Adding support for Jungfrau .dat files (#152)

closes #150 

**Not addressed in this PR:** 

- pixels_per_frame, bytes_per_frame and tell should be made cost in
FileInterface

include/aare/FilePtr.hpp

@@ -0,0 +1,30 @@
+#pragma once
+#include <cstdio>
+#include <filesystem>
+
+namespace aare {
+
+/**
+ * \brief RAII wrapper for FILE pointer
+ */
+class FilePtr {
+    FILE *fp_{nullptr};
+
+  public:
+    FilePtr() = default;
+    FilePtr(const std::filesystem::path& fname, const std::string& mode);
+    FilePtr(const FilePtr &) = delete;            // we don't want a copy
+    FilePtr &operator=(const FilePtr &) = delete; // since we handle a resource
+    FilePtr(FilePtr &&other);
+    FilePtr &operator=(FilePtr &&other);
+    FILE *get();
+    int64_t tell();
+    void seek(int64_t offset, int whence = SEEK_SET) {
+        if (fseek(fp_, offset, whence) != 0)
+            throw std::runtime_error("Error seeking in file");
+    }
+    std::string error_msg();
+    ~FilePtr();
+};
+
+} // namespace aare

include/aare/JungfrauDataFile.hpp

@@ -0,0 +1,112 @@
+#pragma once
+#include <cstdint>
+#include <filesystem>
+#include <vector>
+
+#include "aare/FilePtr.hpp"
+#include "aare/defs.hpp"
+#include "aare/NDArray.hpp"
+#include "aare/FileInterface.hpp"
+namespace aare {
+
+
+struct JungfrauDataHeader{
+    uint64_t framenum;
+    uint64_t bunchid;
+};
+
+class JungfrauDataFile : public FileInterface {
+
+    size_t m_rows{};     //!< number of rows in the image, from find_frame_size();
+    size_t m_cols{};     //!< number of columns in the image, from find_frame_size();
+    size_t m_bytes_per_frame{}; //!< number of bytes per frame excluding header
+    size_t m_total_frames{};    //!< total number of frames in the series of files
+    size_t m_offset{}; //!< file index of the first file, allow starting at non zero file
+    size_t m_current_file_index{};   //!< The index of the open file
+    size_t m_current_frame_index{};  //!< The index of the current frame (with reference to all files)
+
+    std::vector<size_t> m_last_frame_in_file{}; //!< Used for seeking to the correct file
+    std::filesystem::path m_path; //!< path to the files
+    std::string m_base_name;      //!< base name used for formatting file names
+
+    FilePtr m_fp; //!< RAII wrapper for a FILE* 
+
+    
+    using pixel_type = uint16_t;
+    static constexpr size_t header_size = sizeof(JungfrauDataHeader); 
+    static constexpr size_t n_digits_in_file_index = 6; //!< to format file names
+
+  public:
+    JungfrauDataFile(const std::filesystem::path &fname);
+
+    std::string base_name() const;      //!< get the base name of the file (without path and extension)
+    size_t bytes_per_frame() override;           
+    size_t pixels_per_frame() override;    
+    size_t bytes_per_pixel() const;  
+    size_t bitdepth() const override;
+    void seek(size_t frame_index) override;  //!< seek to the given frame index (note not byte offset)
+    size_t tell() override;            //!< get the frame index of the file pointer
+    size_t total_frames() const override;
+    size_t rows() const override;
+    size_t cols() const override;
+    size_t n_files() const; //!< get the number of files in the series. 
+
+    // Extra functions needed for FileInterface
+    Frame read_frame() override;
+    Frame read_frame(size_t frame_number) override;
+    std::vector<Frame> read_n(size_t n_frames=0) override;
+    void read_into(std::byte *image_buf) override;
+    void read_into(std::byte *image_buf, size_t n_frames) override;
+    size_t frame_number(size_t frame_index) override;
+    DetectorType detector_type() const override;
+
+    /**
+     * @brief Read a single frame from the file into the given buffer.  
+     * @param image_buf buffer to read the frame into. (Note the caller is responsible for allocating the buffer)
+     * @param header pointer to a JungfrauDataHeader or nullptr to skip header)
+     */
+    void read_into(std::byte *image_buf, JungfrauDataHeader *header = nullptr);
+
+    /**
+     * @brief Read a multiple frames from the file into the given buffer.  
+     * @param image_buf buffer to read the frame into. (Note the caller is responsible for allocating the buffer)
+     * @param n_frames number of frames to read
+     * @param header pointer to a JungfrauDataHeader or nullptr to skip header)
+     */
+    void read_into(std::byte *image_buf, size_t n_frames, JungfrauDataHeader *header = nullptr);
+    
+    /** 
+     * @brief Read a single frame from the file into the given NDArray
+     * @param image NDArray to read the frame into.
+     */
+    void read_into(NDArray<uint16_t>* image, JungfrauDataHeader* header = nullptr);
+
+    /**
+     * @brief Read a single frame from the file. Allocated a new NDArray for the output data
+     * @param header pointer to a JungfrauDataHeader or nullptr to skip header)
+     * @return NDArray with the image data
+     */
+    NDArray<uint16_t> read_frame(JungfrauDataHeader* header = nullptr);
+
+    JungfrauDataHeader read_header();
+    std::filesystem::path current_file() const { return fpath(m_current_file_index+m_offset); }
+
+    
+    private:
+    /**
+     * @brief Find the size of the frame in the file. (256x256, 256x1024, 512x1024)
+     * @param fname path to the file
+     * @throws std::runtime_error if the file is empty or the size cannot be determined
+     */
+     void find_frame_size(const std::filesystem::path &fname);
+
+
+     void parse_fname(const std::filesystem::path &fname);
+     void scan_files();
+     void open_file(size_t file_index);
+     std::filesystem::path fpath(size_t frame_index) const;
+
+
+  };
+
+} // namespace aare

