summaryrefslogtreecommitdiffstats
path: root/gfx/harfbuzz/src/hb-subset.cc
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--gfx/harfbuzz/src/hb-subset.cc639
1 files changed, 639 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-subset.cc b/gfx/harfbuzz/src/hb-subset.cc
new file mode 100644
index 0000000000..9c066e6d78
--- /dev/null
+++ b/gfx/harfbuzz/src/hb-subset.cc
@@ -0,0 +1,639 @@
+/*
+ * Copyright © 2018 Google, 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.
+ *
+ * Google Author(s): Garret Rieger, Rod Sheeter, Behdad Esfahbod
+ */
+
+#include "hb.hh"
+#include "hb-open-type.hh"
+
+#include "hb-subset.hh"
+
+#include "hb-open-file.hh"
+#include "hb-ot-cmap-table.hh"
+#include "hb-ot-glyf-table.hh"
+#include "hb-ot-hdmx-table.hh"
+#include "hb-ot-head-table.hh"
+#include "hb-ot-hhea-table.hh"
+#include "hb-ot-hmtx-table.hh"
+#include "hb-ot-maxp-table.hh"
+#include "OT/Color/CBDT/CBDT.hh"
+#include "OT/Color/COLR/COLR.hh"
+#include "OT/Color/CPAL/CPAL.hh"
+#include "OT/Color/sbix/sbix.hh"
+#include "hb-ot-os2-table.hh"
+#include "hb-ot-post-table.hh"
+#include "hb-ot-post-table-v2subset.hh"
+#include "hb-ot-cff1-table.hh"
+#include "hb-ot-cff2-table.hh"
+#include "hb-ot-vorg-table.hh"
+#include "hb-ot-name-table.hh"
+#include "hb-ot-layout-gsub-table.hh"
+#include "hb-ot-layout-gpos-table.hh"
+#include "hb-ot-var-cvar-table.hh"
+#include "hb-ot-var-fvar-table.hh"
+#include "hb-ot-var-gvar-table.hh"
+#include "hb-ot-var-hvar-table.hh"
+#include "hb-ot-math-table.hh"
+#include "hb-ot-stat-table.hh"
+#include "hb-repacker.hh"
+#include "hb-subset-accelerator.hh"
+
+using OT::Layout::GSUB;
+using OT::Layout::GPOS;
+
+/**
+ * SECTION:hb-subset
+ * @title: hb-subset
+ * @short_description: Subsets font files.
+ * @include: hb-subset.h
+ *
+ * Subsetting reduces the codepoint coverage of font files and removes all data
+ * that is no longer needed. A subset input describes the desired subset. The input is
+ * provided along with a font to the subsetting operation. Output is a new font file
+ * containing only the data specified in the input.
+ *
+ * Currently most outline and bitmap tables are supported: glyf, CFF, CFF2, sbix,
+ * COLR, and CBDT/CBLC. This also includes fonts with variable outlines via OpenType
+ * variations. Notably EBDT/EBLC and SVG are not supported. Layout subsetting is supported
+ * only for OpenType Layout tables (GSUB, GPOS, GDEF). Notably subsetting of graphite or AAT tables
+ * is not yet supported.
+ *
+ * Fonts with graphite or AAT tables may still be subsetted but will likely need to use the
+ * retain glyph ids option and configure the subset to pass through the layout tables untouched.
+ */
+
+
+hb_user_data_key_t _hb_subset_accelerator_user_data_key = {};
+
+
+/*
+ * The list of tables in the open type spec. Used to check for tables that may need handling
+ * if we are unable to list the tables in a face.
