#337 modify comment in the LzmaLib.h

[Bruce Stark]

I encountered an error when I used the LzmaCompress API:
1. Did not assign the initial value to the variable destLen;
2. the return value of LzmaCompress was SZ_ERROR_OUTPUT_EOF;

{
...
size_t destLen;
My_STDAPI Res = LzmaCompress(dest,&destLen,src,srcLen,outProps,&outPropsSize,
                0,1<<16,3,0,2,32,2);
...
}

But, I found the source code is that:

{
    ...
    LzmaCompress(...)
    {
        Lzmacode(...)
        {
            ...
            LzmaEnc_MemEncode(...)
            {
                ...
                outStream.rem = *destLen;
                ...
            }
            ...
        }
    }
...
}

SO,I think the destLen is not only an output value, but also an input value.

[Igor Pavlov]

Yes, it's obvious.
If you provide the output buffer, some function's parameter contains the size of that buffer.
I'll add comment in h file about.
Thanks!

[Bruce Stark]

However, the LzmaLib.h file shows that the destLen is just an output value.

/*
...
Out:
    destLen - processed output size
Return:
    SZ_OK   - OK
 ...
*/

In order to solve the error above, I give destLen an initial value and test it again. The result is OK.
{
...
size_t destLen = srcLen;
My_STDAPI Res = LzmaCompress(dest,&destLen,src,srcLen,outProps,&outPropsSize,
0,1<<16,3,0,2,32,2);
...
}

So, I suggest to modify the comment in the LzmaLib.h file , and the destLen have to give an initial value.

/*
...
In/Out:
    destLen - processed output size
Return:
    SZ_OK   - OK
 ...
*/

[Igor Pavlov]

Look LzmaUncompress description.
It has similar parameters.

[Bruce Stark]

Yes, that's right.
I have modified it according the LzmaUncompress description