Reimplement basic RGBGFX features in C++

Currently missing from the old version:
- `-f` ("fixing" the input image to be indexed)
- `-m` (the code for detecting mirrored tiles is missing, but all of the
        "plumbing" is otherwise there)
- `-C`
- `-d`
- `-x` (though I need to check the exact functionality the old one has)
- Also the man page is still a draft and needs to be fleshed out

More planned features are not implemented yet either:
- Explicit palette spec
- Better error messages, also error "images"
- Better 8x16 support, as well as other "dedup unit" sizes
- Support for arbitrary number of palettes & colors per palette
- Other output formats (for example, a "full" palette map for "streaming"
  use cases like gb-open-world)
- Quantization?

Some things may also be bugged:
- Transparency support
- Tile offsets (not exposed yet)
- Tile counts per bank (not exposed yet)

...and performance remains to be checked.
We need to set up some tests, honestly.

include/defaultinitalloc.hpp

@@ -0,0 +1,38 @@
+/**
+ * Allocator adaptor that interposes construct() calls to convert value-initialization
+ * (which is what you get with e.g. `vector::resize`) into default-initialization (which does not
+ * zero out non-class types).
+ * From https://stackoverflow.com/questions/21028299/is-this-behavior-of-vectorresizesize-type-n-under-c11-and-boost-container/21028912#21028912
+ */
+
+#ifndef DEFAULT_INIT_ALLOC_H
+#define DEFAULT_INIT_ALLOC_H
+
+#include <memory>
+#include <vector>
+
+template<typename T, typename A = std::allocator<T>>
+class default_init_allocator : public A {
+	using a_t = std::allocator_traits<A>;
+public:
+	template<typename U>
+	struct rebind {
+		using other = default_init_allocator<U, typename a_t::template rebind_alloc<U>>;
+	};
+
+	using A::A; // Inherit the allocator's constructors
+
+	template<typename U>
+	void construct(U * ptr) noexcept(std::is_nothrow_default_constructible_v<U>) {
+		::new(static_cast<void *>(ptr)) U;
+	}
+	template<typename U, typename... Args>
+	void construct(U * ptr, Args && ... args) {
+		a_t::construct(static_cast<A &>(*this), ptr, std::forward<Args>(args)...);
+	}
+};
+
+template<typename T>
+using DefaultInitVec = std::vector<T, default_init_allocator<T>>;
+
+#endif

include/error.h

@@ -12,10 +12,18 @@
 #include "helpers.h"
 #include "platform.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void warn(char const NONNULL(fmt), ...) format_(printf, 1, 2);
 void warnx(char const NONNULL(fmt), ...) format_(printf, 1, 2);
 
 _Noreturn void err(char const NONNULL(fmt), ...) format_(printf, 1, 2);
 _Noreturn void errx(char const NONNULL(fmt), ...) format_(printf, 1, 2);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* RGBDS_ERROR_H */

include/extern/getopt.h

@@ -26,6 +26,10 @@
 #ifndef RGBDS_EXTERN_GETOPT_H
 #define RGBDS_EXTERN_GETOPT_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern char *musl_optarg;
 extern int musl_optind, musl_opterr, musl_optopt, musl_optreset;
 
@@ -43,4 +47,8 @@ int musl_getopt_long_only(int argc, char **argv, char const *optstring,
 #define required_argument  1
 #define optional_argument  2
 
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
 #endif

include/gfx/convert.hpp

@@ -0,0 +1,14 @@
+/*
+ * This file is part of RGBDS.
+ *
+ * Copyright (c) 2022, Eldred Habert and RGBDS contributors.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef RGBDS_GFX_CONVERT_HPP
+#define RGBDS_GFX_CONVERT_HPP
+
+void process();
+
+#endif /* RGBDS_GFX_CONVERT_HPP */

include/gfx/main.h

@@ -1,91 +0,0 @@
-/*
- * This file is part of RGBDS.
- *
- * Copyright (c) 2013-2018, stag019 and RGBDS contributors.
- *
- * SPDX-License-Identifier: MIT
- */
-
-#ifndef RGBDS_GFX_MAIN_H
-#define RGBDS_GFX_MAIN_H
-
-#include <png.h>
-#include <stdbool.h>
-#include <stdint.h>
-
-#include "error.h"
-
-struct Options {
-	bool debug;
-	bool verbose;
-	bool hardfix;
-	bool fix;
-	bool horizontal;
-	bool mirror;
-	bool unique;
-	bool colorcurve;
-	unsigned int trim;
-	char *tilemapfile;
-	bool tilemapout;
-	char *attrmapfile;
-	bool attrmapout;
-	char *palfile;
-	bool palout;
-	char *outfile;
-	char *infile;
-};
-
-struct RGBColor {
-	uint8_t red;
-	uint8_t green;
-	uint8_t blue;
-};
-
-struct ImageOptions {
-	bool horizontal;
-	unsigned int trim;
-	char *tilemapfile;
-	bool tilemapout;
-	char *attrmapfile;
-	bool attrmapout;
-	char *palfile;
-	bool palout;
-};
-
-struct PNGImage {
-	png_struct *png;
-	png_info *info;
-
-	png_byte **data;
-	int width;
-	int height;
-	png_byte depth;
-	png_byte type;
-};
-
-struct RawIndexedImage {
-	uint8_t **data;
-	struct RGBColor *palette;
-	int num_colors;
-	unsigned int width;
-	unsigned int height;
-};
-
-struct GBImage {
-	uint8_t *data;
-	int size;
-	bool horizontal;
-	int trim;
-};
-
-struct Mapfile {
-	uint8_t *data;
-	int size;
-};
-
-extern int depth, colors;
-
-#include "gfx/makepng.h"
-#include "gfx/gb.h"
-
-#endif /* RGBDS_GFX_MAIN_H */

