ring_buffer tweaks.

Adding basic ring_buffer test (cherry-pick from master).

Changing rb_safe_insert()'s type to match that of rb_push_insert().
(Makes it easier to pass around insertion functions.)

2 files changed, 120 insertions, 2 deletions

diff --git a/examples/test-ring-buffer-insertion.cpp b/examples/test-ring-buffer-insertion.cpp
new file mode 100644
index 0000000..8372a96
--- /dev/null
+++ b/examples/test-ring-buffer-insertion.cpp
@@ -0,0 +1,114 @@
+/*
+ * Simple ring_buffer test.
+ *
+ * Does a basic test of functionality on rb_full_count(), rb_reset(),
+ * rb_push_insert(), and rb_safe_insert().
+ *
+ * To test (no external hardware required):
+ *
+ *     - Connect a serial monitor to SerialUSB
+ *     - Press any key
+ *
+ * This file is released into the public domain.
+ */
+
+#include "wirish.h"
+
+#include "ring_buffer.h"
+
+#define BUF_SIZE 64
+ring_buffer ring_buf;
+ring_buffer *rb;
+uint8 rb_buffer[BUF_SIZE];
+
+void test_rb_push_insert(int num_bytes_to_insert);
+void test_rb_safe_insert(int num_bytes_to_insert);
+void test_rb_insertion_function(int num_bytes_to_insert,
+                                int (*insertion_fn)(ring_buffer*, uint8),
+                                const char insertion_fn_name[]);
+void print_rb_contents(void);
+
+void setup() {
+    rb = &ring_buf;
+    rb_init(rb, BUF_SIZE, rb_buffer);
+
+    while (!SerialUSB.available())
+        ;
+
+    SerialUSB.println("Beginning test.");
+    SerialUSB.println();
+}
+
+void loop() {
+    test_rb_push_insert(63);
+    SerialUSB.println("------------------------------");
+    test_rb_push_insert(64);
+    SerialUSB.println("------------------------------");
+    test_rb_safe_insert(63);
+    SerialUSB.println("------------------------------");
+    test_rb_safe_insert(64);
+    SerialUSB.println("------------------------------");
+
+    SerialUSB.println();
+    SerialUSB.println("Test finished.");
+    while (true)
+        ;
+}
+
+void test_rb_push_insert(int num_bytes_to_insert) {
+    test_rb_insertion_function(num_bytes_to_insert,
+                               rb_push_insert,
+                               "rb_push_insert()");
+}
+
+void test_rb_safe_insert(int num_bytes_to_insert) {
+    test_rb_insertion_function(num_bytes_to_insert,
+                               rb_safe_insert,
+                               "rb_safe_insert()");
+}
+
+void test_rb_insertion_function(int num_bytes_to_insert,
+                                int (*insertion_fn)(ring_buffer *, uint8),
+                                const char insertion_fn_name[]) {
+    SerialUSB.println("resetting ring buffer.");
+    rb_reset(rb);
+    print_rb_contents();
+
+    SerialUSB.print(insertion_fn_name);
+    SerialUSB.print("-ing ");
+    SerialUSB.print(num_bytes_to_insert);
+    SerialUSB.println(" bytes.");
+    for (uint8 i = 1; i <= num_bytes_to_insert; i++)
+        insertion_fn(rb, i);
+
+    uint16 count = rb_full_count(rb);
+    SerialUSB.print("rb_full_count(rb) = ");
+    SerialUSB.println(count);
+
+    print_rb_contents();
+}
+
+void print_rb_contents() {
+    uint16 count = rb_full_count(rb);
+    SerialUSB.print("ring buffer contents: ");
+    for (uint16 i = 0; i < count; i++) {
+        SerialUSB.print((int)rb_remove(rb));
+        if (i < count - 1) SerialUSB.print(", ");
+    }
+    SerialUSB.println();
+}
+
+// Force init to be called *first*, i.e. before static object allocation.
+// Otherwise, statically allocated objects that need libmaple may fail.
+__attribute__((constructor)) void premain() {
+    init();
+}
+
+int main(void) {
+    setup();
+
+    while (true) {
+        loop();
+    }
+    return 0;
+}
diff --git a/libmaple/ring_buffer.h b/libmaple/ring_buffer.h
index eadb292..9f35d3d 100644
--- a/libmaple/ring_buffer.h
+++ b/libmaple/ring_buffer.h
@@ -118,8 +118,12 @@ static inline int16 rb_safe_remove(ring_buffer *rb) {
 }
 
 /**
- * If rb is not full, appends element and returns true; otherwise,
- * does nothing and returns false. */
+ * @brief Attempt to insert an element into a ring buffer.
+ *
+ * @brief rb Buffer to insert into.
+ * @brief element Value to insert into rb.
+ * @sideeffect If rb is not full, appends element onto buffer.
+ * @return If element was appended, then true; otherwise, false. */
 static inline int rb_safe_insert(ring_buffer *rb, uint8 element) {
     if (rb_is_full(rb)) {
         return 0;