Move Codec2-related code from hardware/google/av

Test: None
Bug: 112362730
Change-Id: Ie2f8ff431d65c40333f267ab9877d47089adeea4
diff --git a/media/codec2/vndk/util/C2InterfaceUtils.cpp b/media/codec2/vndk/util/C2InterfaceUtils.cpp
new file mode 100644
index 0000000..61ec911
--- /dev/null
+++ b/media/codec2/vndk/util/C2InterfaceUtils.cpp
@@ -0,0 +1,1292 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunused-parameter"
+#pragma clang diagnostic ignored "-Wunused-variable"
+#pragma clang diagnostic ignored "-Wunused-value"
+
+#define C2_LOG_VERBOSE
+
+#include <C2Debug.h>
+#include <C2Param.h>
+#include <C2ParamDef.h>
+#include <C2ParamInternal.h>
+#include <util/C2InterfaceUtils.h>
+
+#include <cmath>
+#include <limits>
+#include <map>
+#include <type_traits>
+
+#include <android-base/stringprintf.h>
+
+std::ostream& operator<<(std::ostream& os, const _C2FieldId &i);
+
+std::ostream& operator<<(std::ostream& os, const C2ParamField &i);
+
+/* ---------------------------- C2SupportedRange ---------------------------- */
+
+/**
+ * Helper class for supported values range calculations.
+ */
+template<typename T, bool FP=std::is_floating_point<T>::value>
+struct _C2TypedSupportedRangeHelper {
+    /**
+     * type of range size: a - b if a >= b and a and b are of type T
+     */
+    typedef typename std::make_unsigned<T>::type DiffType;
+
+    /**
+     * calculate (high - low) mod step
+     */
+    static DiffType mod(T low, T high, T step) {
+        return DiffType(high - low) % DiffType(step);
+    }
+};
+
+template<typename T>
+struct _C2TypedSupportedRangeHelper<T, true> {
+    typedef T DiffType;
+
+    static DiffType mod(T low, T high, T step) {
+        return fmod(high - low, step);
+    }
+};
+
+template<typename T>
+C2SupportedRange<T>::C2SupportedRange(const C2FieldSupportedValues &values) {
+    if (values.type == C2FieldSupportedValues::RANGE) {
+        _mMin = values.range.min.ref<ValueType>();
+        _mMax = values.range.max.ref<ValueType>();
+        _mStep = values.range.step.ref<ValueType>();
+        _mNum = values.range.num.ref<ValueType>();
+        _mDenom = values.range.denom.ref<ValueType>();
+    } else {
+        _mMin = MAX_VALUE;
+        _mMax = MIN_VALUE;
+        _mStep = MIN_STEP;
+        _mNum = 0;
+        _mDenom = 0;
+    }
+}
+
+template<typename T>
+bool C2SupportedRange<T>::contains(T value) const {
+    // value must fall between min and max
+    if (value < _mMin || value > _mMax) {
+        return false;
+    }
+    // simple ranges contain all values between min and max
+    if (isSimpleRange()) {
+        return true;
+    }
+    // min is always part of the range
+    if (value == _mMin) {
+        return true;
+    }
+    // stepped ranges require (val - min) % step to be zero
+    if (isArithmeticSeries()) {
+        return _C2TypedSupportedRangeHelper<T>::mod(_mMin, value, _mStep) == 0;
+    }
+    // pure geometric series require (val / min) to be integer multiple of (num/denom)
+    if (isGeometricSeries()) {
+        if (value <= 0) {
+            return false;
+        }
+        double log2base = log2(_mNum / _mDenom);
+        double power = llround(log2(value / double(_mMin)) / log2base);
+        // TODO: validate that result falls within precision (other than round)
+        return value == T(_mMin * pow(_mNum / _mDenom, power) + MIN_STEP / 2);
+    }
+    // multiply-accumulate series require validating by walking through the series
+    if (isMacSeries()) {
+        double lastValue = _mMin;
+        double base = _mNum / _mDenom;
+        while (true) {
+            // this cast is safe as _mMin <= lastValue <= _mMax
+            if (T(lastValue + MIN_STEP / 2) == value) {
+                return true;
+            }
+            double nextValue = fma(lastValue, base, _mStep);
+            if (nextValue <= lastValue || nextValue > _mMax) {
+                return false; // series is no longer monotonic or within range
+            }
+            lastValue = nextValue;
+        };
+    }
+    // if we are here, this must be an invalid range
+    return false;
+}
+
+template<typename T>
+C2SupportedRange<T> C2SupportedRange<T>::limitedTo(const C2SupportedRange<T> &limit) const {
+    // TODO - this only works for simple ranges
+    return C2SupportedRange(std::max(_mMin, limit._mMin), std::min(_mMax, limit._mMax),
+                                 std::max(_mStep, limit._mStep));
+}
+
+template class C2SupportedRange<uint8_t>;
+template class C2SupportedRange<char>;
+template class C2SupportedRange<int32_t>;
+template class C2SupportedRange<uint32_t>;
+//template class C2SupportedRange<c2_cntr32_t>;
+template class C2SupportedRange<int64_t>;
+template class C2SupportedRange<uint64_t>;
+//template class C2SupportedRange<c2_cntr64_t>;
+template class C2SupportedRange<float>;
+
+/* -------------------------- C2SupportedFlags -------------------------- */
+
+/**
+ * Ordered supported flag set for a field of a given type.
