First features to support cell meta data

src/db/db/db.pro

@@ -124,6 +124,7 @@ SOURCES = \
   gsiDeclDbLibrary.cc \
   gsiDeclDbManager.cc \
   gsiDeclDbMatrix.cc \
+  gsiDeclDbMetaInfo.cc \
   gsiDeclDbPath.cc \
   gsiDeclDbPoint.cc \
   gsiDeclDbPolygon.cc \

src/db/db/dbLayout.cc

@@ -1204,6 +1204,11 @@ Layout::take_cell (cell_index_type ci)
 
   m_cell_ptrs [ci] = 0;
 
+  auto mi = m_meta_info_by_cell.find (ci);
+  if (mi != m_meta_info_by_cell.end ()) {
+    m_meta_info_by_cell.erase (mi);
+  }
+
   //  Using free cell indices does have one significant drawback:
   //  The cellview references cannot be uniquely classified as being invalid - because the
   //  ID might be reused. This causes problems, when a cell is being deleted and subsequently a
@@ -1748,6 +1753,58 @@ Layout::do_update ()
   delete pr;
 }
 
+static Layout::meta_info s_empty_meta;
+
+Layout::meta_info_iterator
+Layout::begin_meta (db::cell_index_type ci) const
+{
+  auto m = m_meta_info_by_cell.find (ci);
+  if (m != m_meta_info_by_cell.find (ci)) {
+    return m->second.begin ();
+  } else {
+    return s_empty_meta.begin ();
+  }
+}
+
+Layout::meta_info_iterator
+Layout::end_meta (db::cell_index_type ci) const
+{
+  auto m = m_meta_info_by_cell.find (ci);
+  if (m != m_meta_info_by_cell.find (ci)) {
+    return m->second.end ();
+  } else {
+    return s_empty_meta.end ();
+  }
+}
+
+const std::string &
+Layout::meta_info_name (Layout::meta_info_name_id_type name_id) const
+{
+  static std::string empty;
+  return name_id < m_meta_info_names.size () ? m_meta_info_names[name_id] : empty;
+}
+
+Layout::meta_info_name_id_type
+Layout::meta_info_name_id (const std::string &name)
+{
+  auto n = m_meta_info_name_map.find (name);
+  if (n != m_meta_info_name_map.end ()) {
+    return n->second;
+  } else {
+    size_t id = m_meta_info_names.size ();
+    m_meta_info_names.push_back (name);
+    m_meta_info_name_map.insert (std::make_pair (name, id));
+    return id;
+  }
+}
+
+Layout::meta_info_name_id_type
+Layout::meta_info_name_id (const std::string &name) const
+{
+  auto n = m_meta_info_name_map.find (name);
+  return n != m_meta_info_name_map.end () ? n->second : std::numeric_limits<meta_info_name_id_type>::max ();
+}
+
 void
 Layout::clear_meta ()
 {
@@ -1755,39 +1812,59 @@ Layout::clear_meta ()
 }
 
 void
-Layout::add_meta_info (const MetaInfo &i)
+Layout::add_meta_info (meta_info_name_id_type name_id, const MetaInfo &i)
 {
-  for (meta_info::iterator m = m_meta_info.begin (); m != m_meta_info.end (); ++m) {
+  m_meta_info[name_id] = i;
-    if (m->name == i.name) {
-      *m = i;
-      return;
-    }
-  }
-  m_meta_info.push_back (i);
 }
 
 void
-Layout::remove_meta_info (const std::string &name)
+Layout::remove_meta_info (meta_info_name_id_type name_id)
 {
-  for (meta_info::iterator m = m_meta_info.begin (); m != m_meta_info.end (); ++m) {
+  m_meta_info.erase (name_id);
-    if (m->name == name) {
+}
-      m_meta_info.erase (m);
+
-      return;
+const tl::Variant &
-    }
+Layout::meta_info_value (meta_info_name_id_type name_id) const
+{
+  auto n = m_meta_info.find (name_id);
+  static tl::Variant null_value;
+  return n != m_meta_info.end () ? n->second.value : null_value;
+}
+
+void
+Layout::clear_meta (db::cell_index_type ci)
+{
+  m_meta_info_by_cell.erase (ci);
+}
+
+void
+Layout::add_meta_info (db::cell_index_type ci, meta_info_name_id_type name_id, const MetaInfo &i)
+{
+  m_meta_info_by_cell[ci][name_id] = i;
+}
+
+void
+Layout::remove_meta_info (db::cell_index_type ci, meta_info_name_id_type name_id)
+{
+  auto c = m_meta_info_by_cell.find (ci);
+  if (c != m_meta_info_by_cell.end ()) {
+    c->second.erase (name_id);
   }
 }
 
