--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/tesseract/src/classify/ocrfeatures.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,132 @@
+/******************************************************************************
+ ** Filename:    features.h
+ ** Purpose:     Generic definition of a feature.
+ ** Author:      Dan Johnson
+ **
+ ** (c) Copyright Hewlett-Packard Company, 1988.
+ ** 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 FEATURES_H
+#define FEATURES_H
+
+#include "blobs.h"
+
+#include <cstdio>
+#include <string> // for std::string
+
+namespace tesseract {
+
+class DENORM;
+
+#undef Min
+#undef Max
+#define FEAT_NAME_SIZE 80
+
+// A character is described by multiple sets of extracted features.  Each
+// set contains a number of features of a particular type, for example, a
+// set of bays, or a set of closures, or a set of microfeatures.  Each
+// feature consists of a number of parameters.  All features within a
+// feature set contain the same number of parameters.  All circular
+// parameters are required to be the first parameters in the feature.
+
+struct PARAM_DESC {
+  bool Circular;     // true if dimension wraps around
+  bool NonEssential; // true if dimension not used in searches
+  float Min;         // low end of range for circular dimensions
+  float Max;         // high end of range for circular dimensions
+  float Range;       // Max - Min
+  float HalfRange;   // (Max - Min)/2
+  float MidRange;    // (Max + Min)/2
+};
+
+struct FEATURE_DESC_STRUCT {
+  uint16_t NumParams;          // total # of params
+  const char *ShortName;       // short name for feature
+  const PARAM_DESC *ParamDesc; // array - one per param
+};
+using FEATURE_DESC = FEATURE_DESC_STRUCT *;
+
+struct FEATURE_STRUCT {
+  /// Constructor for a new feature of the specified type.
+  /// @param FeatureDesc description of feature to be created.
+  FEATURE_STRUCT(const FEATURE_DESC_STRUCT *FeatureDesc) : Type(FeatureDesc), Params(FeatureDesc->NumParams) {
+  }
+  ~FEATURE_STRUCT() {
+  }
+  const FEATURE_DESC_STRUCT *Type; // points to description of feature type
+  std::vector<float> Params;       // variable size array - params for feature
+};
+using FEATURE = FEATURE_STRUCT *;
+
+struct FEATURE_SET_STRUCT {
+  /// Creator for a new feature set large enough to
+  /// hold the specified number of features.
+  /// @param NumFeatures maximum # of features to be put in feature set
+  FEATURE_SET_STRUCT(int numFeatures) : NumFeatures(0), MaxNumFeatures(numFeatures), Features(numFeatures) {
+  }
+
+  ~FEATURE_SET_STRUCT() {
+    for (uint16_t i = 0; i < NumFeatures; i++) {
+      delete Features[i];
+    }
+  }
+
+  uint16_t NumFeatures;    // number of features in set
+  uint16_t MaxNumFeatures; // maximum size of feature set
+  std::vector<FEATURE_STRUCT *> Features; // variable size array of features
+};
+using FEATURE_SET = FEATURE_SET_STRUCT *;
+
+// A generic character description as a char pointer. In reality, it will be
+// a pointer to some data structure. Paired feature extractors/matchers need
+// to agree on the data structure to be used, however, the high level
+// classifier does not need to know the details of this data structure.
+using CHAR_FEATURES = char *;
+
+/*----------------------------------------------------------------------
+    Macros for defining the parameters of a new features
+----------------------------------------------------------------------*/
+#define StartParamDesc(Name) const PARAM_DESC Name[] = {
+#define DefineParam(Circular, NonEssential, Min, Max) \
+  {Circular,                                          \
+   NonEssential,                                      \
+   Min,                                               \
+   Max,                                               \
+   (Max) - (Min),                                     \
+   (((Max) - (Min)) / 2.0),                           \
+   (((Max) + (Min)) / 2.0)},
+
+#define EndParamDesc \
+  }                  \
+  ;
+
+/*----------------------------------------------------------------------
+Macro for describing a new feature.  The parameters of the macro
+are as follows:
+
+DefineFeature (Name, NumLinear, NumCircular, ShortName, ParamName)
+----------------------------------------------------------------------*/
+#define DefineFeature(Name, NL, NC, SN, PN) \
+  const FEATURE_DESC_STRUCT Name = {((NL) + (NC)), SN, PN};
+
+/*----------------------------------------------------------------------
+        Generic routines that work for all feature types
+----------------------------------------------------------------------*/
+bool AddFeature(FEATURE_SET FeatureSet, FEATURE Feature);
+
+FEATURE_SET ReadFeatureSet(FILE *File, const FEATURE_DESC_STRUCT *FeatureDesc);
+
+void WriteFeatureSet(FEATURE_SET FeatureSet, std::string &str);
+
+} // namespace tesseract
+
+#endif