iOS 記錄藍牙傳輸相關進制轉換/字節轉換/NSData轉換/大小端轉換

項目中有較多的多種藍牙外設的對接 遇到的數據傳輸比較多 打算從使用框架、模塊到傳輸協議一個系列記錄一下
先記錄一些數據傳輸時常用到的轉換方式吧 后面再補充

1、整形轉換成兩個字節

int value = 100; unsigned char byte1 = (value & 0xff00)>>8; //高8位 unsigned char byte2 = (value & 0xff);//低8位 NSLog(@"byte1= %x byte2= %x ",byte1,byte2); //byte1 = 0; byte2= 64; 

2、兩個字節轉換成十進制整數

char bytes[]={byte1,byte2}; unsigned char by1 = (bytes[0] & 0xff); //高8位 unsigned char by2 = (bytes[1] & 0xff);//低8位 int temp = (by2|(by1<<8)); NSLog(@"temp = %d",temp); 

3、整形轉換成三個字節

int value =134456; unsigned char byte1 = (value & 0xff0000)>>16;//最高8位 unsigned char byte2 = (value & 0xff00)>>8;//中間8位 unsigned char byte3 = (value & 0xff);//低8位 NSLog(@"byte1= %x byte2= %x byte3= %x ",byte1,byte2,byte3); //byte1= 2 byte2= d byte3= 38 

4、三個字節轉換成十進制整數

char bytes[]={byte1,byte2,byte3}; unsigned char by1 = (bytes[0] & 0xff); //高8位 unsigned char by2 = (bytes[1] & 0xff);//中8位 unsigned char by3 = (bytes[2] & 0xff);//低8位 int temp = (by3|(by2<<8)|(by1<<16)); NSLog(@"temp = %d",temp); //temp = 134456 

——————有更多的需求以此類推——————

5、16進制字符串轉10進制number

// 16進制字符串轉10進制 + (NSNumber *) numberHexString:(NSString *)aHexString { if (nil == aHexString){ return nil; } NSScanner * scanner = [NSScanner scannerWithString:aHexString]; unsigned long long longlongValue; [scanner scanHexLongLong:&longlongValue]; //將整數轉換為NSNumber,存儲到數組中,並返回. NSNumber * hexNumber = [NSNumber numberWithLongLong:longlongValue]; return hexNumber; } 

6、16進制字符串轉NSData

//將16進制的字符串轉換成NSData + (NSMutableData *)convertHexStrToData:(NSString *)str { if (!str || [str length] == 0) { return nil; } NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:8]; NSRange range; if ([str length] %2 == 0) { range = NSMakeRange(0,2); } else { range = NSMakeRange(0,1); } for (NSInteger i = range.location; i < [str length]; i += 2) { unsigned int anInt; NSString *hexCharStr = [str substringWithRange:range]; NSScanner *scanner = [[NSScanner alloc] initWithString:hexCharStr]; [scanner scanHexInt:&anInt]; NSData *entity = [[NSData alloc] initWithBytes:&anInt length:1]; [hexData appendData:entity]; range.location += range.length; range.length = 2; } return hexData; } 

7、簡單的10進制轉16進制字符串

//int 轉16進制 + (NSString *)hexFromInt:(NSInteger)val { return [NSString stringWithFormat:@"%X", val]; } 

8、NSData轉器16進制

+ (NSString *)hexStringFromData:(NSData *)data { NSAssert(data.length > 0, @"data.length <= 0"); NSMutableString *hexString = [[NSMutableString alloc] init]; const Byte *bytes = data.bytes; for (NSUInteger i=0; i<data.length; i++) { Byte value = bytes[i]; Byte high = (value & 0xf0) >> 4; Byte low = value & 0xf; [hexString appendFormat:@"%x%x", high, low]; }//for return hexString; } 

9、NSString 轉NSData

NSData *data = [aString dataUsingEncoding:NSUTF8StringEncoding];// 通過utf-8轉為data 

10、uint8、NSData(占兩位)互轉

//uint8轉NSData + (NSData *)byteFromUInt8:(uint8_t)val { NSMutableData *valData = [[NSMutableData alloc] init]; unsigned char valChar[1]; valChar[0] = 0xff & val; [valData appendBytes:valChar length:1]; return [self dataWithReverse:valData]; } //NSData轉uint8_t + (uint8_t)uint8FromBytes:(NSData *)fData { NSAssert(fData.length == 1, @"uint8FromBytes: (data length != 1)"); NSData *data = fData; uint8_t val = 0; [data getBytes:&val length:1]; return val; } 

