轉換的NSString，數據類型的表達，以實際的NSData

Question

NSString *string1 = @"<616263>"; 

I want to make this into NSData *data1 = <616263>; 

這樣，當我

NSString *string2 = [[NSString alloc] initWithData:data1 encoding:NSUTF8StringEncoding]; 

的NSLog（@ 「％@」，字符串2）;

結果：ABC

會出來

附：

< 616263>，這是數據表達@ 「ABC」

Answer 1

訣竅是轉換616263爲abc。由於您從字符代碼的ASCII表示開始，因此您需要將NSString轉換爲字節數組（或將原始數據源轉換爲數組，而不是首先將其保存爲NSString）。

NSString *string1 = @"616263"; 

// Make sure that buffer is big enough! 
char sourceChars[7]; 
[string1 getCString:sourceChars maxLength:7 encoding:NSUTF8StringEncoding]; 

char destBuffer[3]; 
char charBuffer[3]; 

// Loop through sourceChars and convert the ASCII character groups to char's 
// NOTE: I assume that these are always two character groupings per your example! 
for (int index = 0; index < [string1 length]; index = index + 2) { 
    // Copy the next two digits into charBuffer 
    strncpy(charBuffer, &sourceChars[index], 2); 
    charBuffer[2] = '\0'; 
    // convert charBuffer (ie 61) from hex to decimal 
    destBuffer[index/2] = strtol(charBuffer, NULL, 16); 
} 

// destBuffer is properly formatted: init data1 with it. 
NSData *data1 = [NSData dataWithBytes:destBuffer length:[string1 length]/2]; 

// Test 
NSString *string2 = [[NSString alloc] initWithData:data1 encoding:NSUTF8StringEncoding]; 
NSLog(@"%@", string2); // Prints abc