Push subsetter code upstream

third_party/sfntly/src/subsetter/subsetter_impl.cc

-/*
- * Copyright 2011 Google Inc. All Rights Reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "third_party/sfntly/src/subsetter/subsetter_impl.h"
-
-#include <string.h>
-
-#include <algorithm>
-#include <iterator>
-#include <map>
-#include <set>
-
-#include "third_party/sfntly/src/sfntly/table/bitmap/eblc_table.h"
-#include "third_party/sfntly/src/sfntly/table/bitmap/ebdt_table.h"
-#include "third_party/sfntly/src/sfntly/table/bitmap/index_sub_table.h"
-#include "third_party/sfntly/src/sfntly/table/bitmap/index_sub_table_format1.h"
-#include "third_party/sfntly/src/sfntly/table/bitmap/index_sub_table_format2.h"
-#include "third_party/sfntly/src/sfntly/table/bitmap/index_sub_table_format3.h"
-#include "third_party/sfntly/src/sfntly/table/bitmap/index_sub_table_format4.h"
-#include "third_party/sfntly/src/sfntly/table/bitmap/index_sub_table_format5.h"
-#include "third_party/sfntly/src/sfntly/table/core/name_table.h"
-#include "third_party/sfntly/src/sfntly/tag.h"
-#include "third_party/sfntly/src/sfntly/data/memory_byte_array.h"
-#include "third_party/sfntly/src/sfntly/port/memory_input_stream.h"
-#include "third_party/sfntly/src/sfntly/port/memory_output_stream.h"
-
-#if defined U_USING_ICU_NAMESPACE
-  U_NAMESPACE_USE
-#endif
-
-namespace {
-
-using namespace sfntly;
-
-// The bitmap tables must be greater than 16KB to trigger bitmap subsetter.
-static const int BITMAP_SIZE_THRESHOLD = 16384;
-
-void ConstructName(UChar* name_part, UnicodeString* name, int32_t name_id) {
-  switch (name_id) {
-    case NameId::kFullFontName:
-      *name = name_part;
-      break;
-    case NameId::kFontFamilyName:
-    case NameId::kPreferredFamily:
-    case NameId::kWWSFamilyName: {
-      UnicodeString original = *name;
-      *name = name_part;
-      *name += original;
-      break;
-    }
-    case NameId::kFontSubfamilyName:
-    case NameId::kPreferredSubfamily:
-    case NameId::kWWSSubfamilyName:
-      *name += name_part;
-      break;
-    default:
-      // This name part is not used to construct font name (e.g. copyright).
-      // Simply ignore it.
-      break;
-  }
-}
-
-int32_t HashCode(int32_t platform_id, int32_t encoding_id, int32_t language_id,
-                 int32_t name_id) {
-  int32_t result = platform_id << 24 | encoding_id << 16 | language_id << 8;
-  if (name_id == NameId::kFullFontName) {
-    result |= 0xff;
-  } else if (name_id == NameId::kPreferredFamily ||
-             name_id == NameId::kPreferredSubfamily) {
-    result |= 0xf;
-  } else if (name_id == NameId::kWWSFamilyName ||
-             name_id == NameId::kWWSSubfamilyName) {
-    result |= 1;
-  }
-  return result;
-}
-
-bool HasName(const char* font_name, Font* font) {
-  UnicodeString font_string = UnicodeString::fromUTF8(font_name);
-  if (font_string.isEmpty())
-    return false;
-  UnicodeString regular_suffix = UnicodeString::fromUTF8(" Regular");
-  UnicodeString alt_font_string = font_string;
-  alt_font_string += regular_suffix;
-
-  typedef std::map<int32_t, UnicodeString> NameMap;
-  NameMap names;
