feat: modularize reader

src/reader.c

@@ -0,0 +1,33 @@
+#include "reader.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+char *read_a_line(FILE *file_to_read) {
+  size_t initial_buffer_size = 64;
+  size_t buffer_size = initial_buffer_size;
+  unsigned int how_many_characters_to_read = buffer_size + 1;
+  char *input_buffer = malloc(how_many_characters_to_read);
+  char *initial_buffer_position = input_buffer;
+
+  while (fgets(input_buffer, how_many_characters_to_read, file_to_read) !=
+             NULL &&
+         input_buffer[strlen(input_buffer) - 1] != '\n') {
+    size_t new_buffer_size = buffer_size * 2;
+    if (buffer_size != initial_buffer_size) {
+      how_many_characters_to_read = buffer_size + 1;
+    }
+    input_buffer = realloc(initial_buffer_position, new_buffer_size + 1);
+    initial_buffer_position = input_buffer;
+    input_buffer += buffer_size;
+    buffer_size = new_buffer_size;
+  }
+  input_buffer = initial_buffer_position;
+
+  if (!feof(file_to_read)) {
+    return input_buffer;
+  } else {
+    return NULL;
+  }
+}

src/reader.h

@@ -0,0 +1,8 @@
+#ifndef READER_H
+#define READER_H
+
+#include <stdio.h>
+
+char *read_a_line(FILE *file_to_read);
+
+#endif /* READER_H */