-const std::string &
+const tl::Variant &
-Layout::meta_info_value (const std::string &name) const
+Layout::meta_info_value (db::cell_index_type ci, meta_info_name_id_type name_id) const
 {
-  for (meta_info::const_iterator m = m_meta_info.begin (); m != m_meta_info.end (); ++m) {
+  auto c = m_meta_info_by_cell.find (ci);
-    if (m->name == name) {
+  if (c != m_meta_info_by_cell.end ()) {
-      return m->value;
+    auto i = c->second.find (name_id);
+    if (i != c->second.end ()) {
+      return i->second.value;
     }
   }
 
-  static const std::string s_empty;
+  static tl::Variant null_value;
-  return s_empty;
+  return null_value;
 }
 
 void 

src/db/db/dbLayout.h

@@ -465,7 +465,8 @@ public:
   typedef pcell_name_map::const_iterator pcell_iterator;
   typedef std::map<std::pair<lib_id_type, cell_index_type>, cell_index_type> lib_proxy_map;
   typedef LayerIterator layer_iterator;
-  typedef std::vector<MetaInfo> meta_info;
+  typedef size_t meta_info_name_id_type;
+  typedef std::map<meta_info_name_id_type, MetaInfo> meta_info;
   typedef meta_info::const_iterator meta_info_iterator;
 
   /**
@@ -1812,6 +1813,31 @@ public:
     return m_meta_info.end ();
   }
 
+  /**
+   *  @brief Delivers the meta information (begin iterator) per cell
+   */
+  meta_info_iterator begin_meta (db::cell_index_type ci) const;
+
+  /**
+   *  @brief Delivers the meta information (end iterator) per cell
+   */
+  meta_info_iterator end_meta (db::cell_index_type ci) const;
+
+  /**
+   *  @brief Gets the meta informatio name by ID
+   */
+  const std::string &meta_info_name (meta_info_name_id_type name_id) const;
+
+  /**
+   *  @brief Gets the meta information name ID for a specific string
+   */
+  meta_info_name_id_type meta_info_name_id (const std::string &name) const;
+
+  /**
+   *  @brief Gets the meta information name ID for a specific string (const version)
+   */
+  meta_info_name_id_type meta_info_name_id (const std::string &name);
+
   /**
    *  @brief Clears the meta information
    */
@@ -1819,22 +1845,98 @@ public:
 
   /**
    *  @brief Adds meta information
-   *  The given meta information object is appended at the end of the meta information list.
+   *  The given meta information object is added to the meta information list.
    *  If a meta info object with the same name already exists it is overwritten.
    */
-  void add_meta_info (const MetaInfo &i);
+  void add_meta_info (const std::string &name, const MetaInfo &i)
+  {
+    add_meta_info (meta_info_name_id (name), i);
+  }
+
+  /**
+   *  @brief Adds meta information (variant with name ID)
+   */
+  void add_meta_info (meta_info_name_id_type name_id, const MetaInfo &i);
 
   /**
    *  @brief Removes the meta information object with the given name
    *  The method will do nothing if no object with that name exists.
    */
-  void remove_meta_info (const std::string &name);
+  void remove_meta_info (const std::string &name)
+  {
+    remove_meta_info (meta_info_name_id (name));
+  }
+
+  /**
+   *  @brief Removes the meta information object with the given name ID
+   */
+  void remove_meta_info (meta_info_name_id_type name_id);
 
