gfx/harfbuzz/src/hb-subset-repacker.cc

   1 /*
   2  * Copyright © 2022  Google, Inc.
   3  *
   4  *  This is part of HarfBuzz, a text shaping library.
   5  *
   6  * Permission is hereby granted, without written agreement and without
   7  * license or royalty fees, to use, copy, modify, and distribute this
   8  * software and its documentation for any purpose, provided that the
   9  * above copyright notice and the following two paragraphs appear in
  10  * all copies of this software.
  11  *
  12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  16  * DAMAGE.
  17  *
  18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  23  *
  24  */
  25 #include "hb-repacker.hh"
  26
  27 #ifdef HB_EXPERIMENTAL_API
  28
  29 /**
  30  * hb_subset_repack_or_fail:
  31  * @table_tag: tag of the table being packed, needed to allow table specific optimizations.
  32  * @hb_objects: raw array of struct hb_object_t, which provides
  33  * object graph info
  34  * @num_hb_objs: number of hb_object_t in the hb_objects array.
  35  *
  36  * Given the input object graph info, repack a table to eliminate
  37  * offset overflows. A nullptr is returned if the repacking attempt fails.
  38  * Table specific optimizations (eg. extension promotion in GSUB/GPOS) may be performed.
  39  * Passing HB_TAG_NONE will disable table specific optimizations.
  40  *
  41  * XSince: EXPERIMENTAL
  42  **/
  43 hb_blob_t* hb_subset_repack_or_fail (hb_tag_t table_tag,
  44                                      hb_object_t* hb_objects,
  45                                      unsigned num_hb_objs)
  46 {
  47   hb_vector_t<const hb_object_t *> packed;
  48   packed.alloc (num_hb_objs + 1);
  49   packed.push (nullptr);
  50   for (unsigned i = 0 ; i < num_hb_objs ; i++)
  51     packed.push (&(hb_objects[i]));
  52
  53   return hb_resolve_overflows (packed,
  54                                table_tag,
  55                                20,
  56                                true);
  57 }
  58 #endif