--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/tesseract/src/ccstruct/imagedata.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,362 @@
+///////////////////////////////////////////////////////////////////////
+// File:        imagedata.h
+// Description: Class to hold information about a single image and its
+//              corresponding boxes or text file.
+// 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_IMAGE_IMAGEDATA_H_
+#define TESSERACT_IMAGE_IMAGEDATA_H_
+
+#include "image.h"
+#include "points.h" // for FCOORD
+
+#include <mutex>  // for std::mutex
+#include <thread> // for std::thread
+
+struct Pix;
+
+namespace tesseract {
+
+class TFile;
+class ScrollView;
+class TBOX;
+
+// Amount of padding to apply in output pixels in feature mode.
+const int kFeaturePadding = 2;
+// Number of pixels to pad around text boxes.
+const int kImagePadding = 4;
+
+// Enum to determine the caching and data sequencing strategy.
+enum CachingStrategy {
+  // Reads all of one file before moving on to the next. Requires samples to be
+  // shuffled across files. Uses the count of samples in the first file as
+  // the count in all the files to achieve high-speed random access. As a
+  // consequence, if subsequent files are smaller, they get entries used more
+  // than once, and if subsequent files are larger, some entries are not used.
+  // Best for larger data sets that don't fit in memory.
+  CS_SEQUENTIAL,
+  // Reads one sample from each file in rotation. Does not require shuffled
+  // samples, but is extremely disk-intensive. Samples in smaller files also
+  // get used more often than samples in larger files.
+  // Best for smaller data sets that mostly fit in memory.
+  CS_ROUND_ROBIN,
+};
+
+// Class to hold information on a single image:
+// Filename, cached image as a Pix*, character boxes, text transcription.
+// The text transcription is the ground truth UTF-8 text for the image.
+// Character boxes are optional and indicate the desired segmentation of
+// the text into recognition units.
+class TESS_API ImageData {
+public:
+  ImageData();
+  // Takes ownership of the pix.
+  ImageData(bool vertical, Image pix);
+  ~ImageData();
+
+  // Builds and returns an ImageData from the basic data. Note that imagedata,
+  // truth_text, and box_text are all the actual file data, NOT filenames.
+  static ImageData *Build(const char *name, int page_number, const char *lang,
+                          const char *imagedata, int imagedatasize, const char *truth_text,
+                          const char *box_text);
+
+  // Writes to the given file. Returns false in case of error.
+  bool Serialize(TFile *fp) const;
+  // Reads from the given file. Returns false in case of error.
+  bool DeSerialize(TFile *fp);
+  // As DeSerialize, but only seeks past the data - hence a static method.
+  static bool SkipDeSerialize(TFile *fp);
+
+  // Other accessors.
+  const std::string &imagefilename() const {
+    return imagefilename_;
+  }
+  void set_imagefilename(const std::string &name) {
+    imagefilename_ = name;
+  }
+  int page_number() const {
+    return page_number_;
+  }
+  void set_page_number(int num) {
+    page_number_ = num;
+  }
+  const std::vector<char> &image_data() const {
+    return image_data_;
+  }
+  const std::string &language() const {
+    return language_;
+  }
+  void set_language(const std::string &lang) {
+    language_ = lang;
+  }
+  const std::string &transcription() const {
+    return transcription_;
+  }
+  const std::vector<TBOX> &boxes() const {
+    return boxes_;
+  }
+  const std::vector<std::string> &box_texts() const {
+    return box_texts_;
+  }
+  const std::string &box_text(int index) const {
+    return box_texts_[index];
+  }
+  // Saves the given Pix as a PNG-encoded string and destroys it.
+  // In case of missing PNG support in Leptonica use PNM format,
+  // which requires more memory.
+  void SetPix(Image pix);
+  // Returns the Pix image for *this. Must be pixDestroyed after use.
+  Image GetPix() const;
+  // Gets anything and everything with a non-nullptr pointer, prescaled to a
+  // given target_height (if 0, then the original image height), and aligned.
+  // Also returns (if not nullptr) the width and height of the scaled image.
+  // The return value is the scaled Pix, which must be pixDestroyed after use,
+  // and scale_factor (if not nullptr) is set to the scale factor that was
+  // applied to the image to achieve the target_height.
+  Image PreScale(int target_height, int max_height, float *scale_factor, int *scaled_width,
+                int *scaled_height, std::vector<TBOX> *boxes) const;
+
+  int MemoryUsed() const;
+
+  // Draws the data in a new window.
