1 files changed, 64 insertions, 9 deletions

diff --git a/ringbuff.c b/ringbuff.c
index e101073..47d4cbf 100644
--- a/ringbuff.c
+++ b/ringbuff.c
@@ -1,3 +1,4 @@
+#include <assert.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -18,7 +19,21 @@ ring_init(struct ring_buffer *rb)
 }
 
 bool
-ring_put(struct ring_buffer *rb, T data)
+ring_push_front(struct ring_buffer *rb, T data)
+{
+        const size_t prev = (rb->tail + NELEM(rb->array) - 1) % NELEM(rb->array);
+
+        if ( prev == rb->head )
+                return false;
+
+        rb->array[prev] = data;
+        rb->tail        = prev;
+
+        return true;
+}
+
+bool
+ring_push_back(struct ring_buffer *rb, T data)
 {
         const size_t next = (rb->head + 1) % NELEM(rb->array);
 
@@ -32,7 +47,7 @@ ring_put(struct ring_buffer *rb, T data)
 }
 
 bool
-ring_get(struct ring_buffer *rb, T *data)
+ring_pop_front(struct ring_buffer *rb, T *data)
 {
         if ( rb->head == rb->tail )
                 return false;
@@ -45,12 +60,32 @@ ring_get(struct ring_buffer *rb, T *data)
         return true;
 }
 
+bool
+ring_pop_back(struct ring_buffer *rb, T *data)
+{
+        if ( rb->head == rb->tail )
+                return false;
+
+        const size_t prev = (rb->head + NELEM(rb->array) - 1) % NELEM(rb->array);
+
+        *data    = rb->array[prev];
+        rb->head = prev;
+
+        return true;
+}
+
 void
 f()
 {
         ERROR("");
 }
 
+void
+debug_print(const char *msg, struct ring_buffer *rb)
+{
+        printf("%s: head: %zu, tail: %zu\n", msg, rb->head, rb->tail);
+}
+
 int
 main(void)
 {
@@ -61,15 +96,35 @@ main(void)
         struct ring_buffer rb = { .head = 0, .tail = 0 };
 #endif
 
-        for ( int i = 0; i != 30; ++i ) {
-                if ( !ring_put(&rb, i) )
-                        break;
-        }
+        assert(ring_push_back(&rb, 1) == true); // 1
+        assert(ring_push_back(&rb, 2) == true); // 1, 2
+        assert(ring_push_back(&rb, 3) == true); // 1, 2, 3
+        assert(ring_push_back(&rb, 4) == true); // 1, 2, 3, 4
 
-        int j;
-        while ( ring_get(&rb, &j) ) {
-                printf("%d\n", j);
+        debug_print("Stand", &rb);
+
+        assert(ring_push_front(&rb, 0) == true);  // 0, 1, 2, 3, 4
+        assert(ring_push_front(&rb, -1) == true); // -1, 0, 1, 2, 3, 4
+
+        debug_print("Stand", &rb);
+
+        T temp;
+        assert(ring_pop_back(&rb, &temp) == true);  // -1, 0, 1, 2, 3
+        assert(ring_pop_front(&rb, &temp) == true); // 0, 1, 2, 3
+
+        debug_print("Stand", &rb);
+
+        assert(ring_push_back(&rb, 4) == true);   // 0, 1, 2, 3, 4
+        assert(ring_push_back(&rb, 5) == true);   // 0, 1, 2, 3, 4, 5
+        assert(ring_push_back(&rb, 6) == true);   // 0, 1, 2, 3, 4, 5, 6
+        assert(ring_push_back(&rb, 7) == false);  // 0, 1, 2, 3, 4, 5, 6
+        assert(ring_push_front(&rb, 7) == false); // 0, 1, 2, 3, 4, 5, 6
+
+        while ( ring_pop_back(&rb, &temp) ) {
+                printf("temp: %d\n", temp);
         }
 
+        debug_print("Stand", &rb);
+
         return EXIT_SUCCESS;
 }