optimize (safety 1)))
  (row-major-aref simple-bit-array
		  (%array-row-major-index simple-bit-array subscripts)))

(defun %sbitset (simple-bit-array &rest stuff)
  (declare (type (simple-array bit) simple-bit-array) (optimize (safety 1)))
  (let ((subscripts (butlast stuff))
	(new-value (car (last stuff))))
    (setf (row-major-aref simple-bit-array
			  (%array-row-major-index simple-bit-array subscripts))
	  new-value)))
 
(declaim (inline (setf sbit)))
(defun (setf sbit) (new-value bit-array &rest subscripts)
  (declare (type (simple-array bit) bit-array) (optimize (safety 1)))
  (setf (row-major-aref bit-array
			(%array-row-major-index bit-array subscripts))
	new-value))


;;;; Random array properties.

(defun array-element-type (array)
  "Returns the type of the elements of the array"
  (let ((type (get-type array)))
    (macrolet ((pick-element-type (&rest stuff)
		 `(cond ,@(mapcar #'(lambda (stuff)
				      (cons
				       (let ((item (car stuff)))
					 (cond ((eq item t)
						t)
					       ((listp item)
						(cons 'or
						      (mapcar #'(lambda (x)
								  `(= type ,x))
							      item)))
					       (t
						`(= type ,item))))
				       (cdr stuff)))
						   stuff))))
      (pick-element-type
       ((vm:simple-string-type vm:complex-string-type) 'base-char)
       ((vm:simple-bit-vector-type vm:complex-bit-vector-type) 'bit)
       (vm:simple-vector-type t)
       (vm:simple-array-unsigned-byte-2-type '(unsigned-byte 2))
       (vm:simple-array-unsigned-byte-4-type '(unsigned-byte 4))
       (vm:simple-array-unsigned-byte-8-type '(unsigned-byte 8))
       (vm:simple-array-unsigned-byte-16-type '(unsigned-byte 16))
       (vm:simple-array-unsigned-byte-32-type '(unsigned-byte 32))
       #+signed-array (vm:simple-array-signed-byte-8-type '(signed-byte 8))
       #+signed-array (vm:simple-array-signed-byte-16-type '(signed-byte 16))
       #+signed-array (vm:simple-array-signed-byte-30-type '(signed-byte 30))
       #+signed-array (vm:simple-array-signed-byte-32-type '(signed-byte 32))
       (vm:simple-array-single-float-type 'single-float)
       (vm:simple-array-double-float-type 'double-float)
       ((vm:simple-array-type vm:complex-vector-type vm:complex-array-type)
	(with-array-data ((array array) (start) (end))
	  (declare (ignore start end))
	  (array-element-type array)))
       (t
	(error "~S is not an array." array))))))


(defun array-rank (array)
  "Returns the number of dimensions of the Array."
  (if (array-header-p array)
      (%array-rank array)
      1))

(defun array-dimension (array axis-number)
  "Returns length of dimension Axis-Number of the Array."
  (declare (array array) (type index axis-number))
  (cond ((not (array-header-p array))
	 (unless (= axis-number 0)
	   (error "Vector axis is not zero: ~S" axis-number))
	 (length (the (simple-array * (*)) array)))
	((>= axis-number (%array-rank array))
	 (error "~D is too big; ~S only has ~D dimension~:P"
		axis-number array (%array-rank array)))
	(t
	 (%array-dimension array axis-number))))

(defun array-dimensions (array)
  "Returns a list whose elements are the dimensions of the array"
  (declare (array array))
  (if (array-header-p array)
      (do ((results nil (cons (array-dimension array index) results))
	   (index (1- (array-rank array)) (1- index)))
	  ((minusp index) results))
      (list (array-dimension array 0))))

(defun array-total-size (array)
  "Returns the total number of elements in the Array."
  (declare (array array))
  (if (array-header-p array)
      (%array-available-elements array)
      (length (the vector array))))

(defun array-displacement (array)
  "Returns values of :displaced-to and :displaced-index-offset options to
   make-array, or the defaults nil and 0 if not a displaced array."
  (declare (array array))
  (values (%array-data-vector array) (%array-displacement array)))

(defun adjustable-array-p (array)
  "Returns T if (adjust-array array...) would return an array identical
   to the argument, this happens for complex arrays."
  (declare (array array))
  (not (typep array 'simple-array)))


;;;; Fill pointer frobbing stuff.

