Update sk1/README.md

sk1/README.md

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+Súbor compressor.c
+#include <stdio.h> 
+#include <stdlib.h> 
+#define WSIZE 250 
+#define BSIZE 50 
+///----------------------------LZ77------------- 
+typedef struct { 
+unsigned char pos; 
+unsigned char n; 
+char symb; 
+} LZ77Token; 
+int compress_1(const char* input_file, const char* output_file) 
+{ 
+int compr_size = 0, sz = 0; 
+FILE* input = fopen(input_file, "rb"); 
+FILE* output = fopen(output_file, "wb"); 
+
+if (!input || !output) 
+{ 
+exit(-1); 
+} 
+
+char window[WSIZE] = { 0 }; 
+char buffer[BSIZE] = { 0 }; 
+
+int w_start = 0; 
+int w_end = 0; 
+
+while (!feof(input)) 
+{ 
+int blen = fread(buffer, 1, BSIZE, input); 
+
+for (int bpos = 0; bpos < blen; ++bpos) 
+{ 
+int best_pos = 0; 
+int best_n = 0; 
+
+for (int spos = w_start; spos < w_end; ++spos) 
+{ 
+int mlength = 0; 
+
+while (mlength < blen - bpos && 
+mlength < WSIZE && 
+(spos + mlength) < w_end && 
+window[(spos + mlength) % WSIZE] == buffer[bpos + mlength]) 
+{ 
+++mlength; 
+} 
+
+if (mlength > best_n) 
+{ 
+best_pos = w_end - spos; 
+best_n = mlength; 
+} 
+} 
+
+LZ77Token token; 
+token.pos = best_pos; 
+token.n = best_n; 
+
+if (bpos + best_n < blen) 
+{ 
+token.symb = buffer[bpos + best_n]; 
+} 
+else 
+{ 
+token.symb = '\0'; 
+} 
+
+sz=fwrite(&token, sizeof(LZ77Token), 1, output); 
+compr_size += sizeof(LZ77Token) * sz; 
+
+for (int j = 0; j <= best_n && bpos < blen; ++j) 
+{ 
+if (bpos + j < blen) 
+{ 
+window[w_end % WSIZE] = buffer[bpos + j]; 
+w_end++; 
+
+if (w_end - w_start > WSIZE) 
+{ 
+w_start++; 
+} 
+} 
+} 
+bpos += best_n; 
+} 
+} 
+
+fclose(input); 
+fclose(output); 
+
+return compr_size; 
+} 
+
+int decompress_1(const char* input_file, const char* output_file) 
+{ 
+int compr_size = 0; 
+FILE* input = fopen(input_file, "rb"); 
+FILE* output = fopen(output_file, "wb"); 
+
+if (!input || !output) 
+{ 
+exit(-1); 
+} 
+
+char window[WSIZE] = { 0 }; 
+int window_end = 0; 
+
+LZ77Token token; 
+while (fread(&token, sizeof(LZ77Token), 1, input)) 
+{ 
+if (token.pos == 0 && token.n == 0 && token.symb == '\0') 
+{ 
+continue; 
+} 
+
+int start_index = (window_end - token.pos + WSIZE) % WSIZE; 
+
+for (int i = 0; i < token.n; ++i) 
+{ 
+char ch = window[(start_index + i) % WSIZE]; 
+compr_size += fwrite(&ch, 1, 1, output); 
+window[window_end % WSIZE] = ch; 
+window_end = (window_end + 1) % WSIZE; 
+} 
+
+if (token.symb != '\0') 
+{ 
+compr_size += fwrite(&token.symb, 1, 1, output); 
+window[window_end % WSIZE] = token.symb; 
+window_end = (window_end + 1) % WSIZE; 
+} 
+} 
+fclose(input); 
+fclose(output); 
+
+
+return compr_size; 
+}//-------------------------------------RLE-------------------- 
+int compress_2(const char* input_file, const char* output_file) { 
+int ch, nchar; 
+unsigned char count = 1; 
+int compr_size = 0; 
+
+FILE* in = fopen(input_file, "rb"); 
+FILE* out = fopen(output_file, "wb"); 
+
+if (!in || !out) { 
+if (in) fclose(in); 
+if (out) fclose(out); 
+return -1; 
+} 
+
+ch = fgetc(in); 
+while (ch != EOF) { 
+nchar = fgetc(in); 
+
+if (nchar == ch) { 
+
+count++; 
+if (count == 127) { 
+fputc(count, out); 
+fputc(ch, out); 
+compr_size += 2; 
+count = 1; 
+ch = fgetc(in); 
+} 
+} 
+else { 
+if (count > 1) { 
+fputc(count, out); 
+fputc(ch, out); 
+compr_size += 2; 
+} 
+else { 
+int rizn = 1; 
+char buffer[127]; 
+buffer[0] = ch; 
+
+while (nchar != EOF && nchar != ch && rizn < 127) { 
+buffer[rizn] = nchar; 
+rizn++; 
+ch = nchar; 
+nchar = fgetc(in); 
+} 
+
+fputc(0x80 | rizn, out); 
+compr_size += 1; 
+for (int i = 0; i < rizn; i++) { 
+fputc(buffer[i], out); 
+compr_size += 1; 
+} 
+} 
+count = 1; 
+ch = nchar; 
+} 
+} 
+
+fclose(in); 
+fclose(out); 
+return compr_size; 
+} 
+
+int decompress_2(const char* input_file, const char* output_file) { 
+int byte; 
+int compr_size = 0; 
+
+FILE* in = fopen(input_file, "rb"); 
+FILE* out = fopen(output_file, "wb"); 
+
+if (!in || !out) { 
+if (in) fclose(in); 
+if (out) fclose(out); 
+return -1; 
+} 
+
+while ((byte = fgetc(in)) != EOF) { 
+if (byte & 0x80) { 
+
+int count = byte & 0x7F; 
