From 60291e0f668f8d45aa1e4a83068e0a9067749e60 Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Sun, 11 Sep 2022 14:24:01 +0200
Subject: Implemented file extraction in dat utility

---
 ArchiveEx/dat.cpp | 43 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/ArchiveEx/dat.cpp b/ArchiveEx/dat.cpp
index a8f112d..3c026b2 100644
--- a/ArchiveEx/dat.cpp
+++ b/ArchiveEx/dat.cpp
@@ -1,10 +1,15 @@
+#include <fnmatch.h>
 #include <unistd.h>
 
+#include <cstdint>
 #include <exception>
 #include <filesystem>
+#include <fstream>
 #include <iostream>
+#include <memory>
 #include <ostream>
 #include <string>
+#include <system_error>
 #include <vector>
 
 #include <Archive.h>
@@ -42,10 +47,14 @@ public:
 };
 
 
+class ExtractError : std::exception {};
+
+
 static Options ParseArgs(int argc, char* argv[]);
 static void PrintUsage(std::ostream& out=std::cerr);
 static void PrintHelp(std::ostream& out=std::cout);
 static void UpdateFile(ArchiveEx::Archive& archive, const std::string& path, bool warn=true);
+static void ExtractFile(ArchiveEx::Archive& archive, const char* filepath);
 
 
 static const char* program {"dat"};
@@ -77,7 +86,16 @@ try {
 			UpdateFile(archive, file);
 		break;
 	case Action::EXTRACT:
-		break;  // Not implemented
+		archive.ForEachEntry([opts, &archive](const char* name){
+			for (const auto& pattern : opts.files) {
+				const int match = fnmatch(pattern.c_str(), name, FNM_PATHNAME | FNM_LEADING_DIR);
+				if (match == 0) {
+					ExtractFile(archive, name);
+					break;
+				}
+			}
+		});
+		break;
 	}
 }
 catch (const ArgsError& err) {
@@ -172,3 +190,26 @@ UpdateFile(ArchiveEx::Archive& archive, const std::string& path, bool warn)
 		break;
 	}
 }
+
+
+void
+ExtractFile(ArchiveEx::Archive& archive, const char* filepath)
+try {
+	fs::path path{filepath};
+	std::uint8_t* tmp{nullptr};
+	const int length = archive.Extract(filepath, tmp);
+	if (0 > length)
+		throw ExtractError();
+	std::unique_ptr<std::uint8_t[]> buf{tmp};
+	std::error_code ec;
+	const bool created = fs::create_directories(path.parent_path(), ec);
+	if (!created)
+		throw ExtractError();
+	std::ofstream file{path};
+	if (!file.is_open())
+		throw ExtractError();
+	file.write(reinterpret_cast<const char*>(buf.get()), length);
+}
+catch (const ExtractError& err) {
+	std::cerr << "could not extract: " << filepath << std::endl;
+}
-- 
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