(defun array-has-fill-pointer-p (array)
  "Returns T if the given Array has a fill pointer, or Nil otherwise."
  (declare (array array))
  (and (array-header-p array) (%array-fill-pointer-p array)))

(defun fill-pointer (vector)
  "Returns the Fill-Pointer of the given Vector."
  (declare (vector vector))
  (if (and (array-header-p vector) (%array-fill-pointer-p vector))
      (%array-fill-pointer vector)
      (error "~S is not an array with a fill-pointer." vector)))

(defun %set-fill-pointer (vector new)
  (declare (vector vector) (fixnum new))
  (if (and (array-header-p vector) (%array-fill-pointer-p vector))
      (if (> new (%array-available-elements vector))
	(error "New fill pointer, ~S, is larger than the length of the vector."
	       new)
	(setf (%array-fill-pointer vector) new))
      (error "~S is not an array with a fill-pointer." vector)))

(defun vector-push (new-el array)
  "Attempts to set the element of Array designated by the fill pointer
   to New-El and increment fill pointer by one.  If the fill pointer is
   too large, Nil is returned, otherwise the index of the pushed element is 
   returned."
  (declare (vector array))
  (let ((fill-pointer (fill-pointer array)))
    (declare (fixnum fill-pointer))
    (cond ((= fill-pointer (%array-available-elements array))
	   nil)
	  (t
	   (setf (aref array fill-pointer) new-el)
	   (setf (%array-fill-pointer array) (1+ fill-pointer))
	   fill-pointer))))

(defun vector-push-extend (new-el array &optional
				  (extension (if (zerop (length array))
						 1
						 (length array))))
  "Like Vector-Push except that if the fill pointer gets too large, the
   Array is extended rather than Nil being returned."
  (declare (vector array) (fixnum extension))
  (let ((fill-pointer (fill-pointer array)))
    (declare (fixnum fill-pointer))
    (when (= fill-pointer (%array-available-elements array))
      (adjust-array array (+ fill-pointer extension)))
    (setf (aref array fill-pointer) new-el)
    (setf (%array-fill-pointer array) (1+ fill-pointer))
    fill-pointer))

(defun vector-pop (array)
  "Attempts to decrease the fill-pointer by 1 and return the element
   pointer to by the new fill pointer.  If the original value of the fill
   pointer is 0, an error occurs."
  (declare (vector array))
  (let ((fill-pointer (fill-pointer array)))
    (declare (fixnum fill-pointer))
    (if (zerop fill-pointer)
	(error "Nothing left to pop.")
	(aref array
	      (setf (%array-fill-pointer array)
		    (1- fill-pointer))))))


