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Source file src/hash/crc32/example_test.go

Documentation: hash/crc32

		 1  // Copyright 2015 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  package crc32_test
		 6  
		 7  import (
		 8  	"fmt"
		 9  	"hash/crc32"
		10  )
		11  
		12  func ExampleMakeTable() {
		13  	// In this package, the CRC polynomial is represented in reversed notation,
		14  	// or LSB-first representation.
		15  	//
		16  	// LSB-first representation is a hexadecimal number with n bits, in which the
		17  	// most significant bit represents the coefficient of x⁰ and the least significant
		18  	// bit represents the coefficient of xⁿ⁻¹ (the coefficient for xⁿ is implicit).
		19  	//
		20  	// For example, CRC32-Q, as defined by the following polynomial,
		21  	//	x³²+ x³¹+ x²⁴+ x²²+ x¹⁶+ x¹⁴+ x⁸+ x⁷+ x⁵+ x³+ x¹+ x⁰
		22  	// has the reversed notation 0b11010101100000101000001010000001, so the value
		23  	// that should be passed to MakeTable is 0xD5828281.
		24  	crc32q := crc32.MakeTable(0xD5828281)
		25  	fmt.Printf("%08x\n", crc32.Checksum([]byte("Hello world"), crc32q))
		26  	// Output:
		27  	// 2964d064
		28  }
		29  

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