137 lines
2.5 KiB
C
137 lines
2.5 KiB
C
#define _GNU_SOURCE
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "compressor.h"
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#define BUFSIZE 2000000
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#define BSIZE 9
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int mycompress(char* buff,int size,char* outbuf){
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//memcpy(outbuf,buff,size);
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int k = 0;
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int head = 0;
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while(head < size && buff[head] > 0 ){
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//
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//
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// Kod inspirovany riesenim
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// pana Ing. Daniela Hladeka
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// 2019 Technical University of Kosice
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//
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//
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int bufferSize = BSIZE;
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if (head < bufferSize){
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bufferSize = head;
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}
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char* searchBuffer = buff + head - bufferSize;
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char* window = buff + head;
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int lookAheadSize = BSIZE;
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if((size - head) < lookAheadSize){
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lookAheadSize = BSIZE - head;
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}
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int wsz = BSIZE;
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int msz = wsz;
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if (bufferSize < wsz){
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msz = bufferSize;
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}
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int offset = -1;
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int size = -1;
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for(int i = 1; i<msz; i++){
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char* r = memmem(searchBuffer, bufferSize, window, i);
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if(r > 0){
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offset = bufferSize - ( r - searchBuffer );
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size = i+1;
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}else {
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break;
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}
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}
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if(size > 0){
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sprintf(&outbuf[k],"%d%d%c",offset,size-1,buff[head+size-1]);
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k+=3;
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head+=size;
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}else {
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sprintf(&outbuf[k],"00%c",buff[head]);
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k+=3;
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head+=1;
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}
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}
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return k;
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}
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void compress(FILE* infile,FILE* outfile){
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char buffer[BUFSIZE];
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memset(buffer,0,BUFSIZE);
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while(1){
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int insize = fread(buffer,sizeof(char),BUFSIZE,infile);
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if (insize == 0){
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if (feof(infile)){
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// end of file
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break;
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}
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assert(!ferror(infile));
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}
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char outbuf[BUFSIZE*2];
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// Doplnte implementaciu kompresie.
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int outsize = mycompress(buffer,insize,outbuf);
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if (outsize > 0){
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fwrite(outbuf,sizeof(char),outsize,outfile);
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}
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}
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}
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void decompress(FILE* infile,FILE* outfile){
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char code[3];
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char buffer[BUFSIZE];
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int size = 0;
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int k = 0;
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fseek(infile, 0, SEEK_END);
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long fileSize = ftell(infile);
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fseek(infile, 0, SEEK_SET);
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printf("size: %ld\n", fileSize);
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char letter;
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while(!feof(infile)){
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size = 0;
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memset(buffer,0,BUFSIZE);
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for(int j = 0; j < 4096; j++){
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fread(code, sizeof(char), 3, infile);
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int offset = atoi(code);
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int length = atoi(&code[1]);
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letter = code[2];
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offset=(offset-length)/10;
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if(offset == 0){
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buffer[size] = letter;
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size++;
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}else {
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for(int i = 0; i < length; i++){
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buffer[size] = buffer[size-offset];
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size++;
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}
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buffer[size] = letter;
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size++;
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}
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printf("%d\n",k);
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k+=3;
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}
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fwrite(buffer, sizeof(char), size-1, outfile);
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}
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}
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