Use libcppbor for much much nicer db encoding

6 files changed, 2567 insertions, 0 deletions

diff --git a/lib/libcppbor/CMakeLists.txt b/lib/libcppbor/CMakeLists.txt
new file mode 100644
index 00000000..f68a820c
--- /dev/null
+++ b/lib/libcppbor/CMakeLists.txt
@@ -0,0 +1,7 @@
+# Copyright 2023 jacqueline <me@jacqueline.id.au>
+#
+# SPDX-License-Identifier: GPL-3.0-only
+idf_component_register(
+  SRCS cppbor.cpp cppbor_parse.cpp
+  INCLUDE_DIRS "include/cppbor"
+)
diff --git a/lib/libcppbor/LICENSE b/lib/libcppbor/LICENSE
new file mode 100644
index 00000000..d6456956
--- /dev/null
+++ b/lib/libcppbor/LICENSE
@@ -0,0 +1,202 @@
+
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diff --git a/lib/libcppbor/cppbor.cpp b/lib/libcppbor/cppbor.cpp
new file mode 100644
index 00000000..c66ca752
--- /dev/null
+++ b/lib/libcppbor/cppbor.cpp
@@ -0,0 +1,599 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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.
+ */
+
+#include "cppbor.h"
+
+#include <inttypes.h>
+#include <cstdint>
+
+#include "cppbor_parse.h"
+
+using std::string;
+using std::vector;
+
+#define CHECK(x) (void)(x)
+
+namespace cppbor {
+
+namespace {
+
+template <typename T, typename Iterator, typename = std::enable_if<std::is_unsigned<T>::value>>
+Iterator writeBigEndian(T value, Iterator pos) {
+    for (unsigned i = 0; i < sizeof(value); ++i) {
+        *pos++ = static_cast<uint8_t>(value >> (8 * (sizeof(value) - 1)));
+        value = static_cast<T>(value << 8);
+    }
+    return pos;
+}
+
+template <typename T, typename = std::enable_if<std::is_unsigned<T>::value>>
+void writeBigEndian(T value, std::function<void(uint8_t)>& cb) {
+    for (unsigned i = 0; i < sizeof(value); ++i) {
+        cb(static_cast<uint8_t>(value >> (8 * (sizeof(value) - 1))));
+        value = static_cast<T>(value << 8);
+    }
+}
+
+bool cborAreAllElementsNonCompound(const Item* compoundItem) {
+    if (compoundItem->type() == ARRAY) {
+        const Array* array = compoundItem->asArray();
+        for (size_t n = 0; n < array->size(); n++) {
+            const Item* entry = (*array)[n].get();
+            switch (entry->type()) {
+                case ARRAY:
+                case MAP:
+                    return false;
+                default:
+                    break;
+            }
+        }
+    } else {
+        const Map* map = compoundItem->asMap();
+        for (auto& [keyEntry, valueEntry] : *map) {
+            switch (keyEntry->type()) {
+                case ARRAY:
+                case MAP:
+                    return false;
+                default:
+                    break;
+            }
+            switch (valueEntry->type()) {
+                case ARRAY:
+                case MAP:
+                    return false;
+                default:
+                    break;
+            }
+        }
+    }
+    return true;
+}
+
+bool prettyPrintInternal(const Item* item, string& out, size_t indent, size_t maxBStrSize,
+                         const vector<string>& mapKeysToNotPrint) {
+    if (!item) {
+        out.append("<NULL>");
+        return false;
+    }
+
+    char buf[80];
+
+    string indentString(indent, ' ');
+
+    size_t tagCount = item->semanticTagCount();
+    while (tagCount > 0) {
+        --tagCount;
+        snprintf(buf, sizeof(buf), "tag %" PRIu64 " ", item->semanticTag(tagCount));
+        out.append(buf);
+    }
+
+    switch (item->type()) {
+        case SEMANTIC:
+            // Handled above.
+            break;
+
+        case UINT:
+            snprintf(buf, sizeof(buf), "%" PRIu64, item->asUint()->unsignedValue());
+            out.append(buf);
+            break;
+
+        case NINT:
+            snprintf(buf, sizeof(buf), "%" PRId64, item->asNint()->value());
+            out.append(buf);
+            break;
+
+        case BSTR: {
+            const uint8_t* valueData;
+            size_t valueSize;
+            const Bstr* bstr = item->asBstr();
+            if (bstr != nullptr) {
+                const vector<uint8_t>& value = bstr->value();
+                valueData = value.data();
+                valueSize = value.size();
+            } else {
+                const ViewBstr* viewBstr = item->asViewBstr();
+                assert(viewBstr != nullptr);
+
+                valueData = viewBstr->view().data();
+                valueSize = viewBstr->view().size();
+            }
+
+            if (valueSize > maxBStrSize) {
+                snprintf(buf, sizeof(buf), "<bstr size=%zd>", valueSize);
+                out.append(buf);
+            } else {
+                out.append("{");
+                for (size_t n = 0; n < valueSize; n++) {
+                    if (n > 0) {
+                        out.append(", ");
+                    }
+                    snprintf(buf, sizeof(buf), "0x%02x", valueData[n]);
+                    out.append(buf);
+                }
+                out.append("}");
+            }
+        } break;
+
+        case TSTR:
+            out.append("'");
+            {
+                // TODO: escape "'" characters
+                if (item->asTstr() != nullptr) {
+                    out.append(item->asTstr()->value().c_str());
+                } else {
+                    const ViewTstr* viewTstr = item->asViewTstr();
+                    assert(viewTstr != nullptr);
+                    out.append(viewTstr->view());
+                }
+            }
+            out.append("'");
+            break;
+
+        case ARRAY: {
+            const Array* array = item->asArray();
+            if (array->size() == 0) {
+                out.append("[]");
+            } else if (cborAreAllElementsNonCompound(array)) {
+                out.append("[");
+                for (size_t n = 0; n < array->size(); n++) {
+                    if (!prettyPrintInternal((*array)[n].get(), out, indent + 2, maxBStrSize,
+                                             mapKeysToNotPrint)) {
+                        return false;
+                    }
+                    out.append(", ");
+                }
+                out.append("]");
+            } else {
+                out.append("[\n" + indentString);
+                for (size_t n = 0; n < array->size(); n++) {
+                    out.append("  ");
+                    if (!prettyPrintInternal((*array)[n].get(), out, indent + 2, maxBStrSize,
+                                             mapKeysToNotPrint)) {
+                        return false;
+                    }
+                    out.append(",\n" + indentString);
+                }
+                out.append("]");
+            }
+        } break;
+
+        case MAP: {
+            const Map* map = item->asMap();
+
+            if (map->size() == 0) {
+                out.append("{}");
+            } else {
+                out.append("{\n" + indentString);
+                for (auto& [map_key, map_value] : *map) {
+                    out.append("  ");
+
+                    if (!prettyPrintInternal(map_key.get(), out, indent + 2, maxBStrSize,
+                                             mapKeysToNotPrint)) {
+                        return false;
+                    }
+                    out.append(" : ");
+                    if (map_key->type() == TSTR &&
+                        std::find(mapKeysToNotPrint.begin(), mapKeysToNotPrint.end(),
+                                  map_key->asTstr()->value()) != mapKeysToNotPrint.end()) {
+                        out.append("<not printed>");
+                    } else {
+                        if (!prettyPrintInternal(map_value.get(), out, indent + 2, maxBStrSize,
+                                                 mapKeysToNotPrint)) {
+                            return false;
+                        }
+                    }
+                    out.append(",\n" + indentString);
+                }
+                out.append("}");
+            }
+        } break;
+
+        case SIMPLE:
+            const Bool* asBool = item->asSimple()->asBool();
+            const Null* asNull = item->asSimple()->asNull();
+            if (asBool != nullptr) {
+                out.append(asBool->value() ? "true" : "false");
+            } else if (asNull != nullptr) {
+                out.append("null");
+            } else {
+                return false;
+            }
+            break;
+    }
+
+    return true;
+}
+
+}  // namespace
+
+size_t headerSize(uint64_t addlInfo) {
+    if (addlInfo < ONE_BYTE_LENGTH) return 1;
+    if (addlInfo <= std::numeric_limits<uint8_t>::max()) return 2;
+    if (addlInfo <= std::numeric_limits<uint16_t>::max()) return 3;
+    if (addlInfo <= std::numeric_limits<uint32_t>::max()) return 5;
+    return 9;
+}
+
+uint8_t* encodeHeader(MajorType type, uint64_t addlInfo, uint8_t* pos, const uint8_t* end) {
+    size_t sz = headerSize(addlInfo);
+    if (end - pos < static_cast<ssize_t>(sz)) return nullptr;
+    switch (sz) {
+        case 1:
+            *pos++ = type | static_cast<uint8_t>(addlInfo);
+            return pos;
+        case 2:
+            *pos++ = type | ONE_BYTE_LENGTH;
+            *pos++ = static_cast<uint8_t>(addlInfo);
+            return pos;
+        case 3:
+            *pos++ = type | TWO_BYTE_LENGTH;
+            return writeBigEndian(static_cast<uint16_t>(addlInfo), pos);
+        case 5:
+            *pos++ = type | FOUR_BYTE_LENGTH;
+            return writeBigEndian(static_cast<uint32_t>(addlInfo), pos);
+        case 9:
+            *pos++ = type | EIGHT_BYTE_LENGTH;
+            return writeBigEndian(addlInfo, pos);
+        default:
+            CHECK(false);  // Impossible to get here.
+            return nullptr;
+    }
+}
+
+void encodeHeader(MajorType type, uint64_t addlInfo, EncodeCallback encodeCallback) {
+    size_t sz = headerSize(addlInfo);
+    switch (sz) {
+        case 1:
+            encodeCallback(type | static_cast<uint8_t>(addlInfo));
+            break;
+        case 2:
+            encodeCallback(type | ONE_BYTE_LENGTH);
+            encodeCallback(static_cast<uint8_t>(addlInfo));
+            break;
+        case 3:
+            encodeCallback(type | TWO_BYTE_LENGTH);
+            writeBigEndian(static_cast<uint16_t>(addlInfo), encodeCallback);
+            break;
+        case 5:
+            encodeCallback(type | FOUR_BYTE_LENGTH);
+            writeBigEndian(static_cast<uint32_t>(addlInfo), encodeCallback);
+            break;
+        case 9:
+            encodeCallback(type | EIGHT_BYTE_LENGTH);
+            writeBigEndian(addlInfo, encodeCallback);
+            break;
+        default:
+            CHECK(false);  // Impossible to get here.
+    }
+}
+
+bool Item::operator==(const Item& other) const& {
+    if (type() != other.type()) return false;
+    switch (type()) {
+        case UINT:
+            return *asUint() == *(other.asUint());
+        case NINT:
+            return *asNint() == *(other.asNint());
+        case BSTR:
+            if (asBstr() != nullptr && other.asBstr() != nullptr) {
+                return *asBstr() == *(other.asBstr());
+            }
+            if (asViewBstr() != nullptr && other.asViewBstr() != nullptr) {
+                return *asViewBstr() == *(other.asViewBstr());
+            }
+            // Interesting corner case: comparing a Bstr and ViewBstr with
+            // identical contents. The function currently returns false for
+            // this case.
