Re: A little compression...

[Harry Potter <maspethrose7@aol.com>]

On May 24, 5:02 pm, Harry Potter <maspethro...@aol.com> wrote:
> It's closed source.  Do I have another choice?  Perhaps a general
> guide on the internet for optimizing C++ code?

Maybe this will help:

//Compares a block at loc. Cur to loc. Prev in the input buffer c.In
and returns the length.
unsigned ByteRef::ChkBlock (unsigned Cur, unsigned Prev, compbuffer
&c)
{
	unsigned int i, j, k;
	register unsigned char* in2=c.In;
	//Get max. compare len. in j
	j=Cur-Prev;
	k=c.InLen-Cur; if (k<j) j=k;
	if (j>65) j=65;	//Max. possible ref. len. =65 bytes
	for (i=0; i<j && in2[Cur+i]==in2[Prev+i]; i++);
	if (i<3) i=0;

	return i;
}

unsigned ByteRef::ScanRef (int pos, compbuffer &c)
{
	int i;			//Temp. variables
	int j, k;
	unsigned char *in=c.In, *cu=in+pos;	//Just to speed access.
	len=0;	//Len.=0 for init. block.
	if (c.InLen-pos<3||pos<1) return 0;
	//Scan from current p0os.-1 to beginning of input.
	for (i=pos-1;pos<=ByteRefDepth-2?i>=0:i>=pos-(ByteRefDepth-1); i--)
	{
		if (*(unsigned short*)(cu)==*(unsigned short*)(in+i) &&
			//If word at current pos.=word at compare block ==,
			(j=ChkBlock(pos,i, c))>len) {	//and better than best,
			len=j; loc=i;		//make current best.
		}
	}
	return len;
}