0.8.13.41: Require robustness

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

diff --git a/src/code/reader.lisp b/src/code/reader.lisp
index 2ad7a3b..0f2df53 100644 (file)
--- a/src/code/reader.lisp
+++ b/src/code/reader.lisp
@@ -256,9 +256,9 @@
                   +char-attr-whitespace+)
               (done-with-fast-read-char)
               char)))
                   +char-attr-whitespace+)
               (done-with-fast-read-char)
               char)))

-       ;; fundamental-stream
+       ;; CLOS stream

        (do ((attribute-table (character-attribute-table *readtable*))
        (do ((attribute-table (character-attribute-table *readtable*))

-            (char (stream-read-char stream) (stream-read-char stream)))
+            (char (read-char stream nil :eof) (read-char stream nil :eof)))

            ((or (eq char :eof)
                 (/= (the fixnum (aref attribute-table (char-code char)))
                     +char-attr-whitespace+))
            ((or (eq char :eof)
                 (/= (the fixnum (aref attribute-table (char-code char)))
                     +char-attr-whitespace+))

@@ -276,6 +276,7 @@
   (let ((*readtable* *standard-readtable*))
 
     (flet ((whitespaceify (char)
   (let ((*readtable* *standard-readtable*))
 
     (flet ((whitespaceify (char)

+            (set-cmt-entry char nil)

             (set-cat-entry char +char-attr-whitespace+)))
       (whitespaceify (code-char tab-char-code))
       (whitespaceify #\linefeed)
             (set-cat-entry char +char-attr-whitespace+)))
       (whitespaceify (code-char tab-char-code))
       (whitespaceify #\linefeed)

@@ -284,7 +285,7 @@
       (whitespaceify (code-char return-char-code)))
 
     (set-cat-entry #\\ +char-attr-escape+)
       (whitespaceify (code-char return-char-code)))
 
     (set-cat-entry #\\ +char-attr-escape+)

-    (set-cmt-entry #\\ #'read-token)
+    (set-cmt-entry #\\ nil)

 
     ;; Easy macro-character definitions are in this source file.
     (set-macro-character #\" #'read-string)
 
     ;; Easy macro-character definitions are in this source file.
     (set-macro-character #\" #'read-string)

@@ -301,8 +302,8 @@
        ((= ichar #O200))
       (setq char (code-char ichar))
       (when (constituentp char *standard-readtable*)
        ((= ichar #O200))
       (setq char (code-char ichar))
       (when (constituentp char *standard-readtable*)

-           (set-cat-entry char (get-secondary-attribute char))
-           (set-cmt-entry char nil)))))
+       (set-cat-entry char (get-secondary-attribute char))
+       (set-cmt-entry char nil)))))

 \f
 ;;;; implementation of the read buffer
 
 \f
 ;;;; implementation of the read buffer
 

@@ -316,7 +317,7 @@
 (defvar *ouch-ptr*)
 
 (declaim (type index *read-buffer-length* *inch-ptr* *ouch-ptr*))
 (defvar *ouch-ptr*)
 
 (declaim (type index *read-buffer-length* *inch-ptr* *ouch-ptr*))

-(declaim (simple-string *read-buffer*))
+(declaim (type (simple-array character (*)) *read-buffer*))

 
 (defmacro reset-read-buffer ()
   ;; Turn *READ-BUFFER* into an empty read buffer.
 
 (defmacro reset-read-buffer ()
   ;; Turn *READ-BUFFER* into an empty read buffer.