+            // TODO: if it should return true, this needs a deep comparison
+            return false;
+        case TSTR:
+            if (asTstr() != nullptr && other.asTstr() != nullptr) {
+                return *asTstr() == *(other.asTstr());
+            }
+            if (asViewTstr() != nullptr && other.asViewTstr() != nullptr) {
+                return *asViewTstr() == *(other.asViewTstr());
+            }
+            // Same corner case as Bstr
+            return false;
+        case ARRAY:
+            return *asArray() == *(other.asArray());
+        case MAP:
+            return *asMap() == *(other.asMap());
+        case SIMPLE:
+            return *asSimple() == *(other.asSimple());
+        case SEMANTIC:
+            return *asSemanticTag() == *(other.asSemanticTag());
+        default:
+            CHECK(false);  // Impossible to get here.
+            return false;
+    }
+}
+
+Nint::Nint(int64_t v) : mValue(v) {
+    CHECK(v < 0);
+}
+
+bool Simple::operator==(const Simple& other) const& {
+    if (simpleType() != other.simpleType()) return false;
+
+    switch (simpleType()) {
+        case BOOLEAN:
+            return *asBool() == *(other.asBool());
+        case NULL_T:
+            return true;
+        default:
+            CHECK(false);  // Impossible to get here.
+            return false;
+    }
+}
+
+uint8_t* Bstr::encode(uint8_t* pos, const uint8_t* end) const {
+    pos = encodeHeader(mValue.size(), pos, end);
+    if (!pos || end - pos < static_cast<ptrdiff_t>(mValue.size())) return nullptr;
+    return std::copy(mValue.begin(), mValue.end(), pos);
+}
+
+void Bstr::encodeValue(EncodeCallback encodeCallback) const {
+    for (auto c : mValue) {
+        encodeCallback(c);
+    }
+}
+
+uint8_t* ViewBstr::encode(uint8_t* pos, const uint8_t* end) const {
+    pos = encodeHeader(mView.size(), pos, end);
+    if (!pos || end - pos < static_cast<ptrdiff_t>(mView.size())) return nullptr;
+    return std::copy(mView.begin(), mView.end(), pos);
+}
+
+void ViewBstr::encodeValue(EncodeCallback encodeCallback) const {
+    for (auto c : mView) {
+        encodeCallback(static_cast<uint8_t>(c));
+    }
+}
+
+uint8_t* Tstr::encode(uint8_t* pos, const uint8_t* end) const {
+    pos = encodeHeader(mValue.size(), pos, end);
+    if (!pos || end - pos < static_cast<ptrdiff_t>(mValue.size())) return nullptr;
+    return std::copy(mValue.begin(), mValue.end(), pos);
+}
+
+void Tstr::encodeValue(EncodeCallback encodeCallback) const {
+    for (auto c : mValue) {
+        encodeCallback(static_cast<uint8_t>(c));
+    }
+}
+
+uint8_t* ViewTstr::encode(uint8_t* pos, const uint8_t* end) const {
+    pos = encodeHeader(mView.size(), pos, end);
+    if (!pos || end - pos < static_cast<ptrdiff_t>(mView.size())) return nullptr;
+    return std::copy(mView.begin(), mView.end(), pos);
+}
+
+void ViewTstr::encodeValue(EncodeCallback encodeCallback) const {
+    for (auto c : mView) {
+        encodeCallback(static_cast<uint8_t>(c));
+    }
+}
+
+bool Array::operator==(const Array& other) const& {
+    return size() == other.size()
+           // Can't use vector::operator== because the contents are pointers.  std::equal lets us
+           // provide a predicate that does the dereferencing.
+           && std::equal(mEntries.begin(), mEntries.end(), other.mEntries.begin(),
+                         [](auto& a, auto& b) -> bool { return *a == *b; });
+}
+
+uint8_t* Array::encode(uint8_t* pos, const uint8_t* end) const {
+    pos = encodeHeader(size(), pos, end);
+    if (!pos) return nullptr;
+    for (auto& entry : mEntries) {
+        pos = entry->encode(pos, end);
+        if (!pos) return nullptr;
+    }
+    return pos;
+}
+
+void Array::encode(EncodeCallback encodeCallback) const {
+    encodeHeader(size(), encodeCallback);
+    for (auto& entry : mEntries) {
+        entry->encode(encodeCallback);
+    }
+}
+
+std::unique_ptr<Item> Array::clone() const {
+    auto res = std::make_unique<Array>();
+    for (size_t i = 0; i < mEntries.size(); i++) {
+        res->add(mEntries[i]->clone());
+    }
+    return res;
+}
+
+bool Map::operator==(const Map& other) const& {
+    return size() == other.size()
+           // Can't use vector::operator== because the contents are pairs of pointers.  std::equal
+           // lets us provide a predicate that does the dereferencing.
+           && std::equal(begin(), end(), other.begin(), [](auto& a, auto& b) {
+                  return *a.first == *b.first && *a.second == *b.second;
+              });
+}
+
+uint8_t* Map::encode(uint8_t* pos, const uint8_t* end) const {
+    pos = encodeHeader(size(), pos, end);
+    if (!pos) return nullptr;
+    for (auto& entry : mEntries) {
+        pos = entry.first->encode(pos, end);
+        if (!pos) return nullptr;
+        pos = entry.second->encode(pos, end);
+        if (!pos) return nullptr;
+    }
+    return pos;
+}
+
+void Map::encode(EncodeCallback encodeCallback) const {
+    encodeHeader(size(), encodeCallback);
+    for (auto& entry : mEntries) {
+        entry.first->encode(encodeCallback);
+        entry.second->encode(encodeCallback);
+    }
+}
+
+bool Map::keyLess(const Item* a, const Item* b) {
+    // CBOR map canonicalization rules are:
+
+    // 1. If two keys have different lengths, the shorter one sorts earlier.
+    if (a->encodedSize() < b->encodedSize()) return true;
+    if (a->encodedSize() > b->encodedSize()) return false;
+
+    // 2. If two keys have the same length, the one with the lower value in (byte-wise) lexical
+    // order sorts earlier.  This requires encoding both items.
+    auto encodedA = a->encode();
+    auto encodedB = b->encode();
+
+    return std::lexicographical_compare(encodedA.begin(), encodedA.end(),  //
+                                        encodedB.begin(), encodedB.end());
+}
+
+void recursivelyCanonicalize(std::unique_ptr<Item>& item) {
+    switch (item->type()) {
+        case UINT:
+        case NINT:
+        case BSTR:
+        case TSTR:
+        case SIMPLE:
+            return;
+
+        case ARRAY:
+            std::for_each(item->asArray()->begin(), item->asArray()->end(),
+                          recursivelyCanonicalize);
+            return;
+
+        case MAP:
+            item->asMap()->canonicalize(true /* recurse */);
+            return;
+
+        case SEMANTIC:
+            // This can't happen.  SemanticTags delegate their type() method to the contained Item's
+            // type.
+            assert(false);
+            return;
+    }
+}
+
+Map& Map::canonicalize(bool recurse) & {
+    if (recurse) {
+        for (auto& entry : mEntries) {
+            recursivelyCanonicalize(entry.first);
+            recursivelyCanonicalize(entry.second);
+        }
+    }
+
+    if (size() < 2 || mCanonicalized) {
+        // Trivially or already canonical; do nothing.
+        return *this;
+    }
+
+    std::sort(begin(), end(),
+              [](auto& a, auto& b) { return keyLess(a.first.get(), b.first.get()); });
+    mCanonicalized = true;
+    return *this;
+}
+
+std::unique_ptr<Item> Map::clone() const {
+    auto res = std::make_unique<Map>();
+    for (auto& [key, value] : *this) {
+        res->add(key->clone(), value->clone());
+    }
+    res->mCanonicalized = mCanonicalized;
+    return res;
+}
+
+std::unique_ptr<Item> SemanticTag::clone() const {
+    return std::make_unique<SemanticTag>(mValue, mTaggedItem->clone());
+}
+
+uint8_t* SemanticTag::encode(uint8_t* pos, const uint8_t* end) const {
+    // Can't use the encodeHeader() method that calls type() to get the major type, since that will
+    // return the tagged Item's type.
+    pos = ::cppbor::encodeHeader(kMajorType, mValue, pos, end);
+    if (!pos) return nullptr;
+    return mTaggedItem->encode(pos, end);
+}
+
+void SemanticTag::encode(EncodeCallback encodeCallback) const {
+    // Can't use the encodeHeader() method that calls type() to get the major type, since that will
+    // return the tagged Item's type.
+    ::cppbor::encodeHeader(kMajorType, mValue, encodeCallback);
+    mTaggedItem->encode(encodeCallback);
+}
+
+size_t SemanticTag::semanticTagCount() const {
+    size_t levelCount = 1;  // Count this level.
+    const SemanticTag* cur = this;
+    while (cur->mTaggedItem && (cur = cur->mTaggedItem->asSemanticTag()) != nullptr) ++levelCount;
+    return levelCount;
+}
+
+uint64_t SemanticTag::semanticTag(size_t nesting) const {
+    // Getting the value of a specific nested tag is a bit tricky, because we start with the outer
+    // tag and don't know how many are inside.  We count the number of nesting levels to find out
+    // how many there are in total, then to get the one we want we have to walk down levelCount -
+    // nesting steps.
+    size_t levelCount = semanticTagCount();
+    if (nesting >= levelCount) return 0;
+
+    levelCount -= nesting;
+    const SemanticTag* cur = this;
+    while (--levelCount > 0) cur = cur->mTaggedItem->asSemanticTag();
+
+    return cur->mValue;
+}
+
+string prettyPrint(const Item* item, size_t maxBStrSize, const vector<string>& mapKeysToNotPrint) {
+    string out;
+    prettyPrintInternal(item, out, 0, maxBStrSize, mapKeysToNotPrint);
+    return out;
+}
+string prettyPrint(const vector<uint8_t>& encodedCbor, size_t maxBStrSize,
+                   const vector<string>& mapKeysToNotPrint) {
+    auto [item, _, message] = parse(encodedCbor);
+    if (item == nullptr) {
+        return "";
+    }
+
+    return prettyPrint(item.get(), maxBStrSize, mapKeysToNotPrint);
+}
+
+}  // namespace cppbor
diff --git a/lib/libcppbor/cppbor_parse.cpp b/lib/libcppbor/cppbor_parse.cpp
new file mode 100644
index 00000000..6d38b622
--- /dev/null
+++ b/lib/libcppbor/cppbor_parse.cpp
@@ -0,0 +1,423 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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.
