Вычесть строку из двоичных NSData на iOS

Question

У меня есть NSData байтов, из которых я хочу вычесть строку. Объект NSData выглядит следующим образом

01 00 00 04 40 00 00 00 00 41 41 41 41 48 47 5A 30 65 58 42 4E 4E 45 45 67 41 
41 41 41 41 45 30 30 51 53 42 74 63 44 51 79 61 58 4E 76 62 51 41 41 41 2B 39 
74 62 32 39 32 41 41 41 41 62 47 31 32 61 47 51 41 41 41 41 41 71 67 59 35 79 
36 6F 47 4F 63 73 41 41 4B 78 45 41 41 43 34 41 41 41 42 41 41 41 42 41 41 41 
41 41 41 41 41 41 41 41 41 41 41 41 41 41 51 41 41 41 41 41 41 41 41 41 41 41 

Я хочу, чтобы извлечь все с первого появления «40 00 00 00» до первого появления «34»

Как я могу это сделать?

Благодаря

МАРК

Answer 1

Не уверен, какие байты вы хотите, здесь извлекали данные в диапазоне от «40 00 00 00» до первого появления «34» и данных с этим диапазоном удален :

const NSUInteger dataLength = 130; 
unsigned char dataBytes[dataLength] = { 
0x01,0x00,0x00,0x04,0x40,0x00,0x00,0x00,0x00,0x41,0x41,0x41,0x41,0x48,0x47,0x5A, 
0x30,0x65,0x58,0x42,0x4E,0x4E,0x45,0x45,0x67,0x41,0x41,0x41,0x41,0x41,0x45,0x30, 
0x30,0x51,0x53,0x42,0x74,0x63,0x44,0x51,0x79,0x61,0x58,0x4E,0x76,0x62,0x51,0x41, 
0x41,0x41,0x2B,0x39,0x74,0x62,0x32,0x39,0x32,0x41,0x41,0x41,0x41,0x62,0x47,0x31, 
0x32,0x61,0x47,0x51,0x41,0x41,0x41,0x41,0x41,0x71,0x67,0x59,0x35,0x79,0x36,0x6F, 
0x47,0x4F,0x63,0x73,0x41,0x41,0x4B,0x78,0x45,0x41,0x41,0x43,0x34,0x41,0x41,0x41, 
0x42,0x41,0x41,0x41,0x42,0x41,0x41,0x41,0x41,0x41,0x41,0x41,0x41,0x41,0x41,0x41, 
0x41,0x41,0x41,0x41,0x41,0x41,0x51,0x41,0x41,0x41,0x41,0x41,0x41,0x41,0x41,0x41, 
0x41,0x41}; 
NSData *data = [NSData dataWithBytes:dataBytes length:130]; 

const NSUInteger startBytesLength = 4; 
unsigned char startBytes[startBytesLength] = {0x40, 0x00, 0x00, 0x00}; 
const NSUInteger stopBytesLength = 1; 
unsigned char stopBytes[stopBytesLength] = {0x34}; 


NSData *startData = [NSData dataWithBytes:startBytes length:startBytesLength]; 
NSData *stopData = [NSData dataWithBytes:stopBytes length:stopBytesLength]; 
NSRange startRange = [data rangeOfData:startData options:0 range:NSMakeRange(0, dataLength)]; 
NSUInteger start = startRange.location; 

NSRange stopRange = [data rangeOfData:stopData options:0 range:NSMakeRange(start+startBytesLength, dataLength-(start+startBytesLength))]; 
NSUInteger length = stopRange.location - start; 
NSUInteger stopLocation = stopRange.location+stopBytesLength; 

NSData *extractData = [data subdataWithRange:NSMakeRange(start, length)]; 
NSLog(@"extractData: %@", extractData); 

NSMutableData *newData = [NSMutableData data]; 
[newData appendData:[data subdataWithRange:NSMakeRange(0, start)]]; 
[newData appendData:[data subdataWithRange:NSMakeRange(stopLocation, dataLength-stopLocation)]]; 
NSLog(@"newData: %@", newData); 

NSLog выход:

extractData: < 00414141 4148475a 3065 5842 4e4e4545 67414141 41414530 30515342 74634451 7961584e 76625141 41412b39 74623239 32414141 41624731 32614751 41414141 41716759 3579366f 474f6373 41414b78 45414143>

NewData: 41414141 41514141 41414141 41414141 41>