From b29fbd16fa82b82bdf0dcb2f13a63f7dc23cf324 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Mon, 6 Feb 2023 13:08:52 -0700
Subject: [PATCH] [gsubgpos] Refactor skippy_iter.match()
Upstream-Status: Backport from [https://github.com/harfbuzz/harfbuzz/commit/b29fbd16fa82b82bdf0dcb2f13a63f7dc23cf324]
Comment1: To backport the fix for CVE-2023-25193, add defination for MATCH, NOT_MATCH and SKIP.
Signed-off-by: Siddharth <sdoshi@mvista.com>
---
src/hb-ot-layout-gsubgpos.hh | 94 +++++++++++++++++++++---------------
1 file changed, 54 insertions(+), 40 deletions(-)
diff --git a/src/hb-ot-layout-gsubgpos.hh b/src/hb-ot-layout-gsubgpos.hh
index d9a068c..d17a4da 100644
--- a/src/hb-ot-layout-gsubgpos.hh
+++ b/src/hb-ot-layout-gsubgpos.hh
@@ -522,33 +522,52 @@ struct hb_ot_apply_context_t :
may_skip (const hb_glyph_info_t &info) const
{ return matcher.may_skip (c, info); }
+ enum match_t {
+ MATCH,
+ NOT_MATCH,
+ SKIP
+ };
+
+ match_t match (hb_glyph_info_t &info)
+ {
+ matcher_t::may_skip_t skip = matcher.may_skip (c, info);
+ if (unlikely (skip == matcher_t::SKIP_YES))
+ return SKIP;
+
+ matcher_t::may_match_t match = matcher.may_match (info, match_glyph_data);
+ if (match == matcher_t::MATCH_YES ||
+ (match == matcher_t::MATCH_MAYBE &&
+ skip == matcher_t::SKIP_NO))
+ return MATCH;
+
+ if (skip == matcher_t::SKIP_NO)
+ return NOT_MATCH;
+
+ return SKIP;
+ }
+
bool next (unsigned *unsafe_to = nullptr)
{
assert (num_items > 0);
while (idx + num_items < end)
{
idx++;
- const hb_glyph_info_t &info = c->buffer->info[idx];
-
- matcher_t::may_skip_t skip = matcher.may_skip (c, info);
- if (unlikely (skip == matcher_t::SKIP_YES))
- continue;
-
- matcher_t::may_match_t match = matcher.may_match (info, match_glyph_data);
- if (match == matcher_t::MATCH_YES ||
- (match == matcher_t::MATCH_MAYBE &&
- skip == matcher_t::SKIP_NO))
- {
- num_items--;
- if (match_glyph_data) match_glyph_data++;
- return true;
- }
-
- if (skip == matcher_t::SKIP_NO)
+ switch (match (c->buffer->info[idx]))
{
- if (unsafe_to)
- *unsafe_to = idx + 1;
- return false;
+ case MATCH:
+ {
+ num_items--;
+ if (match_glyph_data) match_glyph_data++;
+ return true;
+ }
+ case NOT_MATCH:
+ {
+ if (unsafe_to)
+ *unsafe_to = idx + 1;
+ return false;
+ }
+ case SKIP:
+ continue;
}
}
if (unsafe_to)
@@ -561,27 +580,22 @@ struct hb_ot_apply_context_t :
while (idx > num_items - 1)
{
idx--;
- const hb_glyph_info_t &info = c->buffer->out_info[idx];
-
- matcher_t::may_skip_t skip = matcher.may_skip (c, info);
- if (unlikely (skip == matcher_t::SKIP_YES))
- continue;
-
- matcher_t::may_match_t match = matcher.may_match (info, match_glyph_data);
- if (match == matcher_t::MATCH_YES ||
- (match == matcher_t::MATCH_MAYBE &&
- skip == matcher_t::SKIP_NO))
- {
- num_items--;
- if (match_glyph_data) match_glyph_data++;
- return true;
- }
-
- if (skip == matcher_t::SKIP_NO)
+ switch (match (c->buffer->out_info[idx]))
{
- if (unsafe_from)
- *unsafe_from = hb_max (1u, idx) - 1u;
- return false;
+ case MATCH:
+ {
+ num_items--;
+ if (match_glyph_data) match_glyph_data++;
+ return true;
+ }
+ case NOT_MATCH:
+ {
+ if (unsafe_from)
+ *unsafe_from = hb_max (1u, idx) - 1u;
+ return false;
+ }
+ case SKIP:
+ continue;
}
}
if (unsafe_from)
--
2.25.1