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#include <u.h>
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#include <libc.h>
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#include <draw.h>
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/*
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 * compressed data are seuences of byte codes.
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 * if the first byte b has the 0x80 bit set, the next (b^0x80)+1 bytes
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 * are data.  otherwise, it's two bytes specifying a previous string to repeat.
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 */
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void
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_twiddlecompressed(uchar *buf, int n)
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{
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	uchar *ebuf;
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	int j, k, c;
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	ebuf = buf+n;
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	while(buf < ebuf){
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		c = *buf++;
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		if(c >= 128){
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			k = c-128+1;
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			for(j=0; j<k; j++, buf++)
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				*buf ^= 0xFF;
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		}else
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			buf++;
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	}
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}
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int
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_compblocksize(Rectangle r, int depth)
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{
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	int bpl;
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	bpl = bytesperline(r, depth);
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	bpl = 2*bpl;	/* add plenty extra for blocking, etc. */
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	if(bpl < NCBLOCK)
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		return NCBLOCK;
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	return bpl;
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}