Add sfntly library for font subsetting used in print preview.

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 <map>
+#include <set>
+
+#include "third_party/sfntly/src/sfntly/glyph_table.h"
+#include "third_party/sfntly/src/sfntly/loca_table.h"
+#include "third_party/sfntly/src/sfntly/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_output_stream.h"
+
+namespace sfntly {
+
+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;
+}
+
+SubsetterImpl::SubsetterImpl() {
+}
+
+SubsetterImpl::~SubsetterImpl() {
+}
+
+bool SubsetterImpl::LoadFont(const char* font_name,
+                             const unsigned char* original_font,
+                             size_t font_size) {
+  ByteArrayPtr raw_font =
+      new MemoryByteArray((byte_t*)original_font, font_size);
+  if (factory_ == NULL) {
+    factory_.attach(FontFactory::getInstance());
+  }
+
+  FontArray font_array;
+  factory_->loadFonts(raw_font, &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;
+  }
+
+  FontPtr new_font;
+  new_font.attach(Subset(glyph_ids, glyph_count));
+  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;
+}
+
+Font* SubsetterImpl::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 b = font_array.begin(), e = font_array.end();
+         b != e; ++b) {
+      if (HasName(font_name, (*b).p_)) {
+        return (*b).p_;
+      }
+    }
+  }
+
+  return font_array[0].p_;
+}
+
+bool SubsetterImpl::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->table(Tag::name));
+
+  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));
+        break;
+      }
+      default:
+        break;
+    }
+  }
+
+  if (!names.empty()) {
+    for (NameMap::iterator b = names.begin(), e = names.end(); b != e; ++b) {
+      if (b->second.caseCompare(font_string, 0) == 0 ||
+          b->second.caseCompare(alt_font_string, 0) == 0) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+CALLER_ATTACH Font* SubsetterImpl::Subset(const unsigned int* glyph_ids,
+                                          size_t glyph_count) {
+  if (glyph_ids == NULL || glyph_count == 0) {
+    return NULL;
+  }
+
+  // Find glyf and loca table.
+  GlyphTablePtr glyph_table = down_cast<GlyphTable*>(font_->table(Tag::glyf));
+  LocaTablePtr loca_table = down_cast<LocaTable*>(font_->table(Tag::loca));
+  if (glyph_table == NULL || loca_table == NULL) {
+    // The font is invalid.
+    return NULL;
+  }
+
+  // Setup font builders we need.
+  FontBuilderPtr font_builder;
+  font_builder.attach(factory_->newFontBuilder());
+
+  GlyphTableBuilderPtr glyph_table_builder;
+  glyph_table_builder.attach(down_cast<GlyphTable::Builder*>(
+      font_builder->newTableBuilder(Tag::glyf)));
+  LocaTableBuilderPtr loca_table_builder;
+  loca_table_builder.attach(down_cast<LocaTable::Builder*>(
+      font_builder->newTableBuilder(Tag::loca)));
+  if (glyph_table_builder == NULL || loca_table_builder == NULL) {
+    // Out of memory.
+    return NULL;
+  }
+
+  // Sort and uniquify glyph ids.
+  IntegerSet glyph_id_set;
+  glyph_id_set.insert(0);  // Always include glyph id 0.
+  for (size_t i = 0; i < glyph_count; ++i) {
+    glyph_id_set.insert(glyph_ids[i]);
+  }
+
+  // Extract glyphs and setup loca list.
+  IntegerList loca_list;
+  loca_list.resize(loca_table->numGlyphs());
+  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::iterator i = glyph_id_set.begin(), e = glyph_id_set.end();
+       i != e; ++i) {
+    if (*i < 0 || *i >= loca_table->numGlyphs()) {
+      // 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->glyph(offset, length));
+    if (glyph == NULL) {
+      // Error finding glyph, ignore.
+      continue;
+    }
+
+    // Add glyph to new glyf table.
+    ReadableFontDataPtr data = glyph->readFontData();
+    WritableFontDataPtr copy_data;
+    copy_data.attach(font_builder->getNewData(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->numGlyphs(); ++j) {
+    loca_list[j] = last_offset;
+  }
+  loca_table_builder->setLocaList(&loca_list);
+
+  // Setup remaining builders.
+  for (TableMap::iterator i = font_->tables()->begin(),
+                          e = font_->tables()->end(); i != e; ++i) {
+    // We already build the builder for glyph and loca.
+    if (i->first != Tag::glyf && i->first != Tag::loca) {
+      // The newTableBuilder() call will alter internal state of font_builder
+      // AND the reference count of returned object.  Therefore we need to
+      // dereference it.
+      TableBuilderPtr dereference;
+      dereference.attach(
+          font_builder->newTableBuilder(i->first, i->second->readFontData()));
+    }
+  }
+
+  return font_builder->build();
+}
+
+}  // namespace sfntly