   /**
    *  @brief Gets the meta info value for a meta info object with the given name
    *  If no object with that name exists, an empty string is returned
    */
-  const std::string &meta_info_value (const std::string &name) const;
+  const tl::Variant &meta_info_value (const std::string &name) const
+  {
+    return meta_info_value (meta_info_name_id (name));
+  }
+
+  /**
+   *  @brief Gets the meta info value for a meta info object with the given name ID
+   */
+  const tl::Variant &meta_info_value (meta_info_name_id_type name_id) const;
+
+  /**
+   *  @brief Clears the meta information for a specific cell
+   */
+  void clear_meta (db::cell_index_type ci);
+
+  /**
+   *  @brief Adds meta information for a given cell
+   *  The given meta information object is to the meta information list for the given cell.
+   *  If a meta info object with the same name already exists it is overwritten.
+   */
+  void add_meta_info (db::cell_index_type ci, const std::string &name, const MetaInfo &i)
+  {
+    add_meta_info (ci, meta_info_name_id (name), i);
+  }
+
+  /**
+   *  @brief Adds meta information for a given cell (version with name ID)
+   *  The given meta information object is appended at the end of the meta information list.
+   *  If a meta info object with the same name already exists it is overwritten.
+   */
+  void add_meta_info (db::cell_index_type ci, meta_info_name_id_type name_id, const MetaInfo &i);
+
+  /**
+   *  @brief Removes the meta information object with the given name from the given cell
+   *  The method will do nothing if no object with that name exists.
+   */
+  void remove_meta_info (db::cell_index_type ci, const std::string &name)
+  {
+    remove_meta_info (ci, meta_info_name_id (name));
+  }
+
+  /**
+   *  @brief Removes the meta information object with the given name ID from the given cell
+   *  The method will do nothing if no object with that name exists.
+   */
+  void remove_meta_info (db::cell_index_type ci, meta_info_name_id_type name_id);
+
+  /**
+   *  @brief Gets the meta info value for a meta info object with the given name for the given cell
+   *  If no object with that name exists, an empty string is returned
+   */
+  const tl::Variant &meta_info_value (db::cell_index_type ci, const std::string &name) const
+  {
+    return meta_info_value (ci, meta_info_name_id (name));
+  }
+
+  /**
+   *  @brief Gets the meta info value for a meta info object with the given name ID for the given cell
+   *  If no object with that name exists, an empty string is returned
+   */
+  const tl::Variant &meta_info_value (db::cell_index_type ci, meta_info_name_id_type name_id) const;
 
   /**
    *  @brief This event is triggered when the technology changes
@@ -1876,7 +1978,11 @@ private:
   lib_proxy_map m_lib_proxy_map;
   bool m_do_cleanup;
   bool m_editable;
+  std::map<std::string, meta_info_name_id_type> m_meta_info_name_map;
+  std::vector<std::string> m_meta_info_names;
   meta_info m_meta_info;
+  std::map<db::cell_index_type, meta_info> m_meta_info_by_cell;
+
   std::string m_tech_name;
   tl::Mutex m_lock;
 

src/db/db/dbMetaInfo.h

@@ -36,14 +36,13 @@ namespace db
  *
  *  In the meta information block, the reader provides additional information
  *  about the file and content etc.
- *  "name" is a unique name that can be used to identify the information.
  *  "description" is a "speaking" description of the information.
  *  "value" is the value of the specific part of meta information.
  */
 struct DB_PUBLIC MetaInfo
 {
-  MetaInfo (const std::string &n, const std::string &d, const std::string &v)
+  MetaInfo (const std::string &d, const tl::Variant &v)
-    : name (n), description (d), value (v)
+    : description (d), value (v)
   {
     //  .. nothing else ..
   }
@@ -53,9 +52,8 @@ struct DB_PUBLIC MetaInfo
     //  .. nothing else ..
   }
 
-  std::string name;
   std::string description;
-  std::string value;
+  tl::Variant value;
 };
 
