base: Introducing utility for writing raw data in png format

Originally it was possible to use a Bitmap writer class for dumping a
framebuffer snapshot in a .bmp file. This patch enables you to choose
another format.  In particular it implements the writing of PNG Images
using libpng library.  The latter has to be already installed in your
machine, otherwise gem5 will default to the Bitmap format.  This
configurable writer has been introduced in the VNC frame dumping mechanism,
which is storing changed frame buffers from the VNC server

Change-Id: Id7e5763c82235f1ce90381c8486b85a7cce734ce
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/5181
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

1 files changed, 175 insertions, 0 deletions

diff --git a/src/base/pngwriter.cc b/src/base/pngwriter.cc
new file mode 100644
index 000000000..3b49d479d
--- /dev/null
+++ b/src/base/pngwriter.cc
@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 2017 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Giacomo Travaglini
+ */
+
+/**
+ * @file Definition of a class that writes a frame buffer to a png
+ */
+
+#include "base/pngwriter.hh"
+
+extern "C"
+{
+#include <png.h>
+}
+
+#include <cstdio>
+#include <cstdlib>
+
+#include "base/misc.hh"
+
+const char* PngWriter::_imgExtension = "png";
+
+/**
+ * Write callback to use with libpng APIs
+ *
+ * @param pngPtr  pointer to the png_struct structure
+ * @param data    pointer to the data being written
+ * @param length  number of bytes being written
+ */
+static void
+writePng(png_structp pngPtr, png_bytep data, png_size_t length)
+{
+    // Here we get our IO pointer back from the write struct
+    // and we cast it into a ostream* type.
+    std::ostream* strmPtr = reinterpret_cast<std::ostream*>(
+        png_get_io_ptr(pngPtr)
+    );
+
+    // Write length bytes to data
+    strmPtr->write(reinterpret_cast<const char *>(data), length);
+}
+
+struct PngWriter::PngStructHandle {
+  private:
+    // Make PngStructHandle uncopyable
+    PngStructHandle(const PngStructHandle&) = delete;
+    PngStructHandle& operator=(const PngStructHandle&) = delete;
+  public:
+
+    PngStructHandle() :
+        pngWriteP(NULL), pngInfoP(NULL)
+    {
+        // Creating write structure
+        pngWriteP = png_create_write_struct(
+            PNG_LIBPNG_VER_STRING, NULL, NULL, NULL
+        );
+
+        if (pngWriteP) {
+            // Creating info structure
+            pngInfoP = png_create_info_struct(pngWriteP);
+        }
+    }
+
+    ~PngStructHandle()
+    {
+        if (pngWriteP) {
+            png_destroy_write_struct(&pngWriteP, &pngInfoP);
+        }
+    }
+
+    /** Pointer to PNG Write struct */
+    png_structp pngWriteP;
+
+    /** Pointer to PNG Info struct */
+    png_infop pngInfoP;
+};
+
+void
+PngWriter::write(std::ostream &png) const
+{
+
+    // Height of the frame buffer
+    unsigned height = fb.height();
+    unsigned width  = fb.width();
+
+    // Do not write if frame buffer is empty
+    if (!fb.area()) {
+        png.flush();
+        return;
+    }
+
+    // Initialize Png structures
+    PngStructHandle handle;
+
+    // Png info/write pointers.
+    png_structp pngPtr  = handle.pngWriteP;
+    png_infop   infoPtr = handle.pngInfoP;
+
+    if (!pngPtr) {
+        warn("Frame buffer dump aborted: Unable to create"
+             "Png Write Struct\n");
+        return;
+    }
+
+    if (!infoPtr) {
+        warn("Frame buffer dump aborted: Unable to create"
+             "Png Info Struct\n");
+        return;
+    }
+
+    // We cannot use default libpng write function since it requires
+    // a file pointer (FILE*), whereas we want to use the ostream.
+    // The following function replaces the write function with a custom
+    // one provided by us (writePng)
+    png_set_write_fn(pngPtr, (png_voidp)&png, writePng, NULL);
+
+    png_set_IHDR(pngPtr, infoPtr, width, height, 8,
+                 PNG_COLOR_TYPE_RGB,
+                 PNG_INTERLACE_NONE,
+                 PNG_COMPRESSION_TYPE_DEFAULT,
+                 PNG_FILTER_TYPE_DEFAULT);
+
+    png_write_info(pngPtr, infoPtr);
+
+    // libpng requires an array of pointers to the frame buffer's rows.
+    std::vector<PixelType> rowPacked(width);
+    for (unsigned y=0; y < height; ++y) {
+        for (unsigned x=0; x < height; ++x) {
+            rowPacked[x] = fb.pixel(x, y);
+        }
+
+        png_write_row(pngPtr,
+            reinterpret_cast<png_bytep>(rowPacked.data())
+        );
+    }
+
+    // End of write
+    png_write_end(pngPtr, NULL);
+}
+