+ */
+static hb_tag_t known_tables[] {
+ HB_TAG ('a', 'v', 'a', 'r'),
+ HB_OT_TAG_BASE,
+ HB_OT_TAG_CBDT,
+ HB_OT_TAG_CBLC,
+ HB_OT_TAG_CFF1,
+ HB_OT_TAG_CFF2,
+ HB_OT_TAG_cmap,
+ HB_OT_TAG_COLR,
+ HB_OT_TAG_CPAL,
+ HB_TAG ('c', 'v', 'a', 'r'),
+ HB_TAG ('c', 'v', 't', ' '),
+ HB_TAG ('D', 'S', 'I', 'G'),
+ HB_TAG ('E', 'B', 'D', 'T'),
+ HB_TAG ('E', 'B', 'L', 'C'),
+ HB_TAG ('E', 'B', 'S', 'C'),
+ HB_TAG ('f', 'p', 'g', 'm'),
+ HB_TAG ('f', 'v', 'a', 'r'),
+ HB_TAG ('g', 'a', 's', 'p'),
+ HB_OT_TAG_GDEF,
+ HB_OT_TAG_glyf,
+ HB_OT_TAG_GPOS,
+ HB_OT_TAG_GSUB,
+ HB_OT_TAG_gvar,
+ HB_OT_TAG_hdmx,
+ HB_OT_TAG_head,
+ HB_OT_TAG_hhea,
+ HB_OT_TAG_hmtx,
+ HB_OT_TAG_HVAR,
+ HB_OT_TAG_JSTF,
+ HB_TAG ('k', 'e', 'r', 'n'),
+ HB_OT_TAG_loca,
+ HB_TAG ('L', 'T', 'S', 'H'),
+ HB_OT_TAG_MATH,
+ HB_OT_TAG_maxp,
+ HB_TAG ('M', 'E', 'R', 'G'),
+ HB_TAG ('m', 'e', 't', 'a'),
+ HB_TAG ('M', 'V', 'A', 'R'),
+ HB_TAG ('P', 'C', 'L', 'T'),
+ HB_OT_TAG_post,
+ HB_TAG ('p', 'r', 'e', 'p'),
+ HB_OT_TAG_sbix,
+ HB_TAG ('S', 'T', 'A', 'T'),
+ HB_TAG ('S', 'V', 'G', ' '),
+ HB_TAG ('V', 'D', 'M', 'X'),
+ HB_OT_TAG_vhea,
+ HB_OT_TAG_vmtx,
+ HB_OT_TAG_VORG,
+ HB_OT_TAG_VVAR,
+ HB_OT_TAG_name,
+ HB_OT_TAG_OS2
+};
+
+static bool _table_is_empty (const hb_face_t *face, hb_tag_t tag)
+{
+ hb_blob_t* blob = hb_face_reference_table (face, tag);
+ bool result = (blob == hb_blob_get_empty ());
+ hb_blob_destroy (blob);
+ return result;
+}
+
+static unsigned int
+_get_table_tags (const hb_subset_plan_t* plan,
+ unsigned int start_offset,
+ unsigned int *table_count, /* IN/OUT */
+ hb_tag_t *table_tags /* OUT */)
+{
+ unsigned num_tables = hb_face_get_table_tags (plan->source, 0, nullptr, nullptr);
+ if (num_tables)
+ return hb_face_get_table_tags (plan->source, start_offset, table_count, table_tags);
+
+ // If face has 0 tables associated with it, assume that it was built from
+ // hb_face_create_tables and thus is unable to list its tables. Fallback to
+ // checking each table type we can handle for existence instead.
+ auto it =
+ hb_concat (
+ + hb_array (known_tables)
+ | hb_filter ([&] (hb_tag_t tag) {
+ return !_table_is_empty (plan->source, tag) && !plan->no_subset_tables.has (tag);
+ })
+ | hb_map ([] (hb_tag_t tag) -> hb_tag_t { return tag; }),
+
+ plan->no_subset_tables.iter ()
+ | hb_filter([&] (hb_tag_t tag) {
+ return !_table_is_empty (plan->source, tag);
+ }));
+
+ it += start_offset;
+
+ unsigned num_written = 0;
+ while (bool (it) && num_written < *table_count)
+ table_tags[num_written++] = *it++;
+
+ *table_count = num_written;
+ return num_written;
+}
+
+
+static unsigned
+_plan_estimate_subset_table_size (hb_subset_plan_t *plan,
+ unsigned table_len,
+ bool same_size)
+{
+ unsigned src_glyphs = plan->source->get_num_glyphs ();
+ unsigned dst_glyphs = plan->glyphset ()->get_population ();
+
+ if (unlikely (!src_glyphs) || same_size)
+ return 512 + table_len;
+
+ return 512 + (unsigned) (table_len * sqrt ((double) dst_glyphs / src_glyphs));
+}
+
+/*
+ * Repack the serialization buffer if any offset overflows exist.