+for (int i = 0; i < count; i++) { 
+int ch = fgetc(in); 
+if (ch == EOF) break; 
+fputc(ch, out); 
+compr_size += 1; 
+} 
+} 
+else { 
+
+int count = byte; 
+int ch = fgetc(in); 
+for (int i = 0; i < count; i++) { 
+fputc(ch, out); 
+compr_size += 1; 
+} 
+} 
+} 
+
+fclose(in); 
+fclose(out); 
+return compr_size; 
+}
+
+Súbor main
+#include <stdio.h> 
+#include "compressor.h" 
+int main(int argc, char* argv[]) 
+{ 
+if (argc <3 && argv[1][0] == '-' && argv[1][1] == 'h' ) 
+{ 
+printf("\nna kompresiu použite: compressor -c infile outfile"); 
+printf("\nna dekompresiu použite: compressor -d infile outfile"); 
+return 0; 
+} 
+if (argc == 4) 
+{ 
+if (argv[1][0] == '-' && argv[1][1] == 'c' && argv[1][2] == 0) 
+{ 
+compress_1(argv[2], "tmpjkxqp.tmp"); 
+compress_2("tmpjkxqp.tmp", argv[3]); 
+remove("tmpjkxqp.tmp"); 
+return 0; 
+} 
+if (argv[1][0] == '-' && argv[1][1] == 'd' && argv[1][2] == 0) 
+{ 
+decompress_2(argv[2], "tmpjkxqp.tmp"); 
+decompress_1("tmpjkxqp.tmp", argv[3]); 
+remove("tmpjkxqp.tmp"); 
+return 0; 
+} 
+} 
+
+printf("\nnesprávne argumenty"); 
+
+return 0; 
+}
+Súbor compressor.h
+#include <stdio.h> 
+int compress_1(const char *a, const char *b); 
+int compress_2(const char *a, const char *b); 
+int decompress_1(const char *a, const char *b); 
+int decompress_2(const char *a, const char *b);
+
+
+Napríklad treba komprimovať taký text. (I_love_Slovenska_Republika! )
+Veľkosť okna – 15 						buffer – 8
+okna                      LZ77                buffer
+		                                    I_love_S
++---------------------------------------------------+                                            
+|I	                    |(0;0;I)	|       _love_S |
++-----------------------+-----------+---------------+
+|I_	                    |(0;0;_)	|       love_S  |
++-----------------------+-----------+---------------+
+|I_l	                |(0;0;l)	|       ove_S   |
++-----------------------+-----------+---------------+
+|I_lo	                |(0;0;o)	|       ve_S    |
++-----------------------+-----------+---------------+
+|I_lov	                |(0;0;v)	|       e_S     |
++-----------------------+-----------+---------------+
+|I_love             	|(0;0;e)	|       _S      |
++-----------------------+-----------+---------------+
+|I_love_S           	|(5;1;S)	|   _Slovenska  |
++-----------------------+-----------+---------------+
+|I_love_Sloven	        |(6;4;n)	|       ska     |
++-----------------------+-----------+---------------+
+|I_love_Slovens	        |(0;0;s)	|       ka      |
++-----------------------+-----------+---------------+
+|I_love_Slovensk    	|(0;0;k)	|        a      |
++-----------------------+-----------+---------------+
+|_love_Slovenska	    |(0;0;a)	|   _Republi    |
++-----------------------+-----------+---------------+
+|ove_Slovenska_R	    |(15;1;R)	|   epubli      |
++-----------------------+-----------+---------------+
+|e_Slovenska_Rep	    |(13;1;p)	|   ubli        |
++-----------------------+-----------+---------------+
+|_Slovenska_Repu    	|(0;0;u)	|   bli         |
++-----------------------+-----------+---------------+
+RLE
+Ak kódujeme RLE priamo (I_love_Slovenska_Republika!!!!! ) (1I1_1l1o1v1e1_1S1l1o1v1e1n1s1k1a1_1R1e1p1u1b1l1i1k1a5!)
+Je to veľmi iracionálne, pretože počet znakov sa v skutočnosti zdvojnásobuje, preto sa kódovacia postupnosť delí na dva typy: 1 (séria rôznych znakov, čo je veta, sa kóduje zapísaním počtu rôznych znakov a potom samotných znakov; 2 séria rovnakých znakov sa kóduje zapísaním počtu opakovaní a znaku, ktorý sa opakuje) (26I_love_Slovenska_Republika5!!!!! )
+Je tu však problém 26I - či je to ďalších 26 sérií jedinečných znakov alebo je to 26 opakovaní jedného znaku, preto existuje riešenie nastavením najdôležitejšieho bitu na rozlíšenie týchto dvoch sérií. Neprítomnosť bitu znamená, že toto číslo je dĺžka série jedinečných znakov a nastavený bit znamená, že v dolných 7 bitoch je niekoľko opakovaní jedného znaku.
+ Zakódujme našu správu takto:(26I_love_Slovenska_Republika133!!!!! ) 133 ck 128 +5, t. j. nastavený paritný bit znamená, že ide o 5 opakujúcich sa znakov
+
+