Merge pull request #7663 from jordan-woyak/expression-parser-improve

Expression parser improvements

1 files changed, 526 insertions, 0 deletions

diff --git a/Source/Core/InputCommon/ControlReference/FunctionExpression.cpp b/Source/Core/InputCommon/ControlReference/FunctionExpression.cpp
new file mode 100644
index 0000000000..18b98c5e19
--- /dev/null
+++ b/Source/Core/InputCommon/ControlReference/FunctionExpression.cpp
@@ -0,0 +1,526 @@
+// Copyright 2019 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include <chrono>
+#include <cmath>
+
+#include "InputCommon/ControlReference/FunctionExpression.h"
+
+namespace ciface
+{
+namespace ExpressionParser
+{
+constexpr int LOOP_MAX_REPS = 10000;
+constexpr ControlState CONDITION_THRESHOLD = 0.5;
+
+using Clock = std::chrono::steady_clock;
+using FSec = std::chrono::duration<ControlState>;
+
+// usage: toggle(toggle_state_input, [clear_state_input])
+class ToggleExpression : public FunctionExpression
+{
+private:
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    // Optional 2nd argument for clearing state:
+    if (1 == args.size() || 2 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"toggle_state_input, [clear_state_input]"};
+  }
+
+  ControlState GetValue() const override
+  {
+    const ControlState inner_value = GetArg(0).GetValue();
+
+    if (inner_value < CONDITION_THRESHOLD)
+    {
+      m_released = true;
+    }
+    else if (m_released && inner_value > CONDITION_THRESHOLD)
+    {
+      m_released = false;
+      m_state ^= true;
+    }
+
+    if (2 == GetArgCount() && GetArg(1).GetValue() > CONDITION_THRESHOLD)
+    {
+      m_state = false;
+    }
+
+    return m_state;
+  }
+
+  mutable bool m_released{};
+  mutable bool m_state{};
+};
+
+// usage: not(expression)
+class NotExpression : public FunctionExpression
+{
+private:
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (1 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"expression"};
+  }
+
+  ControlState GetValue() const override { return 1.0 - GetArg(0).GetValue(); }
+  void SetValue(ControlState value) override { GetArg(0).SetValue(1.0 - value); }
+};
+
+// usage: sin(expression)
+class SinExpression : public FunctionExpression
+{
+private:
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (1 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"expression"};
+  }
+
+  ControlState GetValue() const override { return std::sin(GetArg(0).GetValue()); }
+};
+
+// usage: timer(seconds)
+class TimerExpression : public FunctionExpression
+{
+private:
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (1 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"seconds"};
+  }
+
+  ControlState GetValue() const override
+  {
+    const auto now = Clock::now();
+    const auto elapsed = now - m_start_time;
+
+    const ControlState val = GetArg(0).GetValue();
+
+    ControlState progress = std::chrono::duration_cast<FSec>(elapsed).count() / val;
+
+    if (std::isinf(progress) || progress < 0.0)
+    {
+      // User configured a non-positive timer. Reset the timer and return 0.0.
+      progress = 0.0;
+      m_start_time = now;
+    }
+    else if (progress >= 1.0)
+    {
+      const ControlState reset_count = std::floor(progress);
+
+      m_start_time += std::chrono::duration_cast<Clock::duration>(FSec(val * reset_count));
+      progress -= reset_count;
+    }
+
+    return progress;
+  }
+
+private:
+  mutable Clock::time_point m_start_time = Clock::now();
+};
+
+// usage: if(condition, true_expression, false_expression)
+class IfExpression : public FunctionExpression
+{
+private:
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (3 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"condition, true_expression, false_expression"};
+  }
+
+  ControlState GetValue() const override
+  {
+    return (GetArg(0).GetValue() > CONDITION_THRESHOLD) ? GetArg(1).GetValue() :
+                                                          GetArg(2).GetValue();
+  }
+};
+
+// usage: minus(expression)
+class UnaryMinusExpression : public FunctionExpression
+{
+private:
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (1 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"expression"};
+  }
+
+  ControlState GetValue() const override
+  {
+    // Subtraction for clarity:
+    return 0.0 - GetArg(0).GetValue();
+  }
+};
+
+// usage: deadzone(input, amount)
+class DeadzoneExpression : public FunctionExpression
+{
