;;;; predicate functions (EQUAL and friends, and type predicates)

;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.

(in-package "SB!IMPL")

;;;; miscellaneous non-primitive predicates

#!-sb-fluid (declaim (inline streamp))
(defun streamp (stream)
  (typep stream 'stream))

;;; various (VECTOR FOO) type predicates, not implemented as simple
;;; widetag tests
(macrolet
    ((def ()
       `(progn
          ,@(loop for (name spec) in *vector-without-complex-typecode-infos*
                  collect `(defun ,name (x)
                             (or (typep x '(simple-array ,spec (*)))
                                 (and (complex-vector-p x)
                                      (do ((data (%array-data-vector x) (%array-data-vector data)))
                                          ((not (array-header-p data)) (typep data '(simple-array ,spec (*))))))))))))
  (def))

;;; Is X an extended sequence?
(defun extended-sequence-p (x)
  (and (not (listp x))
       (not (vectorp x))
       (let* ((slayout #.(info :type :compiler-layout 'sequence))
             (depthoid #.(layout-depthoid (info :type :compiler-layout 'sequence)))
             (layout (layout-of x)))
        (when (layout-invalid layout)
          (setq layout (update-object-layout-or-invalid x slayout)))
        (if (eq layout slayout)
            t
            (let ((inherits (layout-inherits layout)))
              (declare (optimize (safety 0)))
              (and (> (length inherits) depthoid)
                   (eq (svref inherits depthoid) slayout)))))))

;;; Is X a SEQUENCE?  Harder than just (OR VECTOR LIST)
(defun sequencep (x)
  (or (listp x)
      (vectorp x)
      (let* ((slayout #.(info :type :compiler-layout 'sequence))
             (depthoid #.(layout-depthoid (info :type :compiler-layout 'sequence)))
             (layout (layout-of x)))
        (when (layout-invalid layout)
          (setq layout (update-object-layout-or-invalid x slayout)))
        (if (eq layout slayout)
            t
            (let ((inherits (layout-inherits layout)))
              (declare (optimize (safety 0)))
              (and (> (length inherits) depthoid)
                   (eq (svref inherits depthoid) slayout)))))))

;;;; primitive predicates. These must be supported directly by the
;;;; compiler.

(defun not (object)
  #!+sb-doc
  "Return T if X is NIL, otherwise return NIL."
  (not object))

;;; All the primitive type predicate wrappers share a parallel form..
(macrolet ((def-type-predicate-wrapper (pred)
             (let* ((name (symbol-name pred))
                    (stem (string-left-trim "%" (string-right-trim "P-" name)))
                    (article (if (position (schar name 0) "AEIOU") "an" "a")))
               `(defun ,pred (object)
                  ,(format nil
                           "Return true if OBJECT is ~A ~A, and NIL otherwise."
                           article
                           stem)
                  ;; (falling through to low-level implementation)
                  (,pred object)))))
  (def-type-predicate-wrapper array-header-p)
  (def-type-predicate-wrapper arrayp)
  (def-type-predicate-wrapper atom)
  (def-type-predicate-wrapper base-char-p)
  (def-type-predicate-wrapper base-string-p)
  #!+sb-unicode (def-type-predicate-wrapper character-string-p)
  (def-type-predicate-wrapper bignump)
  (def-type-predicate-wrapper bit-vector-p)
  (def-type-predicate-wrapper characterp)
  (def-type-predicate-wrapper code-component-p)
  (def-type-predicate-wrapper consp)
  (def-type-predicate-wrapper compiled-function-p)
  (def-type-predicate-wrapper complexp)
  (def-type-predicate-wrapper complex-double-float-p)
  (def-type-predicate-wrapper complex-float-p)
  #!+long-float (def-type-predicate-wrapper complex-long-float-p)
  (def-type-predicate-wrapper complex-rational-p)
  (def-type-predicate-wrapper complex-single-float-p)
  ;; (COMPLEX-VECTOR-P is not included here since it's awkward to express
  ;; the type it tests for in the Common Lisp type system, and since it's
  ;; only used in the implementation of a few specialized things.)
  (def-type-predicate-wrapper double-float-p)
  (def-type-predicate-wrapper extended-char-p)
  (def-type-predicate-wrapper fdefn-p)
  (def-type-predicate-wrapper fixnump)
  (def-type-predicate-wrapper floatp)
  (def-type-predicate-wrapper functionp)
  (def-type-predicate-wrapper integerp)
  (def-type-predicate-wrapper listp)
  (def-type-predicate-wrapper long-float-p)
  (def-type-predicate-wrapper lra-p)
  (def-type-predicate-wrapper null)
  (def-type-predicate-wrapper numberp)
  (def-type-predicate-wrapper rationalp)
  (def-type-predicate-wrapper ratiop)
  (def-type-predicate-wrapper realp)
  (def-type-predicate-wrapper short-float-p)
  (def-type-predicate-wrapper single-float-p)
  (def-type-predicate-wrapper %instancep)
  (def-type-predicate-wrapper symbolp)
  (def-type-predicate-wrapper system-area-pointer-p)
  (def-type-predicate-wrapper weak-pointer-p)
  #!+#.(cl:if (cl:= 32 sb!vm:n-word-bits) '(and) '(or))
  (progn
    (def-type-predicate-wrapper unsigned-byte-32-p)
    (def-type-predicate-wrapper signed-byte-32-p))
  #!+#.(cl:if (cl:= 64 sb!vm:n-word-bits) '(and) '(or))
  (progn
    (def-type-predicate-wrapper unsigned-byte-64-p)
    (def-type-predicate-wrapper signed-byte-64-p))
  ;; Specialized array types
  (macrolet ((saetp-defs ()
               `(progn
                  ,@(map 'list
                         (lambda (saetp)
                           `(def-type-predicate-wrapper
                                ,(symbolicate (sb!vm:saetp-primitive-type-name saetp) "-P")))
                         sb!vm:*specialized-array-element-type-properties*))))
    (saetp-defs))
  ;; Other array types
  (def-type-predicate-wrapper simple-array-p)
  (def-type-predicate-wrapper simple-string-p)
  (def-type-predicate-wrapper stringp)
  (def-type-predicate-wrapper vectorp)
  (def-type-predicate-wrapper vector-nil-p))

