source/app.cpp

@@ -11,89 +11,178 @@ import coral.math;
 
 import oar;
 
-export namespace app {
+struct file_reader : public coral::file_reader {
-	struct directory : public coral::fs {
+	enum class [[nodiscard]] close_result {
-		struct rules {
+		ok,
-			bool can_read;
+		io_unavailable,
-
-			bool can_write;
 	};
 
-		directory() : path_buffer{0} {}
+	enum class [[nodiscard]] open_result {
+		ok,
+		io_unavailable,
+		access_denied,
+		not_found,
+	};
 
-		void read_file(coral::path const & file_path,
+	file_reader(coral::fs * fs) : rw_ops{nullptr} {
-			coral::callable<void(coral::readable const &)> const & then) {
+		this->fs = fs;
-
-			if (this->prefix_length == 0) return;
-
-			if (!this->access_rules.can_read) return;
-
-			::SDL_RWops * rw_ops{this->open_rw(file_path, {.can_read = true})};
-
-			if (rw_ops == nullptr) return;
-
-			then([rw_ops](coral::slice<uint8_t> const & buffer) -> size_t {
-				return ::SDL_RWread(rw_ops, buffer.pointer, sizeof(uint8_t), buffer.length);
-			});
-
-			::SDL_RWclose(rw_ops);
 	}
 
-		void target(coral::slice<char const> const & directory_path, rules const & access_rules) {
+	close_result close() {
-			this->access_rules = access_rules;
+		if (::SDL_RWclose(this->rw_ops) != 0) return close_result::io_unavailable;
-			this->prefix_length = coral::min(directory_path.length, path_max - 1);
 
-			{
+		this->rw_ops = nullptr;
-				coral::slice const path_buffer_slice{this->path_buffer};
 
-				coral::copy(path_buffer_slice.sliced(0, this->prefix_length),
+		return close_result::ok;
-					directory_path.sliced(0, this->prefix_length).as_bytes());
-
-				coral::zero(path_buffer_slice.sliced(this->prefix_length, path_max - this->prefix_length));
-			}
 	}
 
-		void write_file(coral::path const & file_path,
+	bool is_open() const {
-			coral::callable<void(coral::writable const &)> const & then) {
+		return this->rw_ops != nullptr;
+	}
 
-			if (this->prefix_length == 0) return;
+	open_result open(coral::path const & file_path) {
+		if (this->is_open()) switch (this->close()) {
+			case close_result::ok: break;
+			case close_result::io_unavailable: return open_result::io_unavailable;
+			default: coral::unreachable();
+		}
 
-			if (!this->access_rules.can_write) return;
+		this->rw_ops = ::SDL_RWFromFile(reinterpret_cast<char const *>(this->path_buffer), "r");
 
-			::SDL_RWops * rw_ops{this->open_rw(file_path, {.can_write = true})};
+		if (this->rw_ops == nullptr) return open_result::not_found;
 
-			if (rw_ops == nullptr) return;
+		return open_result::ok;
+	}
 
-			then([rw_ops](coral::slice<uint8_t const> const & buffer) -> size_t {
+	coral::expected<coral::usize, coral::io_error> read(coral::slice<coral::u8> const & buffer) override {
-				return ::SDL_RWwrite(rw_ops, buffer.pointer, sizeof(uint8_t), buffer.length);
+		if (!this->is_open()) return coral::io_error::unavailable;
-			});
 
-			::SDL_RWclose(rw_ops);
+		coral::usize const bytes_read{::SDL_RWread(this->rw_ops, buffer.pointer, sizeof(uint8_t), buffer.length)};
+
+		if ((bytes_read == 0) && (::SDL_GetError() != nullptr)) return coral::io_error::unavailable;
+
+		return bytes_read;
+	}
+
+	coral::expected<coral::u64, coral::io_error> seek(coral::u64 offset) override {
+		if (!this->is_open()) return coral::io_error::unavailable;
+
+		// TODO: Fix cast.
+		coral::i64 const byte_position{
+			::SDL_RWseek(this->rw_ops, static_cast<coral::i64>(offset), RW_SEEK_SET)};
+
+		if (byte_position == -1) return coral::io_error::unavailable;
+
+		return static_cast<coral::u64>(byte_position);
+	}
+
+	coral::expected<coral::u64, coral::io_error> tell() override {
+		if (!this->is_open()) return coral::io_error::unavailable;
+
+		coral::i64 const byte_position{::SDL_RWseek(this->rw_ops, 0, RW_SEEK_SET)};
+
+		if (byte_position == -1) return coral::io_error::unavailable;
+
+		return static_cast<coral::u64>(byte_position);
 	}
 
 	private:
-		static constexpr coral::usize path_max = 4096;
+	static constexpr coral::usize path_max{4096};
-
-		rules access_rules;
-
-		coral::usize prefix_length;
 
 	coral::u8 path_buffer[path_max];
 