+ */
+static hb_blob_t*
+_repack (hb_tag_t tag, const hb_serialize_context_t& c)
+{
+ if (!c.offset_overflow ())
+ return c.copy_blob ();
+
+ hb_blob_t* result = hb_resolve_overflows (c.object_graph (), tag);
+
+ if (unlikely (!result))
+ {
+ DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c offset overflow resolution failed.",
+ HB_UNTAG (tag));
+ return nullptr;
+ }
+
+ return result;
+}
+
+template<typename TableType>
+static
+bool
+_try_subset (const TableType *table,
+ hb_vector_t<char>* buf,
+ hb_subset_context_t* c /* OUT */)
+{
+ c->serializer->start_serialize<TableType> ();
+ if (c->serializer->in_error ()) return false;
+
+ bool needed = table->subset (c);
+ if (!c->serializer->ran_out_of_room ())
+ {
+ c->serializer->end_serialize ();
+ return needed;
+ }
+
+ unsigned buf_size = buf->allocated;
+ buf_size = buf_size * 2 + 16;
+
+
+
+
+ DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c ran out of room; reallocating to %u bytes.",
+ HB_UNTAG (c->table_tag), buf_size);
+
+ if (unlikely (buf_size > c->source_blob->length * 16 ||
+ !buf->alloc (buf_size, true)))
+ {
+ DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c failed to reallocate %u bytes.",
+ HB_UNTAG (c->table_tag), buf_size);
+ return needed;
+ }
+
+ c->serializer->reset (buf->arrayZ, buf->allocated);
+ return _try_subset (table, buf, c);
+}
+
+template<typename TableType>
+static bool
+_subset (hb_subset_plan_t *plan, hb_vector_t<char> &buf)
+{
+ hb_blob_ptr_t<TableType> source_blob = plan->source_table<TableType> ();
+ const TableType *table = source_blob.get ();
+
+ hb_tag_t tag = TableType::tableTag;
+ if (!source_blob.get_blob()->data)
+ {
+ DEBUG_MSG (SUBSET, nullptr,
+ "OT::%c%c%c%c::subset sanitize failed on source table.", HB_UNTAG (tag));
+ source_blob.destroy ();
+ return false;
+ }
+
+ /* Tables that we want to allocate same space as the source table. For GSUB/GPOS it's
+ * because those are expensive to subset, so giving them more room is fine. */
+ bool same_size_table = TableType::tableTag == HB_OT_TAG_GSUB ||
+ TableType::tableTag == HB_OT_TAG_GPOS ||
+ TableType::tableTag == HB_OT_TAG_name;
+
+ unsigned buf_size = _plan_estimate_subset_table_size (plan, source_blob.get_length (), same_size_table);
+ DEBUG_MSG (SUBSET, nullptr,
+ "OT::%c%c%c%c initial estimated table size: %u bytes.", HB_UNTAG (tag), buf_size);
+ if (unlikely (!buf.alloc (buf_size)))
+ {
+ DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c failed to allocate %u bytes.", HB_UNTAG (tag), buf_size);
+ source_blob.destroy ();
+ return false;
+ }
+
+ bool needed = false;
+ hb_serialize_context_t serializer (buf.arrayZ, buf.allocated);
+ {
+ hb_subset_context_t c (source_blob.get_blob (), plan, &serializer, tag);
+ needed = _try_subset (table, &buf, &c);
+ }
+ source_blob.destroy ();
+
+ if (serializer.in_error () && !serializer.only_offset_overflow ())
+ {
+ DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c::subset FAILED!", HB_UNTAG (tag));
+ return false;
+ }
+
+ if (!needed)
+ {
+ DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c::subset table subsetted to empty.", HB_UNTAG (tag));
+ return true;
+ }
+
+ bool result = false;
+ hb_blob_t *dest_blob = _repack (tag, serializer);
+ if (dest_blob)
+ {
+ DEBUG_MSG (SUBSET, nullptr,
+ "OT::%c%c%c%c final subset table size: %u bytes.",
+ HB_UNTAG (tag), dest_blob->length);
+ result = plan->add_table (tag, dest_blob);
+ hb_blob_destroy (dest_blob);
+ }
+
+ DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c::subset %s",
+ HB_UNTAG (tag), result ? "success" : "FAILED!");
+ return result;
+}
+
+static bool
+_is_table_present (hb_face_t *source, hb_tag_t tag)
+{
+
+ if (!hb_face_get_table_tags (source, 0, nullptr, nullptr)) {
+ // If face has 0 tables associated with it, assume that it was built from
+ // hb_face_create_tables and thus is unable to list its tables. Fallback to
+ // checking if the blob associated with tag is empty.
