From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 26 Aug 2011 11:49:07 +0000 (+0300)
Subject: Separate PNG loading to a separate file
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgui.git;a=commitdiff_plain;h=cc728fda1325c5358f3ec177d31621b5688371fe

Separate PNG loading to a separate file
---

diff --git a/source/graphics/image.cpp b/source/graphics/image.cpp
index 3360b72..56e7c1b 100644
--- a/source/graphics/image.cpp
+++ b/source/graphics/image.cpp
@@ -1,33 +1,17 @@
 #ifdef WITH_DEVIL
 #include <IL/il.h>
 #endif
-#ifdef WITH_LIBPNG
-#include <png.h>
 #include <msp/io/file.h>
 #include <msp/io/memory.h>
-#endif
 #include "image.h"
+#include "image_png.h"
+#include "image_private.h"
 
 using namespace std;
 
 namespace Msp {
 namespace Graphics {
 
-struct Image::Private
-{
-#ifdef WITH_DEVIL
-	unsigned id;
-#endif
-#ifdef WITH_LIBPNG
-	PixelFormat fmt;
-	unsigned width;
-	unsigned height;
-	char *data;
-#endif
-
-	Private();
-};
-
 Image::Private::Private()
 {
 #ifdef WITH_DEVIL
@@ -44,69 +28,6 @@ Image::Private::Private()
 
 namespace {
 
-#ifdef WITH_LIBPNG
-void read(png_struct *png, png_byte *data, png_size_t size)
-{
-	IO::Base *in = reinterpret_cast<IO::Base *>(png_get_io_ptr(png));
-	in->read(reinterpret_cast<char *>(data), size);
-}
-
-void load_png(IO::Base &in, Image::Private &priv)
-{
-	png_struct *png = 0;
-	png_info *info = 0;
-	priv.data = 0;
-
-	try
-	{
-		png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
-		info = png_create_info_struct(png);
-
-		if(setjmp(png_jmpbuf(png)))
-			throw bad_image_data("PNG error");
-
-		png_set_read_fn(png, &in, read);
-		png_read_info(png, info);
-		png_uint_32 width;
-		png_uint_32 height;
-		int depth;
-		int color;
-		png_get_IHDR(png, info, &width, &height, &depth, &color, 0, 0, 0);
-		priv.width = width;
-		priv.height = height;
-		if(depth!=8)
-			throw unsupported_image_format("depth!=8");
-		switch(color)
-		{
-		case PNG_COLOR_TYPE_PALETTE:    priv.fmt = COLOR_INDEX; break;
-		case PNG_COLOR_TYPE_GRAY:       priv.fmt = LUMINANCE; break;
-		case PNG_COLOR_TYPE_GRAY_ALPHA: priv.fmt = LUMINANCE_ALPHA; break;
-		case PNG_COLOR_TYPE_RGB:        priv.fmt = RGB; break;
-		case PNG_COLOR_TYPE_RGB_ALPHA:  priv.fmt = RGBA; break;
-		default: throw unsupported_image_format("unknown color type");
-		}
-
-		unsigned nchans = png_get_channels(png, info);
-		if(nchans==4 && priv.fmt==RGB)
-			png_set_strip_alpha(png);
-
-		unsigned rowstride = priv.width*nchans;
-		priv.data = new char[rowstride*priv.height];
-		for(unsigned y=0; y<priv.height; ++y)
-			png_read_row(png, reinterpret_cast<png_byte *>(priv.data+rowstride*(priv.height-1-y)), 0);
-
-		png_read_end(png, 0);
-		png_destroy_read_struct(&png, &info, 0);
-	}
-	catch(...)
-	{
-		png_destroy_read_struct(&png, &info, 0);
-		delete[] priv.data;
-		throw;
-	}
-}
-#endif
-
 #ifdef WITH_DEVIL
 void ensure_devil_image(unsigned &id)
 {
@@ -174,7 +95,7 @@ void Image::load_file(const string &fn)
 void Image::load_memory(const void *data, unsigned size)
 {
 #ifdef WITH_LIBPNG
-	if(!png_sig_cmp(reinterpret_cast<png_byte *>(const_cast<void *>(data)), 0, 8))
+	if(size>=8 && is_png(data, 8))
 	{
 		IO::Memory mem(reinterpret_cast<const char *>(data), size);
 		load_png(mem, *priv);
diff --git a/source/graphics/image.h b/source/graphics/image.h
index db65010..bc7151b 100644
--- a/source/graphics/image.h
+++ b/source/graphics/image.h
@@ -1,6 +1,7 @@
 #ifndef MSP_GRAPHICS_IMAGE_H_
 #define MSP_GRAPHICS_IMAGE_H_
 