-		::SDL_RWops * open_rw(coral::path const & file_path, rules const & file_rules) {
+	coral::fs * fs;
-			coral::u8 * const path_begin{this->path_buffer + this->prefix_length};
 
-			coral::slice const path_remaining =
+	::SDL_RWops * rw_ops;
-				{path_begin, path_begin + (path_max - this->prefix_length) - 1};
+};
 
-			if (path_remaining.length < file_path.byte_size()) return nullptr;
+struct base_directory : public coral::fs {
+	base_directory() : directory_path{} {
+		char * const path{::SDL_GetBasePath()};
 
-			coral::copy(path_remaining, file_path.as_slice().as_bytes());
+		if (path == nullptr) return;
 
-			return ::SDL_RWFromFile(reinterpret_cast<char const *>(this->path_buffer), "r");
+		coral::usize path_length{0};
+
+		while (path[path_length] != 0) path_length += 1;
+
+		if (path_length == 0) {
+			::SDL_free(path);
+
+			return;
 		}
-	};
 
+		this->directory_path = {path, path_length};
+	}
+
+	~base_directory() override {
+		::SDL_free(this->directory_path.begin());
+	}
+
+	void read_file(coral::path const & file_path, coral::callable<void(coral::file_reader &)> const & then) override {
+		if (this->directory_path.length == 0) return;
+
+		file_reader reader{this};
+
+		if (reader.open(file_path) != file_reader::open_result::ok) return;
+
+		then(reader);
+
+		if (reader.close() != file_reader::close_result::ok) return;
+	}
+
+	void write_file(coral::path const & file_path, coral::callable<void(coral::file_writer &)> const & then) override {
+		// Directory is read-only.
+	}
+
+	protected:
+	coral::slice<char> directory_path;
+};
+
+struct user_directory : public coral::fs {
+	user_directory(coral::path const & title) : directory_path{} {
+		char * const path{::SDL_GetPrefPath("ona", title.begin())};
+
+		if (path == nullptr) return;
+
+		coral::usize path_length{0};
+
+		while (path[path_length] != 0) path_length += 1;
+
+		if (path_length == 0) {
+			::SDL_free(path);
+
+			return;
+		}
+
+		this->directory_path = {path, path_length};
+	}
+
+	~user_directory() override {
+		::SDL_free(this->directory_path.begin());
+	}
+
+	void read_file(coral::path const & file_path, coral::callable<void(coral::file_reader &)> const & then) override {
+		if (this->directory_path.length == 0) return;
+
+		file_reader reader{this};
+
+		if (reader.open(file_path) != file_reader::open_result::ok) return;
+
+		then(reader);
+
+		if (reader.close() != file_reader::close_result::ok) return;
+	}
+
+	void write_file(coral::path const & file_path, coral::callable<void(coral::file_writer &)> const & then) override {
+		// Directory is read-only.
+	}
+
+	protected:
+	coral::slice<char> directory_path;
+};
+
+export namespace app {
 	enum class log_level {
 		notice,
 		warning,
@@ -101,48 +190,10 @@ export namespace app {
 	};
 
 	struct system {
-		system(coral::path const & title) : res_archive{}  {
+		system(coral::path const & title) : res{&base, "base_directory.oar"}, user{title} {}
-			constexpr directory::rules read_only_rules = {.can_read = true};
 
