/***************************************************************************** SLZ - SLZ (un)packer. C. 1993 SilverFox SoftWare. Written by Adisak Pochanayon All Rights Reserved. This program is a simple example of using SLZ compression upon a file. It will allow you to both pack and unpack a file using SLZ compression. The syntax for calling this program from the CLI is: SLZ FLAG SOURCE DESTINATION FLAG can be U - unpack P - pack *****************************************************************************/ // Comment out the following line to save 256K of memory but can slow down // compression (immensely :( ). #define hashing_on #include #include /* defines for interpreting the CLI arguments */ #define arg_flag 1 #define arg_srce 2 #define arg_dest 3 #define arg_count 4 /* defines for handling argument and file errors */ #define slz_error 1024 #define error_read 0 #define error_args 1 #define error_srce 2 #define error_dest 4 #define error_write 8 /* defines for file compression / decompression */ #define FILE_ERROR 0 #define TRUE 1 #define FALSE 0 /*** GLOBAL VARIABLE FOR ERRORS AND FILES ***/ int error=0; long length; short lzhist_offset=0; /* * SHIFT_UPPER is amount to multiply upper in one byte to get into next * higher byte. (H=4096 -> 16, H=2048 -> 8) * LSR_upper is amount to shift codeword to get upper byte into lower byte. * (H=4096 -> 4, H=2048 -> 3) * MAX_COMP_LENGTH = (2 ^ (8-LSR_upper)) + 1 */ #define HISTORY_SIZE 4096 #define MASK_history (HISTORY_SIZE-1) #define MASK_upper (0xF0) #define MASK_lower (0x0F) #define SHIFT_UPPER 16 #define LSR_upper 4 #define MAX_COMP_LEN 17 unsigned char LZ_history[HISTORY_SIZE]; #ifdef hashing_on long far HASH_TABLE[65536]; #define CHASH(a,b,c) ( ((((a&63)<<6)+(b&63))<<4)+c ) #endif void writechar(register unsigned char outchar, register FILE *outfile) { if (putc(outchar,outfile)==EOF) { printf("Error writing output file.\n"); fcloseall(); exit(slz_error + error_write); } LZ_history[lzhist_offset]=outchar; lzhist_offset=(lzhist_offset+1)&MASK_history; } void UnPackSLZ(unsigned char *inbuffer, register FILE *outfile) { short myTAG, mycount, myoffset; long int loop1; for(;;) // loop forever (until goto occurs to break out of loop) { myTAG=*inbuffer++; for(loop1=0;(loop1!=8);loop1++) { if(myTAG&0x80) { if((mycount=*inbuffer++)==0) // Check EXIT { goto skip2; } // goto's are gross but it's efficient :( else { myoffset=HISTORY_SIZE-(((MASK_upper&mycount)*SHIFT_UPPER)+(*inbuffer++)); mycount&=MASK_lower; mycount+=2; while(mycount!=0) { writechar(LZ_history[(lzhist_offset+myoffset)&MASK_history],outfile); mycount--; } } } else { writechar(*inbuffer++,outfile); } myTAG+=myTAG; } } skip2: return; } #ifdef hashing_on void ADDHASH(long a,long b, long c) { long *INHASH,*BEFINHASH; INHASH=&HASH_TABLE[CHASH(a,b,15)]; BEFINHASH=INHASH-1; *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH--)=*(BEFINHASH--); *(INHASH)=*(BEFINHASH); *BEFINHASH=c; } #endif void PackSLZ(unsigned char *inbuffer, register FILE *outfile) { long int loop1,loop2, startvalue, endvalue, wherefound; unsigned char outchars[MAX_COMP_LEN*10]; unsigned char *a_buffer, *b_buffer; short lenoutchars; short myTAG, iter; short done,found,temp; #ifdef hashing_on long *INHASH; short HASHCHECK; for(loop1=0;loop1!