50 lines
2.1 KiB
Diff
50 lines
2.1 KiB
Diff
From 89f69032d6a71f41b96ae6becbf3df4e2f9509a5 Mon Sep 17 00:00:00 2001
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From: Karl Williamson <khw@cpan.org>
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Date: Sat, 27 Apr 2019 13:56:39 -0600
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Subject: [PATCH] S_scan_const() Properly test if need to grow
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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As we parse the input, creating a string constant, we may have to grow
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the destination if it fills up as we go along. It allocates space in an
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SV and populates the string, but it doesn' update the SvCUR until the
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end, so in single stepping the debugger through the code, the SV looks
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empty until the end. It turns out that as a result SvEND also doesn't
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get updated and still points to the beginning of the string until SvCUR
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is finally set. That means that the test changed by this commit was
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always succeeding, because it was using SvEND that didn't get updated,
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so it would attempt to grow each time through the loop. By moving a
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couple of statements earlier, and using SvLEN instead, which does always
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have the correct value, those extra growth attempts are avoided.
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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toke.c | 10 ++++++----
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1 file changed, 6 insertions(+), 4 deletions(-)
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diff --git a/toke.c b/toke.c
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index 68eea0cae6..03c4f2ba26 100644
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--- a/toke.c
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+++ b/toke.c
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@@ -4097,10 +4097,12 @@ S_scan_const(pTHX_ char *start)
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goto default_action; /* Redo, having upgraded so both are UTF-8 */
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}
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else { /* UTF8ness matters: convert this non-UTF8 source char to
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- UTF-8 for output. It will occupy 2 bytes */
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- if (d + 2 >= SvEND(sv)) {
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- const STRLEN extra = 2 + (send - s - 1) + 1;
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- const STRLEN off = d - SvPVX_const(sv);
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+ UTF-8 for output. It will occupy 2 bytes, but don't include
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+ the input byte since we haven't incremented 's' yet. See
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+ Note on sizing above. */
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+ const STRLEN off = d - SvPVX(sv);
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+ const STRLEN extra = 2 + (send - s - 1) + 1;
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+ if (off + extra > SvLEN(sv)) {
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d = off + SvGROW(sv, off + extra);
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}
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*d++ = UTF8_EIGHT_BIT_HI(*s);
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--
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2.20.1
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