From 3060d72234e8e0a09b001ff8ea348dc09f6b56f9 Mon Sep 17 00:00:00 2001
From: Angus Gratton <gus@projectgus.com>
Date: Tue, 6 Oct 2015 17:54:43 +1100
Subject: [PATCH] Add a basic serial_echo example, with a silly Easter Egg

---
 examples/serial_echo/Makefile      |  3 +++
 examples/serial_echo/serial_echo.c | 41 ++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 examples/serial_echo/Makefile
 create mode 100644 examples/serial_echo/serial_echo.c

diff --git a/examples/serial_echo/Makefile b/examples/serial_echo/Makefile
new file mode 100644
index 0000000..717b163
--- /dev/null
+++ b/examples/serial_echo/Makefile
@@ -0,0 +1,3 @@
+# Simple makefile for simple example
+PROGRAM=simple
+include ../../common.mk
diff --git a/examples/serial_echo/serial_echo.c b/examples/serial_echo/serial_echo.c
new file mode 100644
index 0000000..cea3f33
--- /dev/null
+++ b/examples/serial_echo/serial_echo.c
@@ -0,0 +1,41 @@
+/* Extremely simple example that just reads from stdin and echoes back on stdout
+ *
+ * Has an easter egg, which is if you type "QUACK" it'll quack 3 times back at you.
+ *
+ * This example code is in the public domain
+ */
+#include "espressif/esp_common.h"
+#include <esp/uart.h>
+#include <string.h>
+
+void user_init(void)
+{
+    printf("SDK version:%s\n", sdk_system_get_sdk_version());
+    printf("Going into echo mode...\n");
+
+    /* By default stdout is line-buffered, so you only see output
+       after a newline is sent. This is helpful in a multithreaded
+       environment so output doesn't get chopped up within a line.
+
+       Here we want to see the echo immediately, so disable buffering.
+    */
+    setbuf(stdout, NULL);
+
+    while(1) {
+        int c = getchar();
+        if(c != EOF)
+            putchar(c);
+
+        /* Easter egg: check for a quack! */
+        static int quack;
+        if(c == "QUACK"[quack]) {
+            quack++;
+            if(quack == strlen("QUACK")) {
+                printf("\nQUACK\nQUACK\n");
+                quack = 0;
+            }
+        } else {
+            quack = 0;
+        }
+    }
+}