-  NameTablePtr name_table = down_cast<NameTable*>(font->GetTable(Tag::name));
-  if (name_table == NULL) {
-    return false;
-  }
-
-  for (int32_t i = 0; i < name_table->NameCount(); ++i) {
-    switch (name_table->NameId(i)) {
-      case NameId::kFontFamilyName:
-      case NameId::kFontSubfamilyName:
-      case NameId::kFullFontName:
-      case NameId::kPreferredFamily:
-      case NameId::kPreferredSubfamily:
-      case NameId::kWWSFamilyName:
-      case NameId::kWWSSubfamilyName: {
-        int32_t hash_code = HashCode(name_table->PlatformId(i),
-                                     name_table->EncodingId(i),
-                                     name_table->LanguageId(i),
-                                     name_table->NameId(i));
-        UChar* name_part = name_table->Name(i);
-        ConstructName(name_part, &(names[hash_code]), name_table->NameId(i));
-        delete[] name_part;
-        break;
-      }
-      default:
-        break;
-    }
-  }
-
-  if (!names.empty()) {
-    for (NameMap::iterator i = names.begin(), e = names.end(); i != e; ++i) {
-      if (i->second.caseCompare(font_string, 0) == 0 ||
-          i->second.caseCompare(alt_font_string, 0) == 0) {
-        return true;
-      }
-    }
-  }
-  return false;
-}
-
-Font* FindFont(const char* font_name, const FontArray& font_array) {
-  if (font_array.empty() || font_array[0] == NULL) {
-    return NULL;
-  }
-
-  if (font_name && strlen(font_name)) {
-    for (FontArray::const_iterator i = font_array.begin(), e = font_array.end();
-         i != e; ++i) {
-      if (HasName(font_name, i->p_)) {
-        return i->p_;
-      }
-    }
-  }
-
-  return font_array[0].p_;
-}
-
-bool ResolveCompositeGlyphs(GlyphTable* glyph_table,
-                            LocaTable* loca_table,
-                            const unsigned int* glyph_ids,
-                            size_t glyph_count,
-                            IntegerSet* glyph_id_processed) {
-  if (glyph_table == NULL || loca_table == NULL ||
-      glyph_ids == NULL || glyph_count == 0 || glyph_id_processed == NULL) {
-    return false;
-  }
-
-  // Sort and uniquify glyph ids.
-  IntegerSet glyph_id_remaining;
-  glyph_id_remaining.insert(0);  // Always include glyph id 0.
-  for (size_t i = 0; i < glyph_count; ++i) {
-    glyph_id_remaining.insert(glyph_ids[i]);
-  }
-
-  // Identify if any given glyph id maps to a composite glyph.  If so, include
-  // the glyphs referenced by that composite glyph.
-  while (!glyph_id_remaining.empty()) {
-    IntegerSet comp_glyph_id;
-    for (IntegerSet::iterator i = glyph_id_remaining.begin(),
-                              e = glyph_id_remaining.end(); i != e; ++i) {
-      if (*i < 0 || *i >= loca_table->num_glyphs()) {
-        // Invalid glyph id, ignore.
-        continue;
-      }
-
-      int32_t length = loca_table->GlyphLength(*i);
-      if (length == 0) {
-        // Empty glyph, ignore.
-        continue;
-      }
-      int32_t offset = loca_table->GlyphOffset(*i);
-
-      GlyphPtr glyph;
-      glyph.Attach(glyph_table->GetGlyph(offset, length));
-      if (glyph == NULL) {
-        // Error finding glyph, ignore.