+ */
+
+#include "cppbor_parse.h"
+
+#include <memory>
+#include <sstream>
+#include <stack>
+#include <type_traits>
+#include "cppbor.h"
+
+#define CHECK(x) (void)(x)
+
+namespace cppbor {
+
+namespace {
+
+std::string insufficientLengthString(size_t bytesNeeded, size_t bytesAvail,
+                                     const std::string& type) {
+    char buf[1024];
+    snprintf(buf, sizeof(buf), "Need %zu byte(s) for %s, have %zu.", bytesNeeded, type.c_str(),
+             bytesAvail);
+    return std::string(buf);
+}
+
+template <typename T, typename = std::enable_if_t<std::is_unsigned_v<T>>>
+std::tuple<bool, uint64_t, const uint8_t*> parseLength(const uint8_t* pos, const uint8_t* end,
+                                                       ParseClient* parseClient) {
+    if (pos + sizeof(T) > end) {
+        parseClient->error(pos - 1, insufficientLengthString(sizeof(T), end - pos, "length field"));
+        return {false, 0, pos};
+    }
+
+    const uint8_t* intEnd = pos + sizeof(T);
+    T result = 0;
+    do {
+        result = static_cast<T>((result << 8) | *pos++);
+    } while (pos < intEnd);
+    return {true, result, pos};
+}
+
+std::tuple<const uint8_t*, ParseClient*> parseRecursively(const uint8_t* begin, const uint8_t* end,
+                                                          bool emitViews, ParseClient* parseClient);
+
+std::tuple<const uint8_t*, ParseClient*> handleUint(uint64_t value, const uint8_t* hdrBegin,
+                                                    const uint8_t* hdrEnd,
+                                                    ParseClient* parseClient) {
+    std::unique_ptr<Item> item = std::make_unique<Uint>(value);
+    return {hdrEnd,
+            parseClient->item(item, hdrBegin, hdrEnd /* valueBegin */, hdrEnd /* itemEnd */)};
+}
+
+std::tuple<const uint8_t*, ParseClient*> handleNint(uint64_t value, const uint8_t* hdrBegin,
+                                                    const uint8_t* hdrEnd,
+                                                    ParseClient* parseClient) {
+    if (value > std::numeric_limits<int64_t>::max()) {
+        parseClient->error(hdrBegin, "NINT values that don't fit in int64_t are not supported.");
+        return {hdrBegin, nullptr /* end parsing */};
+    }
+    std::unique_ptr<Item> item = std::make_unique<Nint>(-1 - static_cast<int64_t>(value));
+    return {hdrEnd,
+            parseClient->item(item, hdrBegin, hdrEnd /* valueBegin */, hdrEnd /* itemEnd */)};
+}
+
+std::tuple<const uint8_t*, ParseClient*> handleBool(uint64_t value, const uint8_t* hdrBegin,
+                                                    const uint8_t* hdrEnd,
+                                                    ParseClient* parseClient) {
+    std::unique_ptr<Item> item = std::make_unique<Bool>(value == TRUE);
+    return {hdrEnd,
+            parseClient->item(item, hdrBegin, hdrEnd /* valueBegin */, hdrEnd /* itemEnd */)};
+}
+
+std::tuple<const uint8_t*, ParseClient*> handleNull(const uint8_t* hdrBegin, const uint8_t* hdrEnd,
+                                                    ParseClient* parseClient) {
+    std::unique_ptr<Item> item = std::make_unique<Null>();
+    return {hdrEnd,
+            parseClient->item(item, hdrBegin, hdrEnd /* valueBegin */, hdrEnd /* itemEnd */)};
+}
+
+template <typename T>
+std::tuple<const uint8_t*, ParseClient*> handleString(uint64_t length, const uint8_t* hdrBegin,
+                                                      const uint8_t* valueBegin, const uint8_t* end,
+                                                      const std::string& errLabel,
+                                                      ParseClient* parseClient) {
+    ssize_t signed_length = static_cast<ssize_t>(length);
+    if (end - valueBegin < signed_length || signed_length < 0) {
+        parseClient->error(hdrBegin, insufficientLengthString(length, end - valueBegin, errLabel));
+        return {hdrBegin, nullptr /* end parsing */};
+    }
+
+    std::unique_ptr<Item> item = std::make_unique<T>(valueBegin, valueBegin + length);
+    return {valueBegin + length,
+            parseClient->item(item, hdrBegin, valueBegin, valueBegin + length)};
+}
+
+class IncompleteItem {
+  public:
+    static IncompleteItem* cast(Item* item);
+
+    virtual ~IncompleteItem() {}
+    virtual void add(std::unique_ptr<Item> item) = 0;
+    virtual std::unique_ptr<Item> finalize() && = 0;
+};
+
+class IncompleteArray : public Array, public IncompleteItem {
+  public:
+    explicit IncompleteArray(size_t size) : mSize(size) {}
+
+    // We return the "complete" size, rather than the actual size.
+    size_t size() const override { return mSize; }
+
+    void add(std::unique_ptr<Item> item) override {
+        mEntries.push_back(std::move(item));
+    }
+
+    virtual std::unique_ptr<Item> finalize() && override {
+        // Use Array explicitly so the compiler picks the correct ctor overload
+        Array* thisArray = this;
+        return std::make_unique<Array>(std::move(*thisArray));
+    }
+
+  private:
+    size_t mSize;
+};
+
+class IncompleteMap : public Map, public IncompleteItem {
+  public:
+    explicit IncompleteMap(size_t size) : mSize(size) {}
+
+    // We return the "complete" size, rather than the actual size.
+    size_t size() const override { return mSize; }
+
+    void add(std::unique_ptr<Item> item) override {
+        if (mKeyHeldForAdding) {
+            mEntries.push_back({std::move(mKeyHeldForAdding), std::move(item)});
+        } else {
+            mKeyHeldForAdding = std::move(item);
+        }
+    }
+
+    virtual std::unique_ptr<Item> finalize() && override {
+        return std::make_unique<Map>(std::move(*this));
+    }
+
+  private:
+    std::unique_ptr<Item> mKeyHeldForAdding;
+    size_t mSize;
+};
+
+class IncompleteSemanticTag : public SemanticTag, public IncompleteItem {
+  public:
+    explicit IncompleteSemanticTag(uint64_t value) : SemanticTag(value) {}
+
+    // We return the "complete" size, rather than the actual size.
+    size_t size() const override { return 1; }
+
+    void add(std::unique_ptr<Item> item) override { mTaggedItem = std::move(item); }
+
+    virtual std::unique_ptr<Item> finalize() && override {
+        return std::make_unique<SemanticTag>(std::move(*this));
+    }
+};
+
+IncompleteItem* IncompleteItem::cast(Item* item) {
+    CHECK(item->isCompound());
+    // Semantic tag must be check first, because SemanticTag::type returns the wrapped item's type.
+    if (item->asSemanticTag()) {
+#if __has_feature(cxx_rtti)
+        CHECK(dynamic_cast<IncompleteSemanticTag*>(item));
+#endif
+        return static_cast<IncompleteSemanticTag*>(item);
+    } else if (item->type() == ARRAY) {
+#if __has_feature(cxx_rtti)
+        CHECK(dynamic_cast<IncompleteArray*>(item));
+#endif
+        return static_cast<IncompleteArray*>(item);
+    } else if (item->type() == MAP) {
+#if __has_feature(cxx_rtti)
+        CHECK(dynamic_cast<IncompleteMap*>(item));
+#endif
+        return static_cast<IncompleteMap*>(item);
+    } else {
+        CHECK(false);  // Impossible to get here.
+    }
+    return nullptr;
+}
+
+std::tuple<const uint8_t*, ParseClient*> handleEntries(size_t entryCount, const uint8_t* hdrBegin,
+                                                       const uint8_t* pos, const uint8_t* end,
+                                                       const std::string& typeName,
+                                                       bool emitViews,
+                                                       ParseClient* parseClient) {
+    while (entryCount > 0) {
+        --entryCount;
+        if (pos == end) {
+            parseClient->error(hdrBegin, "Not enough entries for " + typeName + ".");
+            return {hdrBegin, nullptr /* end parsing */};
+        }
+        std::tie(pos, parseClient) = parseRecursively(pos, end, emitViews, parseClient);
+        if (!parseClient) return {hdrBegin, nullptr};
+    }
+    return {pos, parseClient};
+}
+
+std::tuple<const uint8_t*, ParseClient*> handleCompound(
+        std::unique_ptr<Item> item, uint64_t entryCount, const uint8_t* hdrBegin,
+        const uint8_t* valueBegin, const uint8_t* end, const std::string& typeName,
+        bool emitViews, ParseClient* parseClient) {
+    parseClient =
+            parseClient->item(item, hdrBegin, valueBegin, valueBegin /* don't know the end yet */);
+    if (!parseClient) return {hdrBegin, nullptr};
+
+    const uint8_t* pos;
+    std::tie(pos, parseClient) =
+            handleEntries(entryCount, hdrBegin, valueBegin, end, typeName, emitViews, parseClient);
+    if (!parseClient) return {hdrBegin, nullptr};
+
+    return {pos, parseClient->itemEnd(item, hdrBegin, valueBegin, pos)};
+}
+
+std::tuple<const uint8_t*, ParseClient*> parseRecursively(const uint8_t* begin, const uint8_t* end,
+                                                          bool emitViews, ParseClient* parseClient) {
+    if (begin == end) {
+        parseClient->error(
+                begin,
+                "Input buffer is empty. Begin and end cannot point to the same location.");
+        return {begin, nullptr};
+    }
+
+    const uint8_t* pos = begin;
+
+    MajorType type = static_cast<MajorType>(*pos & 0xE0);
+    uint8_t tagInt = *pos & 0x1F;
+    ++pos;
+
+    bool success = true;
+    uint64_t addlData;
+    if (tagInt < ONE_BYTE_LENGTH) {
+        addlData = tagInt;
+    } else if (tagInt > EIGHT_BYTE_LENGTH) {
+        parseClient->error(
+                begin,
+                "Reserved additional information value or unsupported indefinite length item.");
+        return {begin, nullptr};
+    } else {
+        switch (tagInt) {
+            case ONE_BYTE_LENGTH:
+                std::tie(success, addlData, pos) = parseLength<uint8_t>(pos, end, parseClient);
+                break;
+
+            case TWO_BYTE_LENGTH:
+                std::tie(success, addlData, pos) = parseLength<uint16_t>(pos, end, parseClient);
+                break;
+
+            case FOUR_BYTE_LENGTH:
+                std::tie(success, addlData, pos) = parseLength<uint32_t>(pos, end, parseClient);
+                break;
+
+            case EIGHT_BYTE_LENGTH:
+                std::tie(success, addlData, pos) = parseLength<uint64_t>(pos, end, parseClient);
+                break;
+
+            default:
+                CHECK(false);  //  It's impossible to get here
+                break;
+        }
+    }
+
+    if (!success) return {begin, nullptr};
+
+    switch (type) {
+        case UINT:
+            return handleUint(addlData, begin, pos, parseClient);
+
+        case NINT:
+            return handleNint(addlData, begin, pos, parseClient);
+
+        case BSTR:
+            if (emitViews) {
+                return handleString<ViewBstr>(addlData, begin, pos, end, "byte string", parseClient);
+            } else {
+                return handleString<Bstr>(addlData, begin, pos, end, "byte string", parseClient);
+            }
+
+        case TSTR:
+            if (emitViews) {
+                return handleString<ViewTstr>(addlData, begin, pos, end, "text string", parseClient);
+            } else {
+                return handleString<Tstr>(addlData, begin, pos, end, "text string", parseClient);
+            }
+
+        case ARRAY:
+            return handleCompound(std::make_unique<IncompleteArray>(addlData), addlData, begin, pos,
+                                  end, "array", emitViews, parseClient);
+
+        case MAP:
+            return handleCompound(std::make_unique<IncompleteMap>(addlData), addlData * 2, begin,
+                                  pos, end, "map", emitViews, parseClient);
+
+        case SEMANTIC:
+            return handleCompound(std::make_unique<IncompleteSemanticTag>(addlData), 1, begin, pos,
+                                  end, "semantic", emitViews, parseClient);
+
+        case SIMPLE:
+            switch (addlData) {
+                case TRUE:
+                case FALSE:
+                    return handleBool(addlData, begin, pos, parseClient);
+                case NULL_V:
+                    return handleNull(begin, pos, parseClient);
+                default:
+                    parseClient->error(begin, "Unsupported floating-point or simple value.");
+                    return {begin, nullptr};
+            }
+    }
+    CHECK(false);  // Impossible to get here.
