Merge pull request jcbritobr#2 from jcbritobr/massa-patch-1-ppmimage-…

…reader-writer

Massa patch 1 ppmimage reader writer

ppmimage.cpp

@@ -1,40 +1,53 @@
-#include <iostream>
 #include "ppmimage.hpp"
 
-int PPMImage::getHeigth() const
-{
-    return heigth;
-}
-
-int PPMImage::getWidth() const
-{
-    return width;
-}
-
-std::vector<Color> PPMImage::getData() const
-{
-    return data;
-}
+//TODO:: write tests -- this code compiles :-)
 
-PPMImage::PPMImage(int width, int heigth):width(width), heigth(heigth)
-{
-    for (int i = 0; i < width * heigth; ++i) {
-        data.push_back(Color(0.0f, 0.0f, 0.0f));
-    }
-}
+constexpr auto P3MARKER = "P3";
+constexpr auto PPMNL = '\n';
+constexpr auto PPMSPACE = ' ';
+constexpr auto PPMMAGIC = 255;
 
 std::ostream &operator <<(std::ostream &stream, const PPMImage &image)
 {
-    stream << "P3\n" << image.getWidth() << " " << image.getHeigth() << "\n255\n";
+    stream << P3MARKER << PPMNL << image.width << PPMSPACE << image.height << PPMNL << PPMMAGIC << PPMNL;
+    if( !stream ) return stream;
 
-    for (auto color: image.getData()) {
-        stream << color.r() << " " << color.g() << " " << color.b() << std::endl;
+    for ( const auto& color: image.data ) {
+        stream << color.r() << PPMSPACE << color.g() << PPMSPACE << color.b() << PPMNL;
+        if( !stream ) return stream;
     }
 
     return stream;
 }
 
 std::istream &operator >>(std::istream &stream, PPMImage &image)
 {
+    if( !stream ) return stream;
+    std::string p3;
+    stream >> p3;
+    if( !stream ) return stream;
+    if( p3 != P3MARKER ) {
+        stream.setstate(std::ios_base::failbit);
+        return stream;
+    }
+    size_t width, height, magic;
+    stream >> width >> height >> magic;
+    if( !stream ) return stream;
+    if( magic != PPMMAGIC ) {
+        stream.setstate(std::ios_base::failbit);
+        return stream;
+    }
+    std::vector<Color> data;
+    data.reserve(width*height); // avoid reallocations and copies
+
+    for( auto count = width*height; count --> 0; ) {
+        float r, g, b;
+        stream >> r >> g >> b;
+        if( !stream ) return stream;
+        data.emplace_back(r, g, b);
+    }
 
+    image = PPMImage { width, height, data };
+
+    return stream;
 }

ppmimage.hpp

@@ -5,17 +5,18 @@
 #include <vector>
 #include "color.hpp"
 
-class PPMImage
-{
-private:
+// PPMImage is semi-immutable: one can manipulate in-place the individual pixels but you can't
+// resize the image. The array of pixels will be moved whenever possible.
+
+struct PPMImage {
+    const size_t width;
+    const size_t height;
     std::vector<Color> data;
-    int width;
-    int heigth;
-public:
-    PPMImage(int width, int heigth);
-    int getHeigth() const;
-    int getWidth() const;
-    std::vector<Color> getData() const;
+    PPMImage(size_t width_, size_t height_) : width {width_}, height {height_}, data {width*height, Color{.0f, .0f, .0f}} {}
+    PPMImage(size_t width_, size_t height_, std::vector<Color> const& data_) : width {width_}, height {height_}, data {data_} {}
+    PPMImage(size_t width_, size_t height_, std::vector<Color> && data_) : width {width_}, height {height_}, data {std::move(data_)} {}
+    PPMImage& operator=(PPMImage const& image) { new(this) PPMImage { image.width, image.height, image.data }; return *this; }
+    PPMImage& operator=(PPMImage && image) { new(this) PPMImage { image.width, image.height, std::move(image.data) }; return *this; }
 };
 
 std::ostream& operator <<(std::ostream &stream, PPMImage const &image);