在Objective-c中编码2D数组

Question

I have a custom object with two 2D arrays as follows:

float a[5][5];
float b[5][10];

And I want to encode this object:

- (void)encodeWithCoder:(NSCoder *)coder
{
    // Encode a
    // Encode b
}

How can I encode and decode these 2D arrays? I couldn't find an appropriate method to do this operation. Thanks in Advance,

Answer 1

You can create a struct with those:

typedef struct myStruct {

    float a[5][5];
    float b[5][10];

}MyStruct;

Then use NSValue to encode them as objects.

MyStruct i;
memset(&i, 0, sizeof(i));
//Set values on struct

NSValue *v = [NSValue valueWithBytes:&i objCType:@encode(MyStruct)];

Now, you can treat your struct as an object and use then with NSArrays and so on.

To read the values you can use:

MyStruct i;

[v getValue:&i];

I did it like this to work with streams and legacy servers and it worked smoothly.

Hope it helps.

Answer 2

将它们粘贴到Objective-C容器中以进行编码/解码过程。

Answer 3

There is no pre-built method for that - you would need to write it yourself. The simplest way would be to write two int s first for the number of rows and the number of columns, and then write all R*C elements one by one.

Decoding is equally simple - read the two ints for R and C , and then run two nested loops reading the float s.

Define two helper functions for that to avoid copy-pasting the same code twice.