-			{
+		coral::fs & base_fs() {
-				char * const path{::SDL_GetBasePath()};
+			return this->base;
-
-				if (path == nullptr) {
-					this->cwd_directory.target("./", read_only_rules);
-				} else {
-					coral::usize path_length{0};
-
-					while (path[path_length] != 0) path_length += 1;
-
-					if (path_length == 0) {
-						this->cwd_directory.target("./", read_only_rules);
-					} else {
-						this->cwd_directory.target({path, path_length}, read_only_rules);
-					}
-				}
-
-				::SDL_free(path);
-			}
-
-			{
-				char * const path{::SDL_GetPrefPath("ona", title.begin())};
-
-				if (path != nullptr) {
-					coral::usize path_length{0};
-
-					while (path[path_length] != 0) path_length += 1;
-
-					if (path_length != 0) this->cwd_directory.target({path, path_length}, {
-						.can_read = true,
-					});
-				}
-
-				::SDL_free(path);
-			}
-		}
-
-		coral::fs & cwd_fs() {
-			return this->cwd_directory;
 		}
 
 		bool poll() {
@@ -156,7 +207,7 @@ export namespace app {
 		}
 
 		coral::fs & res_fs() {
-			return this->res_archive;
+			return this->res;
 		}
 
 		void log(app::log_level level, coral::slice<char const> const & message) {
@@ -172,7 +223,7 @@ export namespace app {
 		}
 
 		coral::fs & user_fs() {
-			return this->user_directory;
+			return this->user;
 		}
 
 		private:
@@ -188,11 +239,11 @@ export namespace app {
 			}
 		} allocator;
 
-		oar::archive res_archive;
+		base_directory base;
 
-		directory cwd_directory;
+		user_directory user;
 
-		directory user_directory;
+		oar::archive res;
 	};
 
 	struct graphics {

source/coral.cpp

@@ -38,13 +38,13 @@ export namespace coral {
 
 	using u32 = uint32_t;
 
-	using i32 = uint32_t;
+	using i32 = int32_t;
 
 	usize const i32_max = 0xffffffff;
 
 	using u64 = uint64_t;
 
-	using i64 = uint64_t;
+	using i64 = int64_t;
 
 	using f32 = float;
 

source/coral/files.cpp

@@ -118,12 +118,6 @@ export namespace coral {
 	 * Platform-generalized file system interface.
 	 */
 	struct fs {
-		struct io_rules {
-			bool can_read;
-
-			bool can_write;
-		};
-
 		virtual ~fs() {};
 
 		/**
@@ -134,11 +128,6 @@ export namespace coral {
 		 */
 		virtual void read_file(path const & file_path, callable<void(file_reader &)> const & then) = 0;
 
-		/**
-		 * Returns the [io_rules] that this file system interface abides by.
-		 */
-		virtual io_rules rules() const = 0;
-
 		/**
 		 * Attempts to write the file in the file system located at `file_path` relative, calling
 		 * `then` if it was successfully opened for writing.

source/kym/environment.cpp

@@ -69,8 +69,8 @@ export namespace kym {
 		return nil;
 	}
 
-	coral::expected<coral::usize, coral::io_error> default_stringify(vm & owning_vm, void * userdata, coral::writable const & output) {
+	coral::expected<coral::usize, coral::io_error> default_stringify(vm & owning_vm, void * userdata, coral::writer & output) {
-		return output(coral::slice{"[object]"}.as_bytes());
+		return output.write(coral::slice{"[object]"}.as_bytes());
 	}
 
 	struct bound_object {
@@ -81,7 +81,7 @@ export namespace kym {
 
 			value(*call)(vm &, void *, coral::slice<value const> const &);
 
-			coral::expected<coral::usize, coral::io_error>(*stringify)(vm &, void *, coral::writable const &);
+			coral::expected<coral::usize, coral::io_error>(*stringify)(vm &, void *, coral::writer &);
 		} behavior;
 
 		bound_object(vm * owning_vm) : userdata{nullptr}, owning_vm{owning_vm}, behavior{
@@ -98,7 +98,7 @@ export namespace kym {
 			return this->behavior.call(*this->owning_vm, this->userdata, arguments);
 		}
 
-		coral::expected<coral::usize, coral::io_error> stringify(coral::writable const & output) {
+		coral::expected<coral::usize, coral::io_error> stringify(coral::writer & output) {
 			return this->behavior.stringify(*this->owning_vm, this->userdata, output);
 		}
 

source/oar.cpp

@@ -3,36 +3,200 @@ export module oar;
 import coral;
 import coral.files;
 
-export namespace oar {
+constexpr coral::usize signature_length{4};
-	constexpr coral::usize signature_length{4};
 
-	constexpr coral::u8 signature_magic[signature_length]{'o', 'a', 'r', 0};
+constexpr coral::usize signature_version_length{1};
 
