How to read large text file in c - c

Question

I'm trying to use linked list to store every line of one big file (from 1 GB to 70 GB), but that's the problem, I can't because it overflows my RAM and forces windows to stop the program execution.
The function I wrote are these:
struct Word {
char word[13];
};
typedef struct Nodo {
struct Word word;
struct Nodo *next;
} TNodo;
typedef TNodo *Nodo;
void NewWord(Nodo *p, struct Word s) {
Nodo temp;
temp = (Nodo)malloc(sizeof(TNodo));
temp->word = s;
temp->next = *p;
*p = temp;
}
void LoadList(Nodo *p) {
FILE *f;
struct Word s;
char *buffer = malloc(sizeof(struct Word));
if (!(f= fopen("wordlist.txt", "r"))) {
fclose(f);
exit(1);
}
while (fgets(buffer, sizeof(struct Word), f)) {
if (sscanf(buffer,"%s", s.word) == 1) {
NewWord(p, s);
}
}
fclose(f);
free(buffer);
}
Is there a better way to process data (like deleting lines of file) from very large text files without storing them?
the text file I'm trying to read has this simple structure:
Word
Worf
Worg

Answer 1

As far as I have read, I found the following 2 ways better than others:
1) Read a larger chunk into a large memory buffer, and then parse out the data from that buffer.
2)Another way may be to instead memory map the file, then the OS will put the file into your process virtual memory map, so you can read it like reading from memory.

Answer 2

I changed the function according to your answers, now the function NewWord just print the word into a second file, skipping unnecessary words according to the functions step1() and step2().
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 67
char letters[SIZE] = {'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
'.','_','1','2','3','4','5','6','7','8','9','0','!','#','$'};
struct Word
{
char word[13];
};
_Bool step1(char * word)
{
for(int i = 0; i < SIZE; i++)
{
for(int j = 0, c = 0; j < strlen(word); j++)
{
if(word[j] == letters[i])
{
c++;
if(c > 3)
{
return 1;
}
}
}
}
return 0;
}
_Bool step2(char * word)
{
for(int i = 0; i < SIZE; i++)
{
for(int j = 0; j < strlen(word); j++)
{
if(word[j] == letters[i] && word[j+1] == letters[i] && word[j+2] == letters[i])
{
return 1;
}
}
}
return 0;
}
void NewWord(FILE *f, struct Word s)
{
if(step1(s.word ) == 1 || step2(s.word) == 1)
return;
fprintf(f, "%s\n", s.word);
}
void LoadList()
{
FILE * f1;
FILE * f2;
struct Word s;
char * buffer = malloc(sizeof(struct Word));
if(!(f1= fopen("wordlist.txt", "r")))
{
fclose(f1);
exit(1);
}
if(!(f2 = fopen("bb.txt", "w")))
{
fclose(f2);
exit(1);
}
while(fgets(buffer, sizeof(struct Word), f1))
{
if(sscanf(buffer,"%s", s.word) == 1)
{
NewWord(f2, s);
}
}
fclose(f1);
fclose(f2);
free(buffer);
}
int main()
{
LoadList();
exit(0);
}