Add missing Fl_Image_Reader files

Forgot to add these files. Sorry for the noise.

1 files changed, 90 insertions, 0 deletions

diff --git a/src/Fl_Image_Reader.h b/src/Fl_Image_Reader.h
new file mode 100644
index 000000000..83d9c366e
--- /dev/null
+++ b/src/Fl_Image_Reader.h
@@ -0,0 +1,90 @@
+//
+// Internal (Image) Reader class for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 2020 by Bill Spitzak and others.
+//
+// This library is free software. Distribution and use rights are outlined in
+// the file "COPYING" which should have been included with this file.  If this
+// file is missing or damaged, see the license at:
+//
+//     https://www.fltk.org/COPYING.php
+//
+// Please report all bugs and problems on the following page:
+//
+//     https://www.fltk.org/str.php
+//
+
+/*
+  This internal (undocumented) class reads data chunks from a file or from
+  memory in LSB-first byte order.
+
+  This class is used in Fl_GIF_Image and Fl_BMP_Image to avoid code
+  duplication and may be extended to be used in similar cases. Future
+  options might be to read data in MSB-first byte order or to add more
+  methods.
+*/
+
+#ifndef FL_IMAGE_READER_H
+#define FL_IMAGE_READER_H
+
+#include <stdio.h>
+
+class Fl_Image_Reader
+{
+public:
+  // Create the reader.
+  Fl_Image_Reader() :
+  pIsFile(0), pIsData(0),
+  pFile(0L), pData(0L),
+  pStart(0L),
+  pName(0L)
+  {}
+
+  // Initialize the reader to access the file system, filename is copied
+  // and stored.
+  int open(const char *filename);
+
+  // Initialize the reader for memory access, name is copied and stored
+  int open(const char *imagename, const unsigned char *data);
+
+  // Close and destroy the reader
+  ~Fl_Image_Reader();
+
+  // Read a single byte from memory or a file
+  unsigned char read_byte();
+
+  // Read a 16-bit unsigned integer, LSB-first
+  unsigned short read_word();
+
+  // Read a 32-bit unsigned integer, LSB-first
+  unsigned int read_dword();
+
+  // Read a 32-bit signed integer, LSB-first
+  int read_long() {
+    return (int)read_dword();
+  };
+
+  // Move the current read position to a byte offset from the beginning
+  // of the file or the original start address in memory
+  void seek(unsigned int n);
+
+  // return the name or filename for this reader
+  const char *name() { return pName; }
+
+private:
+
+  // open() sets this if we read from a file
+  char pIsFile;
+  // open() sets this if we read from memory
+  char pIsData;
+  // a pointer to the opened file
+  FILE *pFile;
+  // a pointer to the current byte in memory
+  const unsigned char *pData;
+  // a pointer to the start of the image data
+  const unsigned char *pStart;
+  // a copy of the name associated with this reader
+  char *pName;
+};
+
+#endif // FL_IMAGE_READER_H