;;;; Adjust-array

(defun adjust-array (array dimensions &key
			   (element-type (array-element-type array))
			   (initial-element nil initial-element-p)
			   initial-contents fill-pointer
			   displaced-to displaced-index-offset)
  "Adjusts the Array's dimensions to the given Dimensions and stuff."
  (let ((dimensions (if (listp dimensions) dimensions (list dimensions))))
    (cond ((/= (the fixnum (length (the list dimensions)))
	       (the fixnum (array-rank array)))
	   (error "Number of dimensions not equal to rank of array."))
	  ((not (subtypep element-type (array-element-type array)))
	   (error "New element type, ~S, is incompatible with old."
		  element-type)))
    (let ((array-rank (length (the list dimensions))))
      (declare (fixnum array-rank))
      (when (and fill-pointer (> array-rank 1))
	(error "Multidimensional arrays can't have fill pointers."))
      (cond (initial-contents
	     ;; Array former contents replaced by initial-contents.
	     (if (or initial-element-p displaced-to)
		 (error "Initial contents may not be specified with ~
		 the :initial-element or :displaced-to option."))
	     (let* ((array-size (apply #'* dimensions))
		    (array-data (data-vector-from-inits
				 dimensions array-size element-type
				 initial-contents initial-element
				 initial-element-p)))
	       (if (adjustable-array-p array)
		   (set-array-header array array-data array-size
				 (get-new-fill-pointer array array-size
						       fill-pointer)
				 0 dimensions nil)
		   (if (array-header-p array)
		       ;; Simple multidimensional or single dimensional array.
		       (make-array dimensions
				   :element-type element-type
				   :initial-contents initial-contents)
		       array-data))))
	    (displaced-to
	     ;; No initial-contents supplied is already established.
	     (when initial-element
	       (error "The :initial-element option may not be specified ~
	       with :displaced-to."))
	     (unless (subtypep element-type (array-element-type displaced-to))
	       (error "One can't displace an array of type ~S into another of ~
	               type ~S."
		      element-type (array-element-type displaced-to)))
	     (let ((displacement (or displaced-index-offset 0))
		   (array-size (apply #'* dimensions)))
	       (declare (fixnum displacement array-size))
	       (if (< (the fixnum (array-total-size displaced-to))
		      (the fixnum (+ displacement array-size)))
		   (error "The :displaced-to array is too small."))
	       (if (adjustable-array-p array)
		   ;; None of the original contents appear in adjusted array.
		   (set-array-header array displaced-to array-size
				     (get-new-fill-pointer array array-size
							   fill-pointer)
				     displacement dimensions t)
		   ;; Simple multidimensional or single dimensional array.
		   (make-array dimensions
			       :element-type element-type
			       :displaced-to displaced-to
			       :displaced-index-offset
			       displaced-index-offset))))
	    ((= array-rank 1)
	     (let ((old-length (array-total-size array))
		   (new-length (car dimensions))
		   new-data)
	       (declare (fixnum old-length new-length))
	       (with-array-data ((old-data array) (old-start)
				 (old-end old-length))
		 (cond ((or (%array-displaced-p array)
			    (< old-length new-length))
			(setf new-data
			      (data-vector-from-inits
			       dimensions new-length element-type
			       initial-contents initial-element
			       initial-element-p))
			(replace new-data old-data
				 :start2 old-start :end2 old-end))
		       (t (setf new-data
				(shrink-vector old-data new-length))))
		 (if (adjustable-array-p array)
		     (set-array-header array new-data new-length
				       (get-new-fill-pointer array new-length
							     fill-pointer)
				       0 dimensions nil)
		     new-data))))
	    (t
	     (let ((old-length (%array-available-elements array))
		   (new-length (apply #'* dimensions)))
	       (declare (fixnum old-length new-length))
	       (with-array-data ((old-data array) (old-start)
				 (old-end old-length))
		 (declare (ignore old-end))
		 (let ((new-data (if (or (%array-displaced-p array)
					 (> new-length old-length))
				     (data-vector-from-inits
				      dimensions new-length
				      element-type () initial-element
				      initial-element-p)
				     old-data)))
		   (if (or (zerop old-length) (zerop new-length))
		       (when initial-element-p (fill new-data initial-element))
		       (zap-array-data old-data (array-dimensions array)
				       old-start
				       new-data dimensions new-length
				       element-type initial-element
				       initial-element-p))
		   (set-array-header array new-data new-length
				     new-length 0 dimensions nil)))))))))