 /**
@@ -63,7 +61,6 @@ struct DB_PUBLIC MetaInfo
  */
 inline void mem_stat (MemStatistics *stat, MemStatistics::purpose_t purpose, int cat, const MetaInfo &v, bool no_self, void *parent)
 {
-  db::mem_stat (stat, purpose, cat, v.name, no_self, parent);
   db::mem_stat (stat, purpose, cat, v.description, no_self, parent);
   db::mem_stat (stat, purpose, cat, v.value, no_self, parent);
 }

src/db/db/gsiDeclDbCell.cc

@@ -20,9 +20,8 @@
 
 */
 
-
-
 #include "gsiDecl.h"
+#include "gsiDeclDbMetaInfo.h"
 
 #include "gsiDeclDbHelpers.h"
 #include "dbLayout.h"
@@ -984,6 +983,46 @@ static db::Layout *layout (db::Cell *cell)
   return cell->layout ();
 }
 
+static void cell_clear_meta_info (db::Cell *cell)
+{
+  if (cell->layout ()) {
+    cell->layout ()->clear_meta (cell->cell_index ());
+  }
+}
+
+static void cell_remove_meta_info (db::Cell *cell, const std::string &name)
+{
+  if (cell->layout ()) {
+    cell->layout ()->remove_meta_info (cell->cell_index (), name);
+  }
+}
+
+static void cell_add_meta_info (db::Cell *cell, const MetaInfo &mi)
+{
+  if (cell->layout ()) {
+    cell->layout ()->add_meta_info (cell->cell_index (), mi.name, db::MetaInfo (mi.description, mi.value));
+  }
+}
+
+static const tl::Variant &cell_meta_info_value (db::Cell *cell, const std::string &name)
+{
+  if (! cell->layout ()) {
+    static tl::Variant null_value;
+    return null_value;
+  } else {
+    return cell->layout ()->meta_info_value (cell->cell_index (), name);
+  }
+}
+
+static gsi::MetaInfoIterator cell_each_meta_info (const db::Cell *cell)
+{
+  if (! cell->layout ()) {
+    return gsi::MetaInfoIterator ();
+  } else {
+    return gsi::MetaInfoIterator (cell->layout (), cell->layout ()->begin_meta (cell->cell_index ()), cell->layout ()->end_meta (cell->cell_index ()));
+  }
+}
+
 static bool cell_has_prop_id (const db::Cell *c)
 {
   return c->prop_id () != 0;
@@ -1780,6 +1819,38 @@ Class<db::Cell> decl_Cell ("db", "Cell",
     "\n"
     "This method has been introduced in version 0.23."
   ) + 
+  gsi::method_ext ("add_meta_info", &cell_add_meta_info, gsi::arg ("info"),
+    "@brief Adds meta information to the cell\n"
+    "See \\LayoutMetaInfo for details about cells and meta information.\n"
+    "\n"
+    "This method has been introduced in version 0.28.7."
+  ) +
+  gsi::method_ext ("clear_meta_info", &cell_clear_meta_info,
+    "@brief Clears the meta information of the cell\n"
+    "See \\LayoutMetaInfo for details about cells and meta information.\n"
+    "\n"
+    "This method has been introduced in version 0.28.7."
+  ) +
+  gsi::method_ext ("remove_meta_info", &cell_remove_meta_info, gsi::arg ("name"),
+    "@brief Removes meta information from the cell\n"
+    "See \\LayoutMetaInfo for details about cells and meta information.\n"
+    "\n"
+    "This method has been introduced in version 0.28.7."
+  ) +
+  gsi::method_ext ("meta_info_value", &cell_meta_info_value, gsi::arg ("name"),
+    "@brief Gets the meta information value for a given name\n"
+    "See \\LayoutMetaInfo for details about cells and meta information.\n"
+    "\n"
+    "If no meta information with the given name exists, an nil value will be returned.\n"
+    "\n"
+    "This method has been introduced in version 0.28.7."
+  ) +
+  gsi::iterator_ext ("each_meta_info", &cell_each_meta_info,
+    "@brief Iterates over the meta information of the cell\n"
+    "See \\LayoutMetaInfo for details about cells and meta information.\n"
+    "\n"
+    "This method has been introduced in version 0.28.7."
+  ) +
   gsi::method_ext ("write", &write_simple, gsi::arg ("file_name"),
     "@brief Writes the cell to a layout file\n"
     "The format of the file will be determined from the file name. Only the cell and "

