--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/tesseract/src/ccstruct/matrix.cpp	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,170 @@
+/******************************************************************************
+ *
+ * File:         matrix.cpp  (Formerly matrix.c)
+ * Description:  Ratings matrix code. (Used by associator)
+ * Author:       Mark Seaman, OCR Technology
+ *
+ * (c) Copyright 1990, Hewlett-Packard Company.
+ ** 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.
+ *
+ *****************************************************************************/
+/*----------------------------------------------------------------------
+              I n c l u d e s
+----------------------------------------------------------------------*/
+#include "matrix.h"
+
+#include "ratngs.h"
+#include "tprintf.h"
+#include "unicharset.h"
+
+namespace tesseract {
+
+// Destructor.
+// It is defined here, so the compiler can create a single vtable
+// instead of weak vtables in every compilation unit.
+MATRIX::~MATRIX() = default;
+
+// Returns true if there are any real classification results.
+bool MATRIX::Classified(int col, int row, int wildcard_id) const {
+  if (get(col, row) == NOT_CLASSIFIED) {
+    return false;
+  }
+  BLOB_CHOICE_IT b_it(get(col, row));
+  for (b_it.mark_cycle_pt(); !b_it.cycled_list(); b_it.forward()) {
+    BLOB_CHOICE *choice = b_it.data();
+    if (choice->IsClassified()) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Expands the existing matrix in-place to make the band wider, without
+// losing any existing data.
+void MATRIX::IncreaseBandSize(int bandwidth) {
+  ResizeWithCopy(dimension(), bandwidth);
+}
+
+// Returns a bigger MATRIX with a new column and row in the matrix in order
+// to split the blob at the given (ind,ind) diagonal location.
+// Entries are relocated to the new MATRIX using the transformation defined
+// by MATRIX_COORD::MapForSplit.
+// Transfers the pointer data to the new MATRIX and deletes *this.
+MATRIX *MATRIX::ConsumeAndMakeBigger(int ind) {
+  int dim = dimension();
+  int band_width = bandwidth();
+  // Check to see if bandwidth needs expanding.
+  for (int col = ind; col >= 0 && col > ind - band_width; --col) {
+    if (array_[col * band_width + band_width - 1] != empty_) {
+      ++band_width;
+      break;
+    }
+  }
+  auto *result = new MATRIX(dim + 1, band_width);
+
+  for (int col = 0; col < dim; ++col) {
+    for (int row = col; row < dim && row < col + bandwidth(); ++row) {
+      MATRIX_COORD coord(col, row);
+      coord.MapForSplit(ind);
+      BLOB_CHOICE_LIST *choices = get(col, row);
+      if (choices != nullptr) {
+        // Correct matrix location on each choice.
+        BLOB_CHOICE_IT bc_it(choices);
+        for (bc_it.mark_cycle_pt(); !bc_it.cycled_list(); bc_it.forward()) {
+          BLOB_CHOICE *choice = bc_it.data();
+          choice->set_matrix_cell(coord.col, coord.row);
+        }
+        ASSERT_HOST(coord.Valid(*result));
+        result->put(coord.col, coord.row, choices);
+      }
+    }
+  }
+  delete this;
+  return result;
+}
+
+// Makes and returns a deep copy of *this, including all the BLOB_CHOICEs
+// on the lists, but not any LanguageModelState that may be attached to the
+// BLOB_CHOICEs.
+MATRIX *MATRIX::DeepCopy() const {
+  int dim = dimension();
+  int band_width = bandwidth();
+  auto *result = new MATRIX(dim, band_width);
+  for (int col = 0; col < dim; ++col) {
+    for (int row = col; row < dim && row < col + band_width; ++row) {
+      BLOB_CHOICE_LIST *choices = get(col, row);
+      if (choices != nullptr) {
+        auto *copy_choices = new BLOB_CHOICE_LIST;
+        copy_choices->deep_copy(choices, &BLOB_CHOICE::deep_copy);
+        result->put(col, row, copy_choices);
+      }
+    }
+  }
+  return result;
+}
+
+// Print the best guesses out of the match rating matrix.
+void MATRIX::print(const UNICHARSET &unicharset) const {
+  tprintf("Ratings Matrix (top 3 choices)\n");
+  int dim = dimension();
+  int band_width = bandwidth();
+  int row, col;
+  for (col = 0; col < dim; ++col) {
+    for (row = col; row < dim && row < col + band_width; ++row) {
+      BLOB_CHOICE_LIST *rating = this->get(col, row);
+      if (rating == NOT_CLASSIFIED) {
+        continue;
+      }
+      BLOB_CHOICE_IT b_it(rating);
+      tprintf("col=%d row=%d ", col, row);
+      for (b_it.mark_cycle_pt(); !b_it.cycled_list(); b_it.forward()) {
+        tprintf("%s rat=%g cert=%g ", unicharset.id_to_unichar(b_it.data()->unichar_id()),
+                b_it.data()->rating(), b_it.data()->certainty());
+      }
+      tprintf("\n");
+    }
+    tprintf("\n");
+  }
+  tprintf("\n");
+  for (col = 0; col < dim; ++col) {
+    tprintf("\t%d", col);
+  }
+  tprintf("\n");
+  for (row = 0; row < dim; ++row) {
+    for (col = 0; col <= row; ++col) {
+      if (col == 0) {
+        tprintf("%d\t", row);
+      }
+      if (row >= col + band_width) {
+        tprintf(" \t");
+        continue;
+      }
+      BLOB_CHOICE_LIST *rating = this->get(col, row);
+      if (rating != NOT_CLASSIFIED) {
+        BLOB_CHOICE_IT b_it(rating);
+        int counter = 0;
+        for (b_it.mark_cycle_pt(); !b_it.cycled_list(); b_it.forward()) {
+          tprintf("%s ", unicharset.id_to_unichar(b_it.data()->unichar_id()));
+          ++counter;
+          if (counter == 3) {
+            break;
+          }
+        }
+        tprintf("\t");
+      } else {
+        tprintf(" \t");
+      }
+    }
+    tprintf("\n");
+  }
+}
+
+} // namespace tesseract