一般多配合蓝牙对话字符校验
#import <Foundation/Foundation.h>
@interface CRC8Check : NSObject
/** crc8 x8+x5+x4+1算法校验
* @pram hexString 十六进制字符串 @"0c 81 11 22 33 44 55 66 02 0c 01"
*/
+(NSString *)crc8_maxin_charCheckWithHexString:(NSString*)hexString;
/** crc8 x8+x5+x4+1算法校验
* @pram hexString 十六进制字符串 @"0c81112233445566020c01"
*/
+(NSString *)crc8_maxin_byteCheckWithHexString:(NSString*)hexString;
@end
#import "CRC8Check.h"
@implementation CRC8Check
+(NSString *)crc8_maxin_charCheckWithHexString:(NSString*)hexString{
//NSString * tempStr = @"11 01 11 22 33 44 55 66 01 06 01 02 03 04 05 06";
NSString * tempStr = 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; /* 计算的初始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;
}
+(NSString *)crc8_maxin_byteCheckWithHexString:(NSString*)hexString{
//NSString *hexString = @"0c81112233445566020c01"; //16进制字符串
int j=0;
Byte bytes[128];
///3ds key的Byte 数组， 128位
for(int i=0;i<[hexString length];i++)
{
int int_ch; /// 两位16进制数转化后的10进制数
unichar hex_char1 = [hexString characterAtIndex:i]; ////两位16进制数中的第一位(高位*16)
int int_ch1;
if(hex_char1 >= '0' && hex_char1 <='9')
int_ch1 = (hex_char1-48)*16; //// 0 的Ascll - 48
else if(hex_char1 >= 'A' && hex_char1 <='F')
int_ch1 = (hex_char1-55)*16; //// A 的Ascll - 65
else{
int_ch1 = (hex_char1-87)*16; //// a 的Ascll - 97
}
i++;
unichar hex_char2 = [hexString characterAtIndex:i]; ///两位16进制数中的第二位(低位)
int int_ch2;
if(hex_char2 >= '0' && hex_char2 <='9')
int_ch2 = (hex_char2-48); //// 0 的Ascll - 48
else if(hex_char2 >= 'A' && hex_char2 <='F')
int_ch2 = hex_char2-55; //// A 的Ascll - 65
else{
int_ch2 = hex_char2-87; //// a 的Ascll - 97
}
int_ch = int_ch1+int_ch2;
//NSLog(@"int_ch=%d",int_ch);
bytes[j] = int_ch; ///将转化后的数放入Byte数组里
j++;
}
unsigned char res = [self crc8_maxin_checkWithBytes:bytes length:j];
return [NSString stringWithFormat:@"%.2x", res];;
}
+( unsigned char)crc8_maxin_checkWithBytes:(Byte *)bytes length:(int)len { // 0c 81 11 22 33 44 55 66 02 0c 01
Byte i;
unsigned char crc=0x00; /* 计算的初始crc值 */
Byte *ptr = bytes;
while(len--)
{
crc ^= *ptr++;
for(i = 0;i < 8;i++)
{
if(crc & 0x01)
{
crc = (crc >> 1) ^ 0x8C;
}else crc >>= 1;
}
}
//NSLog(@"res= %.2x",crc);
return crc;
}
@end