-        continue;
-      }
-
-      if (glyph->GlyphType() == GlyphType::kComposite) {
-        Ptr<GlyphTable::CompositeGlyph> comp_glyph =
-            down_cast<GlyphTable::CompositeGlyph*>(glyph.p_);
-        for (int32_t j = 0; j < comp_glyph->NumGlyphs(); ++j) {
-          int32_t glyph_id = comp_glyph->GlyphIndex(j);
-          if (glyph_id_processed->find(glyph_id) == glyph_id_processed->end() &&
-              glyph_id_remaining.find(glyph_id) == glyph_id_remaining.end()) {
-            comp_glyph_id.insert(comp_glyph->GlyphIndex(j));
-          }
-        }
-      }
-
-      glyph_id_processed->insert(*i);
-    }
-
-    glyph_id_remaining.clear();
-    glyph_id_remaining = comp_glyph_id;
-  }
-
-  return true;
-}
-
-bool SetupGlyfBuilders(Font::Builder* font_builder,
-                       GlyphTable* glyph_table,
-                       LocaTable* loca_table,
-                       const IntegerSet& glyph_ids) {
-  if (!font_builder || !glyph_table || !loca_table) {
-    return false;
-  }
-
-  GlyphTableBuilderPtr glyph_table_builder =
-      down_cast<GlyphTable::Builder*>(font_builder->NewTableBuilder(Tag::glyf));
-  LocaTableBuilderPtr loca_table_builder =
-      down_cast<LocaTable::Builder*>(font_builder->NewTableBuilder(Tag::loca));
-  if (glyph_table_builder == NULL || loca_table_builder == NULL) {
-    // Out of memory.
-    return false;
-  }
-
-  // Extract glyphs and setup loca list.
-  IntegerList loca_list;
-  loca_list.resize(loca_table->num_glyphs());
-  loca_list.push_back(0);
-  int32_t last_glyph_id = 0;
-  int32_t last_offset = 0;
-  GlyphTable::GlyphBuilderList* glyph_builders =
-      glyph_table_builder->GlyphBuilders();
-  for (IntegerSet::const_iterator i = glyph_ids.begin(), e = glyph_ids.end();
-                                  i != e; ++i) {
-    int32_t length = loca_table->GlyphLength(*i);
-    int32_t offset = loca_table->GlyphOffset(*i);
-
-    GlyphPtr glyph;
-    glyph.Attach(glyph_table->GetGlyph(offset, length));
-
-    // Add glyph to new glyf table.
-    ReadableFontDataPtr data = glyph->ReadFontData();
-    WritableFontDataPtr copy_data;
-    copy_data.Attach(WritableFontData::CreateWritableFontData(data->Length()));
-    data->CopyTo(copy_data);
-    GlyphBuilderPtr glyph_builder;
-    glyph_builder.Attach(glyph_table_builder->GlyphBuilder(copy_data));
-    glyph_builders->push_back(glyph_builder);
-
-    // Configure loca list.
-    for (int32_t j = last_glyph_id + 1; j <= *i; ++j) {
-      loca_list[j] = last_offset;
-    }
-    last_offset += length;
-    loca_list[*i + 1] = last_offset;
-    last_glyph_id = *i;
-  }
-  for (int32_t j = last_glyph_id + 1; j <= loca_table->num_glyphs(); ++j) {
-    loca_list[j] = last_offset;
-  }
-  loca_table_builder->SetLocaList(&loca_list);
-
-  return true;
-}
-
-bool HasOverlap(int32_t range_begin, int32_t range_end,
-                const IntegerSet& glyph_ids) {
-  if (range_begin == range_end) {
-    return glyph_ids.find(range_begin) != glyph_ids.end();
-  } else if (range_end > range_begin) {
-    IntegerSet::const_iterator left = glyph_ids.lower_bound(range_begin);
-    IntegerSet::const_iterator right = glyph_ids.lower_bound(range_end);
-    return right != left;
-  }
-  return false;
-}
-
-// Initialize builder, returns false if glyph_id subset is not covered.
-// Not thread-safe, caller to ensure object life-time.
-bool InitializeBitmapBuilder(EbdtTable::Builder* ebdt, EblcTable::Builder* eblc,
-                             const IntegerSet& glyph_ids) {
-  BitmapLocaList loca_list;
-  BitmapSizeTableBuilderList* strikes = eblc->BitmapSizeBuilders();
-
-  // Note: Do not call eblc_builder->GenerateLocaList(&loca_list) and then
-  //       ebdt_builder->SetLoca(loca_list).  For fonts like SimSun, there are
-  //       >28K glyphs inside, where a typical usage will be <1K glyphs.  Doing
-  //       the calls improperly will result in creation of >100K objects that
-  //       will be destroyed immediately, inducing significant slowness.
