Diff: main.cpp

Revision:

0:6228e490f311

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Nov 10 21:11:04 2017 +0900
@@ -0,0 +1,76 @@
+#include "mbed.h"
+
+Serial pc(USBTX, USBRX);
+
+/**
+ * Arduino's Serial#Find method (https://www.arduino.cc/en/Serial/Find) adopted to Mbed OS.
+ * Does not allocate buffers inside.
+ *
+ * Example (finding the string 'ready' in a stream):
+ *      Serial uart(D1, D0);
+ *      uart.baud(115200);
+ *
+ *      bool found = serial_find(&uart, "ready", 10);
+ *      printf("Found it? %d\n", found)
+ *
+ * @param serial Pointer to an initialized UART Serial object
+ * @param str_to_find String to find in the UART stream
+ * @param timeout_s Timeout in seconds
+ * @returns True if found, false if timed out
+ */
+static bool serial_find(Serial *serial, const char *str_to_find, uint32_t timeout_s) {
+    // Use RTC (instead of interrupt) for timeout detection
+    time_t curr = time(NULL);
+
+    bool is_partial_match = false;
+    uint16_t match_ix = 0;
+    size_t str_to_find_len = strlen(str_to_find);
+
+    while (1) {
+        // timeout detection
+        if (time(NULL) - curr > timeout_s) return false;
+
+        while (serial->readable()) {
+            // also do timeout detection here...
+            if (time(NULL) - curr > timeout_s) return false;
+
+            char c = serial->getc();
+
+            if (!is_partial_match) {
+                // Find the first character in the stream
+                if (c == str_to_find[0]) {
+                    if (str_to_find_len == 1) return true;
+
+                    match_ix = 1;
+                    is_partial_match = true;
+                }
+                continue;
+            }
+
+            // is_partial_match is correct, check remaining characters
+            if (c == str_to_find[match_ix]) {
+                if (str_to_find_len == match_ix + 1) return true;
+
+                match_ix++;
+            }
+            else {
+                // not a match anymore, continue
+                is_partial_match = false;
+            }
+        }
+    }
+
+    return false;
+}
+
+int main() {
+    pc.baud(115200);
+    pc.printf("Hello world\n");
+
+    // set up connection over UART, e.g. to ESP8266 WiFi module...
+    Serial uart(D1, D0);
+    uart.baud(115200);
+
+    bool found = serial_find(&uart, "ready", 10);
+    printf("Found it? %d\n", found);
+}