Added ahal
This is a formatted copy of WPILib's default user-visible C++ API, with
a bit of completely unnecessary functionality stripped out. Most of the
stripping so far is only related to weird threading decisions.
Change-Id: Icbfd949b48cd115561862cb909bcc572aba0e753
diff --git a/frc971/wpilib/ahal/Encoder.h b/frc971/wpilib/ahal/Encoder.h
new file mode 100644
index 0000000..2f06e65
--- /dev/null
+++ b/frc971/wpilib/ahal/Encoder.h
@@ -0,0 +1,64 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2008-2017. All Rights Reserved. */
+/* Open Source Software - may be modified and shared by FRC teams. The code */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project. */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include "HAL/Encoder.h"
+
+namespace frc {
+
+class DigitalSource;
+class DigitalGlitchFilter;
+
+/**
+ * Class to read quad encoders.
+ * Quadrature encoders are devices that count shaft rotation and can sense
+ * direction. The output of the QuadEncoder class is an integer that can count
+ * either up or down, and can go negative for reverse direction counting. When
+ * creating QuadEncoders, a direction is supplied that changes the sense of the
+ * output to make code more readable if the encoder is mounted such that forward
+ * movement generates negative values. Quadrature encoders have two digital
+ * outputs, an A Channel and a B Channel that are out of phase with each other
+ * to allow the FPGA to do direction sensing.
+ *
+ * All encoders will immediately start counting - Reset() them if you need them
+ * to be zeroed before use.
+ */
+class Encoder {
+ public:
+ enum EncodingType { k1X, k2X, k4X };
+
+ Encoder(int aChannel, int bChannel, bool reverseDirection = false,
+ EncodingType encodingType = k4X);
+ virtual ~Encoder();
+
+ int GetEncodingScale() const;
+
+ int GetRaw() const;
+
+ double GetPeriod() const;
+ void SetMaxPeriod(double maxPeriod);
+
+ int GetFPGAIndex() const;
+
+ private:
+ void InitEncoder(bool reverseDirection, EncodingType encodingType);
+
+ double DecodingScaleFactor() const;
+
+ std::shared_ptr<DigitalSource> m_aSource; // the A phase of the quad encoder
+ std::shared_ptr<DigitalSource> m_bSource; // the B phase of the quad encoder
+ std::unique_ptr<DigitalSource> m_indexSource = nullptr;
+ HAL_EncoderHandle m_encoder = HAL_kInvalidHandle;
+
+ friend class DigitalGlitchFilter;
+};
+
+} // namespace frc