-  IntegerList removed_strikes;
-  for (size_t i = 0; i < strikes->size(); i++) {
-    if (!HasOverlap((*strikes)[i]->StartGlyphIndex(),
-                    (*strikes)[i]->EndGlyphIndex(), glyph_ids)) {
-      removed_strikes.push_back(i);
-      continue;
-    }
-
-    IndexSubTableBuilderList* index_builders =
-        (*strikes)[i]->IndexSubTableBuilders();
-    IntegerList removed_indexes;
-    BitmapGlyphInfoMap info_map;
-    for (size_t j = 0; j < index_builders->size(); ++j) {
-      int32_t first_glyph_id = (*index_builders)[j]->first_glyph_index();
-      int32_t last_glyph_id = (*index_builders)[j]->last_glyph_index();
-      if (!HasOverlap(first_glyph_id, last_glyph_id, glyph_ids)) {
-        removed_indexes.push_back(j);
-        continue;
-      }
-      for (IntegerSet::const_iterator gid = glyph_ids.begin(),
-                                      gid_end = glyph_ids.end();
-                                      gid != gid_end; gid++) {
-        if (*gid < first_glyph_id) {
-          continue;
-        }
-        if (*gid > last_glyph_id) {
-          break;
-        }
-        BitmapGlyphInfoPtr info;
-        info.Attach((*index_builders)[j]->GlyphInfo(*gid));
-        if (info && info->length()) {  // Do not include gid without bitmap
-          info_map[*gid] = info;
-        }
-      }
-    }
-    if (!info_map.empty()) {
-      loca_list.push_back(info_map);
-    } else {
-      removed_strikes.push_back(i);  // Detected null entries.
-    }
-
-    // Remove unused index sub tables
-    for (IntegerList::reverse_iterator j = removed_indexes.rbegin(),
-                                       e = removed_indexes.rend();
-                                       j != e; j++) {
-      index_builders->erase(index_builders->begin() + *j);
-    }
-  }
-  if (removed_strikes.size() == strikes->size() || loca_list.empty()) {
-    return false;
-  }
-
-  for (IntegerList::reverse_iterator i = removed_strikes.rbegin(),
-                                     e = removed_strikes.rend(); i != e; i++) {
-    strikes->erase(strikes->begin() + *i);
-  }
-
-  if (strikes->empty()) {  // no glyph covered, can safely drop the builders.
-    return false;
-  }
-
-  ebdt->SetLoca(&loca_list);
-  ebdt->GlyphBuilders();  // Initialize the builder.
-  return true;
-}
-
-void CopyBigGlyphMetrics(BigGlyphMetrics::Builder* source,
-                         BigGlyphMetrics::Builder* target) {
-  target->SetHeight(static_cast<byte_t>(source->Height()));
-  target->SetWidth(static_cast<byte_t>(source->Width()));
-  target->SetHoriBearingX(static_cast<byte_t>(source->HoriBearingX()));
-  target->SetHoriBearingY(static_cast<byte_t>(source->HoriBearingY()));
-  target->SetHoriAdvance(static_cast<byte_t>(source->HoriAdvance()));
-  target->SetVertBearingX(static_cast<byte_t>(source->VertBearingX()));
-  target->SetVertBearingY(static_cast<byte_t>(source->VertBearingY()));
-  target->SetVertAdvance(static_cast<byte_t>(source->VertAdvance()));
-}
-
-CALLER_ATTACH IndexSubTable::Builder*
-ConstructIndexFormat4(IndexSubTable::Builder* b, const BitmapGlyphInfoMap& loca,
-                      int32_t* image_data_offset) {
-  IndexSubTableFormat4BuilderPtr builder4;
-  builder4.Attach(IndexSubTableFormat4::Builder::CreateBuilder());
-  CodeOffsetPairBuilderList offset_pairs;
-
-  size_t offset = 0;
-  int32_t lower_bound = b->first_glyph_index();
-  int32_t upper_bound = b->last_glyph_index();