+#include <stdexcept>
 #include <string>
 #include "pixelformat.h"
 
diff --git a/source/graphics/image_png.cpp b/source/graphics/image_png.cpp
new file mode 100644
index 0000000..256159c
--- /dev/null
+++ b/source/graphics/image_png.cpp
@@ -0,0 +1,82 @@
+#ifdef WITH_LIBPNG
+#include <png.h>
+#include "image_png.h"
+#include "image_private.h"
+
+namespace {
+
+void read(png_struct *png, png_byte *data, png_size_t size)
+{
+	Msp::IO::Base *in = reinterpret_cast<Msp::IO::Base *>(png_get_io_ptr(png));
+	in->read(reinterpret_cast<char *>(data), size);
+}
+
+}
+
+
+namespace Msp {
+namespace Graphics {
+
+bool is_png(const void *buf, unsigned len)
+{
+	return !png_sig_cmp(reinterpret_cast<png_byte *>(const_cast<void *>(buf)), 0, len);
+}
+
+void load_png(IO::Base &in, Image::Private &priv)
+{
+	png_struct *png = 0;
+	png_info *info = 0;
+	priv.data = 0;
+
+	try
+	{
+		png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
+		info = png_create_info_struct(png);
+
+		if(setjmp(png_jmpbuf(png)))
+			throw bad_image_data("PNG error");
+
+		png_set_read_fn(png, &in, read);
+		png_read_info(png, info);
+		png_uint_32 width;
+		png_uint_32 height;
+		int depth;
+		int color;
+		png_get_IHDR(png, info, &width, &height, &depth, &color, 0, 0, 0);
+		priv.width = width;
+		priv.height = height;
+		if(depth!=8)
+			throw unsupported_image_format("depth!=8");
+		switch(color)
+		{
+		case PNG_COLOR_TYPE_PALETTE:    priv.fmt = COLOR_INDEX; break;
+		case PNG_COLOR_TYPE_GRAY:       priv.fmt = LUMINANCE; break;
+		case PNG_COLOR_TYPE_GRAY_ALPHA: priv.fmt = LUMINANCE_ALPHA; break;
+		case PNG_COLOR_TYPE_RGB:        priv.fmt = RGB; break;
+		case PNG_COLOR_TYPE_RGB_ALPHA:  priv.fmt = RGBA; break;
+		default: throw unsupported_image_format("unknown color type");
+		}
+
+		unsigned nchans = png_get_channels(png, info);
+		if(nchans==4 && priv.fmt==RGB)
+			png_set_strip_alpha(png);
+
+		unsigned rowstride = priv.width*nchans;
+		priv.data = new char[rowstride*priv.height];
+		for(unsigned y=0; y<priv.height; ++y)
+			png_read_row(png, reinterpret_cast<png_byte *>(priv.data+rowstride*(priv.height-1-y)), 0);
+
+		png_read_end(png, 0);
+		png_destroy_read_struct(&png, &info, 0);
+	}
+	catch(...)
+	{
+		png_destroy_read_struct(&png, &info, 0);
+		delete[] priv.data;
+		throw;
+	}
+}
+
+} // namespace Graphics
+} // namespace Msp
+#endif
diff --git a/source/graphics/image_png.h b/source/graphics/image_png.h
new file mode 100644
index 0000000..e07536a
--- /dev/null
+++ b/source/graphics/image_png.h
@@ -0,0 +1,18 @@
+#ifndef MSP_GRAPHICS_IMAGE_PNG_H_
+#define MSP_GRAPHICS_IMAGE_PNG_H_
+
+#include <msp/io/base.h>
+#include "image.h"
+
+namespace Msp {
+namespace Graphics {
+
+#ifdef WITH_LIBPNG
+bool is_png(const void *, unsigned);
+void load_png(IO::Base &, Image::Private &);
+#endif
+
+} // namespace Graphics
+} // namespace Msp
+
+#endif
diff --git a/source/graphics/image_private.h b/source/graphics/image_private.h
new file mode 100644
index 0000000..19f0cef
--- /dev/null
+++ b/source/graphics/image_private.h
@@ -0,0 +1,27 @@
+#ifndef MSP_GRAPHICS_IMAGE_PRIVATE_H_
+#define MSP_GRAPHICS_IMAGE_PRIVATE_H_
+
+#include "image.h"
+
+namespace Msp {
+namespace Graphics {
+
+struct Image::Private
+{
+#ifdef WITH_DEVIL
+	unsigned id;
+#endif
+#ifdef WITH_LIBPNG
+	PixelFormat fmt;
+	unsigned width;
+	unsigned height;
+	char *data;
+#endif
+
+	Private();
+};
+
+} // namespace Graphics
+} // namespace Msp
+
+#endif