+ return !_table_is_empty (source, tag);
+ }
+
+ hb_tag_t table_tags[32];
+ unsigned offset = 0, num_tables = ARRAY_LENGTH (table_tags);
+ while (((void) hb_face_get_table_tags (source, offset, &num_tables, table_tags), num_tables))
+ {
+ for (unsigned i = 0; i < num_tables; ++i)
+ if (table_tags[i] == tag)
+ return true;
+ offset += num_tables;
+ }
+ return false;
+}
+
+static bool
+_should_drop_table (hb_subset_plan_t *plan, hb_tag_t tag)
+{
+ if (plan->drop_tables.has (tag))
+ return true;
+
+ switch (tag)
+ {
+ case HB_TAG ('c','v','a','r'): /* hint table, fallthrough */
+ return plan->all_axes_pinned || (plan->flags & HB_SUBSET_FLAGS_NO_HINTING);
+
+ case HB_TAG ('c','v','t',' '): /* hint table, fallthrough */
+ case HB_TAG ('f','p','g','m'): /* hint table, fallthrough */
+ case HB_TAG ('p','r','e','p'): /* hint table, fallthrough */
+ case HB_TAG ('h','d','m','x'): /* hint table, fallthrough */
+ case HB_TAG ('V','D','M','X'): /* hint table, fallthrough */
+ return plan->flags & HB_SUBSET_FLAGS_NO_HINTING;
+
+#ifdef HB_NO_SUBSET_LAYOUT
+ // Drop Layout Tables if requested.
+ case HB_OT_TAG_GDEF:
+ case HB_OT_TAG_GPOS:
+ case HB_OT_TAG_GSUB:
+ case HB_TAG ('m','o','r','x'):
+ case HB_TAG ('m','o','r','t'):
+ case HB_TAG ('k','e','r','x'):
+ case HB_TAG ('k','e','r','n'):
+ return true;
+#endif
+
+ case HB_TAG ('a','v','a','r'):
+ case HB_TAG ('f','v','a','r'):
+ case HB_TAG ('g','v','a','r'):
+ case HB_OT_TAG_HVAR:
+ case HB_OT_TAG_VVAR:
+ case HB_TAG ('M','V','A','R'):
+ return plan->all_axes_pinned;
+
+ default:
+ return false;
+ }
+}
+
+static bool
+_passthrough (hb_subset_plan_t *plan, hb_tag_t tag)
+{
+ hb_blob_t *source_table = hb_face_reference_table (plan->source, tag);
+ bool result = plan->add_table (tag, source_table);
+ hb_blob_destroy (source_table);
+ return result;
+}
+
+static bool
+_dependencies_satisfied (hb_subset_plan_t *plan, hb_tag_t tag,
+ const hb_set_t &subsetted_tags,
+ const hb_set_t &pending_subset_tags)
+{
+ switch (tag)
+ {
+ case HB_OT_TAG_hmtx:
+ case HB_OT_TAG_vmtx:
+ case HB_OT_TAG_maxp:
+ return !plan->normalized_coords || !pending_subset_tags.has (HB_OT_TAG_glyf);
+ default:
+ return true;
+ }
+}
+
+static bool
+_subset_table (hb_subset_plan_t *plan,
+ hb_vector_t<char> &buf,
+ hb_tag_t tag)
+{
+ if (plan->no_subset_tables.has (tag)) {
+ return _passthrough (plan, tag);
+ }
+
+ DEBUG_MSG (SUBSET, nullptr, "subset %c%c%c%c", HB_UNTAG (tag));
+ switch (tag)
+ {
+ case HB_OT_TAG_glyf: return _subset<const OT::glyf> (plan, buf);
+ case HB_OT_TAG_hdmx: return _subset<const OT::hdmx> (plan, buf);
+ case HB_OT_TAG_name: return _subset<const OT::name> (plan, buf);
+ case HB_OT_TAG_head:
+ if (_is_table_present (plan->source, HB_OT_TAG_glyf) && !_should_drop_table (plan, HB_OT_TAG_glyf))
+ return true; /* skip head, handled by glyf */
