Homework 07: tailit.c

homework07/tailit.c

@@ -16,18 +16,56 @@ void usage(int status) {
 }
 
 List *tail_stream(FILE *stream, size_t limit) {
-    // TODO
-    return NULL;
+    List *sequence = list_create();
+    char buffer[BUFSIZ];
+
+    while (fgets(buffer, sizeof(buffer), stream) != NULL) {
+        char *line = strdup(buffer);
+        list_append(sequence, (Value){.string = line});
+
+        // If over limit, remove the oldest line (head)
+        if (sequence->size > limit) {
+            Value old = list_pop(sequence, 0);
+            free(old.string);  // Free the popped line's string
+        }
+    }
+
+    return sequence;
 }
 
 /* Main Execution */
 
 int main(int argc, char *argv[]) {
+    size_t limit = 10; // Set baseline limit
+
     // TODO: Parse command line arguments
+    if (argc == 2) {
+        if (strcmp(argv[1], "-h") == 0) {
+            usage(EXIT_SUCCESS);
+        } else {
+            usage(EXIT_FAILURE);
+        }
+    } else if (argc == 3) {
+        if (strcmp(argv[1], "-n") == 0) {
+            limit = (size_t)atoi(argv[2]);
+        } else {
+            usage(EXIT_FAILURE);
+        }
+    } else if (argc > 3) {
+        usage(EXIT_FAILURE);
+    }
 
     // TODO: Construct tail of stream
+    List *lines = tail_stream(stdin, limit);
 
     // TODO: Print out tail
+    while (lines->size > 0) {
+        Value v = list_pop(lines, 0);
+        printf("%s", v.string);
+        free(v.string);
+    }
+
+    list_delete(lines, false);
     return EXIT_SUCCESS;
 }