-  int32_t last_gid = -1;
-  BitmapGlyphInfoMap::const_iterator i = loca.lower_bound(lower_bound);
-  BitmapGlyphInfoMap::const_iterator end = loca.end();
-  if (i != end) {
-    last_gid = i->first;
-    builder4->set_first_glyph_index(last_gid);
-    builder4->set_image_format(b->image_format());
-    builder4->set_image_data_offset(*image_data_offset);
-  }
-  for (; i != end; i++) {
-    int32_t gid = i->first;
-    if (gid > upper_bound) {
-      break;
-    }
-    offset_pairs.push_back(
-        IndexSubTableFormat4::CodeOffsetPairBuilder(gid, offset));
-    offset += i->second->length();
-    last_gid = gid;
-  }
-  offset_pairs.push_back(
-      IndexSubTableFormat4::CodeOffsetPairBuilder(-1, offset));
-  builder4->set_last_glyph_index(last_gid);
-  *image_data_offset += offset;
-  builder4->SetOffsetArray(offset_pairs);
-
-  return builder4.Detach();
-}
-
-CALLER_ATTACH IndexSubTable::Builder*
-ConstructIndexFormat5(IndexSubTable::Builder* b, const BitmapGlyphInfoMap& loca,
-                      int32_t* image_data_offset) {
-  IndexSubTableFormat5BuilderPtr new_builder;
-  new_builder.Attach(IndexSubTableFormat5::Builder::CreateBuilder());
-
-  // Copy BigMetrics
-  int32_t image_size = 0;
-  if (b->index_format() == IndexSubTable::Format::FORMAT_2) {
-    IndexSubTableFormat2BuilderPtr builder2 =
-      down_cast<IndexSubTableFormat2::Builder*>(b);
-    CopyBigGlyphMetrics(builder2->BigMetrics(), new_builder->BigMetrics());
-    image_size = builder2->ImageSize();
-  } else {
-    IndexSubTableFormat5BuilderPtr builder5 =
-      down_cast<IndexSubTableFormat5::Builder*>(b);
-    BigGlyphMetricsBuilderPtr metrics_builder;
-    CopyBigGlyphMetrics(builder5->BigMetrics(), new_builder->BigMetrics());
-    image_size = builder5->ImageSize();
-  }
-
-  IntegerList* glyph_array = new_builder->GlyphArray();
-  size_t offset = 0;
-  int32_t lower_bound = b->first_glyph_index();
-  int32_t upper_bound = b->last_glyph_index();
-  int32_t last_gid = -1;
-  BitmapGlyphInfoMap::const_iterator i = loca.lower_bound(lower_bound);
-  BitmapGlyphInfoMap::const_iterator end = loca.end();
-  if (i != end) {
-    last_gid = i->first;
-    new_builder->set_first_glyph_index(last_gid);
-    new_builder->set_image_format(b->image_format());
-    new_builder->set_image_data_offset(*image_data_offset);
-    new_builder->SetImageSize(image_size);
-  }
-  for (; i != end; i++) {
-    int32_t gid = i->first;
-    if (gid > upper_bound) {
-      break;
-    }
-    glyph_array->push_back(gid);
-    offset += i->second->length();
-    last_gid = gid;
-  }
-  new_builder->set_last_glyph_index(last_gid);
-  *image_data_offset += offset;
-  return new_builder.Detach();
-}
-
-CALLER_ATTACH IndexSubTable::Builder*
-SubsetIndexSubTable(IndexSubTable::Builder* builder,
-                    const BitmapGlyphInfoMap& loca,
-                    int32_t* image_data_offset) {
-  switch (builder->index_format()) {
-    case IndexSubTable::Format::FORMAT_1:
-    case IndexSubTable::Format::FORMAT_3:
-    case IndexSubTable::Format::FORMAT_4:
-      return ConstructIndexFormat4(builder, loca, image_data_offset);
-    case IndexSubTable::Format::FORMAT_2:
-    case IndexSubTable::Format::FORMAT_5:
-      return ConstructIndexFormat5(builder, loca, image_data_offset);
-    default:
-      assert(false);
-      break;
-  }
-  return NULL;
-}
-
-}
-
-namespace sfntly {
-
-// Not thread-safe, caller to ensure object life-time.