;;; Return the specifier for the type of object. This is not simply
;;; (TYPE-SPECIFIER (CTYPE-OF OBJECT)) because CTYPE-OF has different
;;; goals than TYPE-OF. In particular, speed is more important than
;;; precision, and it is not permitted to return member types.
(defun type-of (object)
  #!+sb-doc
  "Return the type of OBJECT."
  (typecase object
    (fixnum
     (cond
       ((<= 0 object 1) 'bit)
       ((< object 0) 'fixnum)
       (t '(integer 0 #.sb!xc:most-positive-fixnum))))
    (integer
     (if (>= object 0)
         '(integer #.(1+ sb!xc:most-positive-fixnum))
         'bignum))
    (standard-char 'standard-char)
    (base-char 'base-char)
    (extended-char 'extended-char)
    ((member t) 'boolean)
    (keyword 'keyword)
    ((or array complex)
     (type-specifier (ctype-of object)))
    (t
     (let* ((classoid (layout-classoid (layout-of object)))
            (name (classoid-name classoid)))
       (if (%instancep object)
           (case name
             (sb!alien-internals:alien-value
              `(sb!alien:alien
                ,(sb!alien-internals:unparse-alien-type
                  (sb!alien-internals:alien-value-type object))))
             (t
              (let ((pname (classoid-proper-name classoid)))
                (if (classoid-p pname)
                    (classoid-pcl-class pname)
                    pname))))
           name)))))

;;;; equality predicates

;;; This is real simple, 'cause the compiler takes care of it.
(defun eq (obj1 obj2)
  #!+sb-doc
  "Return T if OBJ1 and OBJ2 are the same object, otherwise NIL."
  (eq obj1 obj2))

(declaim (inline %eql))
(defun %eql (obj1 obj2)
  #!+sb-doc
  "Return T if OBJ1 and OBJ2 represent the same object, otherwise NIL."
  (or (eq obj1 obj2)
      (if (or (typep obj2 'fixnum)
              (not (typep obj2 'number)))
          nil
          (macrolet ((foo (&rest stuff)
                       `(typecase obj2
                          ,@(mapcar (lambda (foo)
                                      (let ((type (car foo))
                                            (fn (cadr foo)))
                                        `(,type
                                          (and (typep obj1 ',type)
                                               (,fn obj1 obj2)))))
                                    stuff))))
            (foo
             (single-float eql)
             (double-float eql)
             #!+long-float
             (long-float eql)
             (bignum
              (lambda (x y)
                (zerop (bignum-compare x y))))
             (ratio
              (lambda (x y)
                (and (eql (numerator x) (numerator y))
                     (eql (denominator x) (denominator y)))))
             (complex
              (lambda (x y)
                (and (eql (realpart x) (realpart y))
                     (eql (imagpart x) (imagpart y))))))))))

(defun eql (x y)
  (%eql x y))

(defun bit-vector-= (x y)
  (declare (type bit-vector x y))
  (if (and (simple-bit-vector-p x)
           (simple-bit-vector-p y))
      (bit-vector-= x y) ; DEFTRANSFORM
      (and (= (length x) (length y))
           (do ((i 0 (1+ i))
                (length (length x)))
               ((= i length) t)
             (declare (fixnum i))
             (unless (= (bit x i) (bit y i))
               (return nil))))))

