Add way to bundle files in a coral::fs into an Ona archive

source/coral.cpp

@@ -40,6 +40,8 @@ export namespace coral {
 
 	using u32 = uint32_t;
 
+	usize const u32_max = 0xffffffff;
+
 	using i32 = int32_t;
 
 	usize const i32_max = 0xffffffff;
@@ -351,83 +353,160 @@ export namespace coral {
 		result(* dispatch)(void *, arguments...);
 	};
 
+	/**
+	 * Monadic container for a single-`element` value or nothing.
+	 */
+	template<typename element> struct [[nodiscard]] optional {
+		/**
+		 * Constructs an empty [optional].
+		 */
+		constexpr optional() = default;
+
+		/**
+		 * Constructs an [optional] that contains `value`.
+		 */
+		constexpr optional(element const & value) {
+			(*reinterpret_cast<element *>(this->buffer)) = value;
+			this->buffer[sizeof(element)] = 1;
+		}
+
+		/**
+		 * Constructs an [optional] from `that`, copying over its data.
+		 */
+		constexpr optional(optional const & that) {
+			if (that.has_value()) {
+				(*reinterpret_cast<element *>(this->buffer)) = *that;
+				this->buffer[sizeof(element)] = 1;
+			} else {
+				this->buffer[sizeof(element)] = 0;
+			}
+		}
+
+		/**
+		 * Returns `true` if the optional contains a value, otherwise `false`.
+		 */
+		bool has_value() const {
+			return this->buffer[sizeof(element)] == 1;
+		}
+
+		/**
+		 * Monadically maps `apply` to the value if it exists, otherwise doing nothing.
+		 */
+		template<typename result> optional<result> map(closure<result(element const &)> const & apply) const {
+			if (this->has_value()) return apply(this->value());
+
+			return {};
+		}
+
+		/**
+		 * Returns the contained value or `fallback` if the optional is empty.
+		 */
+		element const & or_value(element const & fallback) const {
+			return this->has_value() ? *reinterpret_cast<element const *>(this->buffer) : fallback;
+		}
+
+		/**
+		 * Returns a reference to the contained value.
+		 *
+		 * *Note*: attempting to access the value of an empty optional will trigger safety-checked behavior.
+		 */
+		element & operator *() {
+			if (!this->has_value()) unreachable();
+
+			return *reinterpret_cast<element *>(this->buffer);
+		}
+
+		/**
+		 * Returns a const reference to the contained value.
+		 *
+		 * *Note*: attempting to access the value of an empty optional will trigger safety-checked behavior.
+		 */
+		element const & operator *() const {
+			if (!this->has_value()) unreachable();
+
+			return *reinterpret_cast<element const *>(this->buffer);
+		}
+
+		private:
+		u8 buffer[sizeof(element) + 1] {0};
+	};
+
+
 	/**
 	 * Monadic container for a descriminating union of either `expects` or `errors`.
 	 */
 	template<typename expects, typename errors> struct [[nodiscard]] expected {
-		expected(expects const & value) : buffer{0} {
+		template<typename value> using rebound = expected<value, errors>;
+
+		/**
+		 * Constructs from `value`, creating an [expected] that contains the expected type.
+		 */
+		expected(expects const & value) {
 			(*reinterpret_cast<expects *>(this->buffer)) = value;
 			this->buffer[buffer_size] = 1;
 		}
 
-		expected(errors const & error) : buffer{0} {
+		/**
+		 * Constructs from `error`, creating an [expected] that does not contain the expected type.
+		 */
+		expected(errors const & error) {
 			(*reinterpret_cast<errors *>(this->buffer)) = error;
 		}
 
+		/**
+		 * Returns the contained error as an [optional].
+		 */
+		optional<errors> error() const {
+			if (this->is_error()) return *reinterpret_cast<errors const *>(this->buffer);
+
+			return {};
+		}
+
+		/**
+		 * Returns `true` if the optional holds an error, otherwise `false` if it is ok.
+		 */
+		bool is_error() const {
+			return this->buffer[buffer_size] == 0;
+		}
+
 		/**
 		 * Returns `true` if the optional contains the expected value, otherwise `false` if it holds an error.
 		 */
 		bool is_ok() const {
-			return this->buffer[buffer_size];
+			return this->buffer[buffer_size] == 1;
 		}
 