-void SubsetEBLC(EblcTable::Builder* eblc, const BitmapLocaList& new_loca) {
-  BitmapSizeTableBuilderList* size_builders = eblc->BitmapSizeBuilders();
-  if (size_builders == NULL) {
-    return;
-  }
-
-  int32_t image_data_offset = EbdtTable::Offset::kHeaderLength;
-  for (size_t strike = 0; strike < size_builders->size(); ++strike) {
-    IndexSubTableBuilderList* index_builders =
-        (*size_builders)[strike]->IndexSubTableBuilders();
-    for (size_t index = 0; index < index_builders->size(); ++index) {
-      IndexSubTable::Builder* new_builder_raw =
-          SubsetIndexSubTable((*index_builders)[index], new_loca[strike],
-                              &image_data_offset);
-      if (NULL != new_builder_raw) {
-        (*index_builders)[index].Attach(new_builder_raw);
-      }
-    }
-  }
-}
-
-// EBLC structure (from stuartg)
-//  header
-//  bitmapSizeTable[]
-//    one per strike
-//    holds strike metrics - sbitLineMetrics
-//    holds info about indexSubTableArray
-//  indexSubTableArray[][]
-//    one per strike and then one per indexSubTable for that strike
-//    holds info about the indexSubTable
-//    the indexSubTable entries pointed to can be of different formats
-//  indexSubTable
-//    one per indexSubTableArray entry
-//    tells how to get the glyphs
-//    may hold the glyph metrics if they are uniform for all the glyphs in range
-//
-// There is nothing that says that the indexSubTableArray entries and/or the
-// indexSubTable items need to be unique. They may be shared between strikes.
-//
-// EBDT structure:
-//  header
-//  glyphs
-//    amorphous blob of data
-//    different glyphs that are only able to be figured out from the EBLC table
-//    may hold metrics - depends on the EBLC entry that pointed to them
-
-// Subsetting EBLC table (from arthurhsu)
-//  Most pages use only a fraction (hundreds or less) glyphs out of a given font
-//  (which can have >20K glyphs for CJK).  It's safe to assume that the subset
-//  font will have sparse bitmap glyphs.  So we reconstruct the EBLC table as
-//  format 4 or 5 here.
-
-enum BuildersToRemove {
-  kRemoveNone,
-  kRemoveBDAT,
-  kRemoveBDATAndEBDT
-};
-
-int SetupBitmapBuilders(Font* font, Font::Builder* font_builder,
-                        const IntegerSet& glyph_ids) {
-  if (!font || !font_builder) {
-    return false;
-  }
-
-  // Check if bitmap table exists.
-  EbdtTablePtr ebdt_table = down_cast<EbdtTable*>(font->GetTable(Tag::EBDT));
-  EblcTablePtr eblc_table = down_cast<EblcTable*>(font->GetTable(Tag::EBLC));
-  bool use_ebdt = (ebdt_table != NULL && eblc_table != NULL);
-  if (!use_ebdt) {
-    ebdt_table = down_cast<EbdtTable*>(font->GetTable(Tag::bdat));
-    eblc_table = down_cast<EblcTable*>(font->GetTable(Tag::bloc));
-    if (ebdt_table == NULL || eblc_table == NULL) {
-      return kRemoveNone;
-    }
-  }
-
-  // If the bitmap table's size is too small, skip subsetting.
-  if (ebdt_table->DataLength() + eblc_table->DataLength() <
-      BITMAP_SIZE_THRESHOLD) {
-    return use_ebdt ? kRemoveBDAT : kRemoveNone;
-  }
-
-  // Get the builders.