(defun equal (x y)
  #!+sb-doc
  "Return T if X and Y are EQL or if they are structured components whose
elements are EQUAL. Strings and bit-vectors are EQUAL if they are the same
length and have identical components. Other arrays must be EQ to be EQUAL."
  ;; Non-tail self-recursion implemented with a local auxiliary function
  ;; is a lot faster than doing it the straightforward way (at least
  ;; on x86oids) due to calling convention differences. -- JES, 2005-12-30
  (labels ((equal-aux (x y)
             (cond ((%eql x y)
                    t)
                   ((consp x)
                    (and (consp y)
                         (equal-aux (car x) (car y))
                         (equal-aux (cdr x) (cdr y))))
                   ((stringp x)
                    (and (stringp y) (string= x y)))
                   ((pathnamep x)
                    (and (pathnamep y) (pathname= x y)))
                   ((bit-vector-p x)
                    (and (bit-vector-p y)
                         (bit-vector-= x y)))
                   (t nil))))
    ;; Use MAYBE-INLINE to get the inline expansion only once (instead
    ;; of 200 times with INLINE). -- JES, 2005-12-30
    (declare (maybe-inline equal-aux))
    (equal-aux x y)))

;;; EQUALP comparison of HASH-TABLE values
(defun hash-table-equalp (x y)
  (declare (type hash-table x y))
  (or (eq x y)
      (and (hash-table-p y)
           (eql (hash-table-count x) (hash-table-count y))
           (eql (hash-table-test x) (hash-table-test y))
           (block comparison-of-entries
             (maphash (lambda (key x-value)
                        (multiple-value-bind (y-value y-value-p)
                            (gethash key y)
                          (unless (and y-value-p (equalp x-value y-value))
                            (return-from comparison-of-entries nil))))
                      x)
             t))))

(defun equalp (x y)
  #+nil ; KLUDGE: If doc string, should be accurate: Talk about structures
  ; and HASH-TABLEs.
  "This is like EQUAL, except more liberal in several respects.
  Numbers may be of different types, as long as the values are identical
  after coercion. Characters may differ in alphabetic case. Vectors and
  arrays must have identical dimensions and EQUALP elements, but may differ
  in their type restriction."
  (cond ((eq x y) t)
        ((characterp x) (and (characterp y) (char-equal x y)))
        ((numberp x) (and (numberp y) (= x y)))
        ((consp x)
         (and (consp y)
              (equalp (car x) (car y))
              (equalp (cdr x) (cdr y))))
        ((pathnamep x)
         (and (pathnamep y) (pathname= x y)))
        ((hash-table-p x)
         (and (hash-table-p y)
              (hash-table-equalp x y)))
        ((%instancep x)
         (let* ((layout-x (%instance-layout x))
                (raw-len (layout-n-untagged-slots layout-x))
                (total-len (layout-length layout-x))
                (normal-len (- total-len raw-len)))
           (and (%instancep y)
                (eq layout-x (%instance-layout y))
                (structure-classoid-p (layout-classoid layout-x))
                (dotimes (i normal-len t)
                  (let ((x-el (%instance-ref x i))
                        (y-el (%instance-ref y i)))
                    (unless (or (eq x-el y-el)
                                (equalp x-el y-el))
                      (return nil))))
                (if (zerop raw-len)
                    t
                    (raw-instance-slots-equalp layout-x x y)))))
        ((vectorp x)
         (let ((length (length x)))
           (and (vectorp y)
                (= length (length y))
                (dotimes (i length t)
                  (let ((x-el (aref x i))
                        (y-el (aref y i)))
                    (unless (or (eq x-el y-el)
                                (equalp x-el y-el))
                      (return nil)))))))
        ((arrayp x)
         (and (arrayp y)
              (= (array-rank x) (array-rank y))
              (dotimes (axis (array-rank x) t)
                (unless (= (array-dimension x axis)
                           (array-dimension y axis))
                  (return nil)))
              (dotimes (index (array-total-size x) t)
                (let ((x-el (row-major-aref x index))
                      (y-el (row-major-aref y index)))
                  (unless (or (eq x-el y-el)
                              (equalp x-el y-el))
                    (return nil))))))
        (t nil)))

(/show0 "about to do test cases in pred.lisp")
#!+sb-test
(let ((test-cases `((0.0 ,(load-time-value (make-unportable-float :single-float-negative-zero)) t)
                    (0.0 1.0 nil)
                    (#c(1 0) #c(1.0 0.0) t)
                    (#c(0 1) #c(0.0 1.0) t)
                    (#c(1.1 0.0) #c(11/10 0) nil) ; due to roundoff error
                    ("Hello" "hello" t)
                    ("Hello" #(#\h #\E #\l #\l #\o) t)
                    ("Hello" "goodbye" nil))))
  (/show0 "TEST-CASES bound in pred.lisp")
  (dolist (test-case test-cases)
    (/show0 "about to do a TEST-CASE in pred.lisp")
    (destructuring-bind (x y expected-result) test-case
      (let* ((result (equalp x y))
             (bresult (if result 1 0))
             (expected-bresult (if expected-result 1 0)))
        (unless (= bresult expected-bresult)
          (/show0 "failing test in pred.lisp")
          (error "failed test (EQUALP ~S ~S)" x y))))))
(/show0 "done with test cases in pred.lisp")