11、uint16 、NSData（占四位）互轉

//uint16 轉NSData + (NSData *)bytesFromUInt16:(uint16_t)val { NSMutableData *valData = [[NSMutableData alloc] init]; unsigned char valChar[2]; valChar[0] = 0xff & val; valChar[1] = (0xff00 & val) >> 8; [valData appendBytes:valChar length:2]; return [self dataWithReverse:valData]; } //NSData轉uint16 + (uint16_t)uint16FromBytes:(NSData *)fData { NSAssert(fData.length == 2, @"uint16FromBytes: (data length != 2)"); NSData *data = [self dataWithReverse:fData];; uint16_t val0 = 0; uint16_t val1 = 0; [data getBytes:&val0 range:NSMakeRange(0, 1)]; [data getBytes:&val1 range:NSMakeRange(1, 1)]; uint16_t dstVal = (val0 & 0xff) + ((val1 << 8) & 0xff00); return dstVal; } 

12、uint32 與NSData互轉

//uint32 轉NSData（占八位） + (NSData *)bytesFromUInt32:(uint32_t)val { NSMutableData *valData = [[NSMutableData alloc] init]; unsigned char valChar[4]; valChar[0] = 0xff & val; valChar[1] = (0xff00 & val) >> 8; valChar[2] = (0xff0000 & val) >> 16; valChar[3] = (0xff000000 & val) >> 24; [valData appendBytes:valChar length:4]; return [self dataWithReverse:valData]; } //NSData轉Uint32 + (uint32_t)uint32FromBytes:(NSData *)fData { NSAssert(fData.length == 4, @"uint32FromBytes: (data length != 4)"); NSData *data = [self dataWithReverse:fData]; uint32_t val0 = 0; uint32_t val1 = 0; uint32_t val2 = 0; uint32_t val3 = 0; [data getBytes:&val0 range:NSMakeRange(0, 1)]; [data getBytes:&val1 range:NSMakeRange(1, 1)]; [data getBytes:&val2 range:NSMakeRange(2, 1)]; [data getBytes:&val3 range:NSMakeRange(3, 1)]; uint32_t dstVal = (val0 & 0xff) + ((val1 << 8) & 0xff00) + ((val2 << 16) & 0xff0000) + ((val3 << 24) & 0xff000000); return dstVal; } 

13、data轉byte

uint8_t byteArray[[data length]]; [data getBytes:&byteArray length:[data length]]; for (int i = 0; i < [data length] ; i++ ) { Byte byte = byteArray[i]; NSLog(@"--byte%x",byte); } 

14、NSData轉int (用CFSwapInt32BigToHost)

NSData *data4 = [completeData subdataWithRange:NSMakeRange(0, 4)]; int value = CFSwapInt32BigToHost(*(int*)([data4 bytes])); 

//NSData轉成NSinteger - (NSInteger)intFormData:(NSData *)data { const uint8_t *reportData = [data bytes]; uint16_t bpm = 0; if ((reportData[0] & 0x01) == 0){ /* uint8 bpm */ bpm = reportData[1]; } else{ /* uint16 bpm */ bpm = CFSwapInt16LittleToHost(*(uint16_t *)(&reportData[1])); } return bpm; } 

15、可能會用到的反轉字節序列代碼

+ (NSData *)dataWithReverse:(NSData *)srcData { NSUInteger byteCount = srcData.length; NSMutableData *dstData = [[NSMutableData alloc] initWithData:srcData]; NSUInteger halfLength = byteCount / 2; for (NSUInteger i=0; i<halfLength; i++) { NSRange begin = NSMakeRange(i, 1); NSRange end = NSMakeRange(byteCount - i - 1, 1); NSData *beginData = [srcData subdataWithRange:begin]; NSData *endData = [srcData subdataWithRange:end]; [dstData replaceBytesInRange:begin withBytes:endData.bytes]; [dstData replaceBytesInRange:end withBytes:beginData.bytes]; } return dstData; } 

16、大小端轉換

#define Tranverse16(X) ((((UInt16)(X) & 0xff00) >> 8) |(((UInt16)(X) & 0x00ff) << 8)) #define Tranverse32(X) ((((UInt32)(X) & 0xff000000) >> 24) | (((UInt32)(X) & 0x00ff0000) >> 8) | (((UInt32)(X) & 0x0000ff00) << 8) | (((UInt32)(X) & 0x000000ff) << 24)) #define Tranverse64(X) ((((UInt64)(X) & 0xff00000000000000) >> 56) | (((UInt64)(X) & 0x00ff000000000000) >> 40) | (((UInt64)(X) & 0x0000ff0000000000) >> 24) | (((UInt64)(X) & 0x000000ff00000000) >> 8) | (((UInt64)(X) & 0x00000000ff000000) << 8) | (((UInt64)(X) & 0x0000000000ff0000) << 24) | (((UInt64)(X) & 0x000000000000ff00) << 40) | (((UInt64)(X) & 0x00000000000000ff) << 56))

作者：iii余光
鏈接：https://www.jianshu.com/p/0fadbb15cf7f
來源：簡書
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