+    return {};
+}
+
+class FullParseClient : public ParseClient {
+  public:
+    virtual ParseClient* item(std::unique_ptr<Item>& item, const uint8_t*, const uint8_t*,
+                              const uint8_t* end) override {
+        if (mParentStack.empty() && !item->isCompound()) {
+            // This is the first and only item.
+            mTheItem = std::move(item);
+            mPosition = end;
+            return nullptr;  //  We're done.
+        }
+
+        if (item->isCompound()) {
+            // Starting a new compound data item, i.e. a new parent.  Save it on the parent stack.
+            // It's safe to save a raw pointer because the unique_ptr is guaranteed to stay in
+            // existence until the corresponding itemEnd() call.
+            mParentStack.push(item.get());
+            return this;
+        } else {
+            appendToLastParent(std::move(item));
+            return this;
+        }
+    }
+
+    virtual ParseClient* itemEnd(std::unique_ptr<Item>& item, const uint8_t*, const uint8_t*,
+                                 const uint8_t* end) override {
+        CHECK(item->isCompound() && item.get() == mParentStack.top());
+        mParentStack.pop();
+        IncompleteItem* incompleteItem = IncompleteItem::cast(item.get());
+        std::unique_ptr<Item> finalizedItem = std::move(*incompleteItem).finalize();
+
+        if (mParentStack.empty()) {
+            mTheItem = std::move(finalizedItem);
+            mPosition = end;
+            return nullptr;  // We're done
+        } else {
+            appendToLastParent(std::move(finalizedItem));
+            return this;
+        }
+    }
+
+    virtual void error(const uint8_t* position, const std::string& errorMessage) override {
+        mPosition = position;
+        mErrorMessage = errorMessage;
+    }
+
+    std::tuple<std::unique_ptr<Item> /* result */, const uint8_t* /* newPos */,
+               std::string /* errMsg */>
+    parseResult() {
+        std::unique_ptr<Item> p = std::move(mTheItem);
+        return {std::move(p), mPosition, std::move(mErrorMessage)};
+    }
+
+  private:
+    void appendToLastParent(std::unique_ptr<Item> item) {
+        auto parent = mParentStack.top();
+        IncompleteItem::cast(parent)->add(std::move(item));
+    }
+
+    std::unique_ptr<Item> mTheItem;
+    std::stack<Item*> mParentStack;
+    const uint8_t* mPosition = nullptr;
+    std::string mErrorMessage;
+};
+
+}  // anonymous namespace
+
+void parse(const uint8_t* begin, const uint8_t* end, ParseClient* parseClient) {
+    parseRecursively(begin, end, false, parseClient);
+}
+
+std::tuple<std::unique_ptr<Item> /* result */, const uint8_t* /* newPos */,
+           std::string /* errMsg */>
+parse(const uint8_t* begin, const uint8_t* end) {
+    FullParseClient parseClient;
+    parse(begin, end, &parseClient);
+    return parseClient.parseResult();
+}
+
+void parseWithViews(const uint8_t* begin, const uint8_t* end, ParseClient* parseClient) {
+    parseRecursively(begin, end, true, parseClient);
+}
+
+std::tuple<std::unique_ptr<Item> /* result */, const uint8_t* /* newPos */,
+           std::string /* errMsg */>
+parseWithViews(const uint8_t* begin, const uint8_t* end) {
+    FullParseClient parseClient;
+    parseWithViews(begin, end, &parseClient);
+    return parseClient.parseResult();
+}
+
+}  // namespace cppbor
diff --git a/lib/libcppbor/include/cppbor/cppbor.h b/lib/libcppbor/include/cppbor/cppbor.h
new file mode 100644
index 00000000..f7a2af0c
--- /dev/null
+++ b/lib/libcppbor/include/cppbor/cppbor.h
@@ -0,0 +1,1141 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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 once
+
+#include <cassert>
+#include <cstdint>
+#include <functional>
+#include <iterator>
+#include <memory>
+#include <numeric>
+#include <string>
+#include <string_view>
+#include <vector>
+#include <algorithm>
+
+#ifdef OS_WINDOWS
+#include <basetsd.h>
+
+#define ssize_t SSIZE_T
+#endif // OS_WINDOWS
+
+#ifdef TRUE
+#undef TRUE
+#endif // TRUE
+#ifdef FALSE
+#undef FALSE
+#endif // FALSE
+
+namespace cppbor {
+
+enum MajorType : uint8_t {
+    UINT = 0 << 5,
+    NINT = 1 << 5,
+    BSTR = 2 << 5,
+    TSTR = 3 << 5,
+    ARRAY = 4 << 5,
+    MAP = 5 << 5,
+    SEMANTIC = 6 << 5,
+    SIMPLE = 7 << 5,
+};
+
+enum SimpleType {
+    BOOLEAN,
+    NULL_T,  // Only two supported, as yet.
+};
+
+enum SpecialAddlInfoValues : uint8_t {
+    FALSE = 20,
+    TRUE = 21,
+    NULL_V = 22,
+    ONE_BYTE_LENGTH = 24,
+    TWO_BYTE_LENGTH = 25,
+    FOUR_BYTE_LENGTH = 26,
+    EIGHT_BYTE_LENGTH = 27,
+};
+
+class Item;
+class Uint;
+class Nint;
+class Int;
+class Tstr;
+class Bstr;
+class Simple;
+class Bool;
+class Array;
+class Map;
+class Null;
+class SemanticTag;
+class EncodedItem;
+class ViewTstr;
+class ViewBstr;
+
+/**
+ * Returns the size of a CBOR header that contains the additional info value addlInfo.
+ */
+size_t headerSize(uint64_t addlInfo);
+
+/**
+ * Encodes a CBOR header with the specified type and additional info into the range [pos, end).
+ * Returns a pointer to one past the last byte written, or nullptr if there isn't sufficient space
+ * to write the header.
+ */
+uint8_t* encodeHeader(MajorType type, uint64_t addlInfo, uint8_t* pos, const uint8_t* end);
+
+using EncodeCallback = std::function<void(uint8_t)>;
+
+/**
+ * Encodes a CBOR header with the specified type and additional info, passing each byte in turn to
+ * encodeCallback.
+ */
+void encodeHeader(MajorType type, uint64_t addlInfo, EncodeCallback encodeCallback);
+
+/**
+ * Encodes a CBOR header witht he specified type and additional info, writing each byte to the
+ * provided OutputIterator.
+ */
+template <typename OutputIterator,
+          typename = std::enable_if_t<std::is_base_of_v<
+                  std::output_iterator_tag,
+                  typename std::iterator_traits<OutputIterator>::iterator_category>>>
+void encodeHeader(MajorType type, uint64_t addlInfo, OutputIterator iter) {
+    return encodeHeader(type, addlInfo, [&](uint8_t v) { *iter++ = v; });
+}
+
+/**
+ * Item represents a CBOR-encodeable data item.  Item is an abstract interface with a set of virtual
+ * methods that allow encoding of the item or conversion to the appropriate derived type.
+ */
+class Item {
+  public:
+    virtual ~Item() {}
+
+    /**
+     * Returns the CBOR type of the item.
+     */
+    virtual MajorType type() const = 0;
+
+    // These methods safely downcast an Item to the appropriate subclass.
+    virtual Int* asInt() { return nullptr; }
+    const Int* asInt() const { return const_cast<Item*>(this)->asInt(); }
+    virtual Uint* asUint() { return nullptr; }
+    const Uint* asUint() const { return const_cast<Item*>(this)->asUint(); }
+    virtual Nint* asNint() { return nullptr; }
+    const Nint* asNint() const { return const_cast<Item*>(this)->asNint(); }
+    virtual Tstr* asTstr() { return nullptr; }
+    const Tstr* asTstr() const { return const_cast<Item*>(this)->asTstr(); }
+    virtual Bstr* asBstr() { return nullptr; }
+    const Bstr* asBstr() const { return const_cast<Item*>(this)->asBstr(); }
+    virtual Simple* asSimple() { return nullptr; }
+    const Simple* asSimple() const { return const_cast<Item*>(this)->asSimple(); }
+    virtual Bool* asBool() { return nullptr; }
+    const Bool* asBool() const { return const_cast<Item*>(this)->asBool(); }
+    virtual Null* asNull() { return nullptr; }
+    const Null* asNull() const { return const_cast<Item*>(this)->asNull(); }
+
+    virtual Map* asMap() { return nullptr; }
+    const Map* asMap() const { return const_cast<Item*>(this)->asMap(); }
+    virtual Array* asArray() { return nullptr; }
+    const Array* asArray() const { return const_cast<Item*>(this)->asArray(); }
+
+    virtual ViewTstr* asViewTstr() { return nullptr; }
+    const ViewTstr* asViewTstr() const { return const_cast<Item*>(this)->asViewTstr(); }
+    virtual ViewBstr* asViewBstr() { return nullptr; }
+    const ViewBstr* asViewBstr() const { return const_cast<Item*>(this)->asViewBstr(); }
+
+    // Like those above, these methods safely downcast an Item when it's actually a SemanticTag.
+    // However, if you think you want to use these methods, you probably don't.  Typically, the way
+    // you should handle tagged Items is by calling the appropriate method above (e.g. asInt())
+    // which will return a pointer to the tagged Item, rather than the tag itself.  If you want to
+    // find out if the Item* you're holding is to something with one or more tags applied, see
+    // semanticTagCount() and semanticTag() below.
+    virtual SemanticTag* asSemanticTag() { return nullptr; }
+    const SemanticTag* asSemanticTag() const { return const_cast<Item*>(this)->asSemanticTag(); }
+
+    /**
+     * Returns the number of semantic tags prefixed to this Item.
+     */
+    virtual size_t semanticTagCount() const { return 0; }
+
+    /**
+     * Returns the semantic tag at the specified nesting level `nesting`, iff `nesting` is less than
+     * the value returned by semanticTagCount().
+     *
+     * CBOR tags are "nested" by applying them in sequence.  The "rightmost" tag is the "inner" tag.
+     * That is, given:
+     *
+     *     4(5(6("AES"))) which encodes as C1 C2 C3 63 414553
+     *
+     * The tstr "AES" is tagged with 6.  The combined entity ("AES" tagged with 6) is tagged with 5,
+     * etc.  So in this example, semanticTagCount() would return 3, and semanticTag(0) would return
+     * 5 semanticTag(1) would return 5 and semanticTag(2) would return 4.  For values of n > 2,
+     * semanticTag(n) will return 0, but this is a meaningless value.