src/db/db/gsiDeclDbLayout.cc

@@ -22,6 +22,7 @@
 
 
 #include "gsiDecl.h"
+#include "gsiDeclDbMetaInfo.h"
 #include "dbLayout.h"
 #include "dbClip.h"
 #include "dbRecursiveShapeIterator.h"
@@ -902,39 +903,14 @@ static db::Cell *create_cell4 (db::Layout *layout, const std::string &name, cons
   return &layout->cell (layout->get_lib_proxy (lib, lib_cell));
 }
 
-static db::MetaInfo *layout_meta_info_ctor (const std::string &name, const std::string &value, const std::string &description)
+static void layout_add_meta_info (db::Layout *layout, const MetaInfo &mi)
 {
-  return new db::MetaInfo (name, description, value);
+  layout->add_meta_info (mi.name, db::MetaInfo (mi.description, mi.value));
 }
 
-static void layout_meta_set_name (db::MetaInfo *mi, const std::string &n)
+static MetaInfoIterator layout_each_meta_info (const db::Layout *layout)
 {
-  mi->name = n;
+  return MetaInfoIterator (layout, layout->begin_meta (), layout->end_meta ());
-}
-
-static const std::string &layout_meta_get_name (const db::MetaInfo *mi)
-{
-  return mi->name;
-}
-
-static void layout_meta_set_value (db::MetaInfo *mi, const std::string &n)
-{
-  mi->value = n;
-}
-
-static const std::string &layout_meta_get_value (const db::MetaInfo *mi)
-{
-  return mi->value;
-}
-
-static void layout_meta_set_description (db::MetaInfo *mi, const std::string &n)
-{
-  mi->description = n;
-}
-
-static const std::string &layout_meta_get_description (const db::MetaInfo *mi)
-{
-  return mi->description;
 }
 
 static void scale_and_snap1 (db::Layout *layout, db::Cell &cell, db::Coord g, db::Coord m, db::Coord d)
@@ -997,45 +973,6 @@ static void move_tree_shapes3 (db::Layout *layout, db::Layout &source_layout, co
   db::move_shapes (*layout, source_layout, trans, cm.source_cells (), cm.table (), lm.table ());
 }
 