@@ -483,8 +484,8 @@
                     (fast-read-char nil nil)))
              ((or (not char) (char= char #\newline))
               (done-with-fast-read-char))))
                     (fast-read-char nil nil)))
              ((or (not char) (char= char #\newline))
               (done-with-fast-read-char))))

-       ;; FUNDAMENTAL-STREAM
-       (do ((char (stream-read-char stream) (stream-read-char stream)))
+       ;; CLOS stream
+       (do ((char (read-char stream nil :eof) (read-char stream nil :eof)))

            ((or (eq char :eof) (char= char #\newline))))))
   ;; Don't return anything.
   (values))
            ((or (eq char :eof) (char= char #\newline))))))
   ;; Don't return anything.
   (values))

@@ -547,13 +548,13 @@
               (done-with-fast-read-char))
            (if (escapep char) (setq char (fast-read-char t)))
            (ouch-read-buffer char)))
               (done-with-fast-read-char))
            (if (escapep char) (setq char (fast-read-char t)))
            (ouch-read-buffer char)))

-       ;; FUNDAMENTAL-STREAM
-       (do ((char (stream-read-char stream) (stream-read-char stream)))
+       ;; CLOS stream
+       (do ((char (read-char stream nil :eof) (read-char stream nil :eof)))

            ((or (eq char :eof) (char= char closech))
             (if (eq char :eof)
                 (error 'end-of-file :stream stream)))
          (when (escapep char)
            ((or (eq char :eof) (char= char closech))
             (if (eq char :eof)
                 (error 'end-of-file :stream stream)))
          (when (escapep char)

-           (setq char (stream-read-char stream))
+           (setq char (read-char stream nil :eof))

            (if (eq char :eof)
                (error 'end-of-file :stream stream)))
          (ouch-read-buffer char))))
            (if (eq char :eof)
                (error 'end-of-file :stream stream)))
          (ouch-read-buffer char))))

@@ -658,8 +659,10 @@
         +char-attr-delimiter+
         (if (digit-char-p ,char (max *read-base* 10))
             (if (digit-char-p ,char *read-base*)
         +char-attr-delimiter+
         (if (digit-char-p ,char (max *read-base* 10))
             (if (digit-char-p ,char *read-base*)

-                +char-attr-constituent-digit+
-                +char-attr-constituent+)
+                (if (= att +char-attr-constituent-expt+)
+                    +char-attr-constituent-digit-or-expt+
+                    +char-attr-constituent-digit+)
+                +char-attr-constituent-decimal-digit+)

             att))))
 \f
 ;;;; token fetching
             att))))
 \f
 ;;;; token fetching

@@ -735,13 +738,20 @@
        (package-designator nil)
        (colons 0)
        (possibly-rational t)
        (package-designator nil)
        (colons 0)
        (possibly-rational t)

+       (seen-digit-or-expt nil)

        (possibly-float t)
        (possibly-float t)

-       (escapes ()))
+       (was-possibly-float nil)
+       (escapes ())
+       (seen-multiple-escapes nil))

     (reset-read-buffer)
     (prog ((char firstchar))
       (case (char-class3 char attribute-table)
        (#.+char-attr-constituent-sign+ (go SIGN))
        (#.+char-attr-constituent-digit+ (go LEFTDIGIT))
     (reset-read-buffer)
     (prog ((char firstchar))
       (case (char-class3 char attribute-table)
        (#.+char-attr-constituent-sign+ (go SIGN))
        (#.+char-attr-constituent-digit+ (go LEFTDIGIT))

+       (#.+char-attr-constituent-digit-or-expt+
+        (setq seen-digit-or-expt t)
+        (go LEFTDIGIT))
+       (#.+char-attr-constituent-decimal-digit+ (go LEFTDECIMALDIGIT))

        (#.+char-attr-constituent-dot+ (go FRONTDOT))
        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))
        (#.+char-attr-constituent-dot+ (go FRONTDOT))
        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))

@@ -756,6 +766,10 @@
            possibly-float t)
       (case (char-class3 char attribute-table)
        (#.+char-attr-constituent-digit+ (go LEFTDIGIT))
            possibly-float t)
       (case (char-class3 char attribute-table)
        (#.+char-attr-constituent-digit+ (go LEFTDIGIT))

+       (#.+char-attr-constituent-digit-or-expt+
+        (setq seen-digit-or-expt t)
+        (go LEFTDIGIT))
+       (#.+char-attr-constituent-decimal-digit+ (go LEFTDECIMALDIGIT))