 		/**
-		 * Returns a reference to the contained value.
-		 *
-		 * *Note*: attempting to access the value of an erroneous expected will trigger safety-checked behavior.
+		 * Monadically maps `apply` to the value if it exists, otherwise doing nothing.
 		 */
-		expects & value() {
-			if (!this->is_ok()) unreachable();
+		template<typename result> rebound<result> map(closure<result(expects const &)> const & apply) const {
+			if (this->is_ok()) return apply(*this->ok());
 
-			return *reinterpret_cast<expects *>(this->buffer);
+			return *this->error();
 		}
 
 		/**
-		 * Returns the contained value.
-		 *
-		 * *Note*: attempting to access the value of an erroneous expected will trigger safety-checked behavior.
+		 * Returns the contained ok value as an [optional].
 		 */
-		expects const & value() const {
-			if (!this->is_ok()) unreachable();
+		optional<expects> ok() const {
+			if (this->is_ok()) return *reinterpret_cast<expects const *>(this->buffer);
 
-			return *reinterpret_cast<expects const *>(this->buffer);
+			return {};
 		}
 
 		/**
-		 * Returns a reference to the contained error.
-		 *
-		 * *Note*: attempting to access the error of a non-erroneous expected will trigger safety-checked behavior.
+		 * Returns the contained value or `value` if it is not ok.
 		 */
-		errors & error() {
-			if (this->is_ok()) unreachable();
+		expects ok_or(expects value) const {
+			if (this->is_ok()) return *this->ok();
 
-			return *reinterpret_cast<errors *>(this->buffer);
-		}
-
-		/**
-		 * Returns the contained error.
-		 *
-		 * *Note*: attempting to access the error of a non-erroneous expected will trigger safety-checked behavior.
-		 */
-		errors const & error() const {
-			if (this->is_ok()) unreachable();
-
-			return *reinterpret_cast<errors const *>(this->buffer);
-		}
-
-		/**
-		 *
-		 */
-		template<typename result> expected<result, errors> map(closure<result(expects const &)> const & apply) const {
-			if (this->is_ok()) return apply(this->value());
-
-			return this->error();
+			return value;
 		}
 
 		private:
 		static constexpr usize buffer_size = max(sizeof(expects), sizeof(errors));
 
-		u8 buffer[buffer_size + 1];
+		u8 buffer[buffer_size + 1] {0};
 	};
 
 	/**
@@ -514,11 +593,20 @@ export namespace coral {
 	constexpr bool equals(slice<u8 const> const & a, slice<u8 const> const & b) {
 		if (a.length != b.length) return false;
 
-		for (size_t i = 0; i < a.length; i += 1) if (a[i] != b[i]) return false;
+		for (usize i = 0; i < a.length; i += 1) if (a[i] != b[i]) return false;
 
 		return true;
 	}
 
+	/**
+	 * Performs a linear search from the back of
+	 */
+	constexpr optional<usize> find_last(slice<u8 const> const & bytes, u8 byte) {
+		for (usize i = bytes.length; i >= 0; i -= 1) if (bytes[i] == byte) return i;
+
+		return {};
+	}
+
 	/**
 	 * Returns a hash code generated from the values in `bytes`.
 	 *

source/coral/files.cpp

@@ -153,16 +153,19 @@ export namespace coral {
 			bool can_write;
 		};
 
+		enum class [[nodiscard]] walk_result {
+			ok,
+			not_implemented,
+			access_denied,
+			not_found,
+			io_error,
+		};
+
 		virtual ~fs() {};
 
-		/**
-		 * Attempts to read the files in `directory_path`, calling `apply` for each of the files encountered with the
-		 * fully-qualified file path. If either no files are found or the file-system does not support the operation,
-		 * `apply` is never caled.
-		 *
-		 * `false` may be returned inside of `apply` to halt the enumeration.
-		 */
-		virtual void enumerate_directory(path const & directory_path, closure<bool(path const &)> const & apply) {}
+		virtual walk_result walk_files(path const & target_path, closure<bool(path const &)> const & apply) {
+			return walk_result::not_implemented;
+		}
 
 		/**
 		 * Queries the file-system for its global [access_rules], returning them.
@@ -172,12 +175,12 @@ export namespace coral {
 		/**
 		 * Attempts to read the file in `file_path`, calling `then` if it was successfully opened for reading.
 		 */
-		virtual void read_file(path const & file_path, closure<void(file_reader &)> const & then) {}
+		virtual void read_file(path const & target_path, closure<void(file_reader &)> const & then) {}
 