-Class<db::MetaInfo> decl_LayoutMetaInfo ("db", "LayoutMetaInfo",
-  gsi::constructor ("new", &layout_meta_info_ctor, gsi::arg ("name"), gsi::arg ("value"), gsi::arg ("description", std::string ()),
-    "@brief Creates a layout meta info object\n"
-    "@param name The name\n"
-    "@param value The value\n"
-    "@param description An optional description text\n"
-  ) +
-  gsi::method_ext ("name", &layout_meta_get_name,
-    "@brief Gets the name of the layout meta info object\n"
-  ) +
-  gsi::method_ext ("name=", &layout_meta_set_name,
-    "@brief Sets the name of the layout meta info object\n"
-  ) +
-  gsi::method_ext ("value", &layout_meta_get_value,
-    "@brief Gets the value of the layout meta info object\n"
-  ) +
-  gsi::method_ext ("value=", &layout_meta_set_value,
-    "@brief Sets the value of the layout meta info object\n"
-  ) +
-  gsi::method_ext ("description", &layout_meta_get_description,
-    "@brief Gets the description of the layout meta info object\n"
-  ) +
-  gsi::method_ext ("description=", &layout_meta_set_description,
-    "@brief Sets the description of the layout meta info object\n"
-  ),
-  "@brief A piece of layout meta information\n"
-  "Layout meta information is basically additional data that can be attached to a layout. "
-  "Layout readers may generate meta information and some writers will add layout information to "
-  "the layout object. Some writers will also read meta information to determine certain attributes.\n"
-  "\n"
-  "Multiple layout meta information objects can be attached to one layout using \\Layout#add_meta_info. "
-  "Meta information is identified by a unique name and carries a string value plus an optional description string. "
-  "The description string is for information only and is not evaluated by code.\n"
-  "\n"
-  "See also \\Layout#each_meta_info and \\Layout#meta_info_value and \\Layout#remove_meta_info"
-  "\n"
-  "This class has been introduced in version 0.25."
-);
-
 static void dtransform (db::Layout *layout, const db::DTrans &trans)
 {
   db::CplxTrans dbu_trans (layout->dbu ());
@@ -1097,27 +1034,33 @@ Class<db::Layout> decl_Layout ("db", "Layout",
     "\n"
     "This method has been introduced in version 0.27.9."
   ) +
-  gsi::method ("add_meta_info", &db::Layout::add_meta_info, gsi::arg ("info"),
+  gsi::method_ext ("add_meta_info", &layout_add_meta_info, gsi::arg ("info"),
     "@brief Adds meta information to the layout\n"
     "See \\LayoutMetaInfo for details about layouts and meta information."
     "\n"
     "This method has been introduced in version 0.25."
   ) +
-  gsi::method ("remove_meta_info", &db::Layout::remove_meta_info, gsi::arg ("name"),
+  gsi::method ("clear_meta_info", static_cast<void (db::Layout::*) ()> (&db::Layout::clear_meta),
+    "@brief Clears the meta information of the layout\n"
+    "See \\LayoutMetaInfo for details about layouts and meta information."
+    "\n"
+    "This method has been introduced in version 0.28.7."
+  ) +
+  gsi::method ("remove_meta_info", static_cast<void (db::Layout::*) (const std::string &name)> (&db::Layout::remove_meta_info), gsi::arg ("name"),
     "@brief Removes meta information from the layout\n"
     "See \\LayoutMetaInfo for details about layouts and meta information."
     "\n"
     "This method has been introduced in version 0.25."
   ) +
-  gsi::method ("meta_info_value", &db::Layout::meta_info_value, gsi::arg ("name"),
+  gsi::method ("meta_info_value", static_cast<const tl::Variant &(db::Layout::*) (const std::string &name) const> (&db::Layout::meta_info_value), gsi::arg ("name"),
     "@brief Gets the meta information value for a given name\n"
     "See \\LayoutMetaInfo for details about layouts and meta information.\n"
     "\n"
-    "If no meta information with the given name exists, an empty string will be returned.\n"
+    "If no meta information with the given name exists, an nil value will be returned.\n"
     "\n"
-    "This method has been introduced in version 0.25."
+    "This method has been introduced in version 0.25. Starting with version 0.28.7, the value is of variant type instead of string only.\n"
   ) +
-  gsi::iterator ("each_meta_info", &db::Layout::begin_meta, &db::Layout::end_meta,
+  gsi::iterator_ext ("each_meta_info", &layout_each_meta_info,
     "@brief Iterates over the meta information of the layout\n"
     "See \\LayoutMetaInfo for details about layouts and meta information.\n"
     "\n"

