Libraries: Move to Userland/Libraries/

Userland/Libraries/LibCompress/Deflate.h

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+/*
+ * Copyright (c) 2020, the SerenityOS developers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/BitStream.h>
+#include <AK/ByteBuffer.h>
+#include <AK/CircularDuplexStream.h>
+#include <AK/Endian.h>
+#include <AK/Vector.h>
+
+namespace Compress {
+
+class CanonicalCode {
+public:
+    CanonicalCode() = default;
+    u32 read_symbol(InputBitStream&) const;
+
+    static const CanonicalCode& fixed_literal_codes();
+    static const CanonicalCode& fixed_distance_codes();
+
+    static Optional<CanonicalCode> from_bytes(ReadonlyBytes);
+
+private:
+    Vector<u32> m_symbol_codes;
+    Vector<u32> m_symbol_values;
+};
+
+class DeflateDecompressor final : public InputStream {
+private:
+    class CompressedBlock {
+    public:
+        CompressedBlock(DeflateDecompressor&, CanonicalCode literal_codes, Optional<CanonicalCode> distance_codes);
+
+        bool try_read_more();
+
+    private:
+        bool m_eof { false };
+
+        DeflateDecompressor& m_decompressor;
+        CanonicalCode m_literal_codes;
+        Optional<CanonicalCode> m_distance_codes;
+    };
+
+    class UncompressedBlock {
+    public:
+        UncompressedBlock(DeflateDecompressor&, size_t);
+
+        bool try_read_more();
+
+    private:
+        DeflateDecompressor& m_decompressor;
+        size_t m_bytes_remaining;
+    };
+
+    enum class State {
+        Idle,
+        ReadingCompressedBlock,
+        ReadingUncompressedBlock
+    };
+
+public:
+    friend CompressedBlock;
+    friend UncompressedBlock;
+
+    DeflateDecompressor(InputStream&);
+    ~DeflateDecompressor();
+
+    size_t read(Bytes) override;
+    bool read_or_error(Bytes) override;
+    bool discard_or_error(size_t) override;
+
+    bool unreliable_eof() const override;
+
+    static Optional<ByteBuffer> decompress_all(ReadonlyBytes);
+
+private:
+    u32 decode_length(u32);
+    u32 decode_distance(u32);
+    void decode_codes(CanonicalCode& literal_code, Optional<CanonicalCode>& distance_code);
+
+    bool m_read_final_bock { false };
+
+    State m_state { State::Idle };
+    union {
+        CompressedBlock m_compressed_block;
+        UncompressedBlock m_uncompressed_block;
+    };
+
+    InputBitStream m_input_stream;
+    CircularDuplexStream<32 * 1024> m_output_stream;
+};
+
+}