+  void Display() const;
+
+  // Adds the supplied boxes and transcriptions that correspond to the correct
+  // page number.
+  void AddBoxes(const std::vector<TBOX> &boxes, const std::vector<std::string> &texts,
+                const std::vector<int> &box_pages);
+
+private:
+  // Saves the given Pix as a PNG-encoded string and destroys it.
+  // In case of missing PNG support in Leptonica use PNM format,
+  // which requires more memory.
+  static void SetPixInternal(Image pix, std::vector<char> *image_data);
+  // Returns the Pix image for the image_data. Must be pixDestroyed after use.
+  static Image GetPixInternal(const std::vector<char> &image_data);
+  // Parses the text string as a box file and adds any discovered boxes that
+  // match the page number. Returns false on error.
+  bool AddBoxes(const char *box_text);
+
+private:
+  std::string imagefilename_; // File to read image from.
+  int32_t page_number_;  // Page number if multi-page tif or -1.
+  // see https://github.com/tesseract-ocr/tesseract/pull/2965
+  // EP: reconsider for tess6.0/opencv
+#ifdef TESSERACT_IMAGEDATA_AS_PIX
+  Image internal_pix_;
+#endif
+  std::vector<char> image_data_;  // PNG/PNM file data.
+  std::string language_;          // Language code for image.
+  std::string transcription_;     // UTF-8 ground truth of image.
+  std::vector<TBOX> boxes_;       // If non-empty boxes of the image.
+  std::vector<std::string> box_texts_; // String for text in each box.
+  bool vertical_text_;            // Image has been rotated from vertical.
+};
+
+// A collection of ImageData that knows roughly how much memory it is using.
+class DocumentData {
+public:
+  TESS_API
+  explicit DocumentData(const std::string &name);
+  TESS_API
+  ~DocumentData();
+
+  // Reads all the pages in the given lstmf filename to the cache. The reader
+  // is used to read the file.
+  TESS_API
+  bool LoadDocument(const char *filename, int start_page, int64_t max_memory, FileReader reader);
+  // Sets up the document, without actually loading it.
+  void SetDocument(const char *filename, int64_t max_memory, FileReader reader);
+  // Writes all the pages to the given filename. Returns false on error.
+  TESS_API
+  bool SaveDocument(const char *filename, FileWriter writer);
+
+  // Adds the given page data to this document, counting up memory.
+  TESS_API
+  void AddPageToDocument(ImageData *page);
+
+  const std::string &document_name() const {
+    std::lock_guard<std::mutex> lock(general_mutex_);
+    return document_name_;
+  }
+  int NumPages() const {
+    std::lock_guard<std::mutex> lock(general_mutex_);
+    return total_pages_;
+  }
+  size_t PagesSize() const {
+    return pages_.size();
+  }
+  int64_t memory_used() const {
+    std::lock_guard<std::mutex> lock(general_mutex_);
+    return memory_used_;
+  }
+  // If the given index is not currently loaded, loads it using a separate
+  // thread. Note: there are 4 cases:
+  // Document uncached: IsCached() returns false, total_pages_ < 0.
+  // Required page is available: IsPageAvailable returns true. In this case,
+  // total_pages_ > 0 and
+  // pages_offset_ <= index%total_pages_ <= pages_offset_+pages_.size()
+  // Pages are loaded, but the required one is not.
+  // The requested page is being loaded by LoadPageInBackground. In this case,
+  // index == pages_offset_. Once the loading starts, the pages lock is held
+  // until it completes, at which point IsPageAvailable will unblock and return
+  // true.
+  void LoadPageInBackground(int index);
+  // Returns a pointer to the page with the given index, modulo the total
+  // number of pages. Blocks until the background load is completed.
+  TESS_API
+  const ImageData *GetPage(int index);
+  // Returns true if the requested page is available, and provides a pointer,
+  // which may be nullptr if the document is empty. May block, even though it
+  // doesn't guarantee to return true.
+  bool IsPageAvailable(int index, ImageData **page);
+  // Takes ownership of the given page index. The page is made nullptr in *this.
+  ImageData *TakePage(int index) {
+    std::lock_guard<std::mutex> lock(pages_mutex_);
+    ImageData *page = pages_[index];
+    pages_[index] = nullptr;
+    return page;
+  }
+  // Returns true if the document is currently loaded or in the process of
+  // loading.
+  bool IsCached() const {
+    return NumPages() >= 0;
+  }
+  // Removes all pages from memory and frees the memory, but does not forget
+  // the document metadata. Returns the memory saved.
+  int64_t UnCache();
+  // Shuffles all the pages in the document.
