Migrate IOFile implementation to io_file.cpp

Makes the implementation of `IOFile` private, allowing inclusions and
defines such as `#define fseeko` and `#include <io.h>` to not poison
client-code or the global namespace.

src/io_file.cpp

@@ -0,0 +1,115 @@
+#include "io_file.hpp"
+
+#include "helpers.hpp"
+
+#ifdef _MSC_VER
+// 64 bit offsets for MSVC
+#define fseeko _fseeki64
+#define ftello _ftelli64
+#define fileno _fileno
+
+#pragma warning(disable : 4996)
+#endif
+
+#ifndef _CRT_SECURE_NO_WARNINGS
+#define _CRT_SECURE_NO_WARNINGS
+#endif
+
+#ifdef WIN32
+#include <io.h>  // For _chsize_s
+#else
+#include <unistd.h>  // For ftruncate
+#endif
+
+IOFile::IOFile() {}
+
+IOFile::IOFile(FILE* handle) : handle(handle) {}
+
+IOFile::IOFile(const std::filesystem::path& path, const char* permissions) { open(path, permissions); }
+
+bool IOFile::isOpen() { return handle != nullptr; }
+
+bool IOFile::open(const std::filesystem::path& path, const char* permissions) {
+	const auto str = path.string();  // For some reason converting paths directly with c_str() doesn't work
+	return open(str.c_str(), permissions);
+}
+
+bool IOFile::open(const char* filename, const char* permissions) {
+	handle = std::fopen(filename, permissions);
+	return isOpen();
+}
+
+void IOFile::close() {
+	if (isOpen()) {
+		fclose(handle);
+		handle = nullptr;
+	}
+}
+
+std::pair<bool, std::size_t> IOFile::read(void* data, std::size_t length, std::size_t dataSize) {
+	if (!isOpen()) {
+		return {false, std::numeric_limits<std::size_t>::max()};
+	}
+
+	if (length == 0) return {true, 0};
+	return {true, std::fread(data, dataSize, length, handle)};
+}
+
+std::pair<bool, std::size_t> IOFile::readBytes(void* data, std::size_t count) { return read(data, count, sizeof(std::uint8_t)); }
+
+std::pair<bool, std::size_t> IOFile::write(const void* data, std::size_t length, std::size_t dataSize) {
+	if (!isOpen()) {
+		return {false, std::numeric_limits<std::size_t>::max()};
+	}
+
+	if (length == 0) return {true, 0};
+	return {true, std::fwrite(data, dataSize, length, handle)};
+}
+
+std::pair<bool, std::size_t> IOFile::writeBytes(const void* data, std::size_t count) { return write(data, count, sizeof(std::uint8_t)); }
+
+std::optional<std::uint64_t> IOFile::size() {
+	if (!isOpen()) return {};
+
+	std::uint64_t pos = ftello(handle);
+	if (fseeko(handle, 0, SEEK_END) != 0) {
+		return {};
+	}
+
+	std::uint64_t size = ftello(handle);
+	if ((size != pos) && (fseeko(handle, pos, SEEK_SET) != 0)) {
+		return {};
+	}
+
+	return size;
+}
+
+bool IOFile::seek(std::int64_t offset, int origin) {
+	if (!isOpen() || fseeko(handle, offset, origin) != 0) return false;
+
+	return true;
+}
+
+bool IOFile::rewind() { return seek(0, SEEK_SET); }
+
+FILE* IOFile::getHandle() { return handle; }
+
+void IOFile::setAppDataDir(const std::filesystem::path& dir) {
+	if (dir == "") Helpers::panic("Failed to set app data directory");
+	appData = dir;
+}
+
+bool IOFile::setSize(std::uint64_t size) {
+	if (!isOpen()) return false;
+	bool success;
+
+#ifdef WIN32
+	success = _chsize_s(_fileno(handle), size) == 0;
+#else
+	success = ftruncate(fileno(handle), size) == 0;
+#endif
+	fflush(handle);
+	return success;
+}
+
+std::filesystem::path IOFile::getAppData() { return IOFile::appData; }