[otlayout] Fix (Chain)Context recursion!
Previously we only supported recursive sublookups with
ascending indices. We were also not correctly handling
non-1-to-1 recursed lookups.
Fix all that!
Fixes the three tests in test/shaping/tests/context-matching.tests,
which were derived from NotoSansBengali and NotoSansDevanagari
among others.
diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index 54626db..b778abb 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -139,6 +139,19 @@
return true;
}
+bool
+hb_buffer_t::shift_forward (unsigned int count)
+{
+ assert (have_output);
+ if (unlikely (!ensure (len + count))) return false;
+
+ memmove (info + idx + count, info + idx, (len - idx) * sizeof (info[0]));
+ len += count;
+ idx += count;
+
+ return true;
+}
+
void *
hb_buffer_t::get_scratch_buffer (unsigned int *size)
{
@@ -345,6 +358,39 @@
out_len++;
}
+bool
+hb_buffer_t::move_to (unsigned int i)
+{
+ if (!have_output)
+ {
+ assert (i <= len);
+ idx = i;
+ }
+ else if (out_len < i)
+ {
+ unsigned int count = i - out_len;
+ if (unlikely (!make_room_for (count, count))) return false;
+
+ memmove (out_info + out_len, info + idx, count * sizeof (out_info[0]));
+ idx += count;
+ out_len += count;
+ }
+ else if (out_len > i)
+ {
+ /* Tricky part: rewinding... */
+ unsigned int count = out_len - i;
+
+ if (unlikely (idx < count && !shift_forward (count + 32))) return false;
+
+ assert (idx >= count);
+
+ idx -= count;
+ out_len -= count;
+ memmove (info + idx, out_info + out_len, count * sizeof (out_info[0]));
+ }
+ return true;
+}
+
void
hb_buffer_t::replace_glyph (hb_codepoint_t glyph_index)
{