=65536;loop1++) { HASH_TABLE[loop1]=-1; } HASH_TABLE[CHASH(inbuffer[0],inbuffer[1],0)]=0; #endif loop1=1; loop2=length-1; iter=1; // Always do a literal first byte outchars[1]=inbuffer[0]; lenoutchars=2; done=FALSE; while(! done) { myTAG=0; while((iter<8)&&(! done)) { /***--- This is the slowest part. I should rewrite it in ASM ---***/ startvalue=loop1-MASK_history; if (startvalue<0) startvalue=0; found=0; #ifdef hashing_on INHASH=&HASH_TABLE[CHASH(inbuffer[loop1],inbuffer[loop1+1],0)]; HASHCHECK=16; // Scan for matches in HASH TABLE while((HASHCHECK)&&((endvalue=*INHASH++)>=startvalue)) { temp=0; a_buffer=&inbuffer[loop1]; b_buffer=&inbuffer[endvalue]; while((*(a_buffer++) == *(b_buffer++))&&(templength) { temp=length-loop1; if(found=startvalue) // Scan for matches { temp=0; a_buffer=&inbuffer[loop1]; b_buffer=&inbuffer[endvalue]; while((*(a_buffer++) == *(b_buffer++))&&(templength) { temp=length-loop1; if(found2) // Compression will now occur { myTAG|=(128>>iter); endvalue=loop1-wherefound; startvalue=((endvalue>>LSR_upper)&MASK_upper)+(found-2); outchars[lenoutchars++]=startvalue; outchars[lenoutchars++]=(unsigned char)endvalue; loop2-=found; while(found!=0) { #ifdef hashing_on ADDHASH(inbuffer[loop1],inbuffer[loop1+1],loop1); #endif loop1++; found--; } } else // No Compression, copy literal byte { #ifdef hashing_on ADDHASH(inbuffer[loop1],inbuffer[loop1+1],loop1); #endif outchars[lenoutchars++]=inbuffer[loop1++]; loop2--; } if(loop2<=0) { done=TRUE; if(loop2<0) { printf("HMMM... ooops!!!\n"); } } iter++; } if(! done) { outchars[0]=myTAG; for(startvalue=0;startvalue!=lenoutchars;startvalue++) { // writechar(outchars[startvalue],outfile); /*****/ if (putc(outchars[startvalue],outfile)==EOF) { printf("Error writing output file.\n"); fcloseall(); exit(slz_error + error_write); } /*****/ } lenoutchars=1; iter=0; } } if(iter==8) { outchars[0]=myTAG; for(startvalue=0;startvalue!=lenoutchars;startvalue++) { writechar(outchars[startvalue],outfile); } writechar(255,outfile); writechar(0,outfile); } else { outchars[0]=myTAG|(128>>iter); for(startvalue=0;startvalue!=lenoutchars;startvalue++) { writechar(outchars[startvalue],outfile); } writechar(0,outfile); } } main(int argc, char *argv[]) { FILE *infile, *outfile; unsigned char *inbuffer; printf(" SLZ -- SLZ (un)packer. C. 1993 SilverFox SoftWare.\n"); printf(" Written by Adisak Pochanayon All Rights Reserved.\n\n"); if (argc != arg_count) { error= slz_error + error_args; printf("Error -- Please check arguments.\n"); } else if ((infile = fopen(argv[arg_srce],"r"))==FILE_ERROR) { error= slz_error + error_srce; printf("Error -- SOURCE file could not be opened.\n"); } else if ((outfile = fopen(argv[arg_dest],"w"))==FILE_ERROR) { error= slz_error + error_dest; printf("Error -- DESTINATION file could not be opened.\n"); } else { /* * Get the length of the input file (sorry it takes me 3 calls :( ) * If you have a better way, let me know. */ fseek(infile,0,2); length=ftell(infile); rewind(infile); if (length>2) if ((inbuffer=(unsigned char *)getml(length))!=0) { fread(inbuffer,1,length,infile); // assume this goes no problem :) switch (*argv[arg_flag]) { case 'U' : case 'u' : printf("UnPacking File %s.\n",argv[arg_srce]); UnPackSLZ(inbuffer, outfile); break; case 'P' : case 'p' : printf("Packing File %s.\n",argv[arg_srce]); PackSLZ(inbuffer, outfile); break; default : error=slz_error + error_args; printf("Error -- no FLAG selected.\n"); } rlsml(inbuffer,length); } } if (error!=0) printf("\nSLZ command syntax is: \"SLZ FLAG SOURCE DESTINATION\"\n where FLAG can be U - unpack P - pack.\n\n"); else printf("\nSLZ successfully completed\n"); fcloseall(); exit(error); }