 		/**
 		 * Attempts to write the file in the file system located at `file_path`, calling `then` if it was successfully
 		 * opened for writing.
 		 */
-		virtual void write_file(path const & file_path, closure<void(file_writer &)> const & then) {}
+		virtual void write_file(path const & target_path, closure<void(file_writer &)> const & then) {}
 	};
 }

source/coral/io.cpp

@@ -123,25 +123,25 @@ export namespace coral {
 	 * *Note*: if `buffer` has a length of `0`, no data will be streamed as there is nowhere to temporarily place data
 	 * during streaming.
 	 */
-	expected<usize, io_error> stream(writer & output, reader & input, slice<u8> const & buffer) {
-		usize total_bytes_written = 0;
-		expected bytes_read = input.read(buffer);
+	expected<u64, io_error> stream(writer & output, reader & input, slice<u8> const & buffer) {
+		u64 total_bytes_written {0};
+		expected bytes_read {input.read(buffer)};
 
-		if (!bytes_read.is_ok()) return bytes_read.error();
+		if (bytes_read.is_error()) return *bytes_read.error();
 
-		usize read = bytes_read.value();
+		usize read {*bytes_read.ok()};
 
 		while (read != 0) {
 			expected const bytes_written = output.write(buffer.sliced(0, read));
 
-			if (!bytes_written.is_ok()) return bytes_read.error();
+			if (bytes_written.is_error()) return *bytes_read.error();
 
-			total_bytes_written += bytes_written.value();
+			total_bytes_written += *bytes_written.ok();
 			bytes_read = input.read(buffer);
 
-			if (!bytes_read.is_ok()) return bytes_read.error();
+			if (bytes_read.is_error()) return *bytes_read.error();
 
-			read = bytes_read.value();
+			read = *bytes_read.ok();
 		}
 
 		return total_bytes_written;

source/coral/stack.cpp

@@ -26,12 +26,31 @@ export namespace coral {
 		virtual ~stack() {};
 
 		/**
-		 * Returns a read-only [slice] of the current range values.
-		 *
-		 * *Note*: the behavior of retaining the returned value past the scope of the source [stack] or any subsequent
-		 * modifications to it is implementation-defined.
+		 * Returns `true` if there are no elements in the stack, otherwise `false`.
 		 */
-		virtual slice<element const> as_slice() const = 0;
+		virtual bool is_empty() const = 0;
+
+		/**
+		 * Invokes `apply` on each element in the stack and evaluating a user-defined condition which will return a
+		 * `bool` at the end of each evaluation. After all elements have been evaluated, `true` is returned if every
+		 * element elavuated `true`. Otherwise, `false` is returned to indicate that one of more elements failed
+		 * evaluation.
+		 *
+		 * *Note*: This function uses short-circuit evaluation, so the enumeration will terminate upon the first failure
+		 * case. This may be leveraged to create conditional looping behavior.
+		 */
+		virtual bool every(closure<bool(element &)> apply) = 0;
+
+		/**
+		 * Invokes `apply` on each element in the stack and evaluating a user-defined condition which will return a
+		 * `bool` at the end of each evaluation. After all elements have been evaluated, `true` is returned if every
+		 * element elavuated `true`. Otherwise, `false` is returned to indicate that one of more elements failed
+		 * evaluation.
+		 *
+		 * *Note*: This function uses short-circuit evaluation, so the enumeration will terminate upon the first failure
+		 * case. This may be leveraged to create conditional looping behavior.
+		 */
+		virtual bool every(closure<bool(element const &)> apply) const = 0;
 
 		/**
 		 * Attempts to append `source_elements` to the stack.
@@ -55,28 +74,60 @@ export namespace coral {
 	 * *Note*: the [allocator] referenced in the stack must remain valid for the duration of the stack lifetime.
 	 */
 	template<typename element, usize init_capacity = 1> struct small_stack : public stack<element> {
-		small_stack(allocator * dynamic_allocator) {
-			this->dynamic_allocator = dynamic_allocator;
-		}
+		small_stack(allocator & dynamic_allocator) : dynamic_allocator{dynamic_allocator} {}
 
 		~small_stack() override {
 			if (this->is_dynamic()) {
 				for (element & e : this->elements) e.~element();
 