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (2 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"input, amount"};
+  }
+
+  ControlState GetValue() const override
+  {
+    const ControlState val = GetArg(0).GetValue();
+    const ControlState deadzone = GetArg(1).GetValue();
+    return std::copysign(std::max(0.0, std::abs(val) - deadzone) / (1.0 - deadzone), val);
+  }
+};
+
+// usage: smooth(input, seconds_up, seconds_down = seconds_up)
+// seconds is seconds to change from 0.0 to 1.0
+class SmoothExpression : public FunctionExpression
+{
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (2 == args.size() || 3 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"input, seconds_up, seconds_down = seconds_up"};
+  }
+
+  ControlState GetValue() const override
+  {
+    const auto now = Clock::now();
+    const auto elapsed = now - m_last_update;
+    m_last_update = now;
+
+    const ControlState desired_value = GetArg(0).GetValue();
+
+    const ControlState smooth_up = GetArg(1).GetValue();
+    const ControlState smooth_down = (3 == GetArgCount() ? GetArg(2).GetValue() : smooth_up);
+
+    const ControlState smooth = (desired_value < m_value) ? smooth_down : smooth_up;
+    const ControlState max_move = std::chrono::duration_cast<FSec>(elapsed).count() / smooth;
+
+    if (std::isinf(max_move))
+    {
+      m_value = desired_value;
+    }
+    else
+    {
+      const ControlState diff = desired_value - m_value;
+      m_value += std::copysign(std::min(max_move, std::abs(diff)), diff);
+    }
+
+    return m_value;
+  }
+
+private:
+  mutable ControlState m_value = 0.0;
+  mutable Clock::time_point m_last_update = Clock::now();
+};
+
+// usage: hold(input, seconds)
+class HoldExpression : public FunctionExpression
+{
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (2 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"input, seconds"};
+  }
+
+  ControlState GetValue() const override
+  {
+    const auto now = Clock::now();
+
+    const ControlState input = GetArg(0).GetValue();
+
+    if (input < CONDITION_THRESHOLD)
+    {
+      m_state = false;
+      m_start_time = Clock::now();
+    }
+    else if (!m_state)
+    {
+      const auto hold_time = now - m_start_time;
+
+      if (std::chrono::duration_cast<FSec>(hold_time).count() >= GetArg(1).GetValue())
+        m_state = true;
+    }
+
+    return m_state;
+  }
+
+private:
+  mutable bool m_state = false;
+  mutable Clock::time_point m_start_time = Clock::now();
+};
+
+// usage: tap(input, seconds, taps=2)
+class TapExpression : public FunctionExpression
+{
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (2 == args.size() || 3 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"input, seconds, taps = 2"};
+  }
+
+  ControlState GetValue() const override
+  {
+    const auto now = Clock::now();
+
+    const auto elapsed = std::chrono::duration_cast<FSec>(now - m_start_time).count();
+
+    const ControlState input = GetArg(0).GetValue();
+    const ControlState seconds = GetArg(1).GetValue();
+
+    const bool is_time_up = elapsed > seconds;
+
+    const u32 desired_taps = (3 == GetArgCount()) ? u32(GetArg(2).GetValue() + 0.5) : 2;
+
+    if (input < CONDITION_THRESHOLD)
+    {
+      m_released = true;
+
+      if (m_taps > 0 && is_time_up)
+      {
+        m_taps = 0;
+      }
+    }
+    else
+    {
+      if (m_released)
+      {
+        if (!m_taps)
+        {
+          m_start_time = now;
+        }
+
+        ++m_taps;
+        m_released = false;
+      }
+
+      return desired_taps == m_taps;
+    }
+
+    return 0.0;
+  }
+
+private:
+  mutable bool m_released = true;
+  mutable u32 m_taps = 0;
+  mutable Clock::time_point m_start_time = Clock::now();
+};
+
+// usage: relative(input, speed, [max_abs_value, [shared_state]])
+// speed is max movement per second
+class RelativeExpression : public FunctionExpression
+{
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (args.size() >= 2 && args.size() <= 4)
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"input, speed, [max_abs_value, [shared_state]]"};
+  }
+
+  ControlState GetValue() const override
+  {
+    // There is a lot of funky math in this function but it allows for a variety of uses:
+    //
+    // e.g. A single mapping with a relatively adjusted value between 0.0 and 1.0
+    // Potentially useful for a trigger input
+    //  relative(`Up` - `Down`, 2.0)
+    //
+    // e.g. A value with two mappings (such as analog stick Up/Down)
+    // The shared state allows the two mappings to work together.
