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39 lines
680 B
C
39 lines
680 B
C
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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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}
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