(defun get-new-fill-pointer (old-array new-array-size fill-pointer)
  (cond ((not fill-pointer)
	 (when (array-has-fill-pointer-p old-array)
	   (when (> (%array-fill-pointer old-array) new-array-size)
	     (error "Cannot adjust-array an array (~S) to a size (~S) that is ~
	            smaller than it's fill pointer (~S)."
		    old-array new-array-size (fill-pointer old-array)))
	   (%array-fill-pointer old-array)))
	((not (array-has-fill-pointer-p old-array))
	 (error "Cannot supply a non-NIL value (~S) for :fill-pointer ~
		        in adjust-array unless the array (~S) was originally ~
 			created with a fill pointer."
		       fill-pointer
		       old-array))
	((numberp fill-pointer)
	 (when (> fill-pointer new-array-size)
	   (error "Cannot supply a value for :fill-pointer (~S) that is larger ~
	          than the new length of the vector (~S)."
		  fill-pointer new-array-size))
	 fill-pointer)
	((eq fill-pointer t)
	 new-array-size)
	(t
	 (error "Bogus value for :fill-pointer in adjust-array: ~S"
		fill-pointer))))

(defun shrink-vector (vector new-size)
  "Destructively alters the Vector, changing its length to New-Size, which
   must be less than or equal to its current size."
  (declare (vector vector))
  (unless (array-header-p vector)
    (macrolet ((frob (name &rest things)
		 `(etypecase ,name
		    ,@(mapcar #'(lambda (thing)
				  `(,(car thing)
				    (fill (truly-the ,(car thing) ,name)
					  ,(cadr thing)
					  :start new-size)))
			      things))))
      (frob vector
	(simple-vector 0)
	(simple-base-string (code-char 0))
	(simple-bit-vector 0)
	((simple-array (unsigned-byte 2) (*)) 0)
	((simple-array (unsigned-byte 4) (*)) 0)
	((simple-array (unsigned-byte 8) (*)) 0)
	((simple-array (unsigned-byte 16) (*)) 0)
	((simple-array (unsigned-byte 32) (*)) 0)
	#+signed-array ((simple-array (signed-byte 8) (*)) 0)
	#+signed-array ((simple-array (signed-byte 16) (*)) 0)
	#+signed-array ((simple-array (signed-byte 30) (*)) 0)
	#+signed-array ((simple-array (signed-byte 32) (*)) 0)
	((simple-array single-float (*)) (coerce 0 'single-float))
	((simple-array double-float (*)) (coerce 0 'double-float)))))
  ;; Only arrays have fill-pointers, but vectors have their length parameter
  ;; in the same place.
  (setf (%array-fill-pointer vector) new-size)
  vector)

(defun set-array-header (array data length fill-pointer displacement dimensions
			 &optional displacedp)
  "Fills in array header with provided information.  Returns array."
  (setf (%array-data-vector array) data)
  (setf (%array-available-elements array) length)
  (cond (fill-pointer
	 (setf (%array-fill-pointer array) fill-pointer)
	 (setf (%array-fill-pointer-p array) t))
	(t
	 (setf (%array-fill-pointer array) length)
	 (setf (%array-fill-pointer-p array) nil)))
  (setf (%array-displacement array) displacement)
  (if (listp dimensions)
      (dotimes (axis (array-rank array))
	(declare (type index axis))
	(setf (%array-dimension array axis) (pop dimensions)))
      (setf (%array-dimension array 0) dimensions))
  (setf (%array-displaced-p array) displacedp)
  array)



;;;; ZAP-ARRAY-DATA for ADJUST-ARRAY.

;;; Make a temporary to be used when old-data and new-data are EQ.
;;;
(defvar *zap-array-data-temp* (make-array 1000 :initial-element t))

(defun zap-array-data-temp (length element-type initial-element
			    initial-element-p)
  (declare (fixnum length))
  (when (> length (the fixnum (length *zap-array-data-temp*)))
    (setf *zap-array-data-temp*
	  (make-array length :initial-element t)))
  (when initial-element-p
    (unless (typep initial-element element-type)
      (error "~S cannot be used to initialize an array of type ~S."
	     initial-element element-type))
    (fill (the simple-vector *zap-array-data-temp*) initial-element
	  :end length))
  *zap-array-data-temp*)


