text: ///////////////////////////////////////////////////////////////////////
  // File:        fontinfo.cpp
  // Description: Font information classes abstracted from intproto.h/cpp.
  // Author:      rays@google.com (Ray Smith)
  // Created:     Wed May 18 10:39:01 PDT 2011
  //
  // (C) Copyright 2011, Google Inc.
  // 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 "fontinfo.h"
  #include "bitvector.h"
  #include "unicity_table.h"
  
  namespace tesseract {
  
  // Writes to the given file. Returns false in case of error.
  bool FontInfo::Serialize(FILE* fp) const {
    if (!write_info(fp, *this)) return false;
    if (!write_spacing_info(fp, *this)) return false;
    return true;
  }
  // Reads from the given file. Returns false in case of error.
  // If swap is true, assumes a big/little-endian swap is needed.
  bool FontInfo::DeSerialize(bool swap, FILE* fp) {
    if (!read_info(fp, this, swap)) return false;
    if (!read_spacing_info(fp, this, swap)) return false;
    return true;
  }
  
  FontInfoTable::FontInfoTable() {
    set_compare_callback(NewPermanentTessCallback(CompareFontInfo));
    set_clear_callback(NewPermanentTessCallback(FontInfoDeleteCallback));
  }
  
  FontInfoTable::~FontInfoTable() {
  }
  
  // Writes to the given file. Returns false in case of error.
  bool FontInfoTable::Serialize(FILE* fp) const {
    return this->SerializeClasses(fp);
  }
  // Reads from the given file. Returns false in case of error.
  // If swap is true, assumes a big/little-endian swap is needed.
  bool FontInfoTable::DeSerialize(bool swap, FILE* fp) {
    truncate(0);
    return this->DeSerializeClasses(swap, fp);
  }
  
  // Returns true if the given set of fonts includes one with the same
  // properties as font_id.
  bool FontInfoTable::SetContainsFontProperties(
      int font_id, const GenericVector<int>& font_set) const {
    uinT32 properties = get(font_id).properties;
    for (int f = 0; f < font_set.size(); ++f) {
      if (get(font_set[f]).properties == properties)
        return true;
    }
    return false;
  }
  
  // Returns true if the given set of fonts includes multiple properties.
  bool FontInfoTable::SetContainsMultipleFontProperties(
      const GenericVector<int>& font_set) const {
    if (font_set.empty()) return false;
    int first_font = font_set[0];
    uinT32 properties = get(first_font).properties;
    for (int f = 1; f < font_set.size(); ++f) {
      if (get(font_set[f]).properties != properties)
        return true;
    }
    return false;
  }
  
  // Moves any non-empty FontSpacingInfo entries from other to this.
  void FontInfoTable::MoveSpacingInfoFrom(FontInfoTable* other) {
    set_compare_callback(NewPermanentTessCallback(CompareFontInfo));
    set_clear_callback(NewPermanentTessCallback(FontInfoDeleteCallback));
    for (int i = 0; i < other->size(); ++i) {
      GenericVector<FontSpacingInfo*>* spacing_vec = other->get(i).spacing_vec;
      if (spacing_vec != NULL) {
        int target_index = get_index(other->get(i));
        if (target_index < 0) {
          // Bit copy the FontInfo and steal all the pointers.
          push_back(other->get(i));
          other->get(i).name = NULL;
        } else {
          delete [] get(target_index).spacing_vec;
          get(target_index).spacing_vec = other->get(i).spacing_vec;
        }
        other->get(i).spacing_vec = NULL;
      }
    }
  }
  
  // Moves this to the target unicity table.
  void FontInfoTable::MoveTo(UnicityTable<FontInfo>* target) {
    target->clear();
    target->set_compare_callback(NewPermanentTessCallback(CompareFontInfo));
    target->set_clear_callback(NewPermanentTessCallback(FontInfoDeleteCallback));
    for (int i = 0; i < size(); ++i) {
      // Bit copy the FontInfo and steal all the pointers.
      target->push_back(get(i));
      get(i).name = NULL;
      get(i).spacing_vec = NULL;
    }
  }
  
  
  // Compare FontInfo structures.
  bool CompareFontInfo(const FontInfo& fi1, const FontInfo& fi2) {
    // The font properties are required to be the same for two font with the same
    // name, so there is no need to test them.
    // Consequently, querying the table with only its font name as information is
    // enough to retrieve its properties.
    return strcmp(fi1.name, fi2.name) == 0;
  }
  // Compare FontSet structures.
  bool CompareFontSet(const FontSet& fs1, const FontSet& fs2) {
    if (fs1.size != fs2.size)
      return false;
    for (int i = 0; i < fs1.size; ++i) {
      if (fs1.configs[i] != fs2.configs[i])
        return false;
    }
    return true;
  }
  
  // Callbacks for GenericVector.
  void FontInfoDeleteCallback(FontInfo f) {
    if (f.spacing_vec != NULL) {
      f.spacing_vec->delete_data_pointers();
      delete f.spacing_vec;
    }
    delete[] f.name;
  }
  void FontSetDeleteCallback(FontSet fs) {
    delete[] fs.configs;
  }
  