src/db/db/gsiDeclDbMetaInfo.cc

@@ -0,0 +1,105 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2023 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
+
+#include "gsiDecl.h"
+#include "gsiDeclDbMetaInfo.h"
+
+namespace gsi
+{
+
+static MetaInfo *layout_meta_info_ctor (const std::string &name, const std::string &value, const std::string &description)
+{
+  return new MetaInfo (name, description, value);
+}
+
+static void layout_meta_set_name (MetaInfo *mi, const std::string &n)
+{
+  mi->name = n;
+}
+
+static const std::string &layout_meta_get_name (const MetaInfo *mi)
+{
+  return mi->name;
+}
+
+static void layout_meta_set_value (MetaInfo *mi, const tl::Variant &n)
+{
+  mi->value = n;
+}
+
+static const tl::Variant &layout_meta_get_value (const MetaInfo *mi)
+{
+  return mi->value;
+}
+
+static void layout_meta_set_description (MetaInfo *mi, const std::string &n)
+{
+  mi->description = n;
+}
+
+static const std::string &layout_meta_get_description (const MetaInfo *mi)
+{
+  return mi->description;
+}
+
+
+Class<MetaInfo> decl_LayoutMetaInfo ("db", "LayoutMetaInfo",
+  gsi::constructor ("new", &layout_meta_info_ctor, gsi::arg ("name"), gsi::arg ("value"), gsi::arg ("description", std::string ()),
+    "@brief Creates a layout meta info object\n"
+    "@param name The name\n"
+    "@param value The value\n"
+    "@param description An optional description text\n"
+  ) +
+  gsi::method_ext ("name", &layout_meta_get_name,
+    "@brief Gets the name of the layout meta info object\n"
+  ) +
+  gsi::method_ext ("name=", &layout_meta_set_name,
+    "@brief Sets the name of the layout meta info object\n"
+  ) +
+  gsi::method_ext ("value", &layout_meta_get_value,
+    "@brief Gets the value of the layout meta info object\n"
+  ) +
+  gsi::method_ext ("value=", &layout_meta_set_value,
+    "@brief Sets the value of the layout meta info object\n"
+  ) +
+  gsi::method_ext ("description", &layout_meta_get_description,
+    "@brief Gets the description of the layout meta info object\n"
+  ) +
+  gsi::method_ext ("description=", &layout_meta_set_description,
+    "@brief Sets the description of the layout meta info object\n"
+  ),
+  "@brief A piece of layout meta information\n"
+  "Layout meta information is basically additional data that can be attached to a layout. "
+  "Layout readers may generate meta information and some writers will add layout information to "
+  "the layout object. Some writers will also read meta information to determine certain attributes.\n"
+  "\n"
+  "Multiple layout meta information objects can be attached to one layout using \\Layout#add_meta_info. "
+  "Meta information is identified by a unique name and carries a string value plus an optional description string. "
+  "The description string is for information only and is not evaluated by code.\n"
+  "\n"
+  "See also \\Layout#each_meta_info and \\Layout#meta_info_value and \\Layout#remove_meta_info"
+  "\n"
+  "This class has been introduced in version 0.25."
+);
+
+}

src/db/db/gsiDeclDbMetaInfo.h

@@ -0,0 +1,95 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2023 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
+#ifndef _HDR_gsiDeclDbMetaInfo
+#define _HDR_gsiDeclDbMetaInfo
+
+#include "dbLayout.h"
+#include "tlVariant.h"
+#include "tlObject.h"
+
+#include <string>
+#include <iterator>
+
+namespace gsi
+{
+
+struct MetaInfo
+{
+  MetaInfo (const std::string &n, const std::string &d, const tl::Variant &v)
+    : name (n), description (d), value (v)
+  { }
+
+  MetaInfo ()
+    : name (), description (), value ()
+  { }
+
+  std::string name;
+  std::string description;
+  tl::Variant value;
+};
+
+struct MetaInfoIterator
+{
+  typedef std::forward_iterator_tag iterator_category;
+  typedef MetaInfo value_type;
+  typedef void difference_type;
+  typedef MetaInfo reference;
+  typedef void pointer;
+
+  MetaInfoIterator ()
+    : mp_layout (), m_b (), m_e ()
+  { }
+
+  MetaInfoIterator (const db::Layout *layout, db::Layout::meta_info_iterator b, db::Layout::meta_info_iterator e)
+    : mp_layout (const_cast<db::Layout *> (layout)), m_b (b), m_e (e)
+  { }
+
+  bool at_end () const
+  {
+    return !mp_layout || m_b == m_e;
+  }
+
+  void operator++ ()
+  {
+    if (mp_layout) {
+      ++m_b;
+    }
+  }
+
+  MetaInfo operator* () const
+  {
+    if (mp_layout) {
+      return MetaInfo (mp_layout->meta_info_name (m_b->first), m_b->second.description, m_b->second.value);
+    } else {
+      return MetaInfo ();
+    }
+  }
+
+private:
+  tl::weak_ptr<db::Layout> mp_layout;
+  db::Layout::meta_info_iterator m_b, m_e;
+};
+
+}
+
+#endif