+ */
+// float flags are not supported, but define a few methods to support generic supported values code
+template<>
+bool C2SupportedFlags<float>::contains(float value) const {
+    return false;
+}
+
+template<>
+const std::vector<float> C2SupportedFlags<float>::flags() const {
+    return std::vector<float>();
+}
+
+template<>
+C2SupportedFlags<float> C2SupportedFlags<float>::limitedTo(const C2SupportedFlags<float> &limit) const {
+    std::vector<C2Value::Primitive> values;
+    return C2SupportedFlags(std::move(values));
+}
+
+template<>
+float C2SupportedFlags<float>::min() const {
+    return 0;
+}
+
+template<typename T>
+bool C2SupportedFlags<T>::contains(T value) const {
+    // value must contain the minimal mask
+    T minMask = min();
+    if (~value & minMask) {
+        return false;
+    }
+    value &= ~minMask;
+    // otherwise, remove flags from value and see if we arrive at 0
+    for (const C2Value::Primitive &v : _mValues) {
+        if (value == 0) {
+            break;
+        }
+        if ((~value & v.ref<ValueType>()) == 0) {
+            value &= ~v.ref<ValueType>();
+        }
+    }
+    return value == 0;
+}
+
+template<typename T>
+const std::vector<T> C2SupportedFlags<T>::flags() const {
+    std::vector<T> vals(c2_max(_mValues.size(), 1u) - 1);
+    if (!_mValues.empty()) {
+        std::transform(_mValues.cbegin() + 1, _mValues.cend(), vals.begin(),
+                       [](const C2Value::Primitive &p)->T {
+            return p.ref<ValueType>();
+        });
+    }
+    return vals;
+}
+
+template<typename T>
+C2SupportedFlags<T> C2SupportedFlags<T>::limitedTo(const C2SupportedFlags<T> &limit) const {
+    std::vector<C2Value::Primitive> values = _mValues; // make a copy
+    T minMask = min() | limit.min();
+    // minimum mask must be covered by both this and other
+    if (limit.contains(minMask) && contains(minMask)) {
+        values[0] = minMask;
+        // keep only flags that are covered by limit
+        std::remove_if(values.begin(), values.end(), [&limit, minMask](const C2Value::Primitive &v) -> bool {
+            T value = v.ref<ValueType>() | minMask;
+            return value == minMask || !limit.contains(value); });
+        // we also need to do it vice versa
+        for (const C2Value::Primitive &v : _mValues) {
+            T value = v.ref<ValueType>() | minMask;
+            if (value != minMask && contains(value)) {
+                values.emplace_back((ValueType)value);
+            }
+        }
+    }
+    return C2SupportedFlags(std::move(values));
+}
+
+template<typename T>
+T C2SupportedFlags<T>::min() const {
+    if (!_mValues.empty()) {
+        return _mValues.front().template ref<ValueType>();
+    } else {
+        return T(0);
+    }
+}
+
+template class C2SupportedFlags<uint8_t>;
+template class C2SupportedFlags<char>;
+template class C2SupportedFlags<int32_t>;
+template class C2SupportedFlags<uint32_t>;
+//template class C2SupportedFlags<c2_cntr32_t>;
+template class C2SupportedFlags<int64_t>;
+template class C2SupportedFlags<uint64_t>;
+//template class C2SupportedFlags<c2_cntr64_t>;
+
+/* -------------------------- C2SupportedValueSet -------------------------- */
+
+/**
+ * Ordered supported value set for a field of a given type.
+ */
+template<typename T>
+bool C2SupportedValueSet<T>::contains(T value) const {
+    return std::find_if(_mValues.cbegin(), _mValues.cend(),
+            [value](const C2Value::Primitive &p) -> bool {
+                return value == p.ref<ValueType>();
+            }) != _mValues.cend();
+}
+
+template<typename T>
+C2SupportedValueSet<T> C2SupportedValueSet<T>::limitedTo(const C2SupportedValueSet<T> &limit) const {
+    std::vector<C2Value::Primitive> values = _mValues; // make a copy
+    std::remove_if(values.begin(), values.end(), [&limit](const C2Value::Primitive &v) -> bool {
+        return !limit.contains(v.ref<ValueType>()); });
+    return C2SupportedValueSet(std::move(values));
+}
+
+template<typename T>
+C2SupportedValueSet<T> C2SupportedValueSet<T>::limitedTo(const C2SupportedRange<T> &limit) const {
+    std::vector<C2Value::Primitive> values = _mValues; // make a copy
+    std::remove_if(values.begin(), values.end(), [&limit](const C2Value::Primitive &v) -> bool {
+        return !limit.contains(v.ref<ValueType>()); });
+    return C2SupportedValueSet(std::move(values));
+}
+
+template<typename T>
+C2SupportedValueSet<T> C2SupportedValueSet<T>::limitedTo(const C2SupportedFlags<T> &limit) const {
+    std::vector<C2Value::Primitive> values = _mValues; // make a copy
+    std::remove_if(values.begin(), values.end(), [&limit](const C2Value::Primitive &v) -> bool {
+        return !limit.contains(v.ref<ValueType>()); });
+    return C2SupportedValueSet(std::move(values));
+}
+
+template<typename T>
+const std::vector<T> C2SupportedValueSet<T>::values() const {
+    std::vector<T> vals(_mValues.size());
+    std::transform(_mValues.cbegin(), _mValues.cend(), vals.begin(), [](const C2Value::Primitive &p) -> T {
+        return p.ref<ValueType>();
+    });
+    return vals;
+}
+
+template class C2SupportedValueSet<uint8_t>;
+template class C2SupportedValueSet<char>;
+template class C2SupportedValueSet<int32_t>;
+template class C2SupportedValueSet<uint32_t>;
+//template class C2SupportedValueSet<c2_cntr32_t>;
+template class C2SupportedValueSet<int64_t>;
+template class C2SupportedValueSet<uint64_t>;
+//template class C2SupportedValueSet<c2_cntr64_t>;
+template class C2SupportedValueSet<float>;
+
+/* ---------------------- C2FieldSupportedValuesHelper ---------------------- */
+
+template<typename T>
+struct C2FieldSupportedValuesHelper<T>::Impl {
+    Impl(const C2FieldSupportedValues &values)
+        : _mType(values.type),
+          _mRange(values),
+          _mValues(values),
+          _mFlags(values) { }
+
+    bool supports(T value) const;
+
+private:
+    typedef typename _C2FieldValueHelper<T>::ValueType ValueType;
+    C2FieldSupportedValues::type_t _mType;
+    C2SupportedRange<ValueType> _mRange;
+    C2SupportedValueSet<ValueType> _mValues;
+    C2SupportedValueSet<ValueType> _mFlags;
+
+//    friend std::ostream& operator<< <T>(std::ostream& os, const C2FieldSupportedValuesHelper<T>::Impl &i);
+//    friend std::ostream& operator<<(std::ostream& os, const Impl &i);
+    std::ostream& streamOut(std::ostream& os) const;
+};
+
+template<typename T>
+bool C2FieldSupportedValuesHelper<T>::Impl::supports(T value) const {
+    switch (_mType) {
+        case C2FieldSupportedValues::RANGE: return _mRange.contains(value);
+        case C2FieldSupportedValues::VALUES: return _mValues.contains(value);
+        case C2FieldSupportedValues::FLAGS: return _mFlags.contains(value);
+        default: return false;
+    }
+}
+
+template<typename T>
+C2FieldSupportedValuesHelper<T>::C2FieldSupportedValuesHelper(const C2FieldSupportedValues &values)
+    : _mImpl(std::make_unique<C2FieldSupportedValuesHelper<T>::Impl>(values)) { }
+
+template<typename T>
+C2FieldSupportedValuesHelper<T>::~C2FieldSupportedValuesHelper() = default;
+
+template<typename T>
+bool C2FieldSupportedValuesHelper<T>::supports(T value) const {
+    return _mImpl->supports(value);
+}
+
+template class C2FieldSupportedValuesHelper<uint8_t>;
+template class C2FieldSupportedValuesHelper<char>;
+template class C2FieldSupportedValuesHelper<int32_t>;
+template class C2FieldSupportedValuesHelper<uint32_t>;
+//template class C2FieldSupportedValuesHelper<c2_cntr32_t>;
+template class C2FieldSupportedValuesHelper<int64_t>;
+template class C2FieldSupportedValuesHelper<uint64_t>;
+//template class C2FieldSupportedValuesHelper<c2_cntr64_t>;
+template class C2FieldSupportedValuesHelper<float>;
+
+/* ----------------------- C2ParamFieldValuesBuilder ----------------------- */
+
+template<typename T>
+struct C2ParamFieldValuesBuilder<T>::Impl {
+    Impl(const C2ParamField &field)
+        : _mParamField(field),
+          _mType(type_t::RANGE),
+          _mDefined(false),
+          _mRange(C2SupportedRange<T>::Any()),
+          _mValues(C2SupportedValueSet<T>::None()),
+          _mFlags(C2SupportedFlags<T>::None()) { }
+
+    /**
+     * Get C2ParamFieldValues from this builder.
