Fix for [perl #15986] tell/seek misbehave for :crlf

Test from "Vadim Konovalov" <vkonovalov@peterstar.ru>
fix by Nick I-S based on study of problem based
on Vadim's analysis.

p4raw-id: //depot/perlio@17709

diff --git a/perlio.c b/perlio.c
index 11f600f..ea36d80 100644 (file)
--- a/perlio.c
+++ b/perlio.c
@@ -3839,13 +3839,16 @@ PerlIOCrlf_get_cnt(pTHX_ PerlIO *f)
                        b->ptr++;       /* say we have read it as far as
                                         * flush() is concerned */
                        b->buf++;       /* Leave space in front of buffer */
+                       /* Note as we have moved buf up flush's
+                          posn += ptr-buf
+                          will naturally make posn point at CR
+                        */
                        b->bufsiz--;    /* Buffer is thus smaller */
                        code = PerlIO_fill(f);  /* Fetch some more */
                        b->bufsiz++;    /* Restore size for next time */
                        b->buf--;       /* Point at space */
                        b->ptr = nl = b->buf;   /* Which is what we hand
                                                 * off */
-                       b->posn--;      /* Buffer starts here */
                        *nl = 0xd;      /* Fill in the CR */
                        if (code == 0)
                            goto test;  /* fill() call worked */

diff --git a/t/io/crlf.t b/t/io/crlf.t
index 08ab4fe..484596b 100644 (file)
--- a/t/io/crlf.t
+++ b/t/io/crlf.t
@@ -15,7 +15,7 @@ END {
 }
 
 if (find PerlIO::Layer 'perlio') {
- plan(tests => 7);
+ plan(tests => 8);
  ok(open(FOO,">:crlf",$file));
  ok(print FOO 'a'.((('a' x 14).qq{\n}) x 2000) || close(FOO));
  ok(open(FOO,"<:crlf",$file));
@@ -30,6 +30,18 @@ if (find PerlIO::Layer 'perlio') {
  { local $/; $text = <FOO> }
  is(count_chars($text, "\015\012"), 2000);
 
+ {
+  my $fcontents = join "", map {"$_\r\n"} "a".."zzz";
+  open my $fh, "<:crlf", \$fcontents;
+  local $/ = "xxx";
+  local $_ = <$fh>;
+  my $pos = tell $fh; # pos must be behind "xxx", before "\nyyy\n"
+  seek $fh, $pos, 0;
+  $/ = "\n";
+  $s = <$fh>.<$fh>;
+  ok($s eq "\nxxy\n");
+ }
+
  ok(close(FOO));
 }
 else {