iOS藍牙開發中的CRC8校驗

#pragma mark--CRC8校驗 + (NSString *)crc8_maxin_byteCheckWithHexString:(NSString*)hexString { NSString * tempStr = hexString; NSArray *tempArray = [self getByteForString:hexString]; // NSArray * tempArray = [tempStr componentsSeparatedByString:@" "];//分隔符 unsigned char testChars[(int)tempArray.count]; for(int i=0;i<tempArray.count;i++){ NSString * string = tempArray[i]; unsigned char fristChar = [self hexHighFromChar:[string characterAtIndex:0]]; unsigned char lastChar = [self hexLowFromChar:[string characterAtIndex:1]]; unsigned char temp = fristChar+lastChar; testChars[i] = temp; } unsigned char res = [self crc8_maxin_checkWithChars:testChars length:(int)tempArray.count]; return [NSString stringWithFormat:@"%x", res]; } +(unsigned char)hexHighFromChar:(unsigned char) tempChar{ unsigned char temp = 0x00; switch (tempChar) { case 'a':temp = 0xa0;break; case 'A':temp = 0xA0;break; case 'b':temp = 0xb0;break; case 'B':temp = 0xB0;break; case 'c':temp = 0xc0;break; case 'C':temp = 0xC0;break; case 'd':temp = 0xd0;break; case 'D':temp = 0xD0;break; case 'e':temp = 0xe0;break; case 'E':temp = 0xE0;break; case 'f':temp = 0xf0;break; case 'F':temp = 0xF0;break; case '1':temp = 0x10;break; case '2':temp = 0x20;break; case '3':temp = 0x30;break; case '4':temp = 0x40;break; case '5':temp = 0x50;break; case '6':temp = 0x60;break; case '7':temp = 0x70;break; case '8':temp = 0x80;break; case '9':temp = 0x90;break; default:temp = 0x00;break; } return temp; } +(unsigned char)hexLowFromChar:(unsigned char) tempChar{ unsigned char temp = 0x00; switch (tempChar) { case 'a':temp = 0x0a;break; case 'A':temp = 0x0A;break; case 'b':temp = 0x0b;break; case 'B':temp = 0x0B;break; case 'c':temp = 0x0c;break; case 'C':temp = 0x0C;break; case 'd':temp = 0x0d;break; case 'D':temp = 0x0D;break; case 'e':temp = 0x0e;break; case 'E':temp = 0x0E;break; case 'f':temp = 0x0f;break; case 'F':temp = 0x0F;break; case '1':temp = 0x01;break; case '2':temp = 0x02;break; case '3':temp = 0x03;break; case '4':temp = 0x04;break; case '5':temp = 0x05;break; case '6':temp = 0x06;break; case '7':temp = 0x07;break; case '8':temp = 0x08;break; case '9':temp = 0x09;break; default:temp = 0x00;break; } return temp; } +(char)crc8_maxin_checkWithChars:(unsigned char *)chars length:(int)len{ unsigned char i; unsigned char crc=0x00; /* 計算的初始crc值 */ unsigned char *ptr = chars; while(len--){ crc ^= *ptr++; for(i = 0;i < 8;i++) { if(crc & 0x01){ crc = (crc >> 1) ^ 0x8C; }else crc >>= 1; } } return crc; } + (NSArray *)getByteForString:(NSString *)string { NSMutableArray *strArr = [NSMutableArray array]; for (int i = 0; i < string.length/2; i++) { NSString *str = [string substringWithRange:NSMakeRange(i * 2, 2)]; [strArr addObject:str]; } return [strArr copy]; }