Chunker 是基于滚动 Rabin Hash 实现内容定义组块(CDC)。
CDC 算法是一种变长分块算法,它应用数据指纹(如Rabin指纹)将文件分割成长度大小不等的分块策略。与定长分块算法不同,它是基于文件内容进行数据块切分的,因此数据块大小是可变化的。
**package chunker**
`import "github.com/restic/chunker"`
对于以十六进制系数表示法对指定的多项式列表进行过滤,可以使用以下脚本:
<pre># create x over F_2 = GF(2)
x := Indeterminate(GF(2), "x");
# test if polynomial is irreducible, i.e. the number of factors is one
IrredPoly := function (poly)
return (Length(Factors(poly)) = 1);
end;;
# create a polynomial in x from the hexadecimal representation of the
# coefficients
Hex2Poly := function (s)
return ValuePol(CoefficientsQadic(IntHexString(s), 2), x);
end;;
# list of candidates, in hex
candidates := [ "3DA3358B4DC173" ];
# create real polynomials
L := List(candidates, Hex2Poly);
# filter and display the list of irreducible polynomials contained in L
Display(Filtered(L, x -> (IrredPoly(x))));</pre>