--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/tesseract/src/lstm/series.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,95 @@
+///////////////////////////////////////////////////////////////////////
+// File:        series.h
+// Description: Runs networks in series on the same input.
+// Author:      Ray Smith
+//
+// (C) Copyright 2013, 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.
+///////////////////////////////////////////////////////////////////////
+
+#ifndef TESSERACT_LSTM_SERIES_H_
+#define TESSERACT_LSTM_SERIES_H_
+
+#include "plumbing.h"
+
+namespace tesseract {
+
+// Runs two or more networks in series (layers) on the same input.
+class Series : public Plumbing {
+public:
+  // ni_ and no_ will be set by AddToStack.
+  TESS_API
+  explicit Series(const std::string &name);
+  ~Series() override = default;
+
+  // Returns the shape output from the network given an input shape (which may
+  // be partially unknown ie zero).
+  StaticShape OutputShape(const StaticShape &input_shape) const override;
+
+  std::string spec() const override {
+    std::string spec("[");
+    for (auto &it : stack_) {
+      spec += it->spec();
+    }
+    spec += "]";
+    return spec;
+  }
+
+  // Sets up the network for training. Initializes weights using weights of
+  // scale `range` picked according to the random number generator `randomizer`.
+  // Returns the number of weights initialized.
+  int InitWeights(float range, TRand *randomizer) override;
+  // Recursively searches the network for softmaxes with old_no outputs,
+  // and remaps their outputs according to code_map. See network.h for details.
+  int RemapOutputs(int old_no, const std::vector<int> &code_map) override;
+
+  // Sets needs_to_backprop_ to needs_backprop and returns true if
+  // needs_backprop || any weights in this network so the next layer forward
+  // can be told to produce backprop for this layer if needed.
+  bool SetupNeedsBackprop(bool needs_backprop) override;
+
+  // Returns an integer reduction factor that the network applies to the
+  // time sequence. Assumes that any 2-d is already eliminated. Used for
+  // scaling bounding boxes of truth data.
+  // WARNING: if GlobalMinimax is used to vary the scale, this will return
+  // the last used scale factor. Call it before any forward, and it will return
+  // the minimum scale factor of the paths through the GlobalMinimax.
+  int XScaleFactor() const override;
+
+  // Provides the (minimum) x scale factor to the network (of interest only to
+  // input units) so they can determine how to scale bounding boxes.
+  void CacheXScaleFactor(int factor) override;
+
+  // Runs forward propagation of activations on the input line.
+  // See Network for a detailed discussion of the arguments.
+  void Forward(bool debug, const NetworkIO &input, const TransposedArray *input_transpose,
+               NetworkScratch *scratch, NetworkIO *output) override;
+
+  // Runs backward propagation of errors on the deltas line.
+  // See Network for a detailed discussion of the arguments.
+  bool Backward(bool debug, const NetworkIO &fwd_deltas, NetworkScratch *scratch,
+                NetworkIO *back_deltas) override;
+
+  // Splits the series after the given index, returning the two parts and
+  // deletes itself. The first part, up to network with index last_start, goes
+  // into start, and the rest goes into end.
+  TESS_API
+  void SplitAt(unsigned last_start, Series **start, Series **end);
+
+  // Appends the elements of the src series to this, removing from src and
+  // deleting it.
+  TESS_API
+  void AppendSeries(Network *src);
+};
+
+} // namespace tesseract.
+
+#endif // TESSERACT_LSTM_SERIES_H_