-				this->dynamic_allocator->deallocate(this->elements.pointer);
+				this->dynamic_allocator.deallocate(this->elements.pointer);
 			}
 		}
 
 		/**
-		 * Returns a read-only [slice] of the current stack values.
+		 * Returns a const [slice] of the current stack values.
 		 *
 		 * *Note*: the returned slice should be considered invalid if any mutable operation is performed on the source
 		 * [stack] or it is no longer in scope.
 		 */
-		slice<element const> as_slice() const override {
+		slice<element const> as_slice() const {
 			return this->elements.sliced(0, this->filled);
 		}
 
+		/**
+		 * Invokes `apply` on each element in the stack and evaluating a user-defined condition which will return a
+		 * `bool` at the end of each evaluation. After all elements have been evaluated, `true` is returned if every
+		 * element elavuated `true`. Otherwise, `false` is returned to indicate that one of more elements failed
+		 * evaluation.
+		 *
+		 * *Note*: This function uses short-circuit evaluation, so the enumeration will terminate upon the first failure
+		 * case. This may be leveraged to create conditional looping behavior.
+		 */
+		bool every(closure<bool(element &)> apply) override {
+			for (usize index = 0; index < this->filled; index += 1) {
+				if (!apply(this->elements[index])) return false;
+			}
+
+			return true;
+		}
+
+		/**
+		 * Invokes `apply` on each element in the stack and evaluating a user-defined condition which will return a
+		 * `bool` at the end of each evaluation. After all elements have been evaluated, `true` is returned if every
+		 * element elavuated `true`. Otherwise, `false` is returned to indicate that one of more elements failed
+		 * evaluation.
+		 *
+		 * *Note*: This function uses short-circuit evaluation, so the enumeration will terminate upon the first failure
+		 * case. This may be leveraged to create conditional looping behavior.
+		 */
+		bool every(closure<bool(element const &)> apply) const override {
+			for (usize index = 0; index < this->filled; index += 1) {
+				if (!apply(this->elements[index])) return false;
+			}
+
+			return true;
+		}
+
 		/**
 		 * Returns `true` if the stack is backed by dynamic memory, otherwise `false`.
 		 */
@@ -84,6 +135,13 @@ export namespace coral {
 			return this->elements.pointer != reinterpret_cast<element const *>(this->local_buffer);
 		}
 
+		/**
+		 * Returns `true` if there are no elements in the stack, otherwise `false`.
+		 */
+		bool is_empty() const override {
+			return this->filled == 0;
+		}
+
 		/**
 		 * Attempts to append `source_element` to the top of the stack.
 		 *
@@ -149,7 +207,7 @@ export namespace coral {
 			usize const requested_capacity = this->filled + capacity;
 
 			if (this->is_dynamic()) {
-				u8 * const buffer = this->dynamic_allocator->reallocate(
+				u8 * const buffer = this->dynamic_allocator.reallocate(
 					reinterpret_cast<u8 *>(this->elements.pointer),
 						sizeof(element) * requested_capacity);
 
@@ -162,7 +220,7 @@ export namespace coral {
 				this->elements = {reinterpret_cast<element *>(buffer), requested_capacity};
 			} else {
 				usize const buffer_size = sizeof(element) * requested_capacity;
-				u8 * const buffer = this->dynamic_allocator->reallocate(nullptr, buffer_size);
+				u8 * const buffer = this->dynamic_allocator.reallocate(nullptr, buffer_size);
 
 				if (buffer == nullptr) {
 					this->elements = {};
@@ -179,7 +237,7 @@ export namespace coral {
 		}
 
 		private:
-		allocator * dynamic_allocator{nullptr};
+		allocator & dynamic_allocator;
 
 		usize filled{0};
 
@@ -206,14 +264,18 @@ export namespace coral {
 		 * Reads the data from the target stack into `buffer`, returning the number bytes read.
 		 */
 		expected<usize, io_error> read(slice<u8> const & buffer) override {
-			slice const stack_elements {this->stack->as_slice()};
-			usize const read {min(buffer.length, stack_elements.length - this->cursor)};
+			usize data_written = 0;
 
-			copy(buffer, stack_elements.sliced(cursor, read));
+			this->stack->every([&](u8 byte) -> bool {
+				buffer[data_written] = byte;
+				data_written += 1;
 
-			this->cursor += read;
+				return data_written < buffer.length;
+			});
 
