1 files changed, 106 insertions, 0 deletions
diff --git a/hw2/src/imageIO.ppm.cpp b/hw2/src/imageIO.ppm.cpp
new file mode 100644
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--- /dev/null
+++ b/hw2/src/imageIO.ppm.cpp
@@ -0,0 +1,106 @@
+/******************************************************************/
+/* This file is part of the homework assignments for CSCI-427/527 */
+/* at The College of William & Mary and authored by Pieter Peers. */
+/* No part of this file, whether altered or in original form, can */
+/* be distributed or used outside the context of CSCI-427/527     */
+/* without consent of either the College of William & Mary or     */
+/* Pieter Peers.                                                  */
+/******************************************************************/
+#include "imageIO.ppm.h"
+#include "errorMessage.h"
+
+#include <memory>
+#include <cassert>
+#include <cstdint>
+#include <fstream>
+#include <algorithm>
+
+//////////////////////
+// Helper functions //
+//////////////////////
+static void skipToNewline(std::ifstream& ifs)
+{
+  while(ifs.get() != '\n' && ifs.good()); 
+}
+
+static void skipComments(std::ifstream& ifs)
+{
+  while(!ifs.eof() && ifs.peek() == '#') skipToNewline(ifs); 
+}
+
+
+////////////////
+// Import PPM //
+////////////////
+void importPPM(const std::string& name, image& img)
+{
+  // open file
+  std::ifstream ifs(name.c_str());
+  if(!ifs.is_open()) errorMessage("Unable to open file: '%s'.", name.c_str());
+
+  // read header
+  std::string magicMark;
+  ifs >> magicMark;
+  skipToNewline(ifs);
+  if(magicMark != "P6") errorMessage("Unsupported PPM format (%s).", magicMark.c_str());
+
+  // read width & height
+  image::size_type width, height;
+  skipComments(ifs);
+  ifs >> width >> height;
+  skipToNewline(ifs);
+
+  // allocate
+  img = image(width, height);
+
+  // check magic number (again)
+  skipComments(ifs);
+  ifs >> magicMark;
+  skipToNewline(ifs);
+  if(magicMark != "255") errorMessage("Unsupported bit-depth in PPM file (%s).", magicMark.c_str());
+
+  // read char buffer
+  std::unique_ptr<uint8_t[]> tempBuffer(new uint8_t[img.size() * 3]);
+  ifs.read((char *)(tempBuffer.get()), img.size() * 3);
+
+  // convert to image
+  std::transform(tempBuffer.get(), tempBuffer.get() + (img.size()*3), img.begin()->begin(), [](uint8_t val) 
+  { 
+    return (float)(val) / 255.0f; 
+  });
+
+  // Done.
+}
+
+
+////////////////
+// Export PPM //
+////////////////
+void exportPPM(const std::string& name, const image& img)
+{
+  // sanity check
+  assert(img.width() != 0 && img.height() != 0);
+
+  // open file
+  std::ofstream ofs(name.c_str());
+  if(!ofs.is_open()) errorMessage("Unable to open file: '%s'.", name.c_str());
+
+  // write header
+  ofs << "P6\n" << img.width() << " " << img.height() << "\n" << "255\n";
+
+  // convert to char buffer
+  std::unique_ptr<uint8_t[]> tempBuffer(new uint8_t[img.size() * 3]);
+  std::transform(img.begin()->begin(), img.end()->begin(), tempBuffer.get(), [](float val)
+  { 
+    return (val < 0.0f) ? 0 : 
+           (val > 1.0f) ? 255 : 
+           uint8_t(val*255); 
+   });
+    
+  // write body
+  ofs.write((const char*)(tempBuffer.get()), img.size() * 3);
+
+  // Done.
+}
+
+