+    // This mapping (for up) returns a value clamped between 0.0 and 1.0
+    //  relative(`Up`, 2.0, 1.0, $y)
+    // This mapping (for down) returns the negative value clamped between 0.0 and 1.0
+    // (Adjustments created by `Down` are applied negatively to the shared state)
+    //  relative(`Down`, 2.0, -1.0, $y)
+
+    const auto now = Clock::now();
+
+    if (GetArgCount() >= 4)
+      m_state = GetArg(3).GetValue();
+
+    const auto elapsed = std::chrono::duration_cast<FSec>(now - m_last_update).count();
+    m_last_update = now;
+
+    const ControlState input = GetArg(0).GetValue();
+    const ControlState speed = GetArg(1).GetValue();
+
+    const ControlState max_abs_value = (GetArgCount() >= 3) ? GetArg(2).GetValue() : 1.0;
+
+    const ControlState max_move = input * elapsed * speed;
+    const ControlState diff_from_zero = std::abs(0.0 - m_state);
+    const ControlState diff_from_max = std::abs(max_abs_value - m_state);
+
+    m_state += std::min(std::max(max_move, -diff_from_zero), diff_from_max) *
+               std::copysign(1.0, max_abs_value);
+
+    if (GetArgCount() >= 4)
+      const_cast<Expression&>(GetArg(3)).SetValue(m_state);
+
+    return std::max(0.0, m_state * std::copysign(1.0, max_abs_value));
+  }
+
+private:
+  mutable ControlState m_state = 0.0;
+  mutable Clock::time_point m_last_update = Clock::now();
+};
+
+// usage: pulse(input, seconds)
+class PulseExpression : public FunctionExpression
+{
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (2 == args.size())
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"input, seconds"};
+  }
+
+  ControlState GetValue() const override
+  {
+    const auto now = Clock::now();
+
+    const ControlState input = GetArg(0).GetValue();
+
+    if (input < CONDITION_THRESHOLD)
+    {
+      m_released = true;
+    }
+    else if (m_released)
+    {
+      m_released = false;
+
+      const auto seconds = std::chrono::duration_cast<Clock::duration>(FSec(GetArg(1).GetValue()));
+
+      if (m_state)
+      {
+        m_release_time += seconds;
+      }
+      else
+      {
+        m_state = true;
+        m_release_time = now + seconds;
+      }
+    }
+
+    if (m_state && now >= m_release_time)
+    {
+      m_state = false;
+    }
+
+    return m_state;
+  }
+
+private:
+  mutable bool m_released = false;
+  mutable bool m_state = false;
+  mutable Clock::time_point m_release_time = Clock::now();
+};
+
+std::unique_ptr<FunctionExpression> MakeFunctionExpression(std::string name)
+{
+  if ("not" == name)
+    return std::make_unique<NotExpression>();
+  else if ("if" == name)
+    return std::make_unique<IfExpression>();
+  else if ("sin" == name)
+    return std::make_unique<SinExpression>();
+  else if ("timer" == name)
+    return std::make_unique<TimerExpression>();
+  else if ("toggle" == name)
+    return std::make_unique<ToggleExpression>();
+  else if ("minus" == name)
+    return std::make_unique<UnaryMinusExpression>();
+  else if ("deadzone" == name)
+    return std::make_unique<DeadzoneExpression>();
+  else if ("smooth" == name)
+    return std::make_unique<SmoothExpression>();
+  else if ("hold" == name)
+    return std::make_unique<HoldExpression>();
+  else if ("tap" == name)
+    return std::make_unique<TapExpression>();
+  else if ("relative" == name)
+    return std::make_unique<RelativeExpression>();
+  else if ("pulse" == name)
+    return std::make_unique<PulseExpression>();
+  else
+    return nullptr;
+}
+
+int FunctionExpression::CountNumControls() const
+{
+  int result = 0;
+
+  for (auto& arg : m_args)
+    result += arg->CountNumControls();
+
+  return result;
+}
+
+void FunctionExpression::UpdateReferences(ControlEnvironment& env)
+{
+  for (auto& arg : m_args)
+    arg->UpdateReferences(env);
+}
+
+FunctionExpression::ArgumentValidation
+FunctionExpression::SetArguments(std::vector<std::unique_ptr<Expression>>&& args)
+{
+  m_args = std::move(args);
+
+  return ValidateArguments(m_args);
+}
+
+Expression& FunctionExpression::GetArg(u32 number)
+{
+  return *m_args[number];
+}
+
+const Expression& FunctionExpression::GetArg(u32 number) const
+{
+  return *m_args[number];
+}
+
+u32 FunctionExpression::GetArgCount() const
+{
+  return u32(m_args.size());
+}
+
+void FunctionExpression::SetValue(ControlState)
+{
+}
+
+}  // namespace ExpressionParser
+}  // namespace ciface