-			return read;
+			this->cursor += data_written;
+
+			return data_written;
 		}
 
 		private:

source/oar.cpp

@@ -2,137 +2,151 @@ export module oar;
 
 import coral;
 import coral.files;
+import coral.functional;
+import coral.io;
+import coral.stack;
+
+using coral::closure;
+using coral::expected;
+using coral::file_reader;
+using coral::fs;
+using coral::io_error;
+using coral::path;
+using coral::u8;
+using coral::u64;
+using coral::usize;
 
 /**
  * Length of the full magic signature at the beginning of an Oar file.
  */
-constexpr coral::usize signature_length {4};
-
-/**
- * Length of the magic signature at the beginning of an Oar file without the version indicator
- * byte.
- */
-constexpr coral::usize signature_identifier_length {signature_length - 1};
+constexpr static usize signature_length {4};
 
 /**
  * Hardcoded signature magic value that this implementation of Oar expects when reading archives.
  */
-constexpr coral::u8 signature_magic[signature_length] {'o', 'a', 'r', 0};
+constexpr static u8 signature_magic[signature_length] {'o', 'a', 'r', 1};
 
 /**
  * Oar file header format.
  */
-struct header {
-	coral::u8 signature_magic[signature_length];
+union header {
+	struct {
+		u8 signature[signature_length];
 
-	coral::u32 entry_count;
+		coral::u32 entry_count;
+	} layout;
 
-	coral::u8 padding[504];
+	u8 bytes[512];
+
+	static constexpr bool is_sizeof(usize value) {
+		return value == sizeof(header);
+	}
+
+	expected<bool, io_error> read(coral::reader & archive_reader) {
+		return archive_reader.read(this->bytes).map<bool>(is_sizeof).map<bool>([&](bool is_valid) -> bool {
+			return is_valid && coral::equals(this->layout.signature, signature_magic);
+		});
+	}
 };
 
-static_assert(sizeof(header) == 512);
+static_assert(header::is_sizeof(512));
 
-/**
- * Oar file header format.
- */
-struct entry {
-	coral::path path;
-
-	coral::u64 data_offset;
-
-	coral::u64 data_length;
-
-	coral::u8 padding[240];
+enum class entry_kind {
+	file,
+	directory,
 };
 
-static_assert(sizeof(entry) == 512);
+/**
+ * Oar entry block format.
+ */
+union block {
+	struct {
+		path path;
+
+		u64 data_offset;
+
+		u64 data_length;
+
+		entry_kind kind;
+	} layout;
+
+	u8 bytes[512];
+
+	static constexpr bool is_sizeof(usize value) {
+		return value == sizeof(block);
+	}
+
+	expected<bool, io_error> read(coral::reader & archive_reader) {
+		return archive_reader.read(this->bytes).map<bool>(is_sizeof);
+	}
+};
+
+static_assert(block::is_sizeof(512));
 
 /**
- * Archive file access interface.
+ * Archive entry access interface.
  */
-struct archive_file : public coral::file_reader {
+struct entry : public file_reader {
 	/**
 	 * Results of a find operation performed on an [archive_file].
 	 *
 	 * [find_result::ok] means that the find operation was successful.
 	 *
-	 * [find_result::io_unavailable] signals a failure to communicate with the underlying
-	 * [coral::file_reader] for whatever reason.
+	 * [find_result::io_unavailable] signals a failure to communicate with the underlying [file_reader] for whatever
+	 * reason.
 	 *
-	 * [find_result::archive_invalid] signals that data was read but it does not match the format
-	 * of an Oar archive. This is typically because the underlying [coral::file_reader] is not
-	 * reading from an Oar archive file.
+	 * [find_result::archive_invalid] signals that data was read but it does not match the format of an Oar archive.
+	 * This is typically because the underlying [file_reader] is not reading from an Oar archive file or the archive does
+	 * not match the supported version.
 	 *
-	 * [find_result::archive_unsupported] signals that data was read and was formatted as expected
-	 * for an Oar archive, however, it is from an unsupported version of the archive format.
-	 *
-	 * [find_result::not_found] indicates that no entry in the archive could be found that matches
-	 * the given query.
+	 * [find_result::not_found] indicates that no entry in the archive could be found that matches the given query.
 	 */
 	enum class [[nodiscard]] find_result {
 		ok,
 		io_unavailable,
 		archive_invalid,
-		archive_unsupported,
 		not_found,
 	};
 