include/aare/algorithm.hpp

@@ -7,13 +7,20 @@
 
 namespace aare {
 /**
- * @brief Find the index of the last element smaller than val
- * assume a sorted array
+ * @brief Index of the last element that is smaller than val.
+ * Requires a sorted array. Uses >= for ordering. If all elements
+ * are smaller it returns the last element and if all elements are
+ * larger it returns the first element.
+ * @param first iterator to the first element
+ * @param last iterator to the last element
+ * @param val value to compare
+ * @return index of the last element that is smaller than val
+ * 
  */
 template <typename T>
 size_t last_smaller(const T* first, const T* last, T val) {
     for (auto iter = first+1; iter != last; ++iter) {
-        if (*iter > val) {
+        if (*iter >= val) {
             return std::distance(first, iter-1);
         }
     }
@@ -25,7 +32,49 @@ size_t last_smaller(const NDArray<T, 1>& arr, T val) {
     return last_smaller(arr.begin(), arr.end(), val);
 }
 
+template <typename T>
+size_t last_smaller(const std::vector<T>& vec, T val) {
+    return last_smaller(vec.data(), vec.data()+vec.size(), val);
+}
 
+/**
+ * @brief Index of the first element that is larger than val.
+ * Requires a sorted array. Uses > for ordering. If all elements
+ * are larger it returns the first element and if all elements are
+ * smaller it returns the last element.
+ * @param first iterator to the first element
+ * @param last iterator to the last element
+ * @param val value to compare
+ * @return index of the first element that is larger than val
+ */
+template <typename T>
+size_t first_larger(const T* first, const T* last, T val) {
+    for (auto iter = first; iter != last; ++iter) {
+        if (*iter > val) {
+            return std::distance(first, iter);
+        }
+    }
+    return std::distance(first, last-1);
+}
+
+template <typename T>
+size_t first_larger(const NDArray<T, 1>& arr, T val) {
+    return first_larger(arr.begin(), arr.end(), val);
+}
+
+template <typename T>
+size_t first_larger(const std::vector<T>& vec, T val) {
+    return first_larger(vec.data(), vec.data()+vec.size(), val);
+}
+
+/**
+ * @brief Index of the nearest element to val.
+ * Requires a sorted array. If there is no difference it takes the first element.
+ * @param first iterator to the first element
+ * @param last iterator to the last element
+ * @param val value to compare
+ * @return index of the nearest element
+ */
 template <typename T>
 size_t nearest_index(const T* first, const T* last, T val) {
     auto iter = std::min_element(first, last,
@@ -50,6 +99,13 @@ size_t nearest_index(const std::array<T,N>& arr, T val) {
     return nearest_index(arr.data(), arr.data()+arr.size(), val);
 }
 
+template <typename T>
+std::vector<T> cumsum(const std::vector<T>& vec) {
+    std::vector<T> result(vec.size());
+    std::partial_sum(vec.begin(), vec.end(), result.begin());
+    return result;
+}
+
 
 
 } // namespace aare