        (#.+char-attr-constituent-dot+ (go SIGNDOT))
        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))
        (#.+char-attr-constituent-dot+ (go SIGNDOT))
        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))

@@ -766,12 +780,23 @@
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))
       (unless char (return (make-integer)))
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))
       (unless char (return (make-integer)))

+      (setq was-possibly-float possibly-float)

       (case (char-class3 char attribute-table)
        (#.+char-attr-constituent-digit+ (go LEFTDIGIT))
       (case (char-class3 char attribute-table)
        (#.+char-attr-constituent-digit+ (go LEFTDIGIT))

+       (#.+char-attr-constituent-decimal-digit+ (if possibly-float
+                                                    (go LEFTDECIMALDIGIT)
+                                                    (go SYMBOL)))

        (#.+char-attr-constituent-dot+ (if possibly-float
                                           (go MIDDLEDOT)
                                           (go SYMBOL)))
        (#.+char-attr-constituent-dot+ (if possibly-float
                                           (go MIDDLEDOT)
                                           (go SYMBOL)))

-       (#.+char-attr-constituent-expt+ (go EXPONENT))
+       (#.+char-attr-constituent-digit-or-expt+
+        (if (or seen-digit-or-expt (not was-possibly-float))
+            (progn (setq seen-digit-or-expt t) (go LEFTDIGIT))
+            (progn (setq seen-digit-or-expt t) (go LEFTDIGIT-OR-EXPT))))
+       (#.+char-attr-constituent-expt+
+        (if was-possibly-float
+            (go EXPONENT)
+            (go SYMBOL)))

        (#.+char-attr-constituent-slash+ (if possibly-rational
                                             (go RATIO)
                                             (go SYMBOL)))
        (#.+char-attr-constituent-slash+ (if possibly-rational
                                             (go RATIO)
                                             (go SYMBOL)))

@@ -781,6 +806,43 @@
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))
        (t (go SYMBOL)))
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))
        (t (go SYMBOL)))

+     LEFTDIGIT-OR-EXPT
+      (ouch-read-buffer char)
+      (setq char (read-char stream nil nil))
+      (unless char (return (make-integer)))
+      (case (char-class3 char attribute-table)
+       (#.+char-attr-constituent-digit+ (go LEFTDIGIT))
+       (#.+char-attr-constituent-decimal-digit+ (bug "impossible!"))
+       (#.+char-attr-constituent-dot+ (go SYMBOL))
+       (#.+char-attr-constituent-digit-or-expt+ (go LEFTDIGIT))
+       (#.+char-attr-constituent-expt+ (go SYMBOL))
+       (#.+char-attr-constituent-sign+ (go EXPTSIGN))
+       (#.+char-attr-constituent-slash+ (if possibly-rational
+                                            (go RATIO)
+                                            (go SYMBOL)))
+       (#.+char-attr-delimiter+ (unread-char char stream)
+                                (return (make-integer)))
+       (#.+char-attr-escape+ (go ESCAPE))
+       (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
+       (#.+char-attr-package-delimiter+ (go COLON))
+       (t (go SYMBOL)))
+     LEFTDECIMALDIGIT ; saw "[sign] {decimal-digit}+"
+      (aver possibly-float)
+      (ouch-read-buffer char)
+      (setq char (read-char stream nil nil))
+      (unless char (go RETURN-SYMBOL))
+      (case (char-class char attribute-table)
+       (#.+char-attr-constituent-digit+ (go LEFTDECIMALDIGIT))
+       (#.+char-attr-constituent-dot+ (go MIDDLEDOT))
+       (#.+char-attr-constituent-expt+ (go EXPONENT))
+       (#.+char-attr-constituent-slash+ (aver (not possibly-rational))
+                                        (go SYMBOL))
+       (#.+char-attr-delimiter+ (unread-char char stream)
+                                (go RETURN-SYMBOL))
+       (#.+char-attr-escape+ (go ESCAPE))
+       (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
+       (#.+char-attr-package-delimiter+ (go COLON))
+       (t (go SYMBOL)))

