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diff --git a/gfx/harfbuzz/src/hb-subset-cff-common.cc b/gfx/harfbuzz/src/hb-subset-cff-common.cc
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+/*
+ * Copyright © 2018 Adobe Inc.
+ *
+ * This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Adobe Author(s): Michiharu Ariza
+ */
+
+#include "hb.hh"
+
+#ifndef HB_NO_SUBSET_CFF
+
+#include "hb-ot-cff-common.hh"
+#include "hb-ot-cff2-table.hh"
+#include "hb-subset-cff-common.hh"
+
+/* Disable FDSelect format 0 for compatibility with fonttools which doesn't seem choose it.
+ * Rarely any/much smaller than format 3 anyway. */
+#define CFF_SERIALIZE_FDSELECT_0 0
+
+using namespace CFF;
+
+
+/* Determine an optimal FDSelect format according to a provided plan.
+ *
+ * Return value: FDSelect format, size, and ranges for the most compact subset FDSelect
+ * along with a font index remapping table
+ */
+
+bool
+hb_plan_subset_cff_fdselect (const hb_subset_plan_t *plan,
+ unsigned int fdCount,
+ const FDSelect &src, /* IN */
+ unsigned int &subset_fd_count /* OUT */,
+ unsigned int &subset_fdselect_size /* OUT */,
+ unsigned int &subset_fdselect_format /* OUT */,
+ hb_vector_t<code_pair_t> &fdselect_ranges /* OUT */,
+ hb_inc_bimap_t &fdmap /* OUT */)
+{
+ subset_fd_count = 0;
+ subset_fdselect_size = 0;
+ subset_fdselect_format = 0;
+ unsigned int num_ranges = 0;
+
+ unsigned int subset_num_glyphs = plan->num_output_glyphs ();
+ if (subset_num_glyphs == 0)
+ return true;
+
+ {
+ /* use hb_set to determine the subset of font dicts */
+ hb_set_t set;
+ hb_codepoint_t prev_fd = CFF_UNDEF_CODE;
+ hb_pair_t<unsigned, hb_codepoint_t> last_range {0, 0};
+ auto it = hb_iter (plan->new_to_old_gid_list);
+ auto _ = *it;
+ for (hb_codepoint_t gid = 0; gid < subset_num_glyphs; gid++)
+ {
+ hb_codepoint_t old_glyph;
+ if (gid == _.first)
+ {
+ old_glyph = _.second;
+ _ = *++it;
+ }
+ else
+ {
+ /* fonttools retains FDSelect & font dicts for missing glyphs. do the same */
+ old_glyph = gid;
+ }
+ if (old_glyph >= last_range.second)
+ last_range = src.get_fd_range (old_glyph);
+ unsigned fd = last_range.first;
+
+ if (fd != prev_fd)
+ {
+ set.add (fd);
+ num_ranges++;
+ prev_fd = fd;
+ fdselect_ranges.push (code_pair_t { fd, gid });
+
+ if (gid == old_glyph)
+ gid = hb_min (_.first - 1, last_range.second - 1);
+ }
+ }
+
+ subset_fd_count = set.get_population ();
+ if (subset_fd_count == fdCount)
+ {
+ /* all font dicts belong to the subset. no need to subset FDSelect & FDArray */
+ fdmap.identity (fdCount);
+ }
+ else
+ {
+ /* create a fdmap */
+ fdmap.reset ();
+
+ hb_codepoint_t fd = CFF_UNDEF_CODE;
+ while (set.next (&fd))
+ fdmap.add (fd);
+ if (unlikely (fdmap.get_population () != subset_fd_count))
+ return false;
+ }
+
+ /* update each font dict index stored as "code" in fdselect_ranges */
+ for (unsigned int i = 0; i < fdselect_ranges.length; i++)
+ fdselect_ranges[i].code = fdmap[fdselect_ranges[i].code];
+ }
+
+ /* determine which FDSelect format is most compact */
+ if (subset_fd_count > 0xFF)
+ {
+ if (unlikely (src.format != 4))
+ return false;
+ subset_fdselect_format = 4;
+ subset_fdselect_size = FDSelect::min_size + FDSelect4::min_size + FDSelect4_Range::static_size * num_ranges + HBUINT32::static_size;
+ }
+ else
+ {
+#if CFF_SERIALIZE_FDSELECT_0
+ unsigned int format0_size = FDSelect::min_size + FDSelect0::min_size + HBUINT8::static_size * subset_num_glyphs;
+#endif
+ unsigned int format3_size = FDSelect::min_size + FDSelect3::min_size + FDSelect3_Range::static_size * num_ranges + HBUINT16::static_size;
+
+#if CFF_SERIALIZE_FDSELECT_0
+ if (format0_size <= format3_size)
+ {
+ // subset_fdselect_format = 0;
+ subset_fdselect_size = format0_size;
+ }
+ else
+#endif
+ {
+ subset_fdselect_format = 3;
+ subset_fdselect_size = format3_size;
+ }
+ }
+
+ return true;
+}
+
+template <typename FDSELECT3_4>
+static inline bool
+serialize_fdselect_3_4 (hb_serialize_context_t *c,
+ const unsigned int num_glyphs,
+ const FDSelect &src,
+ unsigned int size,
+ const hb_vector_t<code_pair_t> &fdselect_ranges)
+{
+ TRACE_SERIALIZE (this);
+ FDSELECT3_4 *p = c->allocate_size<FDSELECT3_4> (size);
+ if (unlikely (!p)) return_trace (false);
+ p->nRanges () = fdselect_ranges.length;
+ for (unsigned int i = 0; i < fdselect_ranges.length; i++)
+ {
+ p->ranges[i].first = fdselect_ranges[i].glyph;
+ p->ranges[i].fd = fdselect_ranges[i].code;
+ }
+ p->sentinel () = num_glyphs;
+ return_trace (true);
+}
+
+/* Serialize a subset FDSelect format planned above. */
+bool
+hb_serialize_cff_fdselect (hb_serialize_context_t *c,
+ const unsigned int num_glyphs,
+ const FDSelect &src,
+ unsigned int fd_count,
+ unsigned int fdselect_format,
+ unsigned int size,
+ const hb_vector_t<code_pair_t> &fdselect_ranges)
+{
+ TRACE_SERIALIZE (this);
+ FDSelect *p = c->allocate_min<FDSelect> ();
+ if (unlikely (!p)) return_trace (false);
+ p->format = fdselect_format;
+ size -= FDSelect::min_size;
+
+ switch (fdselect_format)
+ {
+#if CFF_SERIALIZE_FDSELECT_0
+ case 0:
+ {
+ FDSelect0 *p = c->allocate_size<FDSelect0> (size);
+ if (unlikely (!p)) return_trace (false);
+ unsigned int range_index = 0;
+ unsigned int fd = fdselect_ranges[range_index++].code;
+ for (unsigned int i = 0; i < num_glyphs; i++)
+ {
+ if ((range_index < fdselect_ranges.len) &&
+ (i >= fdselect_ranges[range_index].glyph))
+ {
+ fd = fdselect_ranges[range_index++].code;
+ }
+ p->fds[i] = fd;
+ }
+ return_trace (true);
+ }
+#endif /* CFF_SERIALIZE_FDSELECT_0 */
+
+ case 3:
+ return serialize_fdselect_3_4<FDSelect3> (c, num_glyphs, src,
+ size, fdselect_ranges);
+
+ case 4:
+ return serialize_fdselect_3_4<FDSelect4> (c, num_glyphs, src,
+ size, fdselect_ranges);
+
+ default:
+ return_trace (false);
+ }
+}
+
+
+#endif