+ return _subset<const OT::head> (plan, buf);
+ case HB_OT_TAG_hhea: return true; /* skip hhea, handled by hmtx */
+ case HB_OT_TAG_hmtx: return _subset<const OT::hmtx> (plan, buf);
+ case HB_OT_TAG_vhea: return true; /* skip vhea, handled by vmtx */
+ case HB_OT_TAG_vmtx: return _subset<const OT::vmtx> (plan, buf);
+ case HB_OT_TAG_maxp: return _subset<const OT::maxp> (plan, buf);
+ case HB_OT_TAG_sbix: return _subset<const OT::sbix> (plan, buf);
+ case HB_OT_TAG_loca: return true; /* skip loca, handled by glyf */
+ case HB_OT_TAG_cmap: return _subset<const OT::cmap> (plan, buf);
+ case HB_OT_TAG_OS2 : return _subset<const OT::OS2 > (plan, buf);
+ case HB_OT_TAG_post: return _subset<const OT::post> (plan, buf);
+ case HB_OT_TAG_COLR: return _subset<const OT::COLR> (plan, buf);
+ case HB_OT_TAG_CPAL: return _subset<const OT::CPAL> (plan, buf);
+ case HB_OT_TAG_CBLC: return _subset<const OT::CBLC> (plan, buf);
+ case HB_OT_TAG_CBDT: return true; /* skip CBDT, handled by CBLC */
+ case HB_OT_TAG_MATH: return _subset<const OT::MATH> (plan, buf);
+
+#ifndef HB_NO_SUBSET_CFF
+ case HB_OT_TAG_CFF1: return _subset<const OT::cff1> (plan, buf);
+ case HB_OT_TAG_CFF2: return _subset<const OT::cff2> (plan, buf);
+ case HB_OT_TAG_VORG: return _subset<const OT::VORG> (plan, buf);
+#endif
+
+#ifndef HB_NO_SUBSET_LAYOUT
+ case HB_OT_TAG_GDEF: return _subset<const OT::GDEF> (plan, buf);
+ case HB_OT_TAG_GSUB: return _subset<const GSUB> (plan, buf);
+ case HB_OT_TAG_GPOS: return _subset<const GPOS> (plan, buf);
+ case HB_OT_TAG_gvar: return _subset<const OT::gvar> (plan, buf);
+ case HB_OT_TAG_HVAR: return _subset<const OT::HVAR> (plan, buf);
+ case HB_OT_TAG_VVAR: return _subset<const OT::VVAR> (plan, buf);
+#endif
+ case HB_OT_TAG_fvar:
+ if (plan->user_axes_location.is_empty ()) return _passthrough (plan, tag);
+ return _subset<const OT::fvar> (plan, buf);
+ case HB_OT_TAG_STAT:
+ /*TODO(qxliu): change the condition as we support more complex
+ * instancing operation*/
+ if (plan->all_axes_pinned) return _subset<const OT::STAT> (plan, buf);
+ else return _passthrough (plan, tag);
+
+ case HB_TAG ('c', 'v', 't', ' '):
+#ifndef HB_NO_VAR
+ if (_is_table_present (plan->source, HB_OT_TAG_cvar) &&
+ plan->normalized_coords && !plan->pinned_at_default)
+ {
+ auto &cvar = *plan->source->table.cvar;
+ return OT::cvar::add_cvt_and_apply_deltas (plan, cvar.get_tuple_var_data (), &cvar);
+ }
+#endif
+ return _passthrough (plan, tag);
+ default:
+ if (plan->flags & HB_SUBSET_FLAGS_PASSTHROUGH_UNRECOGNIZED)
+ return _passthrough (plan, tag);
+
+ // Drop table
+ return true;
+ }
+}
+
+static void _attach_accelerator_data (hb_subset_plan_t* plan,
+ hb_face_t* face /* IN/OUT */)
+{
+ if (!plan->inprogress_accelerator) return;
+
+ // Transfer the accelerator from the plan to us.
