working on actual unhacky implementation
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d24007c036
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e427fe4c0b
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@ -8,6 +8,8 @@
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#include <sys/types.h>
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#include <unistd.h>
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#define BUFSIZE 512
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// a single node, only having information for a single byte.
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struct Node {
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uint8_t byte;
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@ -22,6 +24,24 @@ struct Heap {
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bool isRoot;
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};
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// global vars for Heaps and Nodes.
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struct Node* nodes;
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struct Heap* heaps;
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// initialize our nodes
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void initNodes(){
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nodes = malloc(sizeof(struct Node)*256);
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heaps = malloc(sizeof(struct Heap)*256); // not sure if i might need more memory for heaps?
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for(int i = 0; i < 256; i++){
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nodes[i].byte = i;
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nodes[i].occurences = 0;
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nodes[i].frequencyPriority = 0;
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heaps[i].isRoot = false;
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}
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}
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// stolen from stackoverflow
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// https://stackoverflow.com/questions/8236/how-do-you-determine-the-size-of-a-file-in-c
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off_t fsize(const char *filename) {
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@ -96,8 +116,8 @@ int main(int argc, char *argv[]) {
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exit(EXIT_FAILURE);
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}
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filelen = fsize(filestring);
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if(verbose)
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printf("filesize: %ldB\n", filelen);
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if(verbose)
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printf("filesize: %ldB\n", filelen);
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}
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else {
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// empty filestring or filestring is NULL
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@ -111,19 +131,20 @@ int main(int argc, char *argv[]) {
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}
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else {
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// compress the file
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if (verbose)
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printf("compressing file...\n");
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// frequency analysis
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uint8_t buf [BUFSIZE];
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// dump start of file if debugging
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// FIXME add conditions if the part to print is smaller than 512B
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if(debug){
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printf("[DEBUG]First 512 bytes are:\n");
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fread(buf, 1, 512, fptrR);
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for(int i=0;i<512;i++){
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fread(buf, 1, BUFSIZE, fptrR);
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for(int i=0;i<BUFSIZE;i++){
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if(i%16==0)
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printf("%08x\t", i);
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printf("%02x ", buf[i]);
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@ -134,66 +155,40 @@ int main(int argc, char *argv[]) {
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}
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}
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}
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uint64_t occurences[256] = { 0 };
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// TODO calculate occurences
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// FIXME this loads the file into RAM completely. Loading a too big file would eat all memory of the system.
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// This is a dirty hack of an algorithm.
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// uint8_t* buf = malloc(filelen);
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for(int i = 0; i < filelen; i++) {
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fread(buf+i, 1, 1, fptrR);
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}
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// now go through all of the stored bytes in the buffer and count the occurences.
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for(int i = 0; i < filelen; i++) {
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occurences[*(buf+i)]++; // FIXME this might get the value of the bytes but +1, not sure about the logic!
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}
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// holy shit i think the dirty hack is working
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// well, at least for smaller files.
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// SEGVAULT for the 10G file, 1G works.
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if(debug){
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printf("Occurences (Hex):\n");
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for(int i=0;i<256;i++){
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if(i%4==0)
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printf("\n");
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printf("0x%02x: %016lx\t", i, occurences[i]);
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initNodes();
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int ret;
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while(!feof(fptrR)){
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ret = fread(buf, 1, BUFSIZE, fptrR);
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if(ret == BUFSIZE){
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// fread success, continue as normal
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// calculate occurences.
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for(int i = 0; i < BUFSIZE; i++){
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nodes[buf[i]].occurences++;
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}
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}
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printf("\n\nfile length(by pointer):\t\t%luB\n", filelen);
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long long int addedUpOccurences = 0; // FIXME might not be enough storage for larger files!
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for(int i=0;i<256;i++){
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addedUpOccurences += occurences[i];
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else if((ret < BUFSIZE) && (ret >= 0)){
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if(!feof(fptrR)) {
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// no EOF, but didn't read full buffer. Assuming an error
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printf("Error while reading file.");
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exit(EXIT_FAILURE);
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}
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else{
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// reached EOF, finished
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break;
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}
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}
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printf("file length(added up occurences):\t%lldB\n", addedUpOccurences);
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else{
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printf("Undefined behaviour while reading file.\n");
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exit(EXIT_FAILURE);
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}
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fseek(fptrR, BUFSIZE, SEEK_CUR);
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}
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if(verbose)
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printf("\n\nDone calculating occurences of bytes.\n");
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// TODO
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// calculate the frequencies of the bytes.
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double frequencies[256];
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for(int i=0;i<256;i++){
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frequencies[i]=((double)occurences[i]/(double)filelen)*100; // calculate frequencies of bytes in percent (example: 05.23 (%))
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}
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if(debug){
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printf("Frequencies:\n");
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for(int i=0;i<256;i++){
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if(i%8==0)
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printf("\n");
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printf("0x%02x: %05.02f%%\t", i, frequencies[i]);
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}
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double addedUpFrequencies = 0;
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for(int i=0;i<256;i++){
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addedUpFrequencies += frequencies[i];
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}
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printf("\n\nadded up frequencies: %05.02f%%\n",addedUpFrequencies);
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}
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}
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fclose(fptrR);
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printf("\n");
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if(debug) // wait for input to end.
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getchar();
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exit(EXIT_SUCCESS);
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}
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