+     */
+    operator C2ParamFieldValues() const {
+        if (!_mDefined) {
+            return C2ParamFieldValues(_mParamField);
+        }
+        switch (_mType) {
+        case type_t::EMPTY:
+        case type_t::VALUES:
+            return C2ParamFieldValues(_mParamField, (C2FieldSupportedValues)_mValues);
+        case type_t::RANGE:
+            return C2ParamFieldValues(_mParamField, (C2FieldSupportedValues)_mRange);
+        case type_t::FLAGS:
+            return C2ParamFieldValues(_mParamField, (C2FieldSupportedValues)_mFlags);
+        default:
+            // TRESPASS
+            // should never get here
+            return C2ParamFieldValues(_mParamField);
+        }
+    }
+
+    /** Define the supported values as the currently supported values of this builder. */
+    void any() {
+        _mDefined = true;
+    }
+
+    /** Restrict (and thus define) the supported values to none. */
+    void none() {
+        _mDefined = true;
+        _mType = type_t::VALUES;
+        _mValues.clear();
+    }
+
+    /** Restrict (and thus define) the supported values to |value| alone. */
+    void equalTo(T value) {
+         return limitTo(C2SupportedValueSet<T>::OneOf({value}));
+    }
+
+    /** Restrict (and thus define) the supported values to a value set. */
+    void limitTo(const C2SupportedValueSet<T> &limit) {
+        if (!_mDefined) {
+            C2_LOG(VERBOSE) << "NA.limitTo(" << C2FieldSupportedValuesHelper<T>(limit) << ")";
+
+            // shortcut for first limit applied
+            _mDefined = true;
+            _mValues = limit;
+            _mType = _mValues.isEmpty() ? type_t::EMPTY : type_t::VALUES;
+        } else {
+            switch (_mType) {
+            case type_t::EMPTY:
+            case type_t::VALUES:
+                C2_LOG(VERBOSE) << "(" << C2FieldSupportedValuesHelper<T>(_mValues) << ").limitTo("
+                        << C2FieldSupportedValuesHelper<T>(limit) << ")";
+
+                _mValues = _mValues.limitedTo(limit);
+                _mType = _mValues.isEmpty() ? type_t::EMPTY : type_t::VALUES;
+                break;
+            case type_t::RANGE:
+                C2_LOG(VERBOSE) << "(" << C2FieldSupportedValuesHelper<T>(_mRange) << ").limitTo("
+                        << C2FieldSupportedValuesHelper<T>(limit) << ")";
+
+                _mValues = limit.limitedTo(_mRange);
+                _mType = _mValues.isEmpty() ? type_t::EMPTY : type_t::VALUES;
+                break;
+            case type_t::FLAGS:
+                C2_LOG(VERBOSE) << "(" << C2FieldSupportedValuesHelper<T>(_mRange) << ").limitTo("
+                        << C2FieldSupportedValuesHelper<T>(limit) << ")";
+
+                _mValues = limit.limitedTo(_mFlags);
+                _mType = _mValues.isEmpty() ? type_t::EMPTY : type_t::VALUES;
+                break;
+            default:
+                C2_LOG(FATAL); // should not be here
+            }
+            // TODO: support flags
+        }
+        C2_LOG(VERBOSE) << " = " << _mType << ":" << C2FieldSupportedValuesHelper<T>(_mValues);
+    }
+
+    /** Restrict (and thus define) the supported values to a flag set. */
+    void limitTo(const C2SupportedFlags<T> &limit) {
+        if (!_mDefined) {
+            C2_LOG(VERBOSE) << "NA.limitTo(" << C2FieldSupportedValuesHelper<T>(limit) << ")";
+
+            // shortcut for first limit applied
+            _mDefined = true;
+            _mFlags = limit;
+            _mType = _mFlags.isEmpty() ? type_t::EMPTY : type_t::FLAGS;
+        } else {
+            switch (_mType) {
+            case type_t::EMPTY:
+            case type_t::VALUES:
+                C2_LOG(VERBOSE) << "(" << C2FieldSupportedValuesHelper<T>(_mValues) << ").limitTo("
+                        << C2FieldSupportedValuesHelper<T>(limit) << ")";
+
+                _mValues = _mValues.limitedTo(limit);
+                _mType = _mValues.isEmpty() ? type_t::EMPTY : type_t::VALUES;
+                C2_LOG(VERBOSE) << " = " << _mType << ":" << C2FieldSupportedValuesHelper<T>(_mValues);
+                break;
+            case type_t::FLAGS:
+                C2_LOG(VERBOSE) << "(" << C2FieldSupportedValuesHelper<T>(_mFlags) << ").limitTo("
+                        << C2FieldSupportedValuesHelper<T>(limit) << ")";
+
+                _mFlags = _mFlags.limitedTo(limit);
+                _mType = _mFlags.isEmpty() ? type_t::EMPTY : type_t::FLAGS;
+                C2_LOG(VERBOSE) << " = " << _mType << ":" << C2FieldSupportedValuesHelper<T>(_mFlags);
+                break;
+            case type_t::RANGE:
+                C2_LOG(FATAL) << "limiting ranges to flags is not supported";
+                _mType = type_t::EMPTY;
+                break;
+            default:
+                C2_LOG(FATAL); // should not be here
+            }
+        }
+    }
+
+    void limitTo(const C2SupportedRange<T> &limit) {
+        if (!_mDefined) {
+            C2_LOG(VERBOSE) << "NA.limitTo(" << C2FieldSupportedValuesHelper<T>(limit) << ")";
+
+            // shortcut for first limit applied
+            _mDefined = true;
+            _mRange = limit;
+            _mType = _mRange.isEmpty() ? type_t::EMPTY : type_t::RANGE;
+            C2_LOG(VERBOSE) << " = " << _mType << ":" << C2FieldSupportedValuesHelper<T>(_mRange);
+        } else {
+            switch (_mType) {
+            case type_t::EMPTY:
+            case type_t::VALUES:
+                C2_LOG(VERBOSE) << "(" << C2FieldSupportedValuesHelper<T>(_mValues) << ").limitTo("
+                        << C2FieldSupportedValuesHelper<T>(limit) << ")";
+                _mValues = _mValues.limitedTo(limit);
+                _mType = _mValues.isEmpty() ? type_t::EMPTY : type_t::VALUES;
+                C2_LOG(VERBOSE) << " = " << _mType << ":" << C2FieldSupportedValuesHelper<T>(_mValues);
+                break;
+            case type_t::FLAGS:
+                C2_LOG(FATAL) << "limiting flags to ranges is not supported";
+                _mType = type_t::EMPTY;
+                break;
+            case type_t::RANGE:
+                C2_LOG(VERBOSE) << "(" << C2FieldSupportedValuesHelper<T>(_mRange) << ").limitTo("
+                        << C2FieldSupportedValuesHelper<T>(limit) << ")";
+                _mRange = _mRange.limitedTo(limit);
+                C2_DCHECK(_mValues.isEmpty());
+                _mType = _mRange.isEmpty() ? type_t::EMPTY : type_t::RANGE;
+                C2_LOG(VERBOSE) << " = " << _mType << ":" << C2FieldSupportedValuesHelper<T>(_mRange);
+                break;
+            default:
+                C2_LOG(FATAL); // should not be here
+            }
+        }
+    }
+
+private:
+    void instantiate() __unused {
+        (void)_mValues.values(); // instantiate non-const values()
+    }
+
+    void instantiate() const __unused {
+        (void)_mValues.values(); // instantiate const values()
+    }
+
+    typedef C2FieldSupportedValues::type_t type_t;
+
+    C2ParamField _mParamField;
+    type_t _mType;
+    bool _mDefined;
+    C2SupportedRange<T> _mRange;
+    C2SupportedValueSet<T> _mValues;
+    C2SupportedFlags<T> _mFlags;
+
+};
+
+template<typename T>
+C2ParamFieldValuesBuilder<T>::operator C2ParamFieldValues() const {
+    return (C2ParamFieldValues)(*_mImpl.get());
+}
+
+template<typename T>
+C2ParamFieldValuesBuilder<T>::C2ParamFieldValuesBuilder(const C2ParamField &field)
+    : _mImpl(std::make_unique<C2ParamFieldValuesBuilder<T>::Impl>(field)) { }
+
+template<typename T>
+C2ParamFieldValuesBuilder<T> &C2ParamFieldValuesBuilder<T>::any() {
+    _mImpl->any();
+    return *this;
+}
+
+template<typename T>
+C2ParamFieldValuesBuilder<T> &C2ParamFieldValuesBuilder<T>::none() {
+    _mImpl->none();
+    return *this;
+}
+
+template<typename T>
+C2ParamFieldValuesBuilder<T> &C2ParamFieldValuesBuilder<T>::equalTo(T value) {
+    _mImpl->equalTo(value);
+    return *this;
+}
+
+template<typename T>
+C2ParamFieldValuesBuilder<T> &C2ParamFieldValuesBuilder<T>::limitTo(const C2SupportedValueSet<T> &limit) {
+    _mImpl->limitTo(limit);
+    return *this;
+}
+
+template<typename T>
+C2ParamFieldValuesBuilder<T> &C2ParamFieldValuesBuilder<T>::limitTo(const C2SupportedFlags<T> &limit) {
+    _mImpl->limitTo(limit);
+    return *this;
+}
+
+template<typename T>
+C2ParamFieldValuesBuilder<T> &C2ParamFieldValuesBuilder<T>::limitTo(const C2SupportedRange<T> &limit) {
+    _mImpl->limitTo(limit);
+    return *this;
+}
+
+template<typename T>
+C2ParamFieldValuesBuilder<T>::C2ParamFieldValuesBuilder(const C2ParamFieldValuesBuilder<T> &other)
+    : _mImpl(std::make_unique<C2ParamFieldValuesBuilder<T>::Impl>(*other._mImpl.get())) { }
+
+template<typename T>
+C2ParamFieldValuesBuilder<T> &C2ParamFieldValuesBuilder<T>::operator=(
+        const C2ParamFieldValuesBuilder<T> &other) {
+    _mImpl = std::make_unique<C2ParamFieldValuesBuilder<T>::Impl>(*other._mImpl.get());
+    return *this;
+}
+
+template<typename T>
+C2ParamFieldValuesBuilder<T>::~C2ParamFieldValuesBuilder() = default;
+
+template class C2ParamFieldValuesBuilder<uint8_t>;
+template class C2ParamFieldValuesBuilder<char>;
+template class C2ParamFieldValuesBuilder<int32_t>;
+template class C2ParamFieldValuesBuilder<uint32_t>;
+//template class C2ParamFieldValuesBuilder<c2_cntr32_t>;
+template class C2ParamFieldValuesBuilder<int64_t>;
+template class C2ParamFieldValuesBuilder<uint64_t>;
+//template class C2ParamFieldValuesBuilder<c2_cntr64_t>;
+template class C2ParamFieldValuesBuilder<float>;
+
+/* ------------------------- C2SettingResultBuilder ------------------------- */
+
+C2SettingConflictsBuilder::C2SettingConflictsBuilder() : _mConflicts() { }
+
+C2SettingConflictsBuilder::C2SettingConflictsBuilder(C2ParamFieldValues &&conflict) {
+    _mConflicts.emplace_back(std::move(conflict));
+}
+
+C2SettingConflictsBuilder& C2SettingConflictsBuilder::with(C2ParamFieldValues &&conflict) {
+    _mConflicts.emplace_back(std::move(conflict));
+    return *this;
+}
+
+std::vector<C2ParamFieldValues> C2SettingConflictsBuilder::retrieveConflicts() {
+    return std::move(_mConflicts);
+}
+
+/* ------------------------- C2SettingResult/sBuilder ------------------------- */
+
+C2SettingResult C2SettingResultBuilder::ReadOnly(const C2ParamField &param) {
+    return C2SettingResult { C2SettingResult::READ_ONLY, { param }, { } };
+}
+
+C2SettingResult C2SettingResultBuilder::BadValue(const C2ParamField &paramField, bool isInfo) {
+    return { isInfo ? C2SettingResult::INFO_BAD_VALUE : C2SettingResult::BAD_VALUE,
+             { paramField }, { } };
+}
+
+C2SettingResult C2SettingResultBuilder::Conflict(
+        C2ParamFieldValues &&paramFieldValues, C2SettingConflictsBuilder &conflicts, bool isInfo) {
+    C2_CHECK(!conflicts.empty());
+    if (isInfo) {
+        return C2SettingResult {
+            C2SettingResult::INFO_CONFLICT,