      MIDDLEDOT ; saw "[sign] {digit}+ dot"
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))
      MIDDLEDOT ; saw "[sign] {digit}+ dot"
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))

@@ -797,16 +859,16 @@
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))
        (t (go SYMBOL)))
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))
        (t (go SYMBOL)))

-     RIGHTDIGIT ; saw "[sign] {digit}* dot {digit}+"
+     RIGHTDIGIT ; saw "[sign] {decimal-digit}* dot {digit}+"

       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))

-      (unless char (return (make-float)))
+      (unless char (return (make-float stream)))

       (case (char-class char attribute-table)
        (#.+char-attr-constituent-digit+ (go RIGHTDIGIT))
        (#.+char-attr-constituent-expt+ (go EXPONENT))
        (#.+char-attr-delimiter+
         (unread-char char stream)
       (case (char-class char attribute-table)
        (#.+char-attr-constituent-digit+ (go RIGHTDIGIT))
        (#.+char-attr-constituent-expt+ (go EXPONENT))
        (#.+char-attr-delimiter+
         (unread-char char stream)

-        (return (make-float)))
+        (return (make-float stream)))

        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))
        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))

@@ -837,6 +899,7 @@
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))
       (unless char (go RETURN-SYMBOL))
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))
       (unless char (go RETURN-SYMBOL))

+      (setq possibly-float t)

       (case (char-class char attribute-table)
        (#.+char-attr-constituent-sign+ (go EXPTSIGN))
        (#.+char-attr-constituent-digit+ (go EXPTDIGIT))
       (case (char-class char attribute-table)
        (#.+char-attr-constituent-sign+ (go EXPTSIGN))
        (#.+char-attr-constituent-digit+ (go EXPTDIGIT))

@@ -859,12 +922,12 @@
      EXPTDIGIT ; got to EXPONENT, saw "[sign] {digit}+"
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))
      EXPTDIGIT ; got to EXPONENT, saw "[sign] {digit}+"
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))

-      (unless char (return (make-float)))
+      (unless char (return (make-float stream)))

       (case (char-class char attribute-table)
        (#.+char-attr-constituent-digit+ (go EXPTDIGIT))
        (#.+char-attr-delimiter+
         (unread-char char stream)
       (case (char-class char attribute-table)
        (#.+char-attr-constituent-digit+ (go EXPTDIGIT))
        (#.+char-attr-delimiter+
         (unread-char char stream)

-        (return (make-float)))
+        (return (make-float stream)))

        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))
        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))

@@ -883,12 +946,12 @@
      RATIODIGIT ; saw "[sign] {digit}+ slash {digit}+"
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))
      RATIODIGIT ; saw "[sign] {digit}+ slash {digit}+"
       (ouch-read-buffer char)
       (setq char (read-char stream nil nil))

-      (unless char (return (make-ratio)))
+      (unless char (return (make-ratio stream)))

       (case (char-class2 char attribute-table)
        (#.+char-attr-constituent-digit+ (go RATIODIGIT))
        (#.+char-attr-delimiter+
         (unread-char char stream)
       (case (char-class2 char attribute-table)
        (#.+char-attr-constituent-digit+ (go RATIODIGIT))
        (#.+char-attr-delimiter+
         (unread-char char stream)

-        (return (make-ratio)))
+        (return (make-ratio stream)))

        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))
        (#.+char-attr-escape+ (go ESCAPE))
        (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
        (#.+char-attr-package-delimiter+ (go COLON))

@@ -926,15 +989,15 @@
                 (#.+char-attr-package-delimiter+ (done-with-fast-read-char)
                                                  (go COLON))
                 (t (go SYMBOL-LOOP)))))
                 (#.+char-attr-package-delimiter+ (done-with-fast-read-char)
                                                  (go COLON))
                 (t (go SYMBOL-LOOP)))))

