Initial QFileInputStream implementation

scwx-qt/scwx-qt.cmake

@@ -161,13 +161,15 @@ set(HDR_UTIL source/scwx/qt/util/color.hpp
              source/scwx/qt/util/json.hpp
              source/scwx/qt/util/streams.hpp
              source/scwx/qt/util/texture_atlas.hpp
-             source/scwx/qt/util/q_file_buffer.hpp)
+             source/scwx/qt/util/q_file_buffer.hpp
+             source/scwx/qt/util/q_file_input_stream.hpp)
 set(SRC_UTIL source/scwx/qt/util/color.cpp
              source/scwx/qt/util/font.cpp
              source/scwx/qt/util/font_buffer.cpp
              source/scwx/qt/util/json.cpp
              source/scwx/qt/util/texture_atlas.cpp
-             source/scwx/qt/util/q_file_buffer.cpp)
+             source/scwx/qt/util/q_file_buffer.cpp
+             source/scwx/qt/util/q_file_input_stream.cpp)
 set(HDR_VIEW source/scwx/qt/view/level2_product_view.hpp
              source/scwx/qt/view/level3_product_view.hpp
              source/scwx/qt/view/level3_radial_view.hpp

scwx-qt/source/scwx/qt/util/q_file_buffer.cpp

@@ -72,6 +72,13 @@ QFileBuffer::~QFileBuffer() = default;
 QFileBuffer::QFileBuffer(QFileBuffer&&) noexcept            = default;
 QFileBuffer& QFileBuffer::operator=(QFileBuffer&&) noexcept = default;
 
+void QFileBuffer::swap(QFileBuffer& other)
+{
+   // Swap the base class and managed implementation pointer
+   std::streambuf::swap(other);
+   p.swap(other.p);
+}
+
 bool QFileBuffer::is_open() const
 {
    return p->file_.isOpen();
@@ -147,7 +154,7 @@ QFileBuffer::int_type QFileBuffer::pbackfail(int_type c)
         traits_type::eq_int_type(traits_type::to_int_type(gptr()[-1]), c)))
    {
       // Just back up position
-      gbump(static_cast<int>(sizeof(char_type)) * -1);
+      gbump(-1);
       return traits_type::not_eof(c);
    }
    else if (!is_open() || traits_type::eq_int_type(traits_type::eof(), c))
@@ -274,7 +281,7 @@ QFileBuffer::int_type QFileBuffer::uflow()
    {
       // Return buffered
       int_type c = traits_type::to_int_type(*gptr());
-      gbump(sizeof(char_type));
+      gbump(1);
       return c;
    }
 

scwx-qt/source/scwx/qt/util/q_file_buffer.hpp

@@ -29,7 +29,7 @@ public:
    explicit QFileBuffer();
 
    /**
-    * Constructs a new QFileBuffer object, then associated the object with a
+    * Constructs a new QFileBuffer object, then associates the object with a
     * file by calling open(filename, mode). If the open call is successful,
     * is_open() returns true.
     */
@@ -43,6 +43,13 @@ public:
    QFileBuffer(QFileBuffer&&) noexcept;
    QFileBuffer& operator=(QFileBuffer&&) noexcept;
 
+   /**
+    * @brief Swaps two QFileBuffer objects
+    *
+    * Exchanges the contents of the QFile buffer with those of the other.
+    */
+   void swap(QFileBuffer& other);
+
    /**
     * @brief Checks if the associated file is open
     *

scwx-qt/source/scwx/qt/util/q_file_input_stream.cpp

@@ -0,0 +1,96 @@
+#include <scwx/qt/util/q_file_input_stream.hpp>
+#include <scwx/qt/util/q_file_buffer.hpp>
+
+namespace scwx
+{
+namespace qt
+{
+namespace util
+{
+
+static const std::string logPrefix_ = "scwx::qt::util::q_file_input_stream";
+
+// Adapted from Microsoft ifstream reference implementation
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+class QFileInputStream::Impl
+{
+public:
+   explicit Impl() : buffer_ {} {};
+   explicit Impl(const std::string& filename, std::ios_base::openmode mode) :
+       buffer_ {filename, mode} {};
+   ~Impl() = default;
+
+   QFileBuffer buffer_;
+};
+
+QFileInputStream::QFileInputStream() :
+    std::istream(nullptr), p(std::make_unique<Impl>())
+{
+   std::basic_ios<char_type, traits_type>::rdbuf(&p->buffer_);
+}
+
+QFileInputStream::QFileInputStream(const std::string&      filename,
+                                   std::ios_base::openmode mode) :
+    std::istream(nullptr),
+    p(std::make_unique<Impl>(filename, mode | std::ios_base::in))
+{
+   std::basic_ios<char_type, traits_type>::rdbuf(&p->buffer_);
+   if (!p->buffer_.is_open())
+   {
+      setstate(std::ios_base::failbit);
+   }
+}
+
+QFileInputStream::~QFileInputStream() = default;
+
+QFileInputStream::QFileInputStream(QFileInputStream&& other) noexcept :
+    std::istream(nullptr), p(std::make_unique<Impl>())
+{
+   swap(other);
+};
+QFileInputStream&
+QFileInputStream::operator=(QFileInputStream&&) noexcept = default;
+
+void QFileInputStream::swap(QFileInputStream& other)
+{
+   // Swap the base class and managed implementation pointer
+   std::istream::swap(other);
+   p.swap(other.p);
+}
+
+bool QFileInputStream::is_open() const
+{
+   return p->buffer_.is_open();
+}
+
+void QFileInputStream::open(const std::string&      filename,
+                            std::ios_base::openmode mode)
+{
+   if (p->buffer_.open(filename, mode | std::ios_base::in) == nullptr)
+   {
+      setstate(std::ios_base::failbit);
+   }
+   else
+   {
+      clear();
+   }
+}
+
+void QFileInputStream::close()
+{
+   if (p->buffer_.close() == nullptr)
+   {
+      setstate(std::ios_base::failbit);
+   }
+}
+
+QFileBuffer* QFileInputStream::rdbuf() const
+{
+   return &p->buffer_;
+}
+
+} // namespace util
+} // namespace qt
+} // namespace scwx

scwx-qt/source/scwx/qt/util/q_file_input_stream.hpp

@@ -0,0 +1,101 @@
+#pragma once
+
+#include <istream>
+
+namespace scwx
+{
+namespace qt
+{
+namespace util
+{
+
+class QFileBuffer;
+
+/**
+ * The QFileInputStream class is a std::istream interface to a QFile, allowing
+ * use with C++ stream-based I/O.
+ *
+ * Documentation for functions derived from
+ * https://en.cppreference.com/ SPDX-License-Identifier: CC BY-SA 3.0
+ */
+class QFileInputStream : public std::istream
+{
+public:
+   /**
+    * Constructs a new QFileInputStream object. The created object is not
+    * associated with a file: default-constructs the QFileBuffer and constructs
+    * the base with the pointer to this default-constructed QFileBuffer member.
+    */
+   explicit QFileInputStream();
+
+   /**
+    * Constructs a new QFileInputStream object, then associates the object with
+    * a file by calling rdbuf()->open(filename, mode | std::ios_base::in). If
+    * the open() call returns a null pointer, sets setstate(failbit).
+    */
+   explicit QFileInputStream(const std::string&      filename,
+                             std::ios_base::openmode mode = std::ios_base::in);
+   ~QFileInputStream();
+
+   QFileInputStream(const QFileInputStream&)            = delete;
+   QFileInputStream& operator=(const QFileInputStream&) = delete;
+
+   QFileInputStream(QFileInputStream&&) noexcept;
+   QFileInputStream& operator=(QFileInputStream&&) noexcept;
+
+   /**
+    * @brief Swaps two QFileInputStream objects
+    *
+    * Exchanges the contents of the QFile input stream with those of the other.
+    */
+   void swap(QFileInputStream& other);
+
+   /**
+    * @brief Checks if the stream has an associated file
+    *
+    * Checks if the file stream has an associated file. Effectively calls
+    * rdbuf()->is_open().
+    *
+    * @return true if the associated file is open, false otherwise
+    */
+   bool is_open() const;
+
+   /**
+    * @brief Opens a file and associates it with the stream
+    *
+    * Opens and associates the file with name filename with the file stream.
+    * Effectively calls rdbuf()->open(filename, mode | ios_base::in). Calls
+    * setstate(failbit) on failure.
+    *
+    * @param filename The file name to open
+    * @param openmode The file opening mode, a binary OR of the std::ios_base
+    * modes
+    */
+   void open(const std::string&      filename,
+             std::ios_base::openmode mode = std::ios_base::in);
+
+   /**
+    * @brief Close the associated file
+    *
+    * Closes the associated file. Effectively calls rdbuf()->close(). If an
+    * error occurs during operation, setstate(failbit) is called.
+    */
+   void close();
+
+   /**
+    * @brief Returns the underlying raw file device object
+    *
+    * Returns a pointer to the underlying raw file device object.
+    *
+    * @return Pointer to the underlying raw file device
+    */
+   QFileBuffer* rdbuf() const;
+
+private:
+   class Impl;
+   std::unique_ptr<Impl> p;
+};
+
+} // namespace util
+} // namespace qt
+} // namespace scwx