-	archive_file(coral::file_reader * archive_reader) {
+	entry(file_reader * archive_reader) {
 		this->archive_reader = archive_reader;
 	}
 
 	/**
-	 * Performs a lookup for a file entry matching the path `file_path` in the archive, returning
-	 * [find_result] to indicate the result of the operation.
+	 * Performs a lookup for a file entry matching the path `file_path` in the archive, returning [find_result] to
+	 * indicate the result of the operation.
 	 */
-	find_result find(coral::path const & file_path) {
+	find_result find(entry_kind kind, path const & entry_path) {
 		this->data_offset = 0;
 		this->data_length = 0;
 		this->data_cursor = 0;
 
 		if (!this->archive_reader->seek(0).is_ok()) return find_result::io_unavailable;
 
-		constexpr coral::usize header_size {sizeof(header)};
-		coral::u8 archive_header_buffer[header_size] {0};
+		header archive_header {};
 
-		if (!this->archive_reader->read(archive_header_buffer).and_test(
-			[](coral::usize value) -> bool { return value == header_size; }))
-				return find_result::archive_invalid;
-
-		header const * const archive_header {
-			reinterpret_cast<header const *>(archive_header_buffer)};
-
-		if (!coral::equals({archive_header->signature_magic, signature_identifier_length},
-			{signature_magic, signature_identifier_length})) return find_result::archive_invalid;
-
-		if (archive_header->signature_magic[signature_identifier_length] !=
-			signature_magic[signature_identifier_length]) return find_result::archive_unsupported;
+		if (!archive_header.read(*this->archive_reader).map<bool>(coral::equality_predicate(true)).is_ok())
+			return find_result::archive_invalid;
 
 		// Read file table.
-		coral::u64 head {0};
-		coral::u64 tail {archive_header->entry_count - 1};
-		constexpr coral::usize entry_size {sizeof(entry)};
-		coral::u8 archive_entry_buffer[entry_size] {0};
+		u64 head {0};
+		u64 tail {archive_header.layout.entry_count - 1};
+		block archive_block {};
 
 		while (head <= tail) {
-			coral::u64 const midpoint {head + ((tail - head) / 2)};
+			u64 const midpoint {head + ((tail - head) / 2)};
 
-			if (!this->archive_reader->seek(header_size + (entry_size * midpoint)).is_ok())
+			if (!archive_block.read(*this->archive_reader).map<bool>(coral::equality_predicate(true)).is_ok())
 				return find_result::archive_invalid;
 
-			if (!this->archive_reader->read(archive_entry_buffer).and_test(
-				[](coral::usize value) -> bool { return value == entry_size; }))
-					return find_result::archive_invalid;
+			if (archive_block.layout.kind == kind) return find_result::not_found;
 
-			entry const * const archive_entry {
-				reinterpret_cast<entry const *>(archive_entry_buffer)};
-
-			coral::size const comparison {file_path.compare(archive_entry->path)};
+			coral::size const comparison {entry_path.compare(archive_block.layout.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;
+				this->data_offset = archive_block.layout.data_offset;
+				this->data_length = archive_block.layout.data_length;
+				this->data_cursor = archive_block.layout.data_offset;
 
 				return find_result::ok;
 			}
@@ -149,65 +163,115 @@ struct archive_file : public coral::file_reader {
 
 	/**
 	 * Attempts to read `data.length` bytes from the file and fill `data` with it, returning the
-	 * number of bytes actually read or a [coral::io_error] value to indicate an error occured.
+	 * number of bytes actually read or a [io_error] value to indicate an error occured.
 	 */
-	coral::expected<coral::usize, coral::io_error> read(coral::slice<coral::u8> const & data) override {
-		if (this->data_offset < sizeof(header)) return coral::io_error::unavailable;
+	expected<usize, io_error> read(coral::slice<u8> const & data) override {
+		if (this->data_offset < sizeof(header)) return io_error::unavailable;
 
-		coral::usize const data_tail {this->data_offset + this->data_length};
+		usize const data_tail {this->data_offset + this->data_length};
 
 		if (!this->archive_reader->seek(coral::clamp(this->data_offset + this->data_cursor,
-			this->data_offset, data_tail)).is_ok()) return coral::io_error::unavailable;
+			this->data_offset, data_tail)).is_ok()) return io_error::unavailable;
 