-           ;; fundamental-stream
+           ;; CLOS stream

            (prog ()
             SYMBOL-LOOP
             (ouch-read-buffer char)
            (prog ()
             SYMBOL-LOOP
             (ouch-read-buffer char)

-            (setq char (stream-read-char stream))
+            (setq char (read-char stream nil :eof))

             (when (eq char :eof) (go RETURN-SYMBOL))
             (case (char-class char attribute-table)
               (#.+char-attr-escape+ (go ESCAPE))
             (when (eq char :eof) (go RETURN-SYMBOL))
             (case (char-class char attribute-table)
               (#.+char-attr-escape+ (go ESCAPE))

-              (#.+char-attr-delimiter+ (stream-unread-char stream char)
+              (#.+char-attr-delimiter+ (unread-char char stream)

                            (go RETURN-SYMBOL))
               (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
               (#.+char-attr-package-delimiter+ (go COLON))
                            (go RETURN-SYMBOL))
               (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
               (#.+char-attr-package-delimiter+ (go COLON))

@@ -956,6 +1019,7 @@
        (#.+char-attr-package-delimiter+ (go COLON))
        (t (go SYMBOL)))
       MULT-ESCAPE
        (#.+char-attr-package-delimiter+ (go COLON))
        (t (go SYMBOL)))
       MULT-ESCAPE

+      (setq seen-multiple-escapes t)

       (do ((char (read-char stream t) (read-char stream t)))
          ((multiple-escape-p char))
        (if (escapep char) (setq char (read-char stream t)))
       (do ((char (read-char stream t) (read-char stream t)))
          ((multiple-escape-p char))
        (if (escapep char) (setq char (read-char stream t)))

@@ -983,7 +1047,9 @@
                ;; a FIND-PACKAGE* function analogous to INTERN*
                ;; and friends?
                (read-buffer-to-string)
                ;; a FIND-PACKAGE* function analogous to INTERN*
                ;; and friends?
                (read-buffer-to-string)

-               *keyword-package*))
+               (if seen-multiple-escapes
+                   (read-buffer-to-string)
+                   *keyword-package*)))

       (reset-read-buffer)
       (setq escapes ())
       (setq char (read-char stream nil nil))
       (reset-read-buffer)
       (setq escapes ())
       (setq char (read-char stream nil nil))

@@ -1147,7 +1213,7 @@
                                 (the index (* num base))))))))
        (setq number (+ num (* number base-power)))))))
 
                                 (the index (* num base))))))))
        (setq number (+ num (* number base-power)))))))
 

-(defun make-float ()
+(defun make-float (stream)

   ;; Assume that the contents of *read-buffer* are a legal float, with nothing
   ;; else after it.
   (read-unwind-read-buffer)
   ;; Assume that the contents of *read-buffer* are a legal float, with nothing
   ;; else after it.
   (read-unwind-read-buffer)

@@ -1181,7 +1247,8 @@
     (cond ((eofp char)
           ;; If not, we've read the whole number.
           (let ((num (make-float-aux number divisor
     (cond ((eofp char)
           ;; If not, we've read the whole number.
           (let ((num (make-float-aux number divisor

-                                     *read-default-float-format*)))
+                                     *read-default-float-format*
+                                     stream)))

             (return-from make-float (if negative-fraction (- num) num))))
          ((exponent-letterp char)
           (setq float-char char)
             (return-from make-float (if negative-fraction (- num) num))))
          ((exponent-letterp char)
           (setq float-char char)

@@ -1206,55 +1273,21 @@
                                  (#\F 'single-float)
                                  (#\D 'double-float)
                                  (#\L 'long-float)))
                                  (#\F 'single-float)
                                  (#\D 'double-float)
                                  (#\L 'long-float)))

