Metro.cpp

00001 /*
00002 The MIT License (MIT)
00003 
00004 Copyright (c) 2013 thomasfredericks
00005 Copyright (c) 2015 Eduardo de Mier
00006 
00007 Permission is hereby granted, free of charge, to any person obtaining a copy of
00008 this software and associated documentation files (the "Software"), to deal in
00009 the Software without restriction, including without limitation the rights to
00010 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
00011 the Software, and to permit persons to whom the Software is furnished to do so,
00012 subject to the following conditions:
00013 
00014 The above copyright notice and this permission notice shall be included in all
00015 copies or substantial portions of the Software.
00016 
00017 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00018 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
00019 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
00020 COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
00021 IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
00022 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00023 */
00024 
00025 #include "Metro.h"
00026 #include "Arduino.h"
00027 
00028 Metro::Metro(unsigned long interval_millis)
00029 {
00030     this->autoreset = 0;
00031     interval(interval_millis);
00032     reset();
00033 }
00034 
00035 // New creator so I can use either the original check behavior or benjamin.soelberg's
00036 // suggested one (see below). 
00037 // autoreset = 0 is benjamin.soelberg's check behavior
00038 // autoreset != 0 is the original behavior
00039 
00040 Metro::Metro(unsigned long interval_millis, uint8_t autoreset)
00041 {   
00042     this->autoreset = autoreset; // Fix by Paul Bouchier
00043     interval(interval_millis);
00044     reset();
00045 }
00046 
00047 void Metro::interval(unsigned long interval_millis)
00048 {
00049   this->interval_millis = interval_millis;
00050 }
00051 
00052 // Benjamin.soelberg's check behavior:
00053 // When a check is true, add the interval to the internal counter.
00054 // This should guarantee a better overall stability.
00055 
00056 // Original check behavior:
00057 // When a check is true, add the interval to the current millis() counter.
00058 // This method can add a certain offset over time.
00059 
00060 char Metro::check()
00061 {
00062   if (millis() - this->previous_millis >= this->interval_millis) {
00063     // As suggested by benjamin.soelberg@gmail.com, the following line 
00064     // this->previous_millis = millis();
00065     // was changed to
00066     // this->previous_millis += this->interval_millis;
00067     
00068     // If the interval is set to 0 we revert to the original behavior
00069     if (this->interval_millis <= 0 || this->autoreset ) {
00070         this->previous_millis = millis();
00071     } else {
00072         this->previous_millis += this->interval_millis; 
00073     }
00074     
00075     return 1;
00076   }
00077   
00078   
00079   
00080   return 0;
00081 
00082 }
00083 
00084 void Metro::reset() 
00085 {
00086  
00087   this->previous_millis = millis();
00088 
00089 }
00090