How to convert C code to Java - Pointer equivalent in Java [closed]

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I am converting some C code into Java which includes image processing. However, I am stuck in a situation where I have to convert some lines of codes which include pointer calculations:

for(i=xMin[k];i<=xMax[k];i++)
{
        for(j=yMin[k];j<=yMax[k];j++)
        {
             if (Bimg[i][j]== k1)
             {
                /* accessing single channel for r g b  value */   

                b = data[i*step + j*channels + 0];
                g = data[i*step + j*channels + 1];
                r = data[i*step + j*channels + 2];
             }       
       }              
}

Can anybody please tell me how to convert this "data" pointer into java equivalent? Here, "data" is a pointer variable.

read this stackoverflow.com/questions/13716041/java-pointers-equivalent — lakshman
– lakshman, Commented Jan 14, 2014 at 5:24

ILMTitan · Accepted Answer · 2014-01-14 05:33:09Z

1

What is data pointing at?

It looks like it is pointing to an array of bytes, so just make data a byte[]. Assuming the C array pointed at and the Java array referred to have the same data, the same calculations should work.

answered Jan 14, 2014 at 5:33

ILMTitan

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1 Comment

shashwat13 Over a year ago

No, the data variable is pointing at BytePointer

Yuanhang Guo · Accepted Answer · 2014-01-14 05:48:40Z

1

I assume that the data you specific in the question is actually an array of unsigned char. Like:

unsigned char *data = (unsigned char*)malloc(datasize*sizeof(unsigned char));

I believe the equivalent in java is

byte[] data = new byte[datasize]

And since java don't allow you to operate pointer. You should use index to manipulate the data array.

Note: byte in java is always signed. You can get the unsigned value by:

int v = b & 0xFF

edited Jan 14, 2014 at 5:48

answered Jan 14, 2014 at 5:33

Yuanhang Guo

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