  /*---------------------------------------------------------------------------*/
  // Callbacks used by UnicityTable to read/write FontInfo/FontSet structures.
  bool read_info(FILE* f, FontInfo* fi, bool swap) {
    inT32 size;
    if (fread(&size, sizeof(size), 1, f) != 1) return false;
    if (swap)
      Reverse32(&size);
    char* font_name = new char[size + 1];
    fi->name = font_name;
    if (static_cast<int>(fread(font_name, sizeof(*font_name), size, f)) != size)
      return false;
    font_name[size] = '\0';
    if (fread(&fi->properties, sizeof(fi->properties), 1, f) != 1) return false;
    if (swap)
      Reverse32(&fi->properties);
    return true;
  }
  
  bool write_info(FILE* f, const FontInfo& fi) {
    inT32 size = strlen(fi.name);
    if (fwrite(&size, sizeof(size), 1, f) != 1) return false;
    if (static_cast<int>(fwrite(fi.name, sizeof(*fi.name), size, f)) != size)
      return false;
    if (fwrite(&fi.properties, sizeof(fi.properties), 1, f) != 1) return false;
    return true;
  }
  
  bool read_spacing_info(FILE *f, FontInfo* fi, bool swap) {
    inT32 vec_size, kern_size;
    if (fread(&vec_size, sizeof(vec_size), 1, f) != 1) return false;
    if (swap) Reverse32(&vec_size);
    ASSERT_HOST(vec_size >= 0);
    if (vec_size == 0) return true;
    fi->init_spacing(vec_size);
    for (int i = 0; i < vec_size; ++i) {
      FontSpacingInfo *fs = new FontSpacingInfo();
      if (fread(&fs->x_gap_before, sizeof(fs->x_gap_before), 1, f) != 1 ||
          fread(&fs->x_gap_after, sizeof(fs->x_gap_after), 1, f) != 1 ||
          fread(&kern_size, sizeof(kern_size), 1, f) != 1) {
        return false;
      }
      if (swap) {
        ReverseN(&(fs->x_gap_before), sizeof(fs->x_gap_before));
        ReverseN(&(fs->x_gap_after), sizeof(fs->x_gap_after));
        Reverse32(&kern_size);
      }
      if (kern_size < 0) {  // indication of a NULL entry in fi->spacing_vec
        delete fs;
        continue;
      }
      if (kern_size > 0 && (!fs->kerned_unichar_ids.DeSerialize(swap, f) ||
                            !fs->kerned_x_gaps.DeSerialize(swap, f))) {
        return false;
      }
      fi->add_spacing(i, fs);
    }
    return true;
  }
  
  bool write_spacing_info(FILE* f, const FontInfo& fi) {
    inT32 vec_size = (fi.spacing_vec == NULL) ? 0 : fi.spacing_vec->size();
    if (fwrite(&vec_size,  sizeof(vec_size), 1, f) != 1) return false;
    inT16 x_gap_invalid = -1;
    for (int i = 0; i < vec_size; ++i) {
      FontSpacingInfo *fs = fi.spacing_vec->get(i);
      inT32 kern_size = (fs == NULL) ? -1 : fs->kerned_x_gaps.size();
      if (fs == NULL) {
        // Valid to have the identical fwrites. Writing invalid x-gaps.
        if (fwrite(&(x_gap_invalid), sizeof(x_gap_invalid), 1, f) != 1 ||
            fwrite(&(x_gap_invalid), sizeof(x_gap_invalid), 1, f) != 1 ||
            fwrite(&kern_size, sizeof(kern_size), 1, f) != 1) {
          return false;
        }
      } else {
        if (fwrite(&(fs->x_gap_before), sizeof(fs->x_gap_before), 1, f) != 1 ||
            fwrite(&(fs->x_gap_after), sizeof(fs->x_gap_after), 1, f) != 1 ||
            fwrite(&kern_size, sizeof(kern_size), 1, f) != 1) {
          return false;
        }
      }
      if (kern_size > 0 && (!fs->kerned_unichar_ids.Serialize(f) ||
                            !fs->kerned_x_gaps.Serialize(f))) {
        return false;
      }
    }
    return true;
  }
  
  bool read_set(FILE* f, FontSet* fs, bool swap) {
    if (fread(&fs->size, sizeof(fs->size), 1, f) != 1) return false;
    if (swap)
      Reverse32(&fs->size);
    fs->configs = new int[fs->size];
    for (int i = 0; i < fs->size; ++i) {
      if (fread(&fs->configs[i], sizeof(fs->configs[i]), 1, f) != 1) return false;
      if (swap)
        Reverse32(&fs->configs[i]);
    }
    return true;
  }
  
  bool write_set(FILE* f, const FontSet& fs) {
    if (fwrite(&fs.size, sizeof(fs.size), 1, f) != 1) return false;
    for (int i = 0; i < fs.size; ++i) {
      if (fwrite(&fs.configs[i], sizeof(fs.configs[i]), 1, f) != 1) return false;
    }
    return true;
  }
  
  }  // namespace tesseract.
  
  