;;; ZAP-ARRAY-DATA  --  Internal.
;;;
;;; This does the grinding work for ADJUST-ARRAY.  It zaps the data from the
;;; Old-Data in an arrangement specified by the Old-Dims to the New-Data in an
;;; arrangement specified by the New-Dims.  Offset is a displaced offset to be
;;; added to computed indexes of Old-Data.  New-Length, Element-Type,
;;; Initial-Element, and Initial-Element-P are used when Old-Data and New-Data
;;; are EQ; in this case, a temporary must be used and filled appropriately.
;;; When Old-Data and New-Data are not EQ, New-Data has already been filled
;;; with any specified initial-element.
;;;
(defun zap-array-data (old-data old-dims offset new-data new-dims new-length
		       element-type initial-element initial-element-p)
  (declare (list old-dims new-dims))
  (setq old-dims (nreverse old-dims))
  (setq new-dims (reverse new-dims))
  (if (eq old-data new-data)
      (let ((temp (zap-array-data-temp new-length element-type
				       initial-element initial-element-p)))
	(zap-array-data-aux old-data old-dims offset temp new-dims)
	(dotimes (i new-length) (setf (aref new-data i) (aref temp i))))
      (zap-array-data-aux old-data old-dims offset new-data new-dims)))
      
(defun zap-array-data-aux (old-data old-dims offset new-data new-dims)
  (declare (fixnum offset))
  (let ((limits (mapcar #'(lambda (x y)
			    (declare (fixnum x y))
			    (1- (the fixnum (min x y))))
			old-dims new-dims)))
    (macrolet ((bump-index-list (index limits)
		 `(do ((subscripts ,index (cdr subscripts))
		       (limits ,limits (cdr limits)))
		      ((null subscripts) nil)
		    (cond ((< (the fixnum (car subscripts))
			      (the fixnum (car limits)))
			   (rplaca subscripts
				   (1+ (the fixnum (car subscripts))))
			   (return ,index))
			  (t (rplaca subscripts 0))))))
      (do ((index (make-list (length old-dims) :initial-element 0)
		  (bump-index-list index limits)))
	  ((null index))
	(setf (aref new-data (row-major-index-from-dims index new-dims))
	      (aref old-data
		    (+ (the fixnum (row-major-index-from-dims index old-dims))
		       offset)))))))

;;; ROW-MAJOR-INDEX-FROM-DIMS  --  Internal.
;;;
;;; This figures out the row-major-order index of an array reference from a
;;; list of subscripts and a list of dimensions.  This is for internal calls
;;; only, and the subscripts and dim-list variables are assumed to be reversed
;;; from what the user supplied.
;;;
(defun row-major-index-from-dims (rev-subscripts rev-dim-list)
  (do ((rev-subscripts rev-subscripts (cdr rev-subscripts))
       (rev-dim-list rev-dim-list (cdr rev-dim-list))
       (chunk-size 1)
       (result 0))
      ((null rev-dim-list) result)
    (declare (fixnum chunk-size result))
    (setq result (+ result
		    (the fixnum (* (the fixnum (car rev-subscripts))
				   chunk-size))))
    (setq chunk-size (* chunk-size (the fixnum (car rev-dim-list))))))



;;;; Some bit stuff.
 
(defun bit-array-same-dimensions-p (array1 array2)
  (declare (type (array bit) array1 array2))
  (and (= (array-rank array1)
	  (array-rank array2))
       (dotimes (index (array-rank array1) t)
	 (when (/= (array-dimension array1 index)
		   (array-dimension array2 index))
	   (return nil)))))

(defun pick-result-array (result-bit-array bit-array-1)
  (case result-bit-array
    ((t) bit-array-1)
    ((nil) (make-array (array-dimensions bit-array-1)
		       :element-type 'bit
		       :initial-element 0))
    (t
     (unless (bit-array-same-dimensions-p bit-array-1
					  result-bit-array)
       (error "~S and ~S do not have the same dimensions."
	      bit-array-1 result-bit-array))
     result-bit-array)))

