tail builds / tests correctly

Author: Joshua Goller

ch-5/Makefile

@@ -41,15 +41,11 @@ ifdef RUN_TESTS
 endif
 
 # tabber covers the entab / detab exercises in 5.11 and 5.12
-tabber: clean
+# tail is exercise 5.13
+tabber tail: clean
 	$(COMPILE) -I ch-5/$@/include ch-5/$@/src/*.c -o bin/$@
 	./ch-5/$@/$@-test.sh
 
-# tail is exercise 5.13; I decided external tests were better than unit tests.
-tail: clean
-	$(COMPILE) -I ch-5/tail/include/ ch-5/tail/src/5.13.c -o bin/tail
-	./tail/tail_test.sh
-
 # sort is exercises 5.14 through 5.17
 sort: clean
 	$(COMPILE) -I ch-5/sort/include/ ch-5/sort/src/{compare,input,main,sort,strings}.c -o bin/$@

ch-5/tail/include/5.13.h ch-5/tail/include/tail.h

@@ -11,8 +11,9 @@ typedef struct {
 } queue;
 
 int check_input(const int argc, const char* const* const argv);
+void read_lines(queue* q);
 
+// queue.c
 queue* new_queue(int max_size);
-void read_lines(queue* q);
 int enqueue(queue* const q, char* data);
 int dequeue(queue* const q, char* data);

ch-5/tail/src/5.13.c ch-5/tail/src/main.c

@@ -1,9 +1,10 @@
-#include "5.13.h"
 #include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+
 #include "common.h"
+#include "tail.h"
 
 /*
  * Exercise 5-13. Write the program tail, which prints the last n lines of its
@@ -89,64 +90,3 @@ void read_lines(queue* q) {
     enqueue(q, line);
   }
 }
-
-// new_queue(): Initialize a queue structure
-queue* new_queue(int max_size) {
-  queue* q = malloc(sizeof(queue));
-
-  q->head = NULL;
-  q->tail = NULL;
-  q->max_size = max_size;
-  q->current_size = 0;
-
-  return q;
-}
-
-// enqueue(): add an item to the queue
-int enqueue(queue* const q, char* data) {
-  if (q->current_size == q->max_size) {
-    // If the queue is full, dequeue the last item to make room
-    char* deleted = malloc(MAXLEN);
-    dequeue(q, deleted);
-    free(deleted);
-  } else if (q->current_size > q->max_size) {
-    printf("enqueue(): Error - queue exceeds maximum size.\n");
-    free(data);
-    return -1;
-  }
-
-  // Make a new node
-  node* new_tail = malloc(sizeof(node));
-  new_tail->next = NULL;
-  new_tail->data = data;
-
-  // Add the node; handle empty queue if necessary.
-  if (q->head == NULL) {
-    q->head = new_tail;
-    q->tail = new_tail;
-  }
-  q->tail->next = new_tail;
-  q->tail = q->tail->next;
-  q->current_size++;
-
-  return 0;
-}
-
-// dequeue(): remove an item from the queue
-int dequeue(queue* const q, char* const data) {
-  if (!(q->current_size && q->head)) {
-    // Queue is empty
-    *data = '\0';
-    return 0;
-  } else {
-    // Remove current head; make the next item the new head
-    node* old_head = q->head;
-    strcpy(data, old_head->data);
-    q->head = old_head->next;
-
-    free(old_head->data);
-    free(old_head);
-    q->current_size--;
-    return 1;
-  }
-}

ch-5/tail/src/queue.c

@@ -0,0 +1,67 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "common.h"
+#include "tail.h"
+
+// new_queue(): Initialize a queue structure
+queue* new_queue(int max_size) {
+  queue* q = malloc(sizeof(queue));
+
+  q->head = NULL;
+  q->tail = NULL;
+  q->max_size = max_size;
+  q->current_size = 0;
+
+  return q;
+}
+
+// enqueue(): add an item to the queue
+int enqueue(queue* const q, char* data) {
+  if (q->current_size == q->max_size) {
+    // If the queue is full, dequeue the last item to make room
+    char* deleted = malloc(MAXLEN);
+    dequeue(q, deleted);
+    free(deleted);
+  } else if (q->current_size > q->max_size) {
+    printf("enqueue(): Error - queue exceeds maximum size.\n");
+    free(data);
+    return -1;
+  }
+
+  // Make a new node
+  node* new_tail = malloc(sizeof(node));
+  new_tail->next = NULL;
+  new_tail->data = data;
+
+  // Add the node; handle empty queue if necessary.
+  if (q->head == NULL) {
+    q->head = new_tail;
+    q->tail = new_tail;
+  }
+  q->tail->next = new_tail;
+  q->tail = q->tail->next;
+  q->current_size++;
+
+  return 0;
+}
+
+// dequeue(): remove an item from the queue
+int dequeue(queue* const q, char* const data) {
+  if (!(q->current_size && q->head)) {
+    // Queue is empty
+    *data = '\0';
+    return 0;
+  } else {
+    // Remove current head; make the next item the new head
+    node* old_head = q->head;
+    strcpy(data, old_head->data);
+    q->head = old_head->next;
+
+    free(old_head->data);
+    free(old_head);
+    q->current_size--;
+    return 1;
+  }
+}

ch-5/tail/tail_test.sh ch-5/tail/tail-test.sh

@@ -28,7 +28,7 @@ function tail_test(){
   local TEST_NAME=${3}
 
   ACTUAL_OUT_LINES=$(cat $TESTFILE | bin/tail $N | wc | awk '{print $1}')
-  
+
   if [[ $ACTUAL_OUT_LINES -ne $EXPECTED_OUT_LINES ]]
   then
     fatal "Test failure, $TEST_NAME: $ACTUAL_OUT_LINES != $EXPECTED_OUT_LINES"
@@ -50,7 +50,7 @@ tail_test 0 0 "n = 0"
 
 clean_up
 echo "Generating huge input for tail; this is slow."
-generate_test_file 2000000
+generate_test_file 20000
 echo "Huge input generated."
 tail_test "" 10 "Huge input"