From e4bb06e7a22d766e7c0c689a9fa392346f5a3daa Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Sat, 20 Aug 2022 22:41:02 +0200
Subject: Merged on-demand Archive creation to constructor

---
 ArchiveEx/Archive.cpp | 50 ++++++++++++++++----------------------------------
 ArchiveEx/Archive.h   |  7 ++-----
 2 files changed, 18 insertions(+), 39 deletions(-)

diff --git a/ArchiveEx/Archive.cpp b/ArchiveEx/Archive.cpp
index 0313eda..808b6fc 100644
--- a/ArchiveEx/Archive.cpp
+++ b/ArchiveEx/Archive.cpp
@@ -38,44 +38,19 @@ static constexpr int UNUSED_BLOCK {-1};
 static constexpr int DIRECTORY_BLOCK {-2};
 
 
-Archive
-CreateEmpty(const char* path)
-{
-	Header header = {VERSION, 0, {0, 0, 0}};
-	std::vector<Entry> entries;
-	entries.reserve(DIRECTORY_MARGIN);
-	const std::size_t uncompressed_size = DIRECTORY_MARGIN * sizeof(Entry);
-	uLongf compressed_size = uncompressed_size * 1.1 + 12;
-	auto compressed = std::make_unique<Bytef[]>(compressed_size);
-	int err = compress(
-		compressed.get(),
-		&compressed_size,
-		reinterpret_cast<Bytef*>(entries.data()),
-		uncompressed_size);
-	if (Z_OK != err)
-		throw "could not compress directory metadata";
-	header.directory.compressed_size = compressed_size;
-	UniqueFileHandle archive {std::fopen(path, "wb"), &std::fclose};
-	err = std::fwrite(&header, sizeof(Header), 1, archive.get());
-	if (1 != err)
-		throw "could not write header (write)";
-	err = std::fwrite(compressed.get(), 1, compressed_size, archive.get());
-	if (static_cast<int>(compressed_size) != err)
-		throw "could not write directory (write)";
-	archive.reset();
-	return Archive(path);
-}
-
-
-Archive::Archive(const char* p) :
+Archive::Archive(const char* p, bool create) :
 	path {p},
 	directory_offset {0},
 	entries {},
-	blocks {}
+	blocks {DIRECTORY_BLOCK}
 {
 	UniqueFileHandle file {std::fopen(path, "rb"), &std::fclose};
-	if (!file)
-		throw "could not open archive";
+	if (!file) {
+		if (!create)
+			throw "could not open archive";
+		WriteMeta(true);
+		return;
+	}
 	Header header {};
 	std::size_t length = std::fread(&header, sizeof(Header), 1, file.get());
 	if (1 != length)
@@ -218,7 +193,7 @@ Archive::Insert(const char* filepath)
 
 
 void
-Archive::WriteMeta()
+Archive::WriteMeta(bool create)
 {
 	const std::size_t total_entries = entries.size();
 	const std::size_t dirsize = total_entries + DIRECTORY_MARGIN;
@@ -251,6 +226,13 @@ Archive::WriteMeta()
 	header.directory.compressed_size = compressed_size;
 	header.directory.offset = directory_offset;
 	UniqueFileHandle archive {std::fopen(path, "rb+"), &std::fclose};
+	if (!archive) {
+		if (!create)
+			throw "could not open archive file";
+		archive.reset(std::fopen(path, "wb"));
+		if (!archive)
+			throw "could not create archive file";
+	}
 	err = std::fseek(archive.get(), 0, SEEK_SET);
 	if (-1 == err)
 		throw "could not write header (seek)";
diff --git a/ArchiveEx/Archive.h b/ArchiveEx/Archive.h
index 189cdbe..7ba32e4 100644
--- a/ArchiveEx/Archive.h
+++ b/ArchiveEx/Archive.h
@@ -24,12 +24,12 @@ struct Entry
 class Archive
 {
 public:
-	explicit Archive(const char* path);
+	explicit Archive(const char* path, bool create=false);
 	int Extract(int index, std::uint8_t*& buffer, bool null_terminated=false) const;
 	int Extract(const char* filepath, std::uint8_t*& buffer, bool null_terminated=false) const;
 	int Find(const char* filepath) const;
 	int Insert(const char* filepath);
-	void WriteMeta();
+	void WriteMeta(bool create=false);
 	void GenerateBlockMap();
 	std::size_t FindFreeSpot(std::size_t bytes) const;
 	void PrintNamesOfEntries() const;
@@ -43,7 +43,4 @@ private:
 };
 
 
-Archive CreateEmpty(const char* path);
-
-
 }  // namespace ArchiveEx
-- 
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