+            std::move(paramFieldValues), conflicts.retrieveConflicts()
+        };
+    } else {
+        return C2SettingResult {
+            C2SettingResult::CONFLICT,
+            std::move(paramFieldValues), conflicts.retrieveConflicts()
+        };
+    }
+}
+
+C2SettingResultsBuilder::C2SettingResultsBuilder(C2SettingResult &&result)
+        : _mStatus(C2_BAD_VALUE) {
+    _mResults.emplace_back(new C2SettingResult(std::move(result)));
+}
+
+C2SettingResultsBuilder C2SettingResultsBuilder::plus(C2SettingResultsBuilder&& results) {
+    for (std::unique_ptr<C2SettingResult> &r : results._mResults) {
+        _mResults.emplace_back(std::move(r));
+    }
+    results._mResults.clear();
+    // TODO: mStatus
+    return std::move(*this);
+}
+
+c2_status_t C2SettingResultsBuilder::retrieveFailures(
+        std::vector<std::unique_ptr<C2SettingResult>>* const failures) {
+    for (std::unique_ptr<C2SettingResult> &r : _mResults) {
+        failures->emplace_back(std::move(r));
+    }
+    _mResults.clear();
+    return _mStatus;
+}
+
+C2SettingResultsBuilder::C2SettingResultsBuilder(c2_status_t status) : _mStatus(status) {
+    // status must be one of OK, BAD_STATE, TIMED_OUT or CORRUPTED
+    // mainly: BLOCKING, BAD_INDEX, BAD_VALUE and NO_MEMORY requires a setting attempt
+}
+
+#pragma clang diagnostic pop
+
+/* ------------------------- C2FieldUtils ------------------------- */
+
+struct C2_HIDE C2FieldUtils::_Inspector {
+    /// returns the implementation object
+    inline static std::shared_ptr<Info::Impl> GetImpl(const Info &info) {
+        return info._mImpl;
+    }
+};
+
+/* ------------------------- C2FieldUtils::Info ------------------------- */
+
+struct C2_HIDE C2FieldUtils::Info::Impl {
+    C2FieldDescriptor field;
+    std::shared_ptr<Impl> parent;
+    uint32_t index;
+    uint32_t depth;
+    uint32_t baseFieldOffset;
+    uint32_t arrayOffset;
+    uint32_t usedExtent;
+
+    /// creates a copy of this object including copies of its parent chain
+    Impl clone() const;
+
+    /// creates a copy of a shared pointer to an object
+    static std::shared_ptr<Impl> Clone(const std::shared_ptr<Impl> &);
+
+    Impl(const C2FieldDescriptor &field_, std::shared_ptr<Impl> parent_,
+            uint32_t index_, uint32_t depth_, uint32_t baseFieldOffset_,
+            uint32_t arrayOffset_, uint32_t usedExtent_)
+        : field(field_), parent(parent_), index(index_), depth(depth_),
+          baseFieldOffset(baseFieldOffset_), arrayOffset(arrayOffset_), usedExtent(usedExtent_) { }
+};
+
+std::shared_ptr<C2FieldUtils::Info::Impl> C2FieldUtils::Info::Impl::Clone(const std::shared_ptr<Impl> &info) {
+    if (info) {
+        return std::make_shared<Impl>(info->clone());
+    }
+    return nullptr;
+}
+
+C2FieldUtils::Info::Impl C2FieldUtils::Info::Impl::clone() const {
+    Impl res = Impl(*this);
+    res.parent = Clone(res.parent);
+    return res;
+}
+
+C2FieldUtils::Info::Info(std::shared_ptr<Impl> impl)
+    : _mImpl(impl) { }
+
+size_t C2FieldUtils::Info::arrayOffset() const {
+    return _mImpl->arrayOffset;
+}
+
+size_t C2FieldUtils::Info::arraySize() const {
+    return extent() * size();
+}
+
+size_t C2FieldUtils::Info::baseFieldOffset() const {
+    return _mImpl->baseFieldOffset;
+};
+
+size_t C2FieldUtils::Info::depth() const {
+    return _mImpl->depth;
+}
+
+size_t C2FieldUtils::Info::extent() const {
+    return _mImpl->usedExtent;
+}
+
+size_t C2FieldUtils::Info::index() const {
+    return _mImpl->index;
+}
+
+bool C2FieldUtils::Info::isArithmetic() const {
+    switch (_mImpl->field.type()) {
+    case C2FieldDescriptor::BLOB:
+    case C2FieldDescriptor::CNTR32:
+    case C2FieldDescriptor::CNTR64:
+    case C2FieldDescriptor::FLOAT:
+    case C2FieldDescriptor::INT32:
+    case C2FieldDescriptor::INT64:
+    case C2FieldDescriptor::STRING:
+    case C2FieldDescriptor::UINT32:
+    case C2FieldDescriptor::UINT64:
+        return true;
+    default:
+        return false;
+    }
+}
+
+bool C2FieldUtils::Info::isFlexible() const {
+    return _mImpl->field.extent() == 0;
+}
+
+C2String C2FieldUtils::Info::name() const {
+    return _mImpl->field.name();
+}
+
+const C2FieldUtils::Info::NamedValuesType &C2FieldUtils::Info::namedValues() const {
+    return _mImpl->field.namedValues();
+}
+
+size_t C2FieldUtils::Info::offset() const {
+    return _C2ParamInspector::GetOffset(_mImpl->field);
+}
+
+C2FieldUtils::Info C2FieldUtils::Info::parent() const {
+    return Info(_mImpl->parent);
+};
+
+size_t C2FieldUtils::Info::size() const {
+    return _C2ParamInspector::GetSize(_mImpl->field);
+}
+
+C2FieldUtils::Info::type_t C2FieldUtils::Info::type() const {
+    return _mImpl->field.type();
+}
+
+/* ------------------------- C2FieldUtils::Iterator ------------------------- */
+
+struct C2_HIDE C2FieldUtils::Iterator::Impl : public _C2ParamInspector {
+    Impl() = default;
+
+    virtual ~Impl() = default;
+
+    /// implements object equality
+    virtual bool equals(const std::shared_ptr<Impl> &other) const {
+        return other != nullptr && mHead == other->mHead;
+    };
+
+    /// returns the info pointed to by this iterator
+    virtual value_type get() const {
+        return Info(mHead);
+    }
+
+    /// increments this iterator
+    virtual void increment() {
+        // note: this cannot be abstract as we instantiate this for List::end(). increment to end()
+        // instead.
