1 files changed, 167 insertions, 0 deletions
diff --git a/source/blender/io/common/intern/dupli_persistent_id.cc b/source/blender/io/common/intern/dupli_persistent_id.cc
new file mode 100644
index 00000000000..b40cd83ef44
--- /dev/null
+++ b/source/blender/io/common/intern/dupli_persistent_id.cc
@@ -0,0 +1,167 @@
+/*
+ * 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 Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2020 Blender Foundation.
+ * All rights reserved.
+ */
+
+#include "dupli_parent_finder.hh"
+
+#include <climits>
+#include <cstring>
+#include <ostream>
+#include <sstream>
+
+namespace blender::io {
+
+PersistentID::PersistentID()
+{
+  persistent_id_[0] = INT_MAX;
+}
+
+PersistentID::PersistentID(const DupliObject *dupli_ob)
+{
+  for (int index = 0; index < array_length_; ++index) {
+    persistent_id_[index] = dupli_ob->persistent_id[index];
+  }
+}
+
+PersistentID::PersistentID(const PIDArray &persistent_id_values)
+{
+  persistent_id_ = persistent_id_values;
+}
+
+bool PersistentID::is_from_same_instancer_as(const PersistentID &other) const
+{
+  if (persistent_id_[0] == INT_MAX || other.persistent_id_[0] == INT_MAX) {
+    /* Either one or the other is not instanced at all, so definitely not from the same instancer.
+     */
+    return false;
+  }
+
+  /* Start at index 1 to skip the first digit. */
+  for (int index = 1; index < array_length_; ++index) {
+    const int pid_digit_a = persistent_id_[index];
+    const int pid_digit_b = other.persistent_id_[index];
+
+    if (pid_digit_a != pid_digit_b) {
+      return false;
+    }
+
+    if (pid_digit_a == INT_MAX) {
+      /* Both persistent IDs were identical so far, and this marks the end of the useful data. */
+      break;
+    }
+  }
+  return true;
+}
+
+PersistentID PersistentID::instancer_pid() const
+{
+  if (persistent_id_[0] == INT_MAX) {
+    return PersistentID();
+  }
+
+  /* Left-shift the entire PID by 1. */
+  PIDArray new_pid_values;
+  int index;
+  for (index = 0; index < array_length_ - 1; ++index) {
+    new_pid_values[index] = persistent_id_[index + 1];
+  }
+  new_pid_values[index] = INT_MAX;
+
+  return PersistentID(new_pid_values);
+}
+
+std::string PersistentID::as_object_name_suffix() const
+{
+  std::stringstream stream;
+
+  /* Find one past the last index. */
+  int index;
+  for (index = 0; index < array_length_ && persistent_id_[index] < INT_MAX; ++index) {
+    ;
+  }
+
+  /* Iterate backward to construct the string. */
+  --index;
+  for (; index >= 0; --index) {
+    stream << persistent_id_[index];
+    if (index > 0) {
+      stream << "-";
+    }
+  }
+
+  return stream.str();
+}
+
+bool operator<(const PersistentID &persistent_id_a, const PersistentID &persistent_id_b)
+{
+  const PersistentID::PIDArray &pid_a = persistent_id_a.persistent_id_;
+  const PersistentID::PIDArray &pid_b = persistent_id_b.persistent_id_;
+
+  for (int index = 0; index < PersistentID::array_length_; ++index) {
+    const int pid_digit_a = pid_a[index];
+    const int pid_digit_b = pid_b[index];
+
+    if (pid_digit_a != pid_digit_b) {
+      return pid_digit_a < pid_digit_b;
+    }
+
+    if (pid_a[index] == INT_MAX) {
+      break;
+    }
+  }
+  /* Both Persistent IDs were equal, so not less-than. */
+  return false;
+}
+
+bool operator==(const PersistentID &persistent_id_a, const PersistentID &persistent_id_b)
+{
+  const PersistentID::PIDArray &pid_a = persistent_id_a.persistent_id_;
+  const PersistentID::PIDArray &pid_b = persistent_id_b.persistent_id_;
+
+  for (int index = 0; index < PersistentID::array_length_; ++index) {
+    const int pid_digit_a = pid_a[index];
+    const int pid_digit_b = pid_b[index];
+
+    if (pid_digit_a != pid_digit_b) {
+      return false;
+    }
+
+    if (pid_a[index] == INT_MAX) {
+      break;
+    }
+  }
+  return true;
+}
+
+std::ostream &operator<<(std::ostream &os, const PersistentID &persistent_id)
+{
+  if (persistent_id.persistent_id_[0] == INT_MAX) {
+    return os;
+  }
+
+  const PersistentID::PIDArray &pid_array = persistent_id.persistent_id_;
+  for (int index = 0; index < PersistentID::array_length_ && pid_array[index] < INT_MAX; ++index) {
+    if (index > 0) {
+      os << "-";
+    }
+    os << pid_array[index];
+  }
+  return os;
+}
+
+}  // namespace blender::io