-  EbdtTableBuilderPtr ebdt_table_builder = down_cast<EbdtTable::Builder*>(
-      font_builder->NewTableBuilder(use_ebdt ? Tag::EBDT : Tag::bdat,
-                                    ebdt_table->ReadFontData()));
-  EblcTableBuilderPtr eblc_table_builder = down_cast<EblcTable::Builder*>(
-      font_builder->NewTableBuilder(use_ebdt ? Tag::EBLC : Tag::bloc,
-                                    eblc_table->ReadFontData()));
-  if (ebdt_table_builder == NULL || eblc_table_builder == NULL) {
-    // Out of memory.
-    return use_ebdt ? kRemoveBDAT : kRemoveNone;
-  }
-
-  if (!InitializeBitmapBuilder(ebdt_table_builder, eblc_table_builder,
-                               glyph_ids)) {
-    // Bitmap tables do not cover the glyphs in our subset.
-    font_builder->RemoveTableBuilder(use_ebdt ? Tag::EBLC : Tag::bloc);
-    font_builder->RemoveTableBuilder(use_ebdt ? Tag::EBDT : Tag::bdat);
-    return kRemoveBDATAndEBDT;
-  }
-
-  BitmapLocaList new_loca;
-  ebdt_table_builder->GenerateLocaList(&new_loca);
-  SubsetEBLC(eblc_table_builder, new_loca);
-
-  return use_ebdt ? kRemoveBDAT : kRemoveNone;
-}
-
-SubsetterImpl::SubsetterImpl() {
-}
-
-SubsetterImpl::~SubsetterImpl() {
-}
-
-bool SubsetterImpl::LoadFont(const char* font_name,
-                             const unsigned char* original_font,
-                             size_t font_size) {
-  MemoryInputStream mis;
-  mis.Attach(original_font, font_size);
-  if (factory_ == NULL) {
-    factory_.Attach(FontFactory::GetInstance());
-  }
-
-  FontArray font_array;
-  factory_->LoadFonts(&mis, &font_array);
-  font_ = FindFont(font_name, font_array);
-  if (font_ == NULL) {
-    return false;
-  }
-
-  return true;
-}
-
-int SubsetterImpl::SubsetFont(const unsigned int* glyph_ids,
-                              size_t glyph_count,
-                              unsigned char** output_buffer) {
-  if (factory_ == NULL || font_ == NULL) {
-    return -1;
-  }
-
-  // Find glyf and loca table.
-  GlyphTablePtr glyph_table =
-      down_cast<GlyphTable*>(font_->GetTable(Tag::glyf));
-  LocaTablePtr loca_table = down_cast<LocaTable*>(font_->GetTable(Tag::loca));
-  if (glyph_table == NULL || loca_table == NULL) {
-    // We are not able to subset the font.
-    return 0;
-  }
-
-  IntegerSet glyph_id_processed;
-  if (!ResolveCompositeGlyphs(glyph_table, loca_table,
-                              glyph_ids, glyph_count, &glyph_id_processed) ||
-      glyph_id_processed.empty()) {
-    return 0;
-  }
-
-  FontPtr new_font;
-  new_font.Attach(Subset(glyph_id_processed, glyph_table, loca_table));
-  if (new_font == NULL) {
-    return 0;
-  }
-
-  MemoryOutputStream output_stream;
-  factory_->SerializeFont(new_font, &output_stream);
-  int length = static_cast<int>(output_stream.Size());
-  if (length > 0) {
-    *output_buffer = new unsigned char[length];
-    memcpy(*output_buffer, output_stream.Get(), length);
-  }
-
-  return length;
-}
-
-// Long comments regarding TTF tables and PDF (from stuartg)
-//
-// According to PDF spec 1.4 (section 5.8), the following tables must be
-// present:
-//  head, hhea, loca, maxp, cvt, prep, glyf, hmtx, fpgm
-//  cmap if font is used with a simple font dict and not a CIDFont dict
-//
-// Other tables we need to keep for PDF rendering to support zoom in/out:
-//  bdat, bloc, ebdt, eblc, ebsc, gasp
-//
-// Special table:
-//  CFF - if you have this table then you shouldn't have a glyf table and this
-//        is the table with all the glyphs.  Shall skip subsetting completely
-//        since sfntly is not capable of subsetting it for now.