-                 num)
-            ;; Raymond Toy writes: We need to watch out if the
-            ;; exponent is too small or too large. We add enough to
-            ;; EXPONENT to make it within range and scale NUMBER
-            ;; appropriately. This should avoid any unnecessary
-            ;; underflow or overflow problems.
-            (multiple-value-bind (min-expo max-expo)
-                ;; FIXME: These forms are broken w.r.t.
-                ;; cross-compilation portability, as the
-                ;; cross-compiler will call the host's LOG function
-                ;; while attempting to constant-fold. Maybe some sort
-                ;; of load-time-form magic could be used instead?
-                (case float-format
-                  (short-float
-                   (values
-                    (log sb!xc:least-positive-normalized-short-float 10s0)
-                    (log sb!xc:most-positive-short-float 10s0)))
-                  (single-float
-                   (values
-                    (log sb!xc:least-positive-normalized-single-float 10f0)
-                    (log sb!xc:most-positive-single-float 10f0)))
-                  (double-float
-                   (values
-                    (log sb!xc:least-positive-normalized-double-float 10d0)
-                    (log sb!xc:most-positive-double-float 10d0)))
-                  (long-float
-                   (values
-                    (log sb!xc:least-positive-normalized-long-float 10L0)
-                    (log sb!xc:most-positive-long-float 10L0))))
-              (let ((correction (cond ((<= exponent min-expo)
-                                       (ceiling (- min-expo exponent)))
-                                      ((>= exponent max-expo)
-                                       (floor (- max-expo exponent)))
-                                      (t
-                                       0))))
-                (incf exponent correction)
-                (setf number (/ number (expt 10 correction)))
-                (setq num (make-float-aux number divisor float-format))
-                (setq num (* num (expt 10 exponent)))
-                (return-from make-float (if negative-fraction
-                                            (- num)
-                                            num))))))
-         ;; should never happen
+                 (result (make-float-aux (* (expt 10 exponent) number)
+                                         divisor float-format stream)))
+            (return-from make-float
+              (if negative-fraction (- result) result))))

          (t (bug "bad fallthrough in floating point reader")))))
 
          (t (bug "bad fallthrough in floating point reader")))))
 

-(defun make-float-aux (number divisor float-format)
-  (coerce (/ number divisor) float-format))
+(defun make-float-aux (number divisor float-format stream)
+  (handler-case
+      (coerce (/ number divisor) float-format)
+    (type-error (c)
+      (error 'reader-impossible-number-error
+            :error c :stream stream
+            :format-control "failed to build float"))))

 
 

-(defun make-ratio ()
+(defun make-ratio (stream)

   ;; Assume *READ-BUFFER* contains a legal ratio. Build the number from
   ;; the string.
   ;;
   ;; Assume *READ-BUFFER* contains a legal ratio. Build the number from
   ;; the string.
   ;;

@@ -1278,7 +1311,12 @@
          (dig ()))
         ((or (eofp ch) (not (setq dig (digit-char-p ch *read-base*)))))
         (setq denominator (+ (* denominator *read-base*) dig)))
          (dig ()))
         ((or (eofp ch) (not (setq dig (digit-char-p ch *read-base*)))))
         (setq denominator (+ (* denominator *read-base*) dig)))

-    (let ((num (/ numerator denominator)))
+    (let ((num (handler-case
+                  (/ numerator denominator)
+                (arithmetic-error (c)
+                  (error 'reader-impossible-number-error
+                         :error c :stream stream
+                         :format-control "failed to build ratio")))))

       (if negative-number (- num) num))))
 \f
 ;;;; cruft for dispatch macros
       (if negative-number (- num) num))))
 \f
 ;;;; cruft for dispatch macros

@@ -1389,9 +1427,10 @@
    and the lisp object built by the reader is returned. Macro chars
    will take effect."
   (declare (string string))
    and the lisp object built by the reader is returned. Macro chars
    will take effect."
   (declare (string string))

+  

   (with-array-data ((string string)
                    (start start)
   (with-array-data ((string string)
                    (start start)