(defmacro def-bit-array-op (name function)
  `(defun ,name (bit-array-1 bit-array-2 &optional result-bit-array)
     ,(format nil
	      "Perform a bit-wise ~A on the elements of BIT-ARRAY-1 and ~
	      BIT-ARRAY-2,~%  putting the results in RESULT-BIT-ARRAY.  ~
	      If RESULT-BIT-ARRAY is T,~%  BIT-ARRAY-1 is used.  If ~
	      RESULT-BIT-ARRAY is NIL or omitted, a new array is~%  created.  ~
	      All the arrays must have the same rank and dimensions."
	      (symbol-name function))
     (declare (type (array bit) bit-array-1 bit-array-2)
	      (type (or (array bit) (member t nil)) result-bit-array))
     (unless (bit-array-same-dimensions-p bit-array-1 bit-array-2)
       (error "~S and ~S do not have the same dimensions."
	      bit-array-1 bit-array-2))
     (let ((result-bit-array (pick-result-array result-bit-array bit-array-1)))
       (if (and (simple-bit-vector-p bit-array-1)
		(simple-bit-vector-p bit-array-2)
		(simple-bit-vector-p result-bit-array))
	   (locally (declare (optimize (speed 3) (safety 0)))
	     (,name bit-array-1 bit-array-2 result-bit-array))
	   (with-array-data ((data1 bit-array-1) (start1) (end1))
	     (declare (ignore end1))
	     (with-array-data ((data2 bit-array-2) (start2) (end2))
	       (declare (ignore end2))
	       (with-array-data ((data3 result-bit-array) (start3) (end3))
		 (do ((index-1 start1 (1+ index-1))
		      (index-2 start2 (1+ index-2))
		      (index-3 start3 (1+ index-3)))
		     ((>= index-3 end3) result-bit-array)
		   (declare (type index index-1 index-2 index-3))
		   (setf (sbit data3 index-3)
			 (logand (,function (sbit data1 index-1)
					    (sbit data2 index-2))
				 1))))))))))

(def-bit-array-op bit-and logand)
(def-bit-array-op bit-ior logior)
(def-bit-array-op bit-xor logxor)
(def-bit-array-op bit-eqv logeqv)
(def-bit-array-op bit-nand lognand)
(def-bit-array-op bit-nor lognor)
(def-bit-array-op bit-andc1 logandc1)
(def-bit-array-op bit-andc2 logandc2)
(def-bit-array-op bit-orc1 logorc1)
(def-bit-array-op bit-orc2 logorc2)

(defun bit-not (bit-array &optional result-bit-array)
  "Performs a bit-wise logical NOT on the elements of BIT-ARRAY,
  putting the results in RESULT-BIT-ARRAY.  If RESULT-BIT-ARRAY is T,
  BIT-ARRAY is used.  If RESULT-BIT-ARRAY is NIL or omitted, a new array is
  created.  Both arrays must have the same rank and dimensions."
  (declare (type (array bit) bit-array)
	   (type (or (array bit) (member t nil)) result-bit-array))
  (let ((result-bit-array (pick-result-array result-bit-array bit-array)))
    (if (and (simple-bit-vector-p bit-array)
	     (simple-bit-vector-p result-bit-array))
	(locally (declare (optimize (speed 3) (safety 0)))
	  (bit-not bit-array result-bit-array))
	(with-array-data ((src bit-array) (src-start) (src-end))
	  (declare (ignore src-end))
	  (with-array-data ((dst result-bit-array) (dst-start) (dst-end))
	    (do ((src-index src-start (1+ src-index))
		 (dst-index dst-start (1+ dst-index)))
		((>= dst-index dst-end) result-bit-array)
	      (declare (type index src-index dst-index))
	      (setf (sbit dst dst-index)
		    (logxor (sbit src src-index) 1))))))))