-	struct entry {
+constexpr coral::usize signature_identifier_length{signature_length - signature_version_length};
+
+constexpr coral::u8 signature_magic[signature_length]{'o', 'a', 'r', 0};
+
+struct header {
 	coral::u8 signature_magic[signature_length];
 
+	coral::u32 entry_count;
+
+	coral::u8 padding[504];
+};
+
+static_assert(sizeof(header) == 512);
+
+struct entry {
 	coral::path path;
 
 	coral::u64 data_offset;
 
 	coral::u64 data_length;
 
-		coral::u8 padding[244];
+	coral::u8 padding[240];
+};
+
+static_assert(sizeof(entry) == 512);
+
+export namespace oar {
+	struct archive_file_reader : public coral::file_reader {
+		enum class [[nodiscard]] close_result {
+			ok,
+		};
+
+		enum class [[nodiscard]] open_result {
+			ok,
+			io_unavailable,
+			archive_invalid,
+			archive_unsupported,
+			not_found,
+		};
+
+		archive_file_reader(coral::file_reader * archive_reader) {
+			this->archive_reader = archive_reader;
+			this->data_offset = 0;
+			this->data_length = 0;
+			this->data_cursor = 0;
+		}
+
+		close_result close() {
+			return close_result::ok;
+		}
+
+		bool is_open() const {
+			return this->data_offset >= sizeof(header);
+		}
+
+		open_result open(coral::path const & file_path) {
+			if (this->is_open()) switch (this->close()) {
+				case close_result::ok: break;
+				default: coral::unreachable();
+			}
+
+			if (!this->archive_reader->seek(0).is_ok()) return open_result::io_unavailable;
+
+			constexpr coral::usize header_size = sizeof(header);
+			coral::u8 archive_header_buffer[header_size]{0};
+
+			{
+				coral::expected const read_bytes{archive_reader->read(archive_header_buffer)};
+
+				if ((!read_bytes.is_ok()) || (read_bytes.value() != header_size))
+					return open_result::archive_invalid;
+			}
+
+			header const * const archive_header{reinterpret_cast<header const *>(archive_header_buffer)};
+
+			if (!coral::equals(coral::slice{archive_header->signature_magic,
+				signature_identifier_length}, coral::slice{signature_magic,
+				signature_identifier_length})) return open_result::archive_invalid;
+
+			if (archive_header->signature_magic[signature_identifier_length] !=
+				signature_magic[signature_identifier_length]) return open_result::archive_unsupported;
+
+			// Read file table.
+			coral::u64 head{0};
+			coral::u64 tail{archive_header->entry_count - 1};
+			constexpr coral::usize entry_size{sizeof(entry)};
+			coral::u8 file_entry_buffer[entry_size]{0};
+
+			while (head <= tail) {
+				coral::u64 const midpoint{head + ((tail - head) / 2)};
+
+				if (!archive_reader->seek(header_size + (entry_size * midpoint)).is_ok())
+					return open_result::archive_invalid;
+
+				{
+					coral::expected const read_bytes{archive_reader->read(file_entry_buffer)};
+
+					if ((!read_bytes.is_ok()) || (read_bytes.value() != header_size))
+						return open_result::archive_invalid;
+				}
+
+				entry const * const archive_entry{reinterpret_cast<entry const *>(file_entry_buffer)};
+				coral::size const comparison{file_path.compare(archive_entry->path)};
+
+				if (comparison == 0) {
+					this->data_offset = archive_entry->data_offset;
+					this->data_length = archive_entry->data_length;
+					this->data_cursor = archive_entry->data_offset;
+
+					return open_result::ok;
+				}
+
+				if (comparison > 0) {
+					head = (midpoint + 1);
+				} else {
+					tail = (midpoint - 1);
+				}
+			}
+
+			return open_result::not_found;
+		}
+
+		coral::expected<coral::usize, coral::io_error> read(coral::slice<coral::u8> const & buffer) override {
+			if (!this->is_open()) return coral::io_error::unavailable;
+
+			if (this->archive_reader->seek(this->data_offset + this->data_cursor).is_ok())
+				return coral::io_error::unavailable;
+
+			coral::expected const bytes_read{this->archive_reader->read(buffer.sliced(0,
+				coral::min(buffer.length, static_cast<coral::usize>((
+					this->data_offset + this->data_length) - this->data_cursor))))};
+
+			if (!bytes_read.is_ok()) this->data_cursor += bytes_read.value();
+
+			return bytes_read;
+		}
+
+		coral::expected<coral::u64, coral::io_error> seek(coral::u64 offset) override {
+			if (!this->is_open()) return coral::io_error::unavailable;
+
+			return coral::io_error::unavailable;
+		}
+
+		coral::expected<coral::u64, coral::io_error> tell() override {
+			if (!this->is_open()) return coral::io_error::unavailable;
+
+			return this->data_cursor;
+		}
+
+		private:
+		coral::file_reader * archive_reader;
+
+		coral::u64 data_offset;
+
+		coral::u64 data_length;
+
+		coral::u64 data_cursor;
 	};
 