-                   (end (or end (length string))))
+                   (end (%check-vector-sequence-bounds string start end)))

     (unless *read-from-string-spares*
       (push (internal-make-string-input-stream "" 0 0)
            *read-from-string-spares*))
     (unless *read-from-string-spares*
       (push (internal-make-string-input-stream "" 0 0)
            *read-from-string-spares*))

@@ -1414,51 +1453,55 @@
   (default to the beginning and end of the string)  It skips over
   whitespace characters and then tries to parse an integer. The
   radix parameter must be between 2 and 36."
   (default to the beginning and end of the string)  It skips over
   whitespace characters and then tries to parse an integer. The
   radix parameter must be between 2 and 36."

-  (with-array-data ((string string)
-                   (start start)
-                   (end (or end (length string))))
-    (let ((index (do ((i start (1+ i)))
-                    ((= i end)
-                     (if junk-allowed
-                         (return-from parse-integer (values nil end))
-                         (error "no non-whitespace characters in number")))
-                  (declare (fixnum i))
-                  (unless (whitespacep (char string i)) (return i))))
-         (minusp nil)
-         (found-digit nil)
-         (result 0))
-      (declare (fixnum index))
-      (let ((char (char string index)))
-       (cond ((char= char #\-)
-              (setq minusp t)
-              (incf index))
-             ((char= char #\+)
-              (incf index))))
-      (loop
-       (when (= index end) (return nil))
-       (let* ((char (char string index))
-              (weight (digit-char-p char radix)))
-         (cond (weight
-                (setq result (+ weight (* result radix))
-                      found-digit t))
-               (junk-allowed (return nil))
-               ((whitespacep char)
-                (do ((jndex (1+ index) (1+ jndex)))
-                    ((= jndex end))
-                  (declare (fixnum jndex))
-                  (unless (whitespacep (char string jndex))
-                    (error "junk in string ~S" string)))
-                (return nil))
-               (t
-                (error "junk in string ~S" string))))
-       (incf index))
-      (values
-       (if found-digit
-          (if minusp (- result) result)
-          (if junk-allowed
-              nil
-              (error "no digits in string ~S" string)))
-       index))))
+  (macrolet ((parse-error (format-control)
+              `(error 'simple-parse-error
+                      :format-control ,format-control
+                      :format-arguments (list string))))
+    (with-array-data ((string string :offset-var offset)
+                     (start start)
+                     (end (%check-vector-sequence-bounds string start end)))
+      (let ((index (do ((i start (1+ i)))
+                      ((= i end)
+                       (if junk-allowed
+                           (return-from parse-integer (values nil end))
+                           (parse-error "no non-whitespace characters in string ~S.")))
+                    (declare (fixnum i))
+                    (unless (whitespacep (char string i)) (return i))))
+           (minusp nil)
+           (found-digit nil)
+           (result 0))
+       (declare (fixnum index))
+       (let ((char (char string index)))
+         (cond ((char= char #\-)
+                (setq minusp t)
+                (incf index))
+               ((char= char #\+)
+                (incf index))))
+       (loop
+        (when (= index end) (return nil))
+        (let* ((char (char string index))
+               (weight (digit-char-p char radix)))
+          (cond (weight
+                 (setq result (+ weight (* result radix))
+                       found-digit t))
+                (junk-allowed (return nil))
+                ((whitespacep char)
+                  (loop
+                   (incf index)
+                   (when (= index end) (return))
+                   (unless (whitespacep (char string index))
+                     (parse-error "junk in string ~S")))
+                 (return nil))
+                (t
+                 (parse-error "junk in string ~S"))))
+        (incf index))
+       (values
+        (if found-digit
+            (if minusp (- result) result)
+            (if junk-allowed
+                nil
+                (parse-error "no digits in string ~S")))
+        (- index offset))))))

 \f
 ;;;; reader initialization code
 
 \f
 ;;;; reader initialization code