IOS byte-byte arrays related operations

1 intercept byte[] Part of the data, starting from begin, length is count

-(void) Bytesplit2byte: (byte[]) src orc: (byte[]) ORC begin: (Nsinteger) Begin count: (Nsinteger) count{

memset (orc, 0, sizeof (char) *count);

for (Nsinteger i = begin; I < Begin+count; i++) {

Orc[i-begin] = Src[i];

}

}

2 The byte array is converted to data of type int, which provides a storage idea

-(int) Lbytestoint: (byte[]) Byte

{

int height = 0;

NSData * TestData =[nsdata datawithbytes:byte length:4];

for (int i = 0; i < [testData length]; i++)

{

if (byte[[testdata Length]-i] >= 0)

{

Height = height + byte[[testdata length]-i];

} else

{

Height = height + 256 + byte[[testdata length]-i];

}

Height = height * 256;

}

if (Byte[0] >= 0)

{

Height = height + byte[0];

} else {

Height = height + 256 + byte[0];

}

return height;

}

3 turn int into byte[]

int jsonlen = Jsondata.length;

Char *p_json = (char *) &jsonlen;

Char Str_json[4] = {0};

for (int i= 0; i < 4; i++)

{

Str_json[i] = *p_json;

P_json + +;

}

Specific use of local, for example, custom socket protocol. The data size needs to be passed in, and the length of the int needs to be converted to byte[] so that it can be placed in the byte of the corresponding protocol