//-------------------------------------------------------------------------------------------------- #if defined(__POWERPC__) static uint32_t LSWAPIB(uint32_t a) { return(((a>>8)&0xff00)+((a&0xff00)<<8)+(a<<24)+(a>>24)); } static uint16_t SSWAPIB(uint16_t a) { return((a>>8)+(a<<8)); } #else #define LSWAPIB(a) (a) #define SSWAPIB(a) (a) #endif #define USENEW 1 int32_t lzwcompress(char *ucompbuf, int32_t ucompleng, char *compbuf) { int32_t i, j, numnodes, *lptr, bitcnt, nbits, oneupnbits, hmask, *child; int32_t *sibly; #if USENEW int32_t *sibry; #endif char *nodev, *cptr, *eptr; nodev = (char *)malloc((ucompleng+256)*sizeof(uint8_t)); if (!nodev) return(0); child = (int32_t *)malloc((ucompleng+256)*sizeof(int32_t)); if (!child) { free(nodev); return(0); } sibly = (int32_t *)malloc((ucompleng+256)*sizeof(int32_t)); if (!sibly) { free(child); free(nodev); return(0); } #if USENEW sibry = (int32_t *)malloc((ucompleng+256)*sizeof(int32_t)); if (!sibry) { free(sibly); free(child); free(nodev); return(0); } #endif for (i=255;i>=0;i--) { nodev[i] = i; child[i] = -1; } memset(compbuf,0,ucompleng+15); cptr = ucompbuf; eptr = &ucompbuf[ucompleng]; numnodes = 256; bitcnt = (4<<3); nbits = 8; oneupnbits = (1<<8); hmask = ((oneupnbits>>1)-1); do { for (i=cptr[0];i>=0;i=j) { cptr++; if (cptr >= eptr) goto lzwcompbreak2b; j = child[i]; if (j < 0) { child[i] = numnodes; break; } #if USENEW //This is about 2x faster when ucompbuf is more random, 5% slower when very compressible while (cptr[0] != nodev[j]) { if (cptr[0] < nodev[j]) { if (sibly[j] < 0) { sibly[j] = numnodes; goto lzwcompbreak2a; } j = sibly[j]; } else { if (sibry[j] < 0) { sibry[j] = numnodes; goto lzwcompbreak2a; } j = sibry[j]; } } #else for (;nodev[j]!=cptr[0];j=sibly[j]) if (sibly[j] < 0) { sibly[j] = numnodes; goto lzwcompbreak2a; } #endif } lzwcompbreak2a: nodev[numnodes] = cptr[0]; lzwcompbreak2b: child[numnodes] = sibly[numnodes] = -1; #if USENEW sibry[numnodes] = -1; #endif lptr = (int32_t *)&compbuf[bitcnt>>3]; lptr[0] |= LSWAPIB(i<<(bitcnt&7)); bitcnt += nbits; if ((i&hmask) > ((numnodes-1)&hmask)) bitcnt--; numnodes++; if (numnodes > oneupnbits) { nbits++; oneupnbits <<= 1; hmask = ((oneupnbits>>1)-1); } } while ((cptr < eptr) && (bitcnt < (ucompleng<<3))); #if USENEW free(sibry); #endif free(sibly); free(child); free(nodev); lptr = (int32_t *)compbuf; if (((bitcnt+7)>>3) < ucompleng) { lptr[0] = LSWAPIB(numnodes); return((bitcnt+7)>>3); } memcpy(compbuf,ucompbuf,ucompleng); return(ucompleng); } int32_t lzwuncompress(char *compbuf, int32_t compleng, char *ucompbuf, int32_t ucompleng) { int32_t i, dat, leng, bitcnt, *lptr, numnodes, totnodes, nbits, oneupnbits, hmask, *prefix; char ch, *ucptr, *suffix; int32_t ucomp = (int32_t)ucompbuf; if (compleng >= ucompleng) { memcpy(ucompbuf,compbuf,ucompleng); return ucompleng; } totnodes = LSWAPIB(((int32_t *)compbuf)[0]); if (totnodes <= 0 || totnodes >= ucompleng+256) return 0; prefix = (int32_t *)malloc(totnodes*sizeof(int32_t)); if (!prefix) return 0; suffix = (char *)malloc(totnodes*sizeof(uint8_t)); if (!suffix) { free(prefix); return 0; } numnodes = 256; bitcnt = (4<<3); nbits = 8; oneupnbits = (1<<8); hmask = ((oneupnbits>>1)-1); do { lptr = (int32_t *)&compbuf[bitcnt>>3]; dat = ((LSWAPIB(lptr[0])>>(bitcnt&7))&(oneupnbits-1)); bitcnt += nbits; if ((dat&hmask) > ((numnodes-1)&hmask)) { dat &= hmask; bitcnt--; } prefix[numnodes] = dat; ucompbuf++; for (leng=0;dat>=256;dat=prefix[dat]) { if ((int32_t)ucompbuf+leng-ucomp > ucompleng) goto bail; ucompbuf[leng++] = suffix[dat]; } ucptr = &ucompbuf[leng-1]; for (i=(leng>>1)-1;i>=0;i--) { ch = ucompbuf[i]; ucompbuf[i] = ucptr[-i]; ucptr[-i] = ch; } ucompbuf[-1] = dat; ucompbuf += leng; suffix[numnodes-1] = suffix[numnodes] = dat; numnodes++; if (numnodes > oneupnbits) { nbits++; oneupnbits <<= 1; hmask = ((oneupnbits>>1)-1); } } while (numnodes < totnodes); bail: free(suffix); free(prefix); return (int32_t)ucompbuf-ucomp; } //--------------------------------------------------------------------------------------------------