-//  post - extra info here for printing on PostScript printers but maybe not
-//         enough to outweigh the space taken by the names
-//
-// Tables to break apart:
-//  name - could throw away all but one language and one platform strings/ might
-//         throw away some of the name entries
-//  cmap - could strip out non-needed cmap subtables
-//       - format 4 subtable can be subsetted as well using sfntly
-//
-// Graphite tables:
-//  silf, glat, gloc, feat - should be okay to strip out
-//
-// Tables that can be discarded:
-//  OS/2 - everything here is for layout and description of the font that is
-//         elsewhere (some in the PDF objects)
-//  BASE, GDEF, GSUB, GPOS, JSTF - all used for layout
-//  kern - old style layout
-//  DSIG - this will be invalid after subsetting
-//  hdmx - layout
-//  PCLT - metadata that's not needed
-//  vmtx - layout
-//  vhea - layout
-//  VDMX
-//  VORG - not used by TT/OT - used by CFF
-//  hsty - would be surprised to see one of these - used on the Newton
-//  AAT tables - mort, morx, feat, acnt, bsin, just, lcar, fdsc, fmtx, prop,
-//               Zapf, opbd, trak, fvar, gvar, avar, cvar
-//             - these are all layout tables and once layout happens are not
-//               needed anymore
-//  LTSH - layout
-
-CALLER_ATTACH
-Font* SubsetterImpl::Subset(const IntegerSet& glyph_ids, GlyphTable* glyf,
-                            LocaTable* loca) {
-  // The const is initialized here to workaround VC bug of rendering all Tag::*
-  // as 0.  These tags represents the TTF tables that we will embed in subset
-  // font.
-  const int32_t TABLES_IN_SUBSET[] = {
-    Tag::head, Tag::hhea, Tag::loca, Tag::maxp, Tag::cvt,
-    Tag::prep, Tag::glyf, Tag::hmtx, Tag::fpgm, Tag::EBDT,
-    Tag::EBLC, Tag::EBSC, Tag::bdat, Tag::bloc, Tag::bhed,
-    Tag::cmap,  // Keep here for future tagged PDF development.
-    Tag::name,  // Keep here due to legal concerns: copyright info inside.
-  };
-
-  // Setup font builders we need.
-  FontBuilderPtr font_builder;
-  font_builder.Attach(factory_->NewFontBuilder());
-  IntegerSet remove_tags;
-
-  if (SetupGlyfBuilders(font_builder, glyf, loca, glyph_ids)) {
-    remove_tags.insert(Tag::glyf);
-    remove_tags.insert(Tag::loca);
-  }
-
-  switch (SetupBitmapBuilders(font_, font_builder, glyph_ids)) {
-    case kRemoveBDATAndEBDT:
-      remove_tags.insert(Tag::EBDT);
-      remove_tags.insert(Tag::EBLC);
-      remove_tags.insert(Tag::EBSC);
-    case kRemoveBDAT:
-      remove_tags.insert(Tag::bdat);
-      remove_tags.insert(Tag::bloc);
-      remove_tags.insert(Tag::bhed);
-      break;
-    default:  // kRemoveNone
-      break;
-  }
-
-  IntegerSet allowed_tags;
-  for (size_t i = 0; i < sizeof(TABLES_IN_SUBSET) / sizeof(int32_t); ++i) {
-    allowed_tags.insert(TABLES_IN_SUBSET[i]);
-  }
-
-  IntegerSet result;
-  std::set_difference(allowed_tags.begin(), allowed_tags.end(),
-                      remove_tags.begin(), remove_tags.end(),
-                      std::inserter(result, result.end()));
-  allowed_tags = result;
-
-  // Setup remaining builders.
-  for (IntegerSet::iterator i = allowed_tags.begin(), e = allowed_tags.end();
-                            i != e; ++i) {
-    Table* table = font_->GetTable(*i);
-    if (table) {
-      font_builder->NewTableBuilder(*i, table->ReadFontData());
-    }
-  }
-
-  return font_builder->Build();
-}
-
-}  // namespace sfntly