CODEWITHSUNDEEP
iosobjective-ccencodingtype-conversion
Alex Markman
Alex Markman

Reputation: 1460

NSCoder encoding and decoding of c data type

I am making and app to transfer audio to the receiving server. I want to encode the audio buffer in order to stream. I made a class which stores this buffer and some other information. When I decode the data after encoding the main object, these two objects have different audio buffer.

So the conclusion is I am making a mistake in encoding/decoding. Here is my code for encoding the buffer

- (void)encodeWithCoder:(NSCoder *)aCoder {
    [aCoder encodeBytes:&_data length:sizeof(float *)];
    [aCoder encodeInt:_numFrames forKey:numFrames];
    [aCoder encodeInt:_numChannels forKey:numChannels];
}

NOTE _data has (float *) c data type

The decoding logic goes here

- (id)initWithCoder:(NSCoder *)aDecoder {
    self = [super init];
    if (self) {

        NSUInteger length = 0;
        {
            const uint8_t *buffer = [aDecoder decodeBytesForKey:data returnedLength:&length];
            assert(length);
            memcpy(&_data, buffer, length);
        }
        _numFrames = [aDecoder decodeInt32ForKey:numFrames];
        _numChannels = [aDecoder decodeInt32ForKey:numChannels];
    }
    return self;
}

I am using this method to compare if they are identical

- (BOOL)isEqual:(id)object {
    AudioPacket *compareObject = (AudioPacket *)object;
    return (_data == compareObject.data && _numFrames == compareObject.numFrames && _numChannels == compareObject.numChannels);
}

Upvotes: 0

Views: 358

Answers (1)

Charlie Burns
Charlie Burns

Reputation: 7044

Not sure, but when you encode _data you don't give it a key:

[aCoder encodeBytes:&_data length:sizeof(float *)];

When you decode _data you use a key data:

 const uint8_t *buffer = [aDecoder decodeBytesForKey:data returnedLength:&length];

Perhaps you want a version of encodeBytes that also takes a key

 encodeBytes:length:forKey:

Upvotes: 1

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