+ hb_subset_accelerator_t* accel = plan->inprogress_accelerator;
+ plan->inprogress_accelerator = nullptr;
+
+ if (accel->in_error ())
+ {
+ hb_subset_accelerator_t::destroy (accel);
+ return;
+ }
+
+ // Populate caches that need access to the final tables.
+ hb_blob_ptr_t<OT::cmap> cmap_ptr (hb_sanitize_context_t ().reference_table<OT::cmap> (face));
+ accel->cmap_cache = OT::cmap::create_filled_cache (cmap_ptr);
+ accel->destroy_cmap_cache = OT::SubtableUnicodesCache::destroy;
+
+ if (!hb_face_set_user_data(face,
+ hb_subset_accelerator_t::user_data_key(),
+ accel,
+ hb_subset_accelerator_t::destroy,
+ true))
+ hb_subset_accelerator_t::destroy (accel);
+}
+
+/**
+ * hb_subset_or_fail:
+ * @source: font face data to be subset.
+ * @input: input to use for the subsetting.
+ *
+ * Subsets a font according to provided input. Returns nullptr
+ * if the subset operation fails.
+ *
+ * Since: 2.9.0
+ **/
+hb_face_t *
+hb_subset_or_fail (hb_face_t *source, const hb_subset_input_t *input)
+{
+ if (unlikely (!input || !source)) return hb_face_get_empty ();
+
+ hb_subset_plan_t *plan = hb_subset_plan_create_or_fail (source, input);
+ if (unlikely (!plan)) {
+ return nullptr;
+ }
+
+ hb_face_t * result = hb_subset_plan_execute_or_fail (plan);
+ hb_subset_plan_destroy (plan);
+ return result;
+}
+
+
+/**
+ * hb_subset_plan_execute_or_fail:
+ * @plan: a subsetting plan.
+ *
+ * Executes the provided subsetting @plan.
+ *
+ * Return value:
+ * on success returns a reference to generated font subset. If the subsetting operation fails
+ * returns nullptr.
+ *
+ * Since: 4.0.0
+ **/
+hb_face_t *
+hb_subset_plan_execute_or_fail (hb_subset_plan_t *plan)
+{
+ if (unlikely (!plan || plan->in_error ())) {
+ return nullptr;
+ }
+
+ hb_tag_t table_tags[32];
+ unsigned offset = 0, num_tables = ARRAY_LENGTH (table_tags);
+
+ hb_set_t subsetted_tags, pending_subset_tags;
+ while (((void) _get_table_tags (plan, offset, &num_tables, table_tags), num_tables))
+ {
+ for (unsigned i = 0; i < num_tables; ++i)
+ {
+ hb_tag_t tag = table_tags[i];
+ if (_should_drop_table (plan, tag)) continue;
+ pending_subset_tags.add (tag);
+ }
+
+ offset += num_tables;
+ }
+
+ hb_vector_t<char> buf;
+ buf.alloc (4096 - 16);
+
+
+ bool success = true;
+
+ while (!pending_subset_tags.is_empty ())
+ {
+ if (subsetted_tags.in_error ()
+ || pending_subset_tags.in_error ()) {
+ success = false;
+ goto end;
+ }
+
+ bool made_changes = false;
+ for (hb_tag_t tag : pending_subset_tags)
+ {
+ if (!_dependencies_satisfied (plan, tag,
+ subsetted_tags,
+ pending_subset_tags))
+ {
+ // delayed subsetting for some tables since they might have dependency on other tables
+ // in some cases: e.g: during instantiating glyf tables, hmetrics/vmetrics are updated
+ // and saved in subset plan, hmtx/vmtx subsetting need to use these updated metrics values
+ continue;
+ }
+
+ pending_subset_tags.del (tag);
+ subsetted_tags.add (tag);
+ made_changes = true;
+
+ success = _subset_table (plan, buf, tag);
+ if (unlikely (!success)) goto end;
+ }
+
+ if (!made_changes)
+ {
+ DEBUG_MSG (SUBSET, nullptr, "Table dependencies unable to be satisfied. Subset failed.");
+ success = false;
+ goto end;
+ }
+ }
+
+ if (success && plan->attach_accelerator_data) {
+ _attach_accelerator_data (plan, plan->dest);
+ }
+
+end:
+ return success ? hb_face_reference (plan->dest) : nullptr;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-09 09:21:00 +0000