1 files changed, 131 insertions, 0 deletions
diff --git a/src/Fl_Image_Reader.cxx b/src/Fl_Image_Reader.cxx
new file mode 100644
index 000000000..083efb471
--- /dev/null
+++ b/src/Fl_Image_Reader.cxx
@@ -0,0 +1,131 @@
+//
+// 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
+//
+
+
+//
+// Include necessary header files...
+//
+
+#include "Fl_Image_Reader.h"
+
+#include <FL/fl_utf8.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+  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.
+*/
+
+// Initialize the reader to access the file system, filename is copied
+// and stored.
+int Fl_Image_Reader::open(const char *filename) {
+  if (!filename)
+    return -1;
+  pName = strdup(filename);
+  if ( (pFile = fl_fopen(filename, "rb")) == NULL ) {
+    return -1;
+  }
+  pIsFile = 1;
+  return 0;
+}
+
+// Initialize the reader for memory access, name is copied and stored
+int Fl_Image_Reader::open(const char *imagename, const unsigned char *data) {
+  if (imagename)
+    pName = strdup(imagename);
+  if (data) {
+    pStart = pData = data;
+    pIsData = 1;
+    return 0;
+  } else {
+    return -1;
+  }
+}
+
+// Close and destroy the reader
+Fl_Image_Reader::~Fl_Image_Reader() {
+  if (pIsFile && pFile) {
+    fclose(pFile);
+  }
+  if (pName)
+    ::free(pName);
+}
+
+// Read a single byte from memory or a file
+uchar Fl_Image_Reader::read_byte() {
+  if (pIsFile) {
+    return getc(pFile);
+  } else if (pIsData) {
+    return *pData++;
+  } else {
+    return 0;
+  }
+}
+
+// Read a 16-bit unsigned integer, LSB-first
+unsigned short Fl_Image_Reader::read_word() {
+  unsigned char b0, b1;  // Bytes from file
+  if (pIsFile) {
+    b0 = (uchar)getc(pFile);
+    b1 = (uchar)getc(pFile);
+    return ((b1 << 8) | b0);
+  } else if (pIsData) {
+    b0 = *pData++;
+    b1 = *pData++;
+    return ((b1 << 8) | b0);
+  } else {
+    return 0;
+  }
+}
+
+// Read a 32-bit unsigned integer, LSB-first
+unsigned int Fl_Image_Reader::read_dword() {
+  unsigned char b0, b1, b2, b3;  // Bytes from file
+  if (pIsFile) {
+    b0 = (uchar)getc(pFile);
+    b1 = (uchar)getc(pFile);
+    b2 = (uchar)getc(pFile);
+    b3 = (uchar)getc(pFile);
+    return ((((((b3 << 8) | b2) << 8) | b1) << 8) | b0);
+  } else if (pIsData) {
+    b0 = *pData++;
+    b1 = *pData++;
+    b2 = *pData++;
+    b3 = *pData++;
+    return ((((((b3 << 8) | b2) << 8) | b1) << 8) | b0);
+  } else {
+    return 0;
+  }
+}
+
+// Read a 32-bit signed integer, LSB-first
+// int Fl_Image_Reader::read_long() -- implementation in header file
+
+// Move the current read position to a byte offset from the beginning
+// of the file or the original start address in memory
+void Fl_Image_Reader::seek(unsigned int n) {
+  if (pIsFile) {
+    fseek(pFile, n , SEEK_SET);
+  } else if (pIsData) {
+    pData = pStart + n;
+  }
+}