+     *
+     * If this layering is confusing, you probably don't have to worry about it. Nested tagging does
+     * not appear to be common, so semanticTag(0) is the only one you'll use.
+     */
+    virtual uint64_t semanticTag(size_t /* nesting */ = 0) const { return 0; }
+
+    /**
+     * Returns true if this is a "compound" item, i.e. one that contains one or more other items.
+     */
+    virtual bool isCompound() const { return false; }
+
+    bool operator==(const Item& other) const&;
+    bool operator!=(const Item& other) const& { return !(*this == other); }
+
+    /**
+     * Returns the number of bytes required to encode this Item into CBOR.  Note that if this is a
+     * complex Item, calling this method will require walking the whole tree.
+     */
+    virtual size_t encodedSize() const = 0;
+
+    /**
+     * Encodes the Item into buffer referenced by range [*pos, end).  Returns a pointer to one past
+     * the last position written.  Returns nullptr if there isn't enough space to encode.
+     */
+    virtual uint8_t* encode(uint8_t* pos, const uint8_t* end) const = 0;
+
+    /**
+     * Encodes the Item by passing each encoded byte to encodeCallback.
+     */
+    virtual void encode(EncodeCallback encodeCallback) const = 0;
+
+    /**
+     * Clones the Item
+     */
+    virtual std::unique_ptr<Item> clone() const = 0;
+
+    /**
+     * Encodes the Item into the provided OutputIterator.
+     */
+    template <typename OutputIterator,
+              typename = typename std::iterator_traits<OutputIterator>::iterator_category>
+    void encode(OutputIterator i) const {
+        return encode([&](uint8_t v) { *i++ = v; });
+    }
+
+    /**
+     * Encodes the Item into a new std::vector<uint8_t>.
+     */
+    std::vector<uint8_t> encode() const {
+        std::vector<uint8_t> retval;
+        retval.reserve(encodedSize());
+        encode(std::back_inserter(retval));
+        return retval;
+    }
+
+    /**
+     * Encodes the Item into a new std::string.
+     */
+    std::string toString() const {
+        std::string retval;
+        retval.reserve(encodedSize());
+        encode([&](uint8_t v) { retval.push_back(v); });
+        return retval;
+    }
+
+    /**
+     * Encodes only the header of the Item.
+     */
+    inline uint8_t* encodeHeader(uint64_t addlInfo, uint8_t* pos, const uint8_t* end) const {
+        return ::cppbor::encodeHeader(type(), addlInfo, pos, end);
+    }
+
+    /**
+     * Encodes only the header of the Item.
+     */
+    inline void encodeHeader(uint64_t addlInfo, EncodeCallback encodeCallback) const {
+        ::cppbor::encodeHeader(type(), addlInfo, encodeCallback);
+    }
+};
+
+/**
+ * EncodedItem represents a bit of already-encoded CBOR. Caveat emptor: It does no checking to
+ * ensure that the provided data is a valid encoding, cannot be meaninfully-compared with other
+ * kinds of items and you cannot use the as*() methods to find out what's inside it.
+ */
+class EncodedItem : public Item {
+  public:
+    explicit EncodedItem(std::vector<uint8_t> value) : mValue(std::move(value)) {}
+
+    bool operator==(const EncodedItem& other) const& { return mValue == other.mValue; }
+
+    // Type can't be meaningfully-obtained. We could extract the type from the first byte and return
+    // it, but you can't do any of the normal things with an EncodedItem so there's no point.
+    MajorType type() const override {
+        assert(false);
+        return static_cast<MajorType>(-1);
+    }
+    size_t encodedSize() const override { return mValue.size(); }
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override {
+        if (end - pos < static_cast<ssize_t>(mValue.size())) return nullptr;
+        return std::copy(mValue.begin(), mValue.end(), pos);
+    }
+    void encode(EncodeCallback encodeCallback) const override {
+        std::for_each(mValue.begin(), mValue.end(), encodeCallback);
+    }
+    std::unique_ptr<Item> clone() const override { return std::make_unique<EncodedItem>(mValue); }
+
+  private:
+    std::vector<uint8_t> mValue;
+};
+
+/**
+ * Int is an abstraction that allows Uint and Nint objects to be manipulated without caring about
+ * the sign.
+ */
+class Int : public Item {
+  public:
+    bool operator==(const Int& other) const& { return value() == other.value(); }
+
+    virtual int64_t value() const = 0;
+    using Item::asInt;
+    Int* asInt() override { return this; }
+};
+
+/**
+ * Uint is a concrete Item that implements CBOR major type 0.
+ */
+class Uint : public Int {
+  public:
+    static constexpr MajorType kMajorType = UINT;
+
+    explicit Uint(uint64_t v) : mValue(v) {}
+
+    bool operator==(const Uint& other) const& { return mValue == other.mValue; }
+
+    MajorType type() const override { return kMajorType; }
+    using Item::asUint;
+    Uint* asUint() override { return this; }
+
+    size_t encodedSize() const override { return headerSize(mValue); }
+
+    int64_t value() const override { return mValue; }
+    uint64_t unsignedValue() const { return mValue; }
+
+    using Item::encode;
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override {
+        return encodeHeader(mValue, pos, end);
+    }
+    void encode(EncodeCallback encodeCallback) const override {
+        encodeHeader(mValue, encodeCallback);
+    }
+
+    std::unique_ptr<Item> clone() const override { return std::make_unique<Uint>(mValue); }
+
+  private:
+    uint64_t mValue;
+};
+
+/**
+ * Nint is a concrete Item that implements CBOR major type 1.
+
+ * Note that it is incapable of expressing the full range of major type 1 values, becaue it can only
+ * express values that fall into the range [std::numeric_limits<int64_t>::min(), -1].  It cannot
+ * express values in the range [std::numeric_limits<int64_t>::min() - 1,
+ * -std::numeric_limits<uint64_t>::max()].
+ */
+class Nint : public Int {
+  public:
+    static constexpr MajorType kMajorType = NINT;
+
+    explicit Nint(int64_t v);
+
+    bool operator==(const Nint& other) const& { return mValue == other.mValue; }
+
+    MajorType type() const override { return kMajorType; }
+    using Item::asNint;
+    Nint* asNint() override { return this; }
+    size_t encodedSize() const override { return headerSize(addlInfo()); }
+
+    int64_t value() const override { return mValue; }
+
+    using Item::encode;
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override {
+        return encodeHeader(addlInfo(), pos, end);
+    }
+    void encode(EncodeCallback encodeCallback) const override {
+        encodeHeader(addlInfo(), encodeCallback);
+    }
+
+    std::unique_ptr<Item> clone() const override { return std::make_unique<Nint>(mValue); }
+
+  private:
+    uint64_t addlInfo() const { return -1ll - mValue; }
+
+    int64_t mValue;
+};
+
+/**
+ * Bstr is a concrete Item that implements major type 2.
+ */
+class Bstr : public Item {
+  public:
+    static constexpr MajorType kMajorType = BSTR;
+
+    // Construct an empty Bstr
+    explicit Bstr() {}
+
+    // Construct from a vector
+    explicit Bstr(std::vector<uint8_t> v) : mValue(std::move(v)) {}
+
+    // Construct from a string
+    explicit Bstr(const std::string& v)
+        : mValue(reinterpret_cast<const uint8_t*>(v.data()),
+                 reinterpret_cast<const uint8_t*>(v.data()) + v.size()) {}
+
+    // Construct from a pointer/size pair
+    explicit Bstr(const std::pair<const uint8_t*, size_t>& buf)
+        : mValue(buf.first, buf.first + buf.second) {}
+
+    // Construct from a pair of iterators
+    template <typename I1, typename I2,
+              typename = typename std::iterator_traits<I1>::iterator_category,
+              typename = typename std::iterator_traits<I2>::iterator_category>
+    explicit Bstr(const std::pair<I1, I2>& pair) : mValue(pair.first, pair.second) {}
+
+    // Construct from an iterator range.
+    template <typename I1, typename I2,
+              typename = typename std::iterator_traits<I1>::iterator_category,
+              typename = typename std::iterator_traits<I2>::iterator_category>
+    Bstr(I1 begin, I2 end) : mValue(begin, end) {}
+
+    bool operator==(const Bstr& other) const& { return mValue == other.mValue; }
+
+    MajorType type() const override { return kMajorType; }
+    using Item::asBstr;
+    Bstr* asBstr() override { return this; }
+    size_t encodedSize() const override { return headerSize(mValue.size()) + mValue.size(); }
+    using Item::encode;
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override;
+    void encode(EncodeCallback encodeCallback) const override {
+        encodeHeader(mValue.size(), encodeCallback);
+        encodeValue(encodeCallback);
+    }
+
+    const std::vector<uint8_t>& value() const { return mValue; }
+    std::vector<uint8_t>&& moveValue() { return std::move(mValue); }
+
+    std::unique_ptr<Item> clone() const override { return std::make_unique<Bstr>(mValue); }
+
+  private:
+    void encodeValue(EncodeCallback encodeCallback) const;
+
+    std::vector<uint8_t> mValue;
+};
+
+/**
+ * ViewBstr is a read-only version of Bstr backed by std::string_view
+ */
+class ViewBstr : public Item {
+  public:
+    static constexpr MajorType kMajorType = BSTR;
+
+    // Construct an empty ViewBstr
+    explicit ViewBstr() {}
+
+    // Construct from a string_view of uint8_t values
+    explicit ViewBstr(std::basic_string_view<uint8_t> v) : mView(std::move(v)) {}
+
+    // Construct from a string_view
+    explicit ViewBstr(std::string_view v)
+        : mView(reinterpret_cast<const uint8_t*>(v.data()), v.size()) {}
+
+    // Construct from an iterator range
+    template <typename I1, typename I2,
+              typename = typename std::iterator_traits<I1>::iterator_category,
+              typename = typename std::iterator_traits<I2>::iterator_category>
+    ViewBstr(I1 begin, I2 end) : mView(begin, end) {}
+
+    // Construct from a uint8_t pointer pair
+    ViewBstr(const uint8_t* begin, const uint8_t* end)
+        : mView(begin, std::distance(begin, end)) {}
+
+    bool operator==(const ViewBstr& other) const& { return mView == other.mView; }
+
+    MajorType type() const override { return kMajorType; }
+    using Item::asViewBstr;
+    ViewBstr* asViewBstr() override { return this; }
+    size_t encodedSize() const override { return headerSize(mView.size()) + mView.size(); }
+    using Item::encode;
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override;
+    void encode(EncodeCallback encodeCallback) const override {
+        encodeHeader(mView.size(), encodeCallback);
+        encodeValue(encodeCallback);
+    }
+
+    const std::basic_string_view<uint8_t>& view() const { return mView; }
+
+    std::unique_ptr<Item> clone() const override { return std::make_unique<ViewBstr>(mView); }
+
+  private:
+    void encodeValue(EncodeCallback encodeCallback) const;
+
+    std::basic_string_view<uint8_t> mView;
+};
+
+/**
+ * Tstr is a concrete Item that implements major type 3.
