[C] Wort in .csv Datei suchen

#include <stdio.h>
#include <stdlib.h>

void cache_set_pos(int pos);
int cache_get_pos(void);

int main()
{
 const char *WORD_TO_FIND="Salzburg";
 int old_temp_pos = cache_get_pos();
 FILE *temps = fopen("TEMPARATUR.CSV", "r");
 char buf[512] = {0}, c=0; int i=0; // buffer, aktuelles zeichen, buffer-offset sowie main() rückgabewert

 enum {lf_kw, lf_temp, end} flags = lf_kw; // flags: suche nach keyword, temparatur oder ende

 if(pos != -1)
 {
 fseek(temps, pos, SEEK_SET);
 }

 while(EOF != (c=fgetc(temps)) || flags == end)
 {
 if(i == 511 && c != ';') // 511 langes keyword, csv tabelle mögl. fehlerhaft
 { 
 i=-1;
 break;
 }

 if(c == ';')
 {
 buf[i + 1] = 0;

 if(flags == lf_kw && 0 == strcmp(WORD_TO_FIND, buf))
 {
 cache_set_pos(ftell(temps) - i);
 flags = lf_temp;
 }
 else if(flags == lf_temp)
 {
 printf("%s\n", buf); // temparatur
 flags = end;
 }

 i=0;
 }
 else
 {
 buf[i++] = c;
 }
 }

 fclose(temps);
 return i;
}

void cache_set_pos(int pos)
{
 FILE *cache = fopen("TEMPARATUR.CACHE", "wb");

 fwrite(&pos, 4, 1, cache);
 fclose(cache);
}

int cache_get_pos(void)
{
 FILE *cache = NULL;
 int pos = -1;

 if(NULL != (cache = fopen("TEMPARATUR.CACHE", "rb")))
 {
 fread(&pos, 4, 1, cache);
 fclose(cache);
 }

 return pos;
}