include/gfx/main.hpp

@@ -0,0 +1,59 @@
+/*
+ * This file is part of RGBDS.
+ *
+ * Copyright (c) 2022, Eldred Habert and RGBDS contributors.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef RGBDS_GFX_MAIN_HPP
+#define RGBDS_GFX_MAIN_HPP
+
+#include <array>
+#include <filesystem>
+#include <stdint.h>
+
+#include "helpers.h"
+
+struct Options {
+	bool beVerbose = false; // -v
+	bool fixInput = false; // -f
+	bool columnMajor = false; // -h; whether to output the tilemap in columns instead of rows
+	bool allowMirroring = false; // -m
+	bool allowDedup = false; // -u
+	bool useColorCurve = false; // -C
+	uint8_t bitDepth = 2; // -d
+	uint64_t trim = 0; // -x
+	uint8_t nbPalettes = 8; // TODO
+	uint8_t nbColorsPerPal = 0; // TODO; 0 means "auto" = 1 << bitDepth;
+	std::array<uint8_t, 2> baseTileIDs{0, 0}; // TODO
+	std::array<uint16_t, 2> maxNbTiles{384, 0}; // TODO
+	std::filesystem::path tilemap{}; // -t, -T
+	std::filesystem::path attrmap{}; // -a, -A
+	std::filesystem::path palettes{}; // -p, -P
+	std::filesystem::path output{}; // -o
+	std::filesystem::path input{}; // positional arg
+
+	format_(printf, 2, 3) void verbosePrint(char const *fmt, ...) const;
+};
+
+extern Options options;
+
+void warning(char const *fmt, ...);
+void error(char const *fmt, ...);
+[[noreturn]] void fatal(char const *fmt, ...);
+
+struct Palette {
+	// An array of 4 GBC-native (RGB555) colors
+	std::array<uint16_t, 4> colors{UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX};
+
+	void addColor(uint16_t color);
+	uint8_t indexOf(uint16_t color) const;
+
+	decltype(colors)::iterator begin();
+	decltype(colors)::iterator end();
+	decltype(colors)::const_iterator begin() const;
+	decltype(colors)::const_iterator end() const;
+};
+
+#endif /* RGBDS_GFX_MAIN_HPP */

include/gfx/pal_packing.hpp

@@ -0,0 +1,32 @@
+/*
+ * This file is part of RGBDS.
+ *
+ * Copyright (c) 2022, Eldred Habert and RGBDS contributors.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef RGBDS_GFX_PAL_PACKING_HPP
+#define RGBDS_GFX_PAL_PACKING_HPP
+
+#include <tuple>
+#include <vector>
+
+#include "defaultinitalloc.hpp"
+
+#include "gfx/main.hpp"
+
+class Palette;
+class ProtoPalette;
+
+namespace packing {
+
+/**
+ * Returns which palette each proto-palette maps to, and how many palettes are necessary
+ */
+std::tuple<DefaultInitVec<size_t>, size_t>
+	overloadAndRemove(std::vector<ProtoPalette> const &protoPalettes);
+
+}
+
+#endif /* RGBDS_GFX_PAL_PACKING_HPP */

include/gfx/pal_sorting.hpp

@@ -0,0 +1,26 @@
+/*
+ * This file is part of RGBDS.
+ *
+ * Copyright (c) 2022, Eldred Habert and RGBDS contributors.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef RGBDS_GFX_PAL_SORTING_HPP
+#define RGBDS_GFX_PAL_SORTING_HPP
+
+#include <png.h>
+#include <vector>
+
+class Palette;
+
+namespace sorting {
+
+void indexed(std::vector<Palette> &palettes, int palSize, png_color const *palRGB,
+             png_byte *palAlpha);
+void grayscale(std::vector<Palette> &palettes);
+void rgb(std::vector<Palette> &palettes);
+
+}
+
+#endif /* RGBDS_GFX_PAL_SORTING_HPP */

include/gfx/proto_palette.hpp

@@ -0,0 +1,44 @@
+/*
+ * This file is part of RGBDS.
+ *
+ * Copyright (c) 2022, Eldred Habert and RGBDS contributors.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef RGBDS_GFX_PROTO_PALETTE_HPP
+#define RGBDS_GFX_PROTO_PALETTE_HPP
+
+#include <algorithm>
+#include <array>
+#include <stddef.h>
+#include <stdint.h>
+
+class ProtoPalette {
+	// Up to 4 colors, sorted, and where SIZE_MAX means the slot is empty
+	// (OK because it's not a valid color index)
+	std::array<uint16_t, 4> _colorIndices{UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX};
+
+public:
+	/**
+	 * Adds the specified color to the set
+	 * Returns false if the set is full
+	 */
+	bool add(uint16_t color);
+
+	enum ComparisonResult {
+		NEITHER,
+		WE_BIGGER,
+		THEY_BIGGER = -1,
+	};
+	ComparisonResult compare(ProtoPalette const &other) const;
+
+	ProtoPalette &operator=(ProtoPalette const &other);
+
+	size_t size() const;
+
+	decltype(_colorIndices)::const_iterator begin() const;
+	decltype(_colorIndices)::const_iterator end() const;
+};
+
+#endif /* RGBDS_GFX_PROTO_PALETTE_HPP */

include/version.h

@@ -9,10 +9,18 @@
 #ifndef EXTERN_VERSION_H
 #define EXTERN_VERSION_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define PACKAGE_VERSION_MAJOR 0
 #define PACKAGE_VERSION_MINOR 5
 #define PACKAGE_VERSION_PATCH 2
 
 char const *get_package_version_string(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* EXTERN_VERSION_H */