mirror of
https://github.com/ZDoom/Raze.git
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118 lines
4.4 KiB
C
118 lines
4.4 KiB
C
//--------------------------------------------------------------------------------------------------
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#if defined(__POWERPC__)
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static unsigned long LSWAPIB (unsigned long a) { return(((a>>8)&0xff00)+((a&0xff00)<<8)+(a<<24)+(a>>24)); }
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static unsigned short SSWAPIB (unsigned short a) { return((a>>8)+(a<<8)); }
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#else
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#define LSWAPIB(a) (a)
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#define SSWAPIB(a) (a)
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#endif
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#define USENEW 1
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long lzwcompress (unsigned char *ucompbuf, long ucompleng, unsigned char *compbuf)
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{
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long i, j, numnodes, *lptr, bitcnt, nbits, oneupnbits, hmask, *child;
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long *sibly;
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#if USENEW
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long *sibry;
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#endif
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unsigned char *nodev, *cptr, *eptr;
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nodev = (unsigned char *)malloc((ucompleng+256)*sizeof(char)); if (!nodev) return(0);
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child = (long *)malloc((ucompleng+256)*sizeof(long)); if (!child) { free(nodev); return(0); }
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sibly = (long *)malloc((ucompleng+256)*sizeof(long)); if (!sibly) { free(child); free(nodev); return(0); }
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#if USENEW
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sibry = (long *)malloc((ucompleng+256)*sizeof(long)); if (!sibry) { free(sibly); free(child); free(nodev); return(0); }
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#endif
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for (i=255;i>=0;i--) { nodev[i] = i; child[i] = -1; }
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memset(compbuf,0,ucompleng+15);
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cptr = ucompbuf; eptr = &ucompbuf[ucompleng];
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numnodes = 256; bitcnt = (4<<3); nbits = 8; oneupnbits = (1<<8); hmask = ((oneupnbits>>1)-1);
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do
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{
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for (i=cptr[0];i>=0;i=j)
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{
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cptr++; if (cptr >= eptr) goto lzwcompbreak2b;
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j = child[i]; if (j < 0) { child[i] = numnodes; break; }
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#if USENEW
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//This is about 2x faster when ucompbuf is more random, 5% slower when very compressible
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while (cptr[0] != nodev[j])
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{
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if (cptr[0] < nodev[j])
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{ if (sibly[j] < 0) { sibly[j] = numnodes; goto lzwcompbreak2a; } j = sibly[j]; }
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else { if (sibry[j] < 0) { sibry[j] = numnodes; goto lzwcompbreak2a; } j = sibry[j]; }
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}
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#else
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for (;nodev[j]!=cptr[0];j=sibly[j])
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if (sibly[j] < 0) { sibly[j] = numnodes; goto lzwcompbreak2a; }
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#endif
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}
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lzwcompbreak2a:
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nodev[numnodes] = cptr[0];
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lzwcompbreak2b:
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child[numnodes] = sibly[numnodes] = -1;
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#if USENEW
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sibry[numnodes] = -1;
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#endif
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lptr = (long *)&compbuf[bitcnt>>3]; lptr[0] |= LSWAPIB(i<<(bitcnt&7));
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bitcnt += nbits; if ((i&hmask) > ((numnodes-1)&hmask)) bitcnt--;
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numnodes++; if (numnodes > oneupnbits) { nbits++; oneupnbits <<= 1; hmask = ((oneupnbits>>1)-1); }
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} while ((cptr < eptr) && (bitcnt < (ucompleng<<3)));
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#if USENEW
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free(sibry);
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#endif
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free(sibly);
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free(child); free(nodev);
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lptr = (long *)compbuf;
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if (((bitcnt+7)>>3) < ucompleng) { lptr[0] = LSWAPIB(numnodes); return((bitcnt+7)>>3); }
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memcpy(compbuf,ucompbuf,ucompleng); return(ucompleng);
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}
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long lzwuncompress (unsigned char *compbuf, long compleng, unsigned char *ucompbuf, long ucompleng)
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{
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long i, dat, leng, bitcnt, *lptr, numnodes, totnodes, nbits, oneupnbits, hmask, *prefix;
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unsigned char ch, *ucptr, *suffix;
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long ucomp = (long)ucompbuf;
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if (compleng >= ucompleng) { memcpy(ucompbuf,compbuf,ucompleng); return ucompleng; }
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totnodes = LSWAPIB(((long *)compbuf)[0]); if (totnodes <= 0 || totnodes >= ucompleng+256) return 0;
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prefix = (long *)malloc(totnodes*sizeof(long)); if (!prefix) return 0;
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suffix = (unsigned char *)malloc(totnodes*sizeof(char)); if (!suffix) { free(prefix); return 0; }
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numnodes = 256; bitcnt = (4<<3); nbits = 8; oneupnbits = (1<<8); hmask = ((oneupnbits>>1)-1);
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do
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{
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lptr = (long *)&compbuf[bitcnt>>3]; dat = ((LSWAPIB(lptr[0])>>(bitcnt&7))&(oneupnbits-1));
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bitcnt += nbits; if ((dat&hmask) > ((numnodes-1)&hmask)) { dat &= hmask; bitcnt--; }
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prefix[numnodes] = dat;
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ucompbuf++;
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for (leng=0;dat>=256;dat=prefix[dat]) {
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if ((long)ucompbuf+leng-ucomp > ucompleng) goto bail;
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ucompbuf[leng++] = suffix[dat];
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}
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ucptr = &ucompbuf[leng-1];
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for (i=(leng>>1)-1;i>=0;i--) { ch = ucompbuf[i]; ucompbuf[i] = ucptr[-i]; ucptr[-i] = ch; }
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ucompbuf[-1] = dat; ucompbuf += leng;
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suffix[numnodes-1] = suffix[numnodes] = dat;
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numnodes++; if (numnodes > oneupnbits) { nbits++; oneupnbits <<= 1; hmask = ((oneupnbits>>1)-1); }
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} while (numnodes < totnodes);
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bail:
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free(suffix); free(prefix);
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return (long)ucompbuf-ucomp;
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}
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//--------------------------------------------------------------------------------------------------
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