Akinori Hashimoto / CheckSum

Calculate checksum(hex) of string with ASCII(unsigned int). Use to detected communication error.

Dependencies:   StrLib

CheckSum.cpp@0:b3a521e42246, 2015-10-21 (annotated)

Committer:
AkinoriHashimoto
Date:
Wed Oct 21 02:10:40 2015 +0000
Revision:
0:b3a521e42246
1st publish.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AkinoriHashimoto 0:b3a521e42246 1 #include "CheckSum.h"
AkinoriHashimoto 0:b3a521e42246 2
AkinoriHashimoto 0:b3a521e42246 3
AkinoriHashimoto 0:b3a521e42246 4 string CheckSum::calc(string str, int Byte)
AkinoriHashimoto 0:b3a521e42246 5 {
AkinoriHashimoto 0:b3a521e42246 6 // calculate SUM.
AkinoriHashimoto 0:b3a521e42246 7 int sum= 0;
AkinoriHashimoto 0:b3a521e42246 8 int size= str.size();
AkinoriHashimoto 0:b3a521e42246 9
AkinoriHashimoto 0:b3a521e42246 10 for(int idx= 0; idx < size; idx++)
AkinoriHashimoto 0:b3a521e42246 11 sum += str[idx];
AkinoriHashimoto 0:b3a521e42246 12
AkinoriHashimoto 0:b3a521e42246 13 // convert HEX. REWRITE/REUSE.
AkinoriHashimoto 0:b3a521e42246 14 str= I2A(sum, 16, (Byte* 2)); // Hex, over 2chars(ex. 0x0f).
AkinoriHashimoto 0:b3a521e42246 15
AkinoriHashimoto 0:b3a521e42246 16 // N[B] with the end of the hex checksum.
AkinoriHashimoto 0:b3a521e42246 17 size= str.size();
AkinoriHashimoto 0:b3a521e42246 18 if(size > (Byte* 2)) // cut tail from str.
AkinoriHashimoto 0:b3a521e42246 19 return str.substr(size- (Byte* 2));
AkinoriHashimoto 0:b3a521e42246 20
AkinoriHashimoto 0:b3a521e42246 21 if(size == (Byte* 2)) // return
AkinoriHashimoto 0:b3a521e42246 22 return str;
AkinoriHashimoto 0:b3a521e42246 23
AkinoriHashimoto 0:b3a521e42246 24 // size < Byte
AkinoriHashimoto 0:b3a521e42246 25 return "ERR";
AkinoriHashimoto 0:b3a521e42246 26 }
AkinoriHashimoto 0:b3a521e42246 27
AkinoriHashimoto 0:b3a521e42246 28 bool CheckSum::compare(string str, string sum)
AkinoriHashimoto 0:b3a521e42246 29 {
AkinoriHashimoto 0:b3a521e42246 30 int Byte= sum.size()/ 2;
AkinoriHashimoto 0:b3a521e42246 31 return strCompareComplete(CheckSum::calc(str, Byte), sum);
AkinoriHashimoto 0:b3a521e42246 32 }
AkinoriHashimoto 0:b3a521e42246 33
AkinoriHashimoto 0:b3a521e42246 34 // EOF