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	This compression scheme was quite popular during the 80's, and we can still find it in use inside file formats such as TIFF or PDF.
		
			
				
	
	
		
			27 lines
		
	
	
	
		
			861 B
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			27 lines
		
	
	
	
		
			861 B
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2023, Lucas Chollet <lucas.chollet@serenityos.org>
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #pragma once
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| 
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| #include <AK/ByteBuffer.h>
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| #include <AK/Optional.h>
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| 
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| namespace Compress::PackBits {
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| 
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| // This implements the PackBits compression scheme, aka run-length compression
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| // It is fairly simple and described here: https://web.archive.org/web/20080705155158/http://developer.apple.com/technotes/tn/tn1023.html
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| // But also in section:
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| //  - 7.4.5 RunLengthDecode Filter of the PDF specification
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| //  - Section 9: PackBits Compression of the TIFF specification
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| 
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| enum class CompatibilityMode {
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|     Original, // 128 is defined as no-op
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|     PDF,      // 128 is defined as end of stream
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| };
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| 
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| ErrorOr<ByteBuffer> decode_all(ReadonlyBytes bytes, Optional<u64> expected_output_size = {}, CompatibilityMode mode = CompatibilityMode::Original);
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| 
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| }
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