+ */
+class Tstr : public Item {
+  public:
+    static constexpr MajorType kMajorType = TSTR;
+
+    // Construct from a string
+    explicit Tstr(std::string v) : mValue(std::move(v)) {}
+
+    // Construct from a string_view
+    explicit Tstr(const std::string_view& v) : mValue(v) {}
+
+    // Construct from a C string
+    explicit Tstr(const char* v) : mValue(std::string(v)) {}
+
+    // Construct from a pair of iterators
+    template <typename I1, typename I2,
+              typename = typename std::iterator_traits<I1>::iterator_category,
+              typename = typename std::iterator_traits<I2>::iterator_category>
+    explicit Tstr(const std::pair<I1, I2>& pair) : mValue(pair.first, pair.second) {}
+
+    // Construct from an iterator range
+    template <typename I1, typename I2,
+              typename = typename std::iterator_traits<I1>::iterator_category,
+              typename = typename std::iterator_traits<I2>::iterator_category>
+    Tstr(I1 begin, I2 end) : mValue(begin, end) {}
+
+    bool operator==(const Tstr& other) const& { return mValue == other.mValue; }
+
+    MajorType type() const override { return kMajorType; }
+    using Item::asTstr;
+    Tstr* asTstr() override { return this; }
+    size_t encodedSize() const override { return headerSize(mValue.size()) + mValue.size(); }
+    using Item::encode;
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override;
+    void encode(EncodeCallback encodeCallback) const override {
+        encodeHeader(mValue.size(), encodeCallback);
+        encodeValue(encodeCallback);
+    }
+
+    const std::string& value() const { return mValue; }
+    std::string&& moveValue() { return std::move(mValue); }
+
+    std::unique_ptr<Item> clone() const override { return std::make_unique<Tstr>(mValue); }
+
+  private:
+    void encodeValue(EncodeCallback encodeCallback) const;
+
+    std::string mValue;
+};
+
+/**
+ * ViewTstr is a read-only version of Tstr backed by std::string_view
+ */
+class ViewTstr : public Item {
+  public:
+    static constexpr MajorType kMajorType = TSTR;
+
+    // Construct an empty ViewTstr
+    explicit ViewTstr() {}
+
+    // Construct from a string_view
+    explicit ViewTstr(std::string_view v) : mView(std::move(v)) {}
+
+    // Construct from an iterator range
+    template <typename I1, typename I2,
+              typename = typename std::iterator_traits<I1>::iterator_category,
+              typename = typename std::iterator_traits<I2>::iterator_category>
+    ViewTstr(I1 begin, I2 end) : mView(begin, end) {}
+
+    // Construct from a uint8_t pointer pair
+    ViewTstr(const uint8_t* begin, const uint8_t* end)
+        : mView(reinterpret_cast<const char*>(begin),
+                std::distance(begin, end)) {}
+
+    bool operator==(const ViewTstr& other) const& { return mView == other.mView; }
+
+    MajorType type() const override { return kMajorType; }
+    using Item::asViewTstr;
+    ViewTstr* asViewTstr() override { return this; }
+    size_t encodedSize() const override { return headerSize(mView.size()) + mView.size(); }
+    using Item::encode;
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override;
+    void encode(EncodeCallback encodeCallback) const override {
+        encodeHeader(mView.size(), encodeCallback);
+        encodeValue(encodeCallback);
+    }
+
+    const std::string_view& view() const { return mView; }
+
+    std::unique_ptr<Item> clone() const override { return std::make_unique<ViewTstr>(mView); }
+
+  private:
+    void encodeValue(EncodeCallback encodeCallback) const;
+
+    std::string_view mView;
+};
+
+/*
+ * Array is a concrete Item that implements CBOR major type 4.
+ *
+ * Note that Arrays are not copyable.  This is because copying them is expensive and making them
+ * move-only ensures that they're never copied accidentally.  If you actually want to copy an Array,
+ * use the clone() method.
+ */
+class Array : public Item {
+  public:
+    static constexpr MajorType kMajorType = ARRAY;
+
+    Array() = default;
+    Array(const Array& other) = delete;
+    Array(Array&&) = default;
+    Array& operator=(const Array&) = delete;
+    Array& operator=(Array&&) = default;
+
+    bool operator==(const Array& other) const&;
+
+    /**
+     * Construct an Array from a variable number of arguments of different types.  See
+     * details::makeItem below for details on what types may be provided.  In general, this accepts
+     * all of the types you'd expect and doest the things you'd expect (integral values are addes as
+     * Uint or Nint, std::string and char* are added as Tstr, bools are added as Bool, etc.).
+     */
+    template <typename... Args, typename Enable>
+    Array(Args&&... args);
+
+    /**
+     * The above variadic constructor is disabled if sizeof(Args) != 1, so special
+     * case an explicit Array constructor for creating an Array with one Item.
+     */
+    template <typename T, typename Enable>
+    explicit Array(T&& v);
+
+    /**
+     * Append a single element to the Array, of any compatible type.
+     */
+    template <typename T>
+    Array& add(T&& v) &;
+    template <typename T>
+    Array&& add(T&& v) &&;
+
+    bool isCompound() const override { return true; }
+
+    virtual size_t size() const { return mEntries.size(); }
+
+    size_t encodedSize() const override {
+        return std::accumulate(mEntries.begin(), mEntries.end(), headerSize(size()),
+                               [](size_t sum, auto& entry) { return sum + entry->encodedSize(); });
+    }
+
+    using Item::encode;  // Make base versions visible.
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override;
+    void encode(EncodeCallback encodeCallback) const override;
+
+    const std::unique_ptr<Item>& operator[](size_t index) const { return get(index); }
+    std::unique_ptr<Item>& operator[](size_t index) { return get(index); }
+
+    const std::unique_ptr<Item>& get(size_t index) const { return mEntries[index]; }
+    std::unique_ptr<Item>& get(size_t index) { return mEntries[index]; }
+
+    MajorType type() const override { return kMajorType; }
+    using Item::asArray;
+    Array* asArray() override { return this; }
+
+    std::unique_ptr<Item> clone() const override;
+
+    auto begin() { return mEntries.begin(); }
+    auto begin() const { return mEntries.begin(); }
+    auto end() { return mEntries.end(); }
+    auto end() const { return mEntries.end(); }
+
+  protected:
+    std::vector<std::unique_ptr<Item>> mEntries;
+};
+
+/*
+ * Map is a concrete Item that implements CBOR major type 5.
+ *
+ * Note that Maps are not copyable.  This is because copying them is expensive and making them
+ * move-only ensures that they're never copied accidentally.  If you actually want to copy a
+ * Map, use the clone() method.
+ */
+class Map : public Item {
+  public:
+    static constexpr MajorType kMajorType = MAP;
+
+    using entry_type = std::pair<std::unique_ptr<Item>, std::unique_ptr<Item>>;
+
+    Map() = default;
+    Map(const Map& other) = delete;
+    Map(Map&&) = default;
+    Map& operator=(const Map& other) = delete;
+    Map& operator=(Map&&) = default;
+
+    bool operator==(const Map& other) const&;
+
+    /**
+     * Construct a Map from a variable number of arguments of different types.  An even number of
+     * arguments must be provided (this is verified statically). See details::makeItem below for
+     * details on what types may be provided.  In general, this accepts all of the types you'd
+     * expect and doest the things you'd expect (integral values are addes as Uint or Nint,
+     * std::string and char* are added as Tstr, bools are added as Bool, etc.).
+     */
+    template <typename... Args, typename Enable>
+    Map(Args&&... args);
+
+    /**
+     * Append a key/value pair to the Map, of any compatible types.
+     */
+    template <typename Key, typename Value>
+    Map& add(Key&& key, Value&& value) &;
+    template <typename Key, typename Value>
+    Map&& add(Key&& key, Value&& value) &&;
+
+    bool isCompound() const override { return true; }
+
+    virtual size_t size() const { return mEntries.size(); }
+
+    size_t encodedSize() const override {
+        return std::accumulate(
+                mEntries.begin(), mEntries.end(), headerSize(size()), [](size_t sum, auto& entry) {
+                    return sum + entry.first->encodedSize() + entry.second->encodedSize();
+                });
+    }
+
+    using Item::encode;  // Make base versions visible.
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override;
+    void encode(EncodeCallback encodeCallback) const override;
+
+    /**
+     * Find and return the value associated with `key`, if any.
+     *
+     * If the searched-for `key` is not present, returns `nullptr`.
+     *
+     * Note that if the map is canonicalized (sorted), Map::get() performs a binary search.  If your
+     * map is large and you're searching in it many times, it may be worthwhile to canonicalize it
+     * to make Map::get() faster.  Any use of a method that might modify the map disables the
+     * speedup.
+     */
+    template <typename Key, typename Enable>
+    const std::unique_ptr<Item>& get(Key key) const;
+
+    // Note that use of non-const operator[] marks the map as not canonicalized.
+    auto& operator[](size_t index) {
+        mCanonicalized = false;
+        return mEntries[index];
+    }
+    const auto& operator[](size_t index) const { return mEntries[index]; }
+
+    MajorType type() const override { return kMajorType; }
+    using Item::asMap;
+    Map* asMap() override { return this; }
+
+    /**
+     * Sorts the map in canonical order, as defined in RFC 7049. Use this before encoding if you
+     * want canonicalization; cppbor does not canonicalize by default, though the integer encodings
+     * are always canonical and cppbor does not support indefinite-length encodings, so map order
+     * canonicalization is the only thing that needs to be done.
+     *
+     * @param recurse If set to true, canonicalize() will also walk the contents of the map and
+     * canonicalize any contained maps as well.
+     */
+    Map& canonicalize(bool recurse = false) &;
+    Map&& canonicalize(bool recurse = false) && {
+        canonicalize(recurse);
+        return std::move(*this);
+    }
+
+    bool isCanonical() { return mCanonicalized; }
+
+    std::unique_ptr<Item> clone() const override;
+
+    auto begin() {
+        mCanonicalized = false;
+        return mEntries.begin();
+    }
+    auto begin() const { return mEntries.begin(); }
+    auto end() {
+        mCanonicalized = false;
+        return mEntries.end();
+    }
+    auto end() const { return mEntries.end(); }
+
+    // Returns true if a < b, per CBOR map key canonicalization rules.
+    static bool keyLess(const Item* a, const Item* b);
+
+  protected:
+    std::vector<entry_type> mEntries;
+
+  private:
+    bool mCanonicalized = false;
+};
+
+class SemanticTag : public Item {
+  public:
+    static constexpr MajorType kMajorType = SEMANTIC;
+
+    template <typename T>
+    SemanticTag(uint64_t tagValue, T&& taggedItem);
+    SemanticTag(const SemanticTag& other) = delete;
+    SemanticTag(SemanticTag&&) = default;
+    SemanticTag& operator=(const SemanticTag& other) = delete;
+    SemanticTag& operator=(SemanticTag&&) = default;
+
+    bool operator==(const SemanticTag& other) const& {
+        return mValue == other.mValue && *mTaggedItem == *other.mTaggedItem;
+    }
+
+    bool isCompound() const override { return true; }
+
+    virtual size_t size() const { return 1; }
+
+    // Encoding returns the tag + enclosed Item.
+    size_t encodedSize() const override { return headerSize(mValue) + mTaggedItem->encodedSize(); }
+
+    using Item::encode;  // Make base versions visible.
