fix open-string-input-port on immutable strings

original commit: 48b0ace8b6fba756d8573698db4244472c64255f

LOG

@@ -1372,3 +1372,5 @@
     5_2.ms
 - added support for Microsoft Visual Studio 2019 on Windows
     BUILDING, c/vs.bat, wininstall/locate-vcredist.bat
+- fixed open-string-input-port on immutable strings
+    cpnanopass.ss, io.ms, release_notes.stex

mats/io.ms

@@ -105,8 +105,9 @@
                       (let ([c (get-u8 p)])
                         (cons (integer->char c) (f)))))))))
           "a b c d e")
+  (andmap (lambda (p)
             (equal? (call-with-port
-           (open-file-input-port "testfile.ss")
+                     p
                      (lambda (p)
                        (list->string
                         (let f ()
@@ -115,7 +116,10 @@
                                 '()
                                 (let ([c (get-u8 p)])
                                   (cons (integer->char c) (f)))))))))
-          "a b c d e")
+                    "a b c d e"))
+          (list (open-file-input-port "testfile.ss")
+                (open-bytevector-input-port '#vu8(97 32 98 32 99 32 100 32 101))
+                (open-bytevector-input-port (bytevector->immutable-bytevector '#vu8(97 32 98 32 99 32 100 32 101)))))
   ; test various errors related to input ports
   (begin (set! ip (open-file-input-port "testfile.ss"))
          (and (port? ip) (input-port? ip)))
@@ -1292,8 +1296,9 @@
     (define $bop (let-values ([(op get) (open-bytevector-output-port)]) (set-binary-port-output-buffer! op #vu8(1 2 3 4 5)) op))
     #t)
   ; textual input
+  (andmap (lambda (str)
             (equal?
-    (let ([ip (open-string-input-port "hello")])
+             (let ([ip (open-string-input-port str)])
                (let ([buffer0 (textual-port-input-buffer ip)]
                      [index0 (textual-port-input-index ip)]
                      [size0 (textual-port-input-size ip)]
@@ -1306,7 +1311,9 @@
                    (textual-port-input-index ip)
                    (textual-port-input-size ip)
                    (textual-port-input-count ip)))))
-    '(("hello" 0 5 5) ("hello" 1 5 4)))
+             '(("hello" 0 5 5) ("hello" 1 5 4))))
+          (list "hello"
+                (string->immutable-string "hello")))
   (equal?
     (let ([ip (open-string-input-port "hello")])
       (let ([buffer0 (textual-port-input-buffer ip)]

release_notes/release_notes.stex

@@ -1695,6 +1695,12 @@ in fasl files does not generally make sense.
 %-----------------------------------------------------------------------------
 \section{Bug Fixes}\label{section:bugfixes}
 
+\subsection{String ports form immutable strings (9.5.4)}
+
+A bug that miscalculated the buffer size for
+\scheme{open-string-input-port} given an immutable string has been
+fixed.
+
 \subsection{Multiplying $-2^{30}$ with itself on 64-bit platforms (9.5.3)}
 
 A bug that produced the wrong sign when multiplying $-2^{30}$ with

s/cpnanopass.ss

@@ -7681,9 +7681,9 @@
                         (build-dirty-store e-p ibuffer-disp e-b))
                    ,(bind #t ([e-length (if (eq? port-type 'textual)
                                             (translate
-                                              (%inline logxor
+                                              (%inline logand
                                                  ,(%mref ,e-b ,(constant string-type-disp))
-                                                 ,(%constant type-string))
+                                                 (immediate ,(fx- (expt 2 (constant string-length-offset)))))
                                               (constant string-length-offset)
                                               (constant string-char-offset))
                                             (%inline srl