From e3929f72b8a52851b5a65d5c5acd342663720670 Mon Sep 17 00:00:00 2001
From: Oleksandr Hryshchenko <oleksandr.hryshchenko@student.tuke.sk>
Date: Sun, 9 Jan 2022 20:19:57 +0000
Subject: [PATCH] =?UTF-8?q?=D0=98=D0=B7=D0=BC=D0=B5=D0=BD=D0=B8=D0=BB(?=
 =?UTF-8?q?=D0=B0)=20=D0=BD=D0=B0=20'sk2a/compressor.c'?=
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---
 sk2a/compressor.c | 178 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 177 insertions(+), 1 deletion(-)

diff --git a/sk2a/compressor.c b/sk2a/compressor.c
index 0045d93..782305b 100644
--- a/sk2a/compressor.c
+++ b/sk2a/compressor.c
@@ -1 +1,177 @@
-wwww
\ No newline at end of file
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include "compressor.h"
+#define BUFSIZE 1024
+
+int basic_string = 0;
+
+
+char *rotateString(char *str, int count) {
+
+    size_t len = strlen(str);
+    int counter;
+
+    for(counter=0;counter < len;counter++) {
+        int value = (int)str[counter];
+
+        if((char)value != ' ') {
+            value = value + count;
+            str[counter] = value;
+        }
+    }
+
+    return str;
+}
+
+char* bwt_compress(char buffer[BUFSIZE * 2]){
+    char* encoded = (char*) calloc(BUFSIZE *2, sizeof(char));
+    char* rotation[strlen(buffer)];
+
+    char* temp = (char*) calloc(BUFSIZE * 2, sizeof(char));
+
+    for(int i = 0; i < strlen(buffer); i++){
+        rotation[i] = (char*) calloc(BUFSIZE * 2, sizeof(char));
+    }
+
+    for(int i = 0; i < strlen(buffer); i++){
+        strcpy(rotation[i], rotateString(buffer, -1));
+    }
+
+
+    for(int i = 0; i < strlen(buffer); i++){
+        for(int j = 0; j < strlen(buffer); j++){
+            if(strcmp(rotation[j], rotation[j+1]) > 0){
+                strcpy(temp, rotation[j]);
+                strcpy(rotation[j], rotation[j+1]);
+                strcpy(rotation[j+1], temp);
+            }
+        }
+    }
+
+    for(int i = 0; i < strlen(buffer); i++){
+        strncat(encoded, &rotation[i][strlen(rotation[i])], 1);
+        if(strcmp(rotation[i], buffer) == 0){
+            basic_string = i;
+        }
+    }
+
+    return encoded;
+}
+
+char* run_length(char buffer[BUFSIZE]){
+    char* encoded = (char*) calloc(BUFSIZE * 2, sizeof(char));
+    int counter = 1;
+    int i = 1;
+
+    while(i < strlen(buffer)+1){
+        for(; i < strlen(buffer)+1; i++){
+            if(buffer[i] == buffer[i-1])
+                counter++;
+            else {
+                char* temp = (char*) calloc(5, sizeof(char));
+                sprintf(temp, "%d", counter);
+                strncat(encoded, temp, strlen(temp));
+                strncat(encoded, &buffer[i-1], 1);
+                i++;
+                counter = 1;
+                break;
+            }
+        }
+    }
+
+    return encoded;
+}
+
+
+void compress(FILE* infile,FILE* outfile){
+    char buffer[BUFSIZE];
+    memset(buffer,0,BUFSIZE);
+    while(1) {
+        int insize = (int) fread(buffer, sizeof(char), BUFSIZE, infile);
+        if (insize == 0) {
+            if (feof(infile)) {
+                // end of file
+                break;
+            }
+            assert(!ferror(infile));
+        }
+
+        char outbuf[BUFSIZE*2];
+        strncpy(outbuf, run_length(bwt_compress(buffer)), BUFSIZE*2-1);
+
+        fwrite(outbuf,sizeof(char), strlen(outbuf),outfile);
+    }
+}
+
+char* bwt_decompress(char buffer[BUFSIZE * 2]){
+    char* rotation[strlen(buffer)];
+
+    for(int i = 0; i < strlen(buffer); i++){
+        rotation[i] = (char*) calloc(BUFSIZE * 2, sizeof(char));
+    }
+
+    for(int i = 0; i < strlen(buffer); i++){
+        for(int j = 0; j < strlen(buffer); j++){
+            rotation[j][i] = buffer[strlen(buffer) - 1 -j];
+        }
+
+        char* temp = (char*) calloc(BUFSIZE * 2, sizeof(char));
+
+        for(int iterator = 0; iterator < strlen(buffer); iterator++){
+            for(int j = 0; j < strlen(buffer); j++){
+                if(strcmp(rotation[j], rotation[j+1]) > 0){
+                    strcpy(temp, rotation[j]);
+                    strcpy(rotation[j], rotation[j+1]);
+                    strcpy(rotation[j+1], temp);
+                }
+            }
+        }
+    }
+
+    return rotation[basic_string];
+}
+
+char* run_length_decompress(char buffer[BUFSIZE * 2]){
+    char* decoded = (char*) calloc(BUFSIZE, sizeof(char));
+    int i = 0;
+
+    while(i < strlen(buffer)){
+        char* temp = (char*) calloc(5, sizeof(char));
+        for(; i < strlen(buffer); i++){
+            if(isdigit(buffer[i])){
+                strncat(temp, &buffer[i], 1);
+            }
+            else{
+                for(int j = 0; j < atoi(temp); j++)
+                    strncat(decoded, &buffer[i], 1);
+                i++;
+                break;
+            }
+        }
+        memset(temp, '\0', 5);
+    }
+
+    return decoded;
+}
+
+void decompress(FILE* infile,FILE* outfile){
+    char buffer[BUFSIZE * 2];
+    memset(buffer, 0, BUFSIZE*2);
+    while(1){
+        int insize = (int)fread(buffer,sizeof(char),BUFSIZE * 2,infile);
+        if (insize == 0){
+            if (feof(infile)){
+                // end of file
+                break;
+            }
+            assert(!ferror(infile));
+        }
+        char outbuf[BUFSIZE];
+        strncpy(outbuf, bwt_decompress(run_length_decompress(buffer)), BUFSIZE-1);
+
+        fwrite(outbuf,sizeof(char), strlen(outbuf),outfile);
+    }
+}
\ No newline at end of file