+        mHead.reset();
+    }
+
+protected:
+    Impl(std::shared_ptr<C2FieldUtils::Info::Impl> head)
+        : mHead(head) { }
+
+    std::shared_ptr<Info::Impl> mHead; ///< current field
+};
+
+C2FieldUtils::Iterator::Iterator(std::shared_ptr<Impl> impl)
+    : mImpl(impl) { }
+
+C2FieldUtils::Iterator::value_type C2FieldUtils::Iterator::operator*() const {
+    return mImpl->get();
+}
+
+C2FieldUtils::Iterator& C2FieldUtils::Iterator::operator++() {
+    mImpl->increment();
+    return *this;
+}
+
+bool C2FieldUtils::Iterator::operator==(const Iterator &other) const {
+    return mImpl->equals(other.mImpl);
+}
+
+/* ------------------------- C2FieldUtils::List ------------------------- */
+
+struct C2_HIDE C2FieldUtils::List::Impl {
+    virtual std::shared_ptr<Iterator::Impl> begin() const = 0;
+
+    /// returns an iterator to the end of the list
+    virtual std::shared_ptr<Iterator::Impl> end() const {
+        return std::make_shared<Iterator::Impl>();
+    }
+
+    virtual ~Impl() = default;
+};
+
+C2FieldUtils::List::List(std::shared_ptr<Impl> impl)
+    : mImpl(impl) { }
+
+C2FieldUtils::Iterator C2FieldUtils::List::begin() const {
+    return C2FieldUtils::Iterator(mImpl->begin());
+}
+
+C2FieldUtils::Iterator C2FieldUtils::List::end() const {
+    return C2FieldUtils::Iterator(mImpl->end());
+}
+
+/* ------------------------- C2FieldUtils::enumerateFields ------------------------- */
+
+namespace {
+
+/**
+ * Iterator base class helper that allows descending into the field hierarchy.
+ */
+struct C2FieldUtilsFieldsIteratorHelper : public C2FieldUtils::Iterator::Impl {
+    virtual ~C2FieldUtilsFieldsIteratorHelper() override = default;
+
+    /// returns the base-field's offset of the parent field (or the param offset if no parent)
+    static inline uint32_t GetParentBaseFieldOffset(
+            const std::shared_ptr<C2FieldUtils::Info::Impl> parent) {
+        return parent == nullptr ? sizeof(C2Param) : parent->baseFieldOffset;
+    }
+
+    /// returns the offset of the parent field (or the param)
+    static inline uint32_t GetParentOffset(const std::shared_ptr<C2FieldUtils::Info::Impl> parent) {
+        return parent == nullptr ? sizeof(C2Param) : GetOffset(parent->field);
+    }
+
+protected:
+    C2FieldUtilsFieldsIteratorHelper(
+            std::shared_ptr<C2ParamReflector> reflector,
+            uint32_t paramSize,
+            std::shared_ptr<C2FieldUtils::Info::Impl> head = nullptr)
+        : C2FieldUtils::Iterator::Impl(head),
+          mParamSize(paramSize),
+          mReflector(reflector) { }
+
+    /// returns a leaf info object at a specific index for a child field
+    std::shared_ptr<C2FieldUtils::Info::Impl> makeLeaf(
+            const C2FieldDescriptor &field, uint32_t index) {
+        uint32_t parentOffset = GetParentOffset(mHead);
+        uint32_t arrayOffset = parentOffset + GetOffset(field);
+        uint32_t usedExtent = field.extent() ? :
+                (std::max(arrayOffset, mParamSize) - arrayOffset) / GetSize(field);
+
+        return std::make_shared<C2FieldUtils::Info::Impl>(
+                OffsetFieldDescriptor(field, parentOffset + index * GetSize(field)),
+                mHead /* parent */, index, mHead == nullptr ? 0 : mHead->depth + 1,
+                GetParentBaseFieldOffset(mHead) + GetOffset(field),
+                arrayOffset, usedExtent);
+    }
+
+    /// returns whether this struct index have been traversed to get to this field
+    bool visited(C2Param::CoreIndex index) const {
+        for (const std::shared_ptr<C2StructDescriptor> &sd : mHistory) {
+            if (sd->coreIndex() == index) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    uint32_t mParamSize;
+    std::shared_ptr<C2ParamReflector> mReflector;
+    std::vector<std::shared_ptr<C2StructDescriptor>> mHistory; // structure types visited
+};
+
+/**
+ * Iterator implementing enumerateFields() that visits each base field.
+ */
+struct C2FieldUtilsFieldsIterator : public C2FieldUtilsFieldsIteratorHelper {
+    /// enumerate base fields of a parameter
+    C2FieldUtilsFieldsIterator(const C2Param &param, std::shared_ptr<C2ParamReflector> reflector)
+        : C2FieldUtilsFieldsIteratorHelper(reflector, param.size()) {
+        descendInto(param.coreIndex());
+    }
+
+    /// enumerate base fields of a field
+    C2FieldUtilsFieldsIterator(std::shared_ptr<C2FieldUtilsFieldsIterator> impl)
+        : C2FieldUtilsFieldsIteratorHelper(impl->mReflector, impl->mParamSize, impl->mHead) {
+        mHistory = impl->mHistory;
+        if (mHead->field.type() & C2FieldDescriptor::STRUCT_FLAG) {
+            C2Param::CoreIndex index = { mHead->field.type() &~C2FieldDescriptor::STRUCT_FLAG };
+            if (!visited(index)) {
+                descendInto(index);
+            }
+        }
+    }
+
+    virtual ~C2FieldUtilsFieldsIterator() override = default;
+
+    /// Increments this iterator by visiting each base field.