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override;
+    void encode(EncodeCallback encodeCallback) const override;
+
+    // type() is a bit special.  In normal usage it should return the wrapped type, but during
+    // parsing when we haven't yet parsed the tagged item, it needs to return SEMANTIC.
+    MajorType type() const override { return mTaggedItem ? mTaggedItem->type() : SEMANTIC; }
+    using Item::asSemanticTag;
+    SemanticTag* asSemanticTag() override { return this; }
+
+    // Type information reflects the enclosed Item.  Note that if the immediately-enclosed Item is
+    // another tag, these methods will recurse down to the non-tag Item.
+    using Item::asInt;
+    Int* asInt() override { return mTaggedItem->asInt(); }
+    using Item::asUint;
+    Uint* asUint() override { return mTaggedItem->asUint(); }
+    using Item::asNint;
+    Nint* asNint() override { return mTaggedItem->asNint(); }
+    using Item::asTstr;
+    Tstr* asTstr() override { return mTaggedItem->asTstr(); }
+    using Item::asBstr;
+    Bstr* asBstr() override { return mTaggedItem->asBstr(); }
+    using Item::asSimple;
+    Simple* asSimple() override { return mTaggedItem->asSimple(); }
+    using Item::asMap;
+    Map* asMap() override { return mTaggedItem->asMap(); }
+    using Item::asArray;
+    Array* asArray() override { return mTaggedItem->asArray(); }
+    using Item::asViewTstr;
+    ViewTstr* asViewTstr() override { return mTaggedItem->asViewTstr(); }
+    using Item::asViewBstr;
+    ViewBstr* asViewBstr() override { return mTaggedItem->asViewBstr(); }
+
+    std::unique_ptr<Item> clone() const override;
+
+    size_t semanticTagCount() const override;
+    uint64_t semanticTag(size_t nesting = 0) const override;
+
+  protected:
+    SemanticTag() = default;
+    SemanticTag(uint64_t value) : mValue(value) {}
+    uint64_t mValue;
+    std::unique_ptr<Item> mTaggedItem;
+};
+
+/**
+ * Simple is abstract Item that implements CBOR major type 7.  It is intended to be subclassed to
+ * create concrete Simple types.  At present only Bool is provided.
+ */
+class Simple : public Item {
+  public:
+    static constexpr MajorType kMajorType = SIMPLE;
+
+    bool operator==(const Simple& other) const&;
+
+    virtual SimpleType simpleType() const = 0;
+    MajorType type() const override { return kMajorType; }
+
+    Simple* asSimple() override { return this; }
+};
+
+/**
+ * Bool is a concrete type that implements CBOR major type 7, with additional item values for TRUE
+ * and FALSE.
+ */
+class Bool : public Simple {
+  public:
+    static constexpr SimpleType kSimpleType = BOOLEAN;
+
+    explicit Bool(bool v) : mValue(v) {}
+
+    bool operator==(const Bool& other) const& { return mValue == other.mValue; }
+
+    SimpleType simpleType() const override { return kSimpleType; }
+    Bool* asBool() override { return this; }
+
+    size_t encodedSize() const override { return 1; }
+
+    using Item::encode;
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override {
+        return encodeHeader(mValue ? TRUE : FALSE, pos, end);
+    }
+    void encode(EncodeCallback encodeCallback) const override {
+        encodeHeader(mValue ? TRUE : FALSE, encodeCallback);
+    }
+
+    bool value() const { return mValue; }
+
+    std::unique_ptr<Item> clone() const override { return std::make_unique<Bool>(mValue); }
+
+  private:
+    bool mValue;
+};
+
+/**
+ * Null is a concrete type that implements CBOR major type 7, with additional item value for NULL
+ */
+class Null : public Simple {
+  public:
+    static constexpr SimpleType kSimpleType = NULL_T;
+
+    explicit Null() {}
+
+    SimpleType simpleType() const override { return kSimpleType; }
+    Null* asNull() override { return this; }
+
+    size_t encodedSize() const override { return 1; }
+
+    using Item::encode;
+    uint8_t* encode(uint8_t* pos, const uint8_t* end) const override {
+        return encodeHeader(NULL_V, pos, end);
+    }
+    void encode(EncodeCallback encodeCallback) const override {
+        encodeHeader(NULL_V, encodeCallback);
+    }
+
+    std::unique_ptr<Item> clone() const override { return std::make_unique<Null>(); }
+};
+
+/**
+ * Returns pretty-printed CBOR for |item|
+ *
+ * If a byte-string is larger than |maxBStrSize| its contents will not be printed, instead the value
+ * of the form "<bstr size=1099016 sha1=ef549cca331f73dfae2090e6a37c04c23f84b07b>" will be
+ * printed. Pass zero for |maxBStrSize| to disable this.
+ *
+ * The |mapKeysToNotPrint| parameter specifies the name of map values to not print. This is useful
+ * for unit tests.
+ */
+std::string prettyPrint(const Item* item, size_t maxBStrSize = 32,
+                        const std::vector<std::string>& mapKeysToNotPrint = {});
+
+/**
+ * Returns pretty-printed CBOR for |value|.
+ *
+ * Only valid CBOR should be passed to this function.
+ *
+ * If a byte-string is larger than |maxBStrSize| its contents will not be printed, instead the value
+ * of the form "<bstr size=1099016 sha1=ef549cca331f73dfae2090e6a37c04c23f84b07b>" will be
+ * printed. Pass zero for |maxBStrSize| to disable this.
+ *
+ * The |mapKeysToNotPrint| parameter specifies the name of map values to not print. This is useful
+ * for unit tests.
+ */
+std::string prettyPrint(const std::vector<uint8_t>& encodedCbor, size_t maxBStrSize = 32,
+                        const std::vector<std::string>& mapKeysToNotPrint = {});
+
+/**
+ * Details. Mostly you shouldn't have to look below, except perhaps at the docstring for makeItem.
+ */
+namespace details {
+
+template <typename T, typename V, typename Enable = void>
+struct is_iterator_pair_over : public std::false_type {};
+
+template <typename I1, typename I2, typename V>
+struct is_iterator_pair_over<
+        std::pair<I1, I2>, V,
+        typename std::enable_if_t<std::is_same_v<V, typename std::iterator_traits<I1>::value_type>>>
+    : public std::true_type {};
+
+template <typename T, typename V, typename Enable = void>
+struct is_unique_ptr_of_subclass_of_v : public std::false_type {};
+
+template <typename T, typename P>
+struct is_unique_ptr_of_subclass_of_v<T, std::unique_ptr<P>,
+                                      typename std::enable_if_t<std::is_base_of_v<T, P>>>
+    : public std::true_type {};
+
+/* check if type is one of std::string (1), std::string_view (2), null-terminated char* (3) or pair
+ *     of iterators (4)*/
+template <typename T, typename Enable = void>
+struct is_text_type_v : public std::false_type {};
+
+template <typename T>
+struct is_text_type_v<
+        T, typename std::enable_if_t<
+                   /* case 1 */  //
+                   std::is_same_v<std::remove_cv_t<std::remove_reference_t<T>>, std::string>
+                   /* case 2 */  //
+                   || std::is_same_v<std::remove_cv_t<std::remove_reference_t<T>>, std::string_view>
+                   /* case 3 */                                                 //
+                   || std::is_same_v<std::remove_cv_t<std::decay_t<T>>, char*>  //
+                   || std::is_same_v<std::remove_cv_t<std::decay_t<T>>, const char*>
+                   /* case 4 */
+                   || details::is_iterator_pair_over<T, char>::value>> : public std::true_type {};
+
+/**
+ * Construct a unique_ptr<Item> from many argument types. Accepts:
+ *
+ * (a) booleans;
+ * (b) integers, all sizes and signs;
+ * (c) text strings, as defined by is_text_type_v above;
+ * (d) byte strings, as std::vector<uint8_t>(d1), pair of iterators (d2) or pair<uint8_t*, size_T>
+ *     (d3); and
+ * (e) Item subclass instances, including Array and Map.  Items may be provided by naked pointer
+ *     (e1), unique_ptr (e2), reference (e3) or value (e3).  If provided by reference or value, will
+ *     be moved if possible.  If provided by pointer, ownership is taken.
+ * (f) null pointer;
+ * (g) enums, using the underlying integer value.
+ */
+template <typename T>
+std::unique_ptr<Item> makeItem(T v) {
+    Item* p = nullptr;
+    if constexpr (/* case a */ std::is_same_v<T, bool>) {
+        p = new Bool(v);
+    } else if constexpr (/* case b */ std::is_integral_v<T>) {  // b
+        if (v < 0) {
+            p = new Nint(v);
+        } else {
+            p = new Uint(static_cast<uint64_t>(v));
+        }
+    } else if constexpr (/* case c */  //
+                         details::is_text_type_v<T>::value) {
+        p = new Tstr(v);
+    } else if constexpr (/* case d1 */  //
+                         std::is_same_v<std::remove_cv_t<std::remove_reference_t<T>>,
+                                        std::vector<uint8_t>>
+                         /* case d2 */  //
+                         || details::is_iterator_pair_over<T, uint8_t>::value
+                         /* case d3 */  //
+                         || std::is_same_v<std::remove_cv_t<std::remove_reference_t<T>>,
+                                           std::pair<uint8_t*, size_t>>) {
+        p = new Bstr(v);
+    } else if constexpr (/* case e1 */  //
+                         std::is_pointer_v<T> &&
+                         std::is_base_of_v<Item, std::remove_pointer_t<T>>) {
+        p = v;
+    } else if constexpr (/* case e2 */  //
+                         details::is_unique_ptr_of_subclass_of_v<Item, T>::value) {
+        p = v.release();
+    } else if constexpr (/* case e3 */  //
+                         std::is_base_of_v<Item, T>) {
+        p = new T(std::move(v));
+    } else if constexpr (/* case f */ std::is_null_pointer_v<T>) {
+        p = new Null();
+    } else if constexpr (/* case g */ std::is_enum_v<T>) {
+        return makeItem(static_cast<std::underlying_type_t<T>>(v));
+    } else {
+        // It's odd that this can't be static_assert(false), since it shouldn't be evaluated if one
+        // of the above ifs matches.  But static_assert(false) always triggers.