-		coral::expected const data_read {this->archive_reader->read(
+		expected const data_read {this->archive_reader->read(
 			data.sliced(0, coral::min(data.length, data_tail - this->data_cursor)))};
 
-		if (data_read.is_ok()) this->data_cursor += data_read.value();
+		if (data_read.is_ok()) this->data_cursor += *data_read.ok();
 
 		return data_read;
 	}
 
 	/**
 	 * Attempts to seek to `offset` absolute position in the file, returning the new absolute
-	 * cursor or a [coral::io_error] value to indicate an error occured.
+	 * cursor or a [io_error] value to indicate an error occured.
 	 */
-	coral::expected<coral::u64, coral::io_error> seek(coral::u64 offset) override {
-		if (this->data_offset < sizeof(header)) return coral::io_error::unavailable;
+	expected<u64, io_error> seek(u64 offset) override {
+		if (this->data_offset < sizeof(header)) return io_error::unavailable;
 
 		this->data_cursor = offset;
 
-		return coral::io_error::unavailable;
+		return io_error::unavailable;
 	}
 
 	/**
-	 * Attempts to read to read the absolute file cursor position, returning it or a
-	 * [coral::io_error] value to indicate an error occured.
+	 * Attempts to read to read the absolute file cursor position, returning it or a [io_error]
+	 * value to indicate an error occured.
 	 */
-	coral::expected<coral::u64, coral::io_error> tell() override {
-		if (this->data_offset < sizeof(header)) return coral::io_error::unavailable;
+	expected<u64, io_error> tell() override {
+		if (this->data_offset < sizeof(header)) return io_error::unavailable;
 
 		return this->data_cursor;
 	}
 
 	private:
-	coral::file_reader * archive_reader {nullptr};
+	file_reader * archive_reader {nullptr};
 
-	coral::u64 data_offset {0};
+	u64 data_offset {0};
 
-	coral::u64 data_length {0};
+	u64 data_length {0};
 
-	coral::u64 data_cursor {0};
+	u64 data_cursor {0};
 };
 
 export namespace oar {
-	struct archive : public coral::fs {
-		archive(coral::fs * backing_fs, coral::path const & archive_path) {
+	struct archive : public fs {
+		archive(fs * backing_fs, path const & archive_path) {
 			this->backing_fs = backing_fs;
 			this->archive_path = archive_path;
 		}
 
+		walk_result walk_files(path const & target_path, closure<bool(path const &)> const & apply) override {
+			bool not_found {false};
+			bool has_io_error {false};
+
+			this->backing_fs->read_file(this->archive_path, [&](file_reader & archive_reader) {
+				entry archive_entry{&archive_reader};
+
+				if (archive_entry.find(entry_kind::directory, target_path) != entry::find_result::ok) {
+					not_found = true;
+
+					return;
+				}
+
+				for (;;) {
+					constexpr usize path_size {sizeof(path)};
+					u8 path_buffer[path_size] {0};
+					expected const data_read {archive_entry.read(path_buffer)};
+
+					if (data_read.is_error()) {
+						has_io_error = true;
+
+						return;
+					}
+
+					if (usize const data_read_value {*data_read.ok()}; data_read_value != path_size) {
+						if (data_read_value != 0) has_io_error = true;
+
+						return;
+					}
+
+					// Verify existence of zero terminator in path.
+					if (!coral::find_last(path_buffer, 0).has_value()) {
+						has_io_error = true;
+
+						return;
+					}
+
+					if (archive_entry.read(path_buffer).map<bool>(coral::equality_predicate(path_size)).ok_or(false))
+
+					if (!apply(*reinterpret_cast<path const *>(path_buffer))) return;
+				}
+			});
+
+			if (not_found) return walk_result::not_found;
+
+			if (has_io_error) return walk_result::io_error;
+
+			return walk_result::ok;
+		}
+
 		/**
-		 * Queries the archive for the [coral::fs::access_rules] and returns them.
+		 * Queries the archive for the [fs::access_rules] and returns them.
 		 */
 		access_rules query_access() override {
 			return {
@@ -217,37 +281,119 @@ export namespace oar {
 		}
 