+  void Shuffle();
+
+private:
+  // Sets the value of total_pages_ behind a mutex.
+  void set_total_pages(int total) {
+    std::lock_guard<std::mutex> lock(general_mutex_);
+    total_pages_ = total;
+  }
+  void set_memory_used(int64_t memory_used) {
+    std::lock_guard<std::mutex> lock(general_mutex_);
+    memory_used_ = memory_used;
+  }
+  // Locks the pages_mutex_ and loads as many pages as will fit into max_memory_
+  // starting at index pages_offset_.
+  bool ReCachePages();
+
+private:
+  // A name for this document.
+  std::string document_name_;
+  // A group of pages that corresponds in some loose way to a document.
+  std::vector<ImageData *> pages_;
+  // Page number of the first index in pages_.
+  int pages_offset_;
+  // Total number of pages in document (may exceed size of pages_.)
+  int total_pages_;
+  // Total of all pix sizes in the document.
+  int64_t memory_used_;
+  // Max memory to use at any time.
+  int64_t max_memory_;
+  // Saved reader from LoadDocument to allow re-caching.
+  FileReader reader_;
+  // Mutex that protects pages_ and pages_offset_ against multiple parallel
+  // loads, and provides a wait for page.
+  std::mutex pages_mutex_;
+  // Mutex that protects other data members that callers want to access without
+  // waiting for a load operation.
+  mutable std::mutex general_mutex_;
+
+  // Thread which loads document.
+  std::thread thread;
+};
+
+// A collection of DocumentData that knows roughly how much memory it is using.
+// Note that while it supports background read-ahead, it assumes that a single
+// thread is accessing documents, ie it is not safe for multiple threads to
+// access different documents in parallel, as one may de-cache the other's
+// content.
+class DocumentCache {
+public:
+  TESS_API
+  explicit DocumentCache(int64_t max_memory);
+  TESS_API
+  ~DocumentCache();
+
+  // Deletes all existing documents from the cache.
+  void Clear() {
+    for (auto *document : documents_) {
+      delete document;
+    }
+    documents_.clear();
+    num_pages_per_doc_ = 0;
+  }
+  // Adds all the documents in the list of filenames, counting memory.
+  // The reader is used to read the files.
+  TESS_API
+  bool LoadDocuments(const std::vector<std::string> &filenames, CachingStrategy cache_strategy,
+                     FileReader reader);
+
+  // Adds document to the cache.
+  bool AddToCache(DocumentData *data);
+
+  // Finds and returns a document by name.
+  DocumentData *FindDocument(const std::string &document_name) const;
+
+  // Returns a page by serial number using the current cache_strategy_ to
+  // determine the mapping from serial number to page.
+  const ImageData *GetPageBySerial(int serial) {
+    if (cache_strategy_ == CS_SEQUENTIAL) {
+      return GetPageSequential(serial);
+    } else {
+      return GetPageRoundRobin(serial);
+    }
+  }
+
+  const std::vector<DocumentData *> &documents() const {
+    return documents_;
+  }
+  // Returns the total number of pages in an epoch. For CS_ROUND_ROBIN cache
+  // strategy, could take a long time.
+  TESS_API
+  int TotalPages();
+
+private:
+  // Returns a page by serial number, selecting them in a round-robin fashion
+  // from all the documents. Highly disk-intensive, but doesn't need samples
+  // to be shuffled between files to begin with.
+  TESS_API
+  const ImageData *GetPageRoundRobin(int serial);
+  // Returns a page by serial number, selecting them in sequence from each file.
+  // Requires the samples to be shuffled between the files to give a random or
+  // uniform distribution of data. Less disk-intensive than GetPageRoundRobin.
+  TESS_API
+  const ImageData *GetPageSequential(int serial);
+
+  // Helper counts the number of adjacent cached neighbour documents_ of index
+  // looking in direction dir, ie index+dir, index+2*dir etc.
+  int CountNeighbourDocs(int index, int dir);
+
+  // A group of pages that corresponds in some loose way to a document.
+  std::vector<DocumentData *> documents_;
+  // Strategy to use for caching and serializing data samples.
+  CachingStrategy cache_strategy_ = CS_SEQUENTIAL;
+  // Number of pages in the first document, used as a divisor in
+  // GetPageSequential to determine the document index.
+  int num_pages_per_doc_ = 0;
+  // Max memory allowed in this cache.
+  int64_t max_memory_ = 0;
+};
+
+} // namespace tesseract
+
+#endif // TESSERACT_IMAGE_IMAGEDATA_H_