+        static_assert(std::is_same_v<T, bool>, "makeItem called with unsupported type");
+    }
+    return std::unique_ptr<Item>(p);
+}
+
+inline void map_helper(Map& /* map */) {}
+
+template <typename Key, typename Value, typename... Rest>
+inline void map_helper(Map& map, Key&& key, Value&& value, Rest&&... rest) {
+    map.add(std::forward<Key>(key), std::forward<Value>(value));
+    map_helper(map, std::forward<Rest>(rest)...);
+}
+
+}  // namespace details
+
+template <typename... Args,
+         /* Prevent implicit construction with a single argument. */
+         typename = std::enable_if_t<(sizeof...(Args)) != 1>>
+Array::Array(Args&&... args) {
+    mEntries.reserve(sizeof...(args));
+    (mEntries.push_back(details::makeItem(std::forward<Args>(args))), ...);
+}
+
+template <typename T,
+         /* Prevent use as copy constructor. */
+         typename = std::enable_if_t<
+            !std::is_same_v<Array, std::remove_cv_t<std::remove_reference_t<T>>>>>
+Array::Array(T&& v) {
+    mEntries.push_back(details::makeItem(std::forward<T>(v)));
+}
+
+template <typename T>
+Array& Array::add(T&& v) & {
+    mEntries.push_back(details::makeItem(std::forward<T>(v)));
+    return *this;
+}
+
+template <typename T>
+Array&& Array::add(T&& v) && {
+    mEntries.push_back(details::makeItem(std::forward<T>(v)));
+    return std::move(*this);
+}
+
+template <typename... Args,
+          /* Prevent use as copy ctor */ typename = std::enable_if_t<(sizeof...(Args)) != 1>>
+Map::Map(Args&&... args) {
+    static_assert((sizeof...(Args)) % 2 == 0, "Map must have an even number of entries");
+    mEntries.reserve(sizeof...(args) / 2);
+    details::map_helper(*this, std::forward<Args>(args)...);
+}
+
+template <typename Key, typename Value>
+Map& Map::add(Key&& key, Value&& value) & {
+    mEntries.push_back({details::makeItem(std::forward<Key>(key)),
+                        details::makeItem(std::forward<Value>(value))});
+    mCanonicalized = false;
+    return *this;
+}
+
+template <typename Key, typename Value>
+Map&& Map::add(Key&& key, Value&& value) && {
+    this->add(std::forward<Key>(key), std::forward<Value>(value));
+    return std::move(*this);
+}
+
+static const std::unique_ptr<Item> kEmptyItemPtr;
+
+template <typename Key,
+          typename = std::enable_if_t<std::is_integral_v<Key> || std::is_enum_v<Key> ||
+                                      details::is_text_type_v<Key>::value>>
+const std::unique_ptr<Item>& Map::get(Key key) const {
+    auto keyItem = details::makeItem(key);
+
+    if (mCanonicalized) {
+        // It's sorted, so binary-search it.
+        auto found = std::lower_bound(begin(), end(), keyItem.get(),
+                                      [](const entry_type& entry, const Item* key) {
+                                          return keyLess(entry.first.get(), key);
+                                      });
+        return (found == end() || *found->first != *keyItem) ? kEmptyItemPtr : found->second;
+    } else {
+        // Unsorted, do a linear search.
+        auto found = std::find_if(
+                begin(), end(), [&](const entry_type& entry) { return *entry.first == *keyItem; });
+        return found == end() ? kEmptyItemPtr : found->second;
+    }
+}
+
+template <typename T>
+SemanticTag::SemanticTag(uint64_t value, T&& taggedItem)
+    : mValue(value), mTaggedItem(details::makeItem(std::forward<T>(taggedItem))) {}
+
+}  // namespace cppbor
diff --git a/lib/libcppbor/include/cppbor/cppbor_parse.h b/lib/libcppbor/include/cppbor/cppbor_parse.h
new file mode 100644
index 00000000..22cd18d0
--- /dev/null
+++ b/lib/libcppbor/include/cppbor/cppbor_parse.h
@@ -0,0 +1,195 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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 once
+
+#include "cppbor.h"
+
+namespace cppbor {
+
+using ParseResult = std::tuple<std::unique_ptr<Item> /* result */, const uint8_t* /* newPos */,
+                               std::string /* errMsg */>;
+
+/**
+ * Parse the first CBOR data item (possibly compound) from the range [begin, end).
+ *
+ * Returns a tuple of Item pointer, buffer pointer and error message.  If parsing is successful, the
+ * Item pointer is non-null, the buffer pointer points to the first byte after the
+ * successfully-parsed item and the error message string is empty.  If parsing fails, the Item
+ * pointer is null, the buffer pointer points to the first byte that was unparseable (the first byte
+ * of a data item header that is malformed in some way, e.g. an invalid value, or a length that is
+ * too large for the remaining buffer, etc.) and the string contains an error message describing the
+ * problem encountered.
+ */
+ParseResult parse(const uint8_t* begin, const uint8_t* end);
+
+/**
+ * Parse the first CBOR data item (possibly compound) from the range [begin, end).
+ *
+ * Returns a tuple of Item pointer, buffer pointer and error message.  If parsing is successful, the
+ * Item pointer is non-null, the buffer pointer points to the first byte after the
+ * successfully-parsed item and the error message string is empty.  If parsing fails, the Item
+ * pointer is null, the buffer pointer points to the first byte that was unparseable (the first byte
+ * of a data item header that is malformed in some way, e.g. an invalid value, or a length that is
+ * too large for the remaining buffer, etc.) and the string contains an error message describing the
+ * problem encountered.
+ *
+ * The returned CBOR data item will contain View* items backed by
+ * std::string_view types over the input range.
+ * WARNING! If the input range changes underneath, the corresponding views will
+ * carry the same change.
+ */
+ParseResult parseWithViews(const uint8_t* begin, const uint8_t* end);
+
+/**
+ * Parse the first CBOR data item (possibly compound) from the byte vector.
+ *
+ * Returns a tuple of Item pointer, buffer pointer and error message.  If parsing is successful, the
+ * Item pointer is non-null, the buffer pointer points to the first byte after the
+ * successfully-parsed item and the error message string is empty.  If parsing fails, the Item
+ * pointer is null, the buffer pointer points to the first byte that was unparseable (the first byte
+ * of a data item header that is malformed in some way, e.g. an invalid value, or a length that is
+ * too large for the remaining buffer, etc.) and the string contains an error message describing the
+ * problem encountered.
+ */
+inline ParseResult parse(const std::vector<uint8_t>& encoding) {
+    return parse(encoding.data(), encoding.data() + encoding.size());
+}
+
+/**
+ * Parse the first CBOR data item (possibly compound) from the range [begin, begin + size).
+ *
+ * Returns a tuple of Item pointer, buffer pointer and error message.  If parsing is successful, the
+ * Item pointer is non-null, the buffer pointer points to the first byte after the
+ * successfully-parsed item and the error message string is empty.  If parsing fails, the Item
+ * pointer is null, the buffer pointer points to the first byte that was unparseable (the first byte
+ * of a data item header that is malformed in some way, e.g. an invalid value, or a length that is
+ * too large for the remaining buffer, etc.) and the string contains an error message describing the
+ * problem encountered.
+ */
+inline ParseResult parse(const uint8_t* begin, size_t size) {
+    return parse(begin, begin + size);
+}
+
+/**
+ * Parse the first CBOR data item (possibly compound) from the range [begin, begin + size).
+ *
+ * Returns a tuple of Item pointer, buffer pointer and error message.  If parsing is successful, the
+ * Item pointer is non-null, the buffer pointer points to the first byte after the
+ * successfully-parsed item and the error message string is empty.  If parsing fails, the Item
+ * pointer is null, the buffer pointer points to the first byte that was unparseable (the first byte
+ * of a data item header that is malformed in some way, e.g. an invalid value, or a length that is
+ * too large for the remaining buffer, etc.) and the string contains an error message describing the
+ * problem encountered.
+ *
+ * The returned CBOR data item will contain View* items backed by
+ * std::string_view types over the input range.
+ * WARNING! If the input range changes underneath, the corresponding views will
+ * carry the same change.
+ */
+inline ParseResult parseWithViews(const uint8_t* begin, size_t size) {
+    return parseWithViews(begin, begin + size);
+}
+
+/**
+ * Parse the first CBOR data item (possibly compound) from the value contained in a Bstr.
+ *
+ * Returns a tuple of Item pointer, buffer pointer and error message.  If parsing is successful, the
+ * Item pointer is non-null, the buffer pointer points to the first byte after the
+ * successfully-parsed item and the error message string is empty.  If parsing fails, the Item
+ * pointer is null, the buffer pointer points to the first byte that was unparseable (the first byte
+ * of a data item header that is malformed in some way, e.g. an invalid value, or a length that is
+ * too large for the remaining buffer, etc.) and the string contains an error message describing the
+ * problem encountered.
+ */
+inline ParseResult parse(const Bstr* bstr) {
+    if (!bstr)
+        return ParseResult(nullptr, nullptr, "Null Bstr pointer");
+    return parse(bstr->value());
+}
+
+class ParseClient;
+
+/**
+ * Parse the CBOR data in the range [begin, end) in streaming fashion, calling methods on the
+ * provided ParseClient when elements are found.
+ */
+void parse(const uint8_t* begin, const uint8_t* end, ParseClient* parseClient);
+
+/**
+ * Parse the CBOR data in the range [begin, end) in streaming fashion, calling methods on the
+ * provided ParseClient when elements are found. Uses the View* item types
+ * instead of the copying ones.
+ */
+void parseWithViews(const uint8_t* begin, const uint8_t* end, ParseClient* parseClient);
+
+/**
+ * Parse the CBOR data in the vector in streaming fashion, calling methods on the
+ * provided ParseClient when elements are found.
+ */
+inline void parse(const std::vector<uint8_t>& encoding, ParseClient* parseClient) {
+    return parse(encoding.data(), encoding.data() + encoding.size(), parseClient);
+}
+
+/**
+ * A pure interface that callers of the streaming parse functions must implement.
+ */
+class ParseClient {
+  public:
+    virtual ~ParseClient() {}
+
+    /**
+     * Called when an item is found.  The Item pointer points to the found item; use type() and
+     * the appropriate as*() method to examine the value.  hdrBegin points to the first byte of the
+     * header, valueBegin points to the first byte of the value and end points one past the end of
+     * the item.  In the case of header-only items, such as integers, and compound items (ARRAY,
+     * MAP or SEMANTIC) whose end has not yet been found, valueBegin and end are equal and point to
+     * the byte past the header.
+     *
+     * Note that for compound types (ARRAY, MAP, and SEMANTIC), the Item will have no content.  For
+     * Map and Array items, the size() method will return a correct value, but the index operators
+     * are unsafe, and the object cannot be safely compared with another Array/Map.
+     *
+     * The method returns a ParseClient*.  In most cases "return this;" will be the right answer,
+     * but a different ParseClient may be returned, which the parser will begin using. If the method
+     * returns nullptr, parsing will be aborted immediately.
+     */
+    virtual ParseClient* item(std::unique_ptr<Item>& item, const uint8_t* hdrBegin,
+                              const uint8_t* valueBegin, const uint8_t* end) = 0;
+
+    /**
+     * Called when the end of a compound item (MAP or ARRAY) is found.  The item argument will be
+     * the same one passed to the item() call -- and may be empty if item() moved its value out.
+     * hdrBegin, valueBegin and end point to the beginning of the item header, the beginning of the
+     * first contained value, and one past the end of the last contained value, respectively.
+     *
+     * Note that the Item will have no content.
+     *
+     * As with item(), itemEnd() can change the ParseClient by returning a different one, or end the
+     * parsing by returning nullptr;
+     */
+    virtual ParseClient* itemEnd(std::unique_ptr<Item>& item, const uint8_t* hdrBegin,
+                                 const uint8_t* valueBegin, const uint8_t* end) = 0;
+
+    /**
+     * Called when parsing encounters an error.  position is set to the first unparsed byte (one
+     * past the last successfully-parsed byte) and errorMessage contains an message explaining what
+     * sort of error occurred.
+     */
+    virtual void error(const uint