 	struct archive : public coral::fs {
-		archive() {
+		archive(coral::fs * backing_fs, coral::path const & archive_path) {
-
+			this->backing_fs = backing_fs;
+			this->archive_path = archive_path;
 		}
 
 		void read_file(coral::path const & file_path,
-			coral::callable<void(coral::readable const &)> const & then) override {
+			coral::callable<void(coral::file_reader &)> const & then) override {
+
+			if ((this->backing_fs == nullptr) || (this->archive_path.byte_size() == 0)) return;
+
+			this->backing_fs->read_file(this->archive_path, [&](coral::file_reader & archive_reader) {
+				archive_file_reader file_reader{&archive_reader};
+
+				if (file_reader.open(file_path) != archive_file_reader::open_result::ok) return;
+
+				then(file_reader);
+
+				if (file_reader.close() != archive_file_reader::close_result::ok) return;
+			});
 		}
 
 		void write_file(coral::path const & file_path,
-			coral::callable<void(coral::writable const &)> const & then) override {
+			coral::callable<void(coral::file_writer &)> const & then) override {
+
+			// Read-only file system.
 		}
+
+		private:
+		coral::fs * backing_fs;
+
+		coral::path archive_path;
 	};
 }
-
-static_assert(sizeof(oar::entry) == 512);

source/runtime.cpp

@@ -15,7 +15,7 @@ extern "C" int main(int argc, char const * const * argv) {
 		constexpr coral::path config_path{"config.kym"};
 		bool is_config_loaded{false};
 
-		system.res_fs().read_file(config_path, [&](coral::readable const & file) {
+		system.res_fs().read_file(config_path, [&](coral::reader & file) {
 			coral::allocator * const allocator{&system.thread_safe_allocator()};
 
 			kym::vm vm{allocator, [&system](coral::slice<char const> const & error_message) {
@@ -29,10 +29,13 @@ extern "C" int main(int argc, char const * const * argv) {
 			}
 
 			coral::stack<coral::u8> script_source{allocator};
-			coral::u8 stream_buffer[1024]{0};
 
-			if (!coral::stream(coral::sequence_writer{&script_source}, file, stream_buffer).is_ok())
+			{
-				return;
+				coral::u8 stream_buffer[1024]{0};
+				coral::sequence_writer script_writer{&script_source};
+
+				if (!coral::stream(script_writer, file, stream_buffer).is_ok()) return;
+			}
 
 			vm.with_object(vm.compile(coral::slice{script_source.begin(), script_source.end()}.as_chars()), [&](kym::bound_object & script) {
 				vm.with_object(script.call({}), [&](kym::bound_object & config) {
@@ -51,8 +54,9 @@ extern "C" int main(int argc, char const * const * argv) {
 
 					vm.with_object(config.get_field("title"), [&](kym::bound_object & title) {
 						coral::stack<coral::u8, 128> title_buffer{&system.thread_safe_allocator()};
+						coral::sequence_writer title_writer{&title_buffer};
 
-						if (!title.stringify(coral::sequence_writer{&title_buffer}).is_ok()) {
+						if (!title.stringify(title_writer).is_ok()) {
 							system.log(app::log_level::error,
 								"failed to decode `title` property of config");
 
@@ -71,10 +75,10 @@ extern "C" int main(int argc, char const * const * argv) {
 			{
 				coral::sequence_writer error_writer{&error_message};
 
-				if (!error_writer(coral::slice{"failed to load "}.as_bytes()).is_ok())
+				if (!error_writer.write(coral::slice{"failed to load "}.as_bytes()).is_ok())
 					return coral::u8_max;
 
-				if (!error_writer(config_path.as_slice().as_bytes()).is_ok())
+				if (!error_writer.write(config_path.as_slice().as_bytes()).is_ok())
 					return coral::u8_max;
 			}