+    virtual void increment() override {
+        // don't go past end
+        if (mHead == nullptr || _mFields.empty()) {
+            return;
+        }
+
+        // descend into structures
+        if (mHead->field.type() & C2FieldDescriptor::STRUCT_FLAG) {
+            C2Param::CoreIndex index = { mHead->field.type() &~C2FieldDescriptor::STRUCT_FLAG };
+            // do not recurse into the same structs
+            if (!visited(index) && descendInto(index)) {
+                return;
+            }
+        }
+
+        // ascend after the last field in the current struct
+        while (!mHistory.empty() && _mFields.back() == mHistory.back()->end()) {
+            mHead = mHead->parent;
+            mHistory.pop_back();
+            _mFields.pop_back();
+        }
+
+        // done if history is now empty
+        if (_mFields.empty()) {
+            // we could be traversing a sub-tree so clear head
+            mHead.reset();
+            return;
+        }
+
+        // move to the next field in the current struct
+        C2StructDescriptor::field_iterator next = _mFields.back();
+        mHead->field = OffsetFieldDescriptor(*next, GetParentOffset(mHead->parent));
+        mHead->index = 0; // reset index just in case for correctness
+        mHead->baseFieldOffset = GetParentBaseFieldOffset(mHead->parent) + GetOffset(*next);
+        mHead->arrayOffset = GetOffset(mHead->field);
+        mHead->usedExtent = mHead->field.extent() ? :
+                (std::max(mHead->arrayOffset, mParamSize) - mHead->arrayOffset)
+                        / GetSize(mHead->field);
+        ++_mFields.back();
+    }
+
+private:
+    /// If the current field is a known, valid (untraversed) structure, it modifies this iterator
+    /// to point to the first field of the structure and returns true. Otherwise, it does not
+    /// modify this iterator and returns false.
+    bool descendInto(C2Param::CoreIndex index) {
+        std::unique_ptr<C2StructDescriptor> descUnique = mReflector->describe(index);
+        // descend into known structs (as long as they have at least one field)
+        if (descUnique && descUnique->begin() != descUnique->end()) {
+            std::shared_ptr<C2StructDescriptor> desc(std::move(descUnique));
+            mHistory.emplace_back(desc);
+            C2StructDescriptor::field_iterator first = desc->begin();
+            mHead = makeLeaf(*first, 0 /* index */);
+            _mFields.emplace_back(++first);
+            return true;
+        }
+        return false;
+    }
+
+    /// next field pointers for each depth.
+    /// note: _mFields may be shorted than mHistory, if iterating at a depth
+    std::vector<C2StructDescriptor::field_iterator> _mFields;
+};
+
+/**
+ * Iterable implementing enumerateFields().
+ */
+struct C2FieldUtilsFieldIterable : public C2FieldUtils::List::Impl {
+    /// returns an iterator to the beginning of the list
+    virtual std::shared_ptr<C2FieldUtils::Iterator::Impl> begin() const override {
+        return std::make_shared<C2FieldUtilsFieldsIterator>(*_mParam, _mReflector);
+    };
+
+    C2FieldUtilsFieldIterable(const C2Param &param, std::shared_ptr<C2ParamReflector> reflector)
+        : _mParam(&param), _mReflector(reflector) { }
+
+private:
+    const C2Param *_mParam;
+    std::shared_ptr<C2ParamReflector> _mReflector;
+};
+
+}
+
+C2FieldUtils::List C2FieldUtils::enumerateFields(
+        const C2Param &param, const std::shared_ptr<C2ParamReflector> &reflector) {
+    return C2FieldUtils::List(std::make_shared<C2FieldUtilsFieldIterable>(param, reflector));
+}
+
+/* ------------------------- C2FieldUtils::enumerate siblings ------------------------- */
+
+namespace {
+
+struct C2FieldUtilsCousinsIterator : public C2FieldUtils::Iterator::Impl {
+    C2FieldUtilsCousinsIterator(
+                const std::shared_ptr<C2FieldUtils::Info::Impl> &info, size_t level)
+          // clone info chain as this iterator will change it
+        : C2FieldUtils::Iterator::Impl(C2FieldUtils::Info::Impl::Clone(info)) {
+        if (level == 0) {
+            return;
+        }
+
+        // store parent chain (up to level) for quick access
+        std::shared_ptr<C2FieldUtils::Info::Impl> node = mHead;
+        size_t ix = 0;
+        for (; ix < level && node; ++ix) {
+            node->index = 0;
+            _mPath.emplace_back(node);
+            node = node->parent;
+        }
+        setupPath(ix);
+    }
+
+    virtual ~C2FieldUtilsCousinsIterator() override = default;
+
+    /// Increments this iterator by visiting each index.
+    virtual void increment() override {
+        size_t ix = 0;
+        while (ix < _mPath.size()) {
+            if (++_mPath[ix]->index < _mPath[ix]->usedExtent) {
+                setupPath(ix + 1);
+                return;
+            }
+            _mPath[ix++]->index = 0;
+        }
+        mHead.reset();
+    }
+
+private:
+    /// adjusts field offsets along the path up to the specific level - 1.
+    /// This in-fact has to be done down the path from parent to child as child fields must
+    /// fall within parent fields.
+    void setupPath(size_t level) {
+        C2_CHECK_LE(level, _mPath.size());
+        uint32_t oldArrayOffset = level ? _mPath[level - 1]->arrayOffset : 0 /* unused */;
+        while (level) {
+            --level;
+            C2FieldUtils::Info::Impl &path = *_mPath[level];
+            uint32_t size = GetSize(path.field);
+            uint32_t offset = path.arrayOffset + size * path.index;
+            SetOffset(path.field, offset);
+            if (level) {
+                // reset child's array offset to fall within current index, but hold onto the
+                // original value of the arrayOffset so that we can adjust subsequent children.
+                // This is because the modulo is only defined within the current array.
+                uint32_t childArrayOffset =
+                    offset + (_mPath[level - 1]->arrayOffset - oldArrayOffset) % size;
+                oldArrayOffset = _mPath[level - 1]->arrayOffset;
+                _mPath[level - 1]->arrayOffset = childArrayOffset;
+            }
+        }
+    }
+
+    std::vector<std::shared_ptr<C2FieldUtils::Info::Impl>> _mPath;
+};
+
+/**
+ * Iterable implementing enumerateFields().
