Add simple PGM and PPM image writers

Makefile.am

@@ -40,6 +40,8 @@ UTIL_FILES   =		\
     guid.hpp		\
     hash.cpp		\
     hash.hpp		\
+    image.cpp		\
+    image.hpp		\
     io.cpp		\
     io.hpp		\
     ip.cpp		\

image.cpp

@@ -0,0 +1,82 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ * 
+ * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2011 Danny Robson <danny@nerdcruft.net>
+ */
+
+
+#include "image.hpp"
+
+#include "debug.hpp"
+#include "except.hpp"
+
+#include <fstream>
+
+
+static void
+write_netpbm (const uint8_t *restrict pixels,
+              size_t width,
+              size_t height,
+              size_t stride,
+              const boost::filesystem::path &path,
+              const char* MAGIC) {
+    CHECK_HARD (pixels);
+    CHECK_HARD (width > 0);
+    CHECK_HARD (stride >= width);
+    CHECK_HARD (height > 0);
+
+    // Establish an output stream
+    std::ofstream output (path.native (), std::ios::binary);
+    if (!output.good ())
+        throw util::output_error ("Unable to open output file");
+
+    // Write the PPM header.
+    output << MAGIC  << "\n"
+           << width  << "\n"
+           << height << "\n"
+           << (size_t)std::numeric_limits<uint8_t>::max () << "\n";
+
+    // Write the data rows
+    for (size_t y = 0; y < height; ++y) {
+        for (size_t x = 0; x < width; ++x)
+            output << (size_t)pixels[y * stride + x] << " ";
+        
+        output << "\n";
+    }
+}
+
+void
+util::pgm::write (const uint8_t *restrict pixels,
+                  size_t width,
+                  size_t height,
+                  size_t stride,
+                  const boost::filesystem::path &path) {
+    // TODO: We should switch between P2 (ascii) and P5 (binary)
+    static const char MAGIC[] = "P2";
+    write_netpbm (pixels, width, height, stride, path, MAGIC);
+}
+
+
+void
+util::ppm::write (const uint8_t *restrict pixels,
+                  size_t width,
+                  size_t height,
+                  size_t stride,
+                  const boost::filesystem::path &path) {
+    // TODO: We should switch between P3 (ascii) and P6 (binary)
+    static const char MAGIC[] = "P6";
+    write_netpbm (pixels, width, height, stride, path, MAGIC);
+}

image.hpp

@@ -0,0 +1,45 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ * 
+ * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2011 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef __UTIL_IMAGE_HPP
+#define __UTIL_IMAGE_HPP
+
+#include <cstdint>
+#include <cstdlib>
+#include <boost/filesystem/path.hpp>
+
+namespace util {
+    struct pgm {
+        static void write (const uint8_t *restrict pixels,
+                           size_t width,
+                           size_t height,
+                           size_t stride,
+                           const boost::filesystem::path &path);
+    };
+
+    struct ppm {
+        static void write (const uint8_t *restrict pixels,
+                           size_t width,
+                           size_t height,
+                           size_t stride,
+                           const boost::filesystem::path &path);
+    };
+}
+
+#endif