Everywhere: Hoist the Libraries folder to the top-level

Libraries/LibArchive/Tar.cpp

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2020, Peter Elliott <pelliott@serenityos.org>
+ * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "Tar.h"
+
+namespace Archive {
+
+unsigned TarFileHeader::expected_checksum() const
+{
+    auto checksum = 0u;
+    u8 const* u8_this = reinterpret_cast<u8 const*>(this);
+    u8 const* u8_m_checksum = reinterpret_cast<u8 const*>(&m_checksum);
+    for (auto i = 0u; i < sizeof(TarFileHeader); ++i) {
+        if (u8_this + i >= u8_m_checksum && u8_this + i < u8_m_checksum + sizeof(m_checksum)) {
+            checksum += ' ';
+        } else {
+            checksum += u8_this[i];
+        }
+    }
+    return checksum;
+}
+
+ErrorOr<void> TarFileHeader::calculate_checksum()
+{
+    memset(m_checksum, ' ', sizeof(m_checksum));
+
+    auto octal = TRY(String::formatted("{:06o}", expected_checksum()));
+    bool copy_successful = octal.bytes_as_string_view().copy_characters_to_buffer(m_checksum, sizeof(m_checksum));
+    VERIFY(copy_successful);
+
+    return {};
+}
+
+bool TarFileHeader::is_zero_block() const
+{
+    u8 const* buffer = reinterpret_cast<u8 const*>(this);
+    for (size_t i = 0; i < sizeof(TarFileHeader); ++i) {
+        if (buffer[i] != 0)
+            return false;
+    }
+    return true;
+}
+
+bool TarFileHeader::content_is_like_extended_header() const
+{
+    return type_flag() == TarFileType::ExtendedHeader || type_flag() == TarFileType::GlobalExtendedHeader;
+}
+
+void TarFileHeader::set_filename_and_prefix(StringView filename)
+{
+    // FIXME: Add support for extended tar headers for longer filenames.
+    VERIFY(filename.length() <= sizeof(m_filename) + sizeof(m_prefix));
+
+    if (filename.length() <= sizeof(m_filename)) {
+        set_prefix(""sv);
+        set_filename(filename);
+        return;
+    }
+
+    Optional<size_t> slash = filename.find('/', filename.length() - sizeof(m_filename));
+
+    VERIFY(slash.has_value());
+    set_prefix(filename.substring_view(0, slash.value() + 1));
+    set_filename(filename.substring_view(slash.value() + 1));
+}
+
+}