+ */
+struct C2FieldUtilsCousinsIterable : public C2FieldUtils::List::Impl {
+    /// returns an iterator to the beginning of the list
+    virtual std::shared_ptr<C2FieldUtils::Iterator::Impl> begin() const override {
+        return std::make_shared<C2FieldUtilsCousinsIterator>(_mHead, _mLevel);
+    };
+
+    C2FieldUtilsCousinsIterable(const C2FieldUtils::Info &field, uint32_t level)
+        : _mHead(C2FieldUtils::_Inspector::GetImpl(field)), _mLevel(level) { }
+
+private:
+    std::shared_ptr<C2FieldUtils::Info::Impl> _mHead;
+    size_t _mLevel;
+};
+
+}
+
+C2FieldUtils::List C2FieldUtils::enumerateCousins(const C2FieldUtils::Info &field, uint32_t level) {
+    return C2FieldUtils::List(std::make_shared<C2FieldUtilsCousinsIterable>(field, level));
+}
+
+/* ------------------------- C2FieldUtils::locateField ------------------------- */
+
+namespace {
+
+/**
+ * Iterator implementing locateField().
+ */
+struct C2FieldUtilsFieldLocator : public C2FieldUtilsFieldsIteratorHelper {
+    C2FieldUtilsFieldLocator(
+            C2Param::CoreIndex index, const _C2FieldId &field, uint32_t paramSize,
+            std::shared_ptr<C2ParamReflector> reflector)
+        : C2FieldUtilsFieldsIteratorHelper(reflector, paramSize),
+          _mField(field) {
+        while (descendInto(index)) {
+            if ((mHead->field.type() & C2FieldDescriptor::STRUCT_FLAG) == 0) {
+                break;
+            }
+            index = C2Param::CoreIndex(mHead->field.type() &~ C2FieldDescriptor::STRUCT_FLAG);
+        }
+    }
+
+    void increment() {
+        mHead = _mTail;
+        _mTail = nullptr;
+    }
+
+private:
+    /// If the current field is a known, valid (untraversed) structure, it modifies this iterator
+    /// to point to the field at the beginning/end of the given field of the structure and returns
+    /// true. Otherwise, including if no such field exists in the structure, it does not modify this
+    /// iterator and returns false.
+    bool descendInto(C2Param::CoreIndex index) {
+        // check that the boundaries of the field to be located are still within the same parent
+        // field
+        if (mHead != _mTail) {
+            return false;
+        }
+
+        std::unique_ptr<C2StructDescriptor> descUnique = mReflector->describe(index);
+        // descend into known structs (as long as they have at least one field)
+        if (descUnique && descUnique->begin() != descUnique->end()) {
+            std::shared_ptr<C2StructDescriptor> desc(std::move(descUnique));
+            mHistory.emplace_back(desc);
+
+            uint32_t parentOffset = GetParentOffset(mHead);
+
+            // locate field using a dummy field descriptor
+            C2FieldDescriptor dummy = {
+                C2FieldDescriptor::BLOB, 1 /* extent */, "name",
+                GetOffset(_mField) - parentOffset, GetSize(_mField)
+            };
+
+            // locate first field where offset is greater than dummy offset (which is one past)
+            auto it = std::upper_bound(
+                    desc->cbegin(), desc->cend(), dummy,
+                    [](const C2FieldDescriptor &a, const C2FieldDescriptor &b) -> bool {
+                return _C2ParamInspector::GetOffset(a) < _C2ParamInspector::GetOffset(b);
+            });
+            if (it == desc->begin()) {
+                // field is prior to first field
+                return false;
+            }
+            --it;
+            const C2FieldDescriptor &field = *it;
+
+            // check that dummy end-offset is within this field
+            uint32_t structSize = std::max(mParamSize, parentOffset) - parentOffset;
+            if (GetEndOffset(dummy) > GetEndOffset(field, structSize)) {
+                return false;
+            }
+
+            uint32_t startIndex = (GetOffset(dummy) - GetOffset(field)) / GetSize(field);
+            uint32_t endIndex =
+                (GetEndOffset(dummy) - GetOffset(field) + GetSize(field) - 1) / GetSize(field);
+            if (endIndex > startIndex) {
+                // Field size could be zero, in which case end index is still on start index.
+                // However, for all other cases, endIndex was rounded up to the next index, so
+                // decrement it.
+                --endIndex;
+            }
+            std::shared_ptr<C2FieldUtils::Info::Impl> startLeaf =
+                makeLeaf(field, startIndex);
+            if (endIndex == startIndex) {
+                _mTail = startLeaf;
+                mHead = startLeaf;
+            } else {
+                _mTail = makeLeaf(field, endIndex);
+                mHead = startLeaf;
+            }
+            return true;
+        }
+        return false;
+    }
+
+    _C2FieldId _mField;
+    std::shared_ptr<C2FieldUtils::Info::Impl> _mTail;
+};
+
+/**
+ * Iterable implementing locateField().
+ */
+struct C2FieldUtilsFieldLocation : public C2FieldUtils::List::Impl {
+    /// returns an iterator to the beginning of the list
+    virtual std::shared_ptr<C2FieldUtils::Iterator::Impl> begin() const override {
+        return std::make_shared<C2FieldUtilsFieldLocator>(
+                _mIndex, _mField, _mParamSize, _mReflector);
+    };
+
+    C2FieldUtilsFieldLocation(
+            const C2ParamField &pf, std::shared_ptr<C2ParamReflector> reflector)
+        : _mIndex(C2Param::CoreIndex(_C2ParamInspector::GetIndex(pf))),
+          _mField(_C2ParamInspector::GetField(pf)),
+          _mParamSize(0),
+          _mReflector(reflector) { }
+
+
+    C2FieldUtilsFieldLocation(
+            const C2Param &param, const _C2FieldId &field,
+            std::shared_ptr<C2ParamReflector> reflector)
+        : _mIndex(param.coreIndex()),
+          _mField(field),
+          _mParamSize(param.size()),
+          _mReflector(reflector) { }
+
+private:
+    C2Param::CoreIndex _mIndex;
+    _C2FieldId _mField;
+    uint32_t _mParamSize;
+    std::shared_ptr<C2ParamReflector> _mReflector;
+};
+
+}
+
+std::vector<C2FieldUtils::Info> C2FieldUtils::locateField(
+        const C2ParamField &pf, const std::shared_ptr<C2ParamReflector> &reflector) {
+    C2FieldUtils::List location = { std::make_shared<C2FieldUtilsFieldLocation>(pf, reflector) };
+    return std::vector<Info>(location.begin(), location.end());
+}
+
+std::vector<C2FieldUtils::Info> C2FieldUtils::locateField(
+        const C2Param &param, const _C2FieldId &field,
+        const std::shared_ptr<C2ParamReflector> &reflector) {
+    C2FieldUtils::List location = {
+        std::make_shared<C2FieldUtilsFieldLocation>(param, field, reflector)
+    };
+    return std::vector<Info>(location.begin(), location.end());
+}
+