Go与Android的CRC32/Adler32算法使用
Go与Android都内置好了这两种算法的实现,直接使用就好。
Go的调用方式如下:
// 校验算法(ADLER32/CRC32)例子 //author: Xiong Chuan Liang //date: 2015-4-12 package main import ( "fmt" "hash/adler32" "hash/crc32" ) var ADLER32 int = 0 var CRC32 int = 1 func main() { for _, v := range []string{"aaaaaaaaaa", "3333sdfsdffsdffsd", "234esrewr234324", `An Adler-32 checksum is obtained by calculating two 16-bit checksums A and B and concatenating their bits into a 32-bit integer. A is the sum of all bytes in the stream plus one, and B is the sum of the individual values of A from each step. At the beginning of an Adler-32 run, A is initialized to 1, B to 0. The sums are done modulo 65521 (the largest prime number smaller than 216). The bytes are stored in network order (big endian), B occupying the two most significant bytes. The function may be expressed as A = 1 + D1 + D2 + ... + Dn (mod 65521) B = (1 + D1) + (1 + D1 + D2) + ... + (1 + D1 + D2 + ... + Dn) (mod 65521) = n×D1 + (n?1)×D2 + (n?2)×D3 + ... + Dn + n (mod 65521) Adler-32(D) = B × 65536 + A where D is the string of bytes for which the checksum is to be calculated, and n is the length of D.`} { calc(ADLER32, []byte(v)) calc(CRC32, []byte(v)) } } func calc(t int, b []byte) { var ret uint32 if ADLER32 == t { ret = adler32.Checksum([]byte(b)) fmt.Printf("ADLER32 %15d : %s... \n", ret, string(b[:5])) } else if CRC32 == t { ret = crc32.ChecksumIEEE([]byte(b)) fmt.Printf("CRC32 %15d : %s... \n", ret, string(b[:5])) } else { return } }
Android的就不举例了,相关包有详细说明:
CRC32:
http://wear.techbrood.com/reference/java/util/zip/CRC32.html
Adler32:
http://wear.techbrood.com/reference/java/util/zip/Adler32.html
两者效果都差不多,不过Adler32相对来说计算量会小些。
BLOG: http://blog.csdn.net/xcl168
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