Diff: TimeService.cpp

Revision:

16:7903152de19f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TimeService.cpp	Mon Dec 28 12:48:19 2015 +0000
@@ -0,0 +1,139 @@
+#include "M2XStreamClient.h"
+
+static int fill_iso8601_timestamp(int32_t seconds, int32_t milli,
+                                  char* buffer, int* length);
+
+TimeService::TimeService(M2XStreamClient* client) : _client(client) {
+}
+
+int TimeService::init() {
+  _timer.start();
+  return reset();
+}
+
+int TimeService::reset() {
+  int32_t ts;
+  int status = _client->getTimestamp32(&ts);
+
+  if (m2x_status_is_success(status)) {
+    _server_timestamp = ts;
+    _local_last_milli = _timer.read_ms();
+  }
+
+  return status;
+}
+
+int TimeService::getTimestamp(char* buffer, int* length) {
+  uint32_t now = _timer.read_ms();
+  if (now < _local_last_milli) {
+    // In case of a timestamp overflow(happens once every 50 days on
+    // Arduino), we reset the server timestamp recorded.
+    int status = reset();
+    if (!m2x_status_is_success(status)) { return status; }
+    now = _timer.read_ms();
+  }
+  if (now < _local_last_milli) {
+    // We have already reseted the timestamp, so this cannot happen
+    // (an HTTP request can take longer than 50 days to finished? You
+    // must be kidding here). Something else must be wrong here
+    return E_TIMESTAMP_ERROR;
+  }
+  uint32_t diff = now - _local_last_milli;
+  _local_last_milli = now;
+  _server_timestamp += (int32_t) (diff / 1000); // Milliseconds to seconds
+  return fill_iso8601_timestamp(_server_timestamp, (int32_t) (diff % 1000),
+                                buffer, length);
+}
+
+#define SIZE_ISO_8601 25
+static inline bool is_leap_year(int16_t y) {
+  return ((1970 + y) > 0) &&
+      !((1970 + y) % 4) &&
+      (((1970 + y) % 100) || !((1970 + y) % 400));
+}
+static inline int32_t days_in_year(int16_t y) {
+  return is_leap_year(y) ? 366 : 365;
+}
+static const uint8_t MONTH_DAYS[]={31,28,31,30,31,30,31,31,30,31,30,31};
+
+static int fill_iso8601_timestamp(int32_t timestamp, int32_t milli,
+                                  char* buffer, int* length) {
+  int16_t year;
+  int8_t month, month_length;
+  int32_t day;
+  int8_t hour, minute, second;
+
+  if (*length < SIZE_ISO_8601) {
+    *length = SIZE_ISO_8601;
+    return E_BUFFER_TOO_SMALL;
+  }
+
+  second = timestamp % 60;
+  timestamp /= 60; // now it is minutes
+
+  minute = timestamp % 60;
+  timestamp /= 60; // now it is hours
+
+  hour = timestamp % 24;
+  timestamp /= 24; // now it is days
+
+  year = 0;
+  day = 0;
+  while ((day += days_in_year(year)) <= timestamp) {
+    year++;
+  }
+  day -= days_in_year(year);
+  timestamp -= day; // now it is days in this year, starting at 0
+
+  day = 0;
+  month_length = 0;
+  for (month = 0; month < 12; month++) {
+    if (month == 1) {
+      // February
+      month_length = is_leap_year(year) ? 29 : 28;
+    } else {
+      month_length = MONTH_DAYS[month];
+    }
+
+    if (timestamp >= month_length) {
+      timestamp -= month_length;
+    } else {
+      break;
+    }
+  }
+  year = 1970 + year;
+  month++; // offset by 1
+  day = timestamp + 1;
+
+  int i = 0, j = 0;
+
+  // NOTE: It seems the snprintf implementation in Arduino has bugs,
+  // we have to manually piece the string together here.
+#define INT_TO_STR(v_, width_) \
+  for (j = 0; j < (width_); j++) { \
+    buffer[i + (width_) - 1 - j] = '0' + ((v_) % 10); \
+    (v_) /= 10; \
+  } \
+  i += (width_)
+
+  INT_TO_STR(year, 4);
+  buffer[i++] = '-';
+  INT_TO_STR(month, 2);
+  buffer[i++] = '-';
+  INT_TO_STR(day, 2);
+  buffer[i++] = 'T';
+  INT_TO_STR(hour, 2);
+  buffer[i++] = ':';
+  INT_TO_STR(minute, 2);
+  buffer[i++] = ':';
+  INT_TO_STR(second, 2);
+  buffer[i++] = '.';
+  INT_TO_STR(milli, 3);
+  buffer[i++] = 'Z';
+  buffer[i++] = '\0';
+
+#undef INT_TO_STR
+
+  *length = i;
+  return E_OK;
+}