PR modula2/115057 TextIO.ReadRestLine raises an exception when buffer is exceeded

TextIO.ReadRestLine will raise an "attempting to read beyond end of file"
exception if the buffer is exceeded.  This bug is caused by the
TextIO.ReadRestLine calling IOChan.Skip without a preceeding IOChan.Look.
The Look procedure will update the status result whereas
Skip always sets read result to allRight.

gcc/m2/ChangeLog:

	PR modula2/115057
	* gm2-libs-iso/TextIO.mod (ReadRestLine): Use ReadChar to
	skip unwanted characters as this calls IOChan.Look and updates
	the cid result status.  A Skip without a Look does not update
	the status.  Skip always sets read result to allRight.
	* gm2-libs-iso/TextUtil.def (SkipSpaces): Improve comments.
	(CharAvailable): Improve comments.
	* gm2-libs-iso/TextUtil.mod (SkipSpaces): Improve comments.
	(CharAvailable): Improve comments.

gcc/testsuite/ChangeLog:

	PR modula2/115057
	* gm2/isolib/run/pass/testrestline.mod: New test.
	* gm2/isolib/run/pass/testrestline2.mod: New test.
	* gm2/isolib/run/pass/testrestline3.mod: New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>

diff --git a/gcc/m2/gm2-libs-iso/TextIO.mod b/gcc/m2/gm2-libs-iso/TextIO.mod
index 78d67187b7991740836fd1e43f43e92e34c449a8..5204467b19213a76a6dd8cb2748a158f669cf975 100644 (file)
--- a/gcc/m2/gm2-libs-iso/TextIO.mod
+++ b/gcc/m2/gm2-libs-iso/TextIO.mod
@@ -114,13 +114,19 @@ PROCEDURE ReadRestLine (cid: IOChan.ChanId; VAR s: ARRAY OF CHAR);
   *)
 VAR
    i, h    : CARDINAL ;
+   ignore  : CHAR ;
    finished: BOOLEAN ;
 BEGIN
    h := HIGH(s) ;
    i := 0 ;
    finished := FALSE ;
-   WHILE (i<=h) AND CharAvailable (cid) AND (NOT finished) DO
-      ReadChar (cid, s[i]) ;
+   WHILE CharAvailable (cid) AND (NOT finished) DO
+      IF i <= h
+      THEN
+         ReadChar (cid, s[i])
+      ELSE
+         ReadChar (cid, ignore)
+      END ;
       IF EofOrEoln (cid)
       THEN
          finished := TRUE
@@ -128,9 +134,6 @@ BEGIN
          INC (i)
       END
    END ;
-   WHILE CharAvailable (cid) DO
-      IOChan.Skip (cid)
-   END ;
    SetNul (cid, i, s, TRUE)
 END ReadRestLine ;
 

diff --git a/gcc/m2/gm2-libs-iso/TextUtil.def b/gcc/m2/gm2-libs-iso/TextUtil.def
index ead045617233d401ac564bf555d263790c10095c..7e6b3ed07dcedbcba6b70a1cf96eefa8b8534548 100644 (file)
--- a/gcc/m2/gm2-libs-iso/TextUtil.def
+++ b/gcc/m2/gm2-libs-iso/TextUtil.def
@@ -45,11 +45,15 @@ IMPORT IOChan ;
 PROCEDURE SkipSpaces (cid: IOChan.ChanId) ;
 
 
-(* The following procedures do not read past line marks.  *)
+(* CharAvailable returns TRUE if IOChan.ReadResult is notKnown or
+   allRight.  *)
 
 PROCEDURE CharAvailable (cid: IOChan.ChanId) : BOOLEAN ;
 
 
+(* EofOrEoln returns TRUE if IOChan.ReadResult is endOfLine or
+   endOfInput.  *)
+
 PROCEDURE EofOrEoln (cid: IOChan.ChanId) : BOOLEAN ;
 
 

diff --git a/gcc/m2/gm2-libs-iso/TextUtil.mod b/gcc/m2/gm2-libs-iso/TextUtil.mod
index 44dbd1c69f8b9bead426fdcb03449b1cbc97d9aa..ad5786ca2fb28f8dd318d2c256305bee4d209b98 100644 (file)
--- a/gcc/m2/gm2-libs-iso/TextUtil.mod
+++ b/gcc/m2/gm2-libs-iso/TextUtil.mod
@@ -23,7 +23,8 @@ BEGIN
 END SkipSpaces ;
 
