Question

我试图将NSData拆分成更小的＆lt; 100长度块，以便我可以通过CoreBluetooth发送它们但是由于某种原因，它决定偶尔搞乱，事实证明，试图结合数据和从同一方法中解码对象失败。因此，我假设我将NSData拆分错误了吗？

以下是我用来拆分它的代码（取自stackoverflow上的某些陌生人！）

// Split up the data and put into Array
NSUInteger length = [data length];
NSUInteger chunkSize = 100;
NSUInteger offset = 0;
do {
    NSUInteger thisChunkSize = length - offset > chunkSize ? chunkSize : length - offset;
    NSData* chunk = [NSData dataWithBytesNoCopy:(char *)[data bytes] + offset  
                    length:thisChunkSize  freeWhenDone:NO];
                    offset += thisChunkSize;

    [orderQueue addObject:chunk];
} while (offset < length);

然后重新组合数据，并将对象取消存档：

 NSMutableData *finishedData = [[NSMutableData alloc] init];
 for (NSData *dataChunk in orderQueue) {
        [finishedData appendData:dataChunk];
    }
 Order *order = [NSKeyedUnarchiver unarchiveObjectWithData:finishedData]; // ERRORS OUT ON THIS LINE

 finishedData = [[NSMutableData alloc] init];
 dataChunks = [[NSMutableArray alloc] init];

在纸面上，老实说，我认为我做得对，但它偶尔也会漏掉。任何想法为什么会这样？：其中我收到以下错误：

*由于未捕获的异常终止应用程序＆＃39; NSInvalidArgumentException＆＃39;，原因：＆＃39; * - [NSKeyedUnarchiver initForReadingWithData：]：难以理解的存档（0x62,0x70,0x6c，0x69 ，0x73,0x74,0x30,0x30）＆＃39;

Answer 1

我刚刚运行此代码来检查您的逻辑并且它是正确的。

NSMutableArray *orderQueue = [[NSMutableArray alloc] init];
NSString *originalString = @"Here are some strings for you.";
for (NSInteger i = 0; i < 1000; ++i)
{
    @autoreleasepool {
        originalString = [originalString stringByAppendingString:@"\nHere are some strings for you."];
    }
}
NSData *data = [originalString dataUsingEncoding:NSUTF8StringEncoding];
// Split up the data and put into Array
NSUInteger length = [data length];
NSUInteger chunkSize = 100;
NSUInteger offset = 0;
do {
    NSUInteger thisChunkSize = length - offset > chunkSize ? chunkSize : length - offset;
    NSData* chunk = [NSData dataWithBytesNoCopy:(char *)[data bytes] + offset
                                         length:thisChunkSize  freeWhenDone:NO];
    offset += thisChunkSize;

    [orderQueue addObject:chunk];
} while (offset < length);

NSMutableData *finishedData = [[NSMutableData alloc] init];
for (NSData *dataChunk in orderQueue) {
    [finishedData appendData:dataChunk];
}
NSString *recreatedString = [[NSString alloc] initWithData:finishedData encoding:NSUTF8StringEncoding];
NSLog(@"%@", recreatedString);
NSLog(@"%@", [originalString isEqualToString:recreatedString] ? @"Equal" : @"Error");

您的错误必须在其他地方，可能与您在<NSCoding>课程中对Order协议做出回应的方式有关。

如何正确拆分NSData？

1 个答案: