1.0.24.17: grab-bag of fixes to make hpux-os smile

[sbcl.git] / src / code / array.lisp

diff --git a/src/code/array.lisp b/src/code/array.lisp
index 7c2790e..266c737 100644 (file)
--- a/src/code/array.lisp
+++ b/src/code/array.lisp
@@ -1083,6 +1083,30 @@ of specialized arrays is supported."
       (setf (%array-dimension array 0) dimensions))
   (setf (%array-displaced-p array) displacedp)
   array)
+
+;;; User visible extension
+(declaim (ftype (function (array) (values (simple-array * (*)) &optional))
+                array-storage-vector))
+(defun array-storage-vector (array)
+  "Returns the underlying storage vector of ARRAY, which must be a non-displaced array.
+
+In SBCL, if ARRAY is a of type \(SIMPLE-ARRAY * \(*)), it is its own storage
+vector. Multidimensional arrays, arrays with fill pointers, and adjustable
+arrays have an underlying storage vector with the same ARRAY-ELEMENT-TYPE as
+ARRAY, which this function returns.
+
+Important note: the underlying vector is an implementation detail. Even though
+this function exposes it, changes in the implementation may cause this
+function to be removed without further warning."
+  ;; KLUDGE: Without TRULY-THE the system is not smart enough to figure out that
+  ;; the return value is always of the known type.
+  (truly-the (simple-array * (*))
+             (if (array-header-p array)
+                 (if (%array-displaced-p array)
+                     (error "~S cannot be used with displaced arrays. Use ~S instead."
+                            'array-storage-vector 'array-displacement)
+                     (%array-data-vector array))
+                 array)))
 \f
 ;;;; used by SORT