 
-(* The following procedures do not read past line marks.  *)
+(* CharAvailable returns TRUE if IOChan.ReadResult is notKnown or
+   allRight.  *)
 
 PROCEDURE CharAvailable (cid: IOChan.ChanId) : BOOLEAN ;
 BEGIN
@@ -32,6 +33,9 @@ BEGIN
 END CharAvailable ;
 
 
+(* EofOrEoln returns TRUE if IOChan.ReadResult is endOfLine or
+   endOfInput.  *)
+
 PROCEDURE EofOrEoln (cid: IOChan.ChanId) : BOOLEAN ;
 BEGIN
    RETURN( (IOChan.ReadResult (cid) = IOConsts.endOfLine) OR

diff --git a/gcc/testsuite/gm2/isolib/run/pass/testrestline.mod b/gcc/testsuite/gm2/isolib/run/pass/testrestline.mod
new file mode 100644 (file)
index 0000000..7702e88
--- /dev/null
+++ b/gcc/testsuite/gm2/isolib/run/pass/testrestline.mod
@@ -0,0 +1,20 @@
+MODULE testrestline ;
+
+IMPORT SeqFile, TextIO ;
+
+VAR
+   chan    : SeqFile.ChanId ;
+   line    : ARRAY [0..5] OF CHAR ;
+   results : SeqFile.OpenResults ;
+BEGIN
+   SeqFile.OpenWrite (chan, "test.input", SeqFile.write, results) ;
+   TextIO.WriteString (chan, "a line of text exceeding 6 chars") ;
+   TextIO.WriteLn (chan) ;
+   TextIO.WriteString (chan, "a second lineline of text exceeding 6 chars") ;
+   TextIO.WriteLn (chan) ;
+   SeqFile.Close (chan) ;
+
+   (* Now see if we can read the first line.  *)
+   SeqFile.OpenRead (chan, "test.input", SeqFile.read, results) ;
+   TextIO.ReadRestLine (chan, line)
+END testrestline.
\ No newline at end of file

diff --git a/gcc/testsuite/gm2/isolib/run/pass/testrestline2.mod b/gcc/testsuite/gm2/isolib/run/pass/testrestline2.mod
new file mode 100644 (file)
index 0000000..00e5c80
--- /dev/null
+++ b/gcc/testsuite/gm2/isolib/run/pass/testrestline2.mod
@@ -0,0 +1,17 @@
+MODULE testrestline2 ;
+
+IMPORT SeqFile, TextIO ;
+
+VAR
+   chan    : SeqFile.ChanId ;
+   line    : ARRAY [0..5] OF CHAR ;
+   results : SeqFile.OpenResults ;
+BEGIN
+   SeqFile.OpenWrite (chan, "test.input", SeqFile.write, results) ;
+   TextIO.WriteString (chan, "a line of text exceeding 6 chars") ;
+   TextIO.WriteLn (chan) ;
+
+   (* Now see if we can read the first line.  *)
+   SeqFile.OpenRead (chan, "test.input", SeqFile.read, results) ;
+   TextIO.ReadRestLine (chan, line)
+END testrestline2.
\ No newline at end of file

diff --git a/gcc/testsuite/gm2/isolib/run/pass/testrestline3.mod b/gcc/testsuite/gm2/isolib/run/pass/testrestline3.mod
new file mode 100644 (file)
index 0000000..04fbad4
--- /dev/null
+++ b/gcc/testsuite/gm2/isolib/run/pass/testrestline3.mod
@@ -0,0 +1,16 @@
+MODULE testrestline3 ;
+
+IMPORT SeqFile, TextIO ;
+
+VAR
+   chan    : SeqFile.ChanId ;
+   line    : ARRAY [0..5] OF CHAR ;
+   results : SeqFile.OpenResults ;
+BEGIN
+   SeqFile.OpenWrite (chan, "test.input", SeqFile.write, results) ;
+   TextIO.WriteString (chan, "a line of text exceeding 6 chars") ;
+
+   (* Now see if we can read the first line.  *)
+   SeqFile.OpenRead (chan, "test.input", SeqFile.read, results) ;
+   TextIO.ReadRestLine (chan, line)
+END testrestline3.
\ No newline at end of file