 		/**
-		 * Attempts to open a readable context for reading from the archive file identified by
-		 * `file_path`, doing nothing if the requested file could not be found.
+		 * Attempts to open a readable context for reading from the archive file identified by `file_path`, doing
+		 * nothing if the requested file could not be found.
 		 */
-		void read_file(coral::path const & file_path,
-			coral::closure<void(coral::file_reader &)> const & then) override {
+		void read_file(path const & file_path, closure<void(file_reader &)> const & then) override {
+			if ((this->backing_fs == nullptr) || (this->archive_path.byte_size() == 0)) return;
 
-				if ((this->backing_fs == nullptr) || (this->archive_path.byte_size() == 0)) return;
+			this->backing_fs->read_file(this->archive_path, [&](file_reader & archive_reader) {
+				entry archive_entry {&archive_reader};
 
-				this->backing_fs->read_file(this->archive_path,
-					[&](coral::file_reader & archive_reader) {
-						archive_file file{&archive_reader};
+				if (archive_entry.find(entry_kind::file, file_path) != entry::find_result::ok) return;
 
-						if (file.find(file_path) != archive_file::find_result::ok) return;
-
-						then(file);
-					});
-			}
-
-		/**
-		 * Attempts to open a writable context for reading from the archive file identified by
-		 * `file_path`, however this will always do nothing as archive file-systems are read-only.
-		 */
-		void write_file(coral::path const & file_path,
-			coral::closure<void(coral::file_writer &)> const & then) override {
-
-				// Read-only file system.
-			}
+				then(archive_entry);
+			});
+		}
 
 		private:
-		coral::fs * backing_fs;
+		fs * backing_fs;
 
-		coral::path archive_path;
+		path archive_path;
 	};
+
+	enum class [[nodiscard]] bundle_result {
+		ok,
+		out_of_memory,
+		too_many_files,
+		io_error,
+	};
+
+	bundle_result bundle(coral::allocator & allocator, fs & output_fs,
+		path const & output_path, fs & input_fs, path const & input_path) {
+
+		coral::small_stack<block, 64> archive_blocks {allocator};
+		u64 file_count {0};
+
+		// Walk input dir to create blocks for all files needed.
+		{
+			bool has_memory {true};
+
+			if (input_fs.walk_files(input_path, [&](path const & entry_path) -> bool {
+				has_memory = archive_blocks.push({.layout = {.path = entry_path}}) == coral::push_result::ok;
+
+				return !has_memory;
+
+				file_count += 1;
+			}) != fs::walk_result::ok) return bundle_result::io_error;
+
+			if (!has_memory) return bundle_result::out_of_memory;
+
+			if (file_count > coral::u32_max) return bundle_result::too_many_files;
+		}
+
+		// Write header, file data, and blocks to archive.
+		{
+			bool has_io_error {false};
+
+			output_fs.write_file(output_path, [&](coral::file_writer & archive_writer) {
+				header archive_header {};
+
+				coral::copy(archive_header.layout.signature, signature_magic);
+
+				archive_header.layout.entry_count = static_cast<coral::u32>(file_count);
+
+				if (!archive_writer.write(archive_header.bytes).map<bool>(header::is_sizeof).ok_or(false)) {
+					has_io_error = true;
+
+					return;
+				}
+
+				if (!archive_blocks.every([&](block & archive_block) -> bool {
+					bool file_read {false};
+
+					input_fs.read_file(archive_block.layout.path, [&](coral::file_reader & entry_reader) {
+						expected const data_position {entry_reader.tell()};
+
+						if (data_position.is_error()) {
+							has_io_error = true;
+
+							return;
+						}
+
+						archive_block.layout.data_offset = *data_position.ok();
+
+						{
+							u8 stream_buffer[4096] {0};
+							expected const data_written {coral::stream(archive_writer, entry_reader, stream_buffer)};
+
+							if (data_written.is_error()) {
+								has_io_error = true;
+
+								return;
+							}
+
+							archive_block.layout.data_length = *data_written.ok();
+						}
+
+						file_read = true;
+					});
+
+					return file_read && (!has_io_error);
+				})) return;
+
+				if (!archive_blocks.every([&](block const & archive_block) -> bool {
+					if (!archive_writer.write(archive_block.bytes).map<bool>(block::is_sizeof).ok_or(false)) {
+						has_io_error = true;
+					}
+
+					return !has_io_error;
+				})) return;
+			});
+
+			if (has_io_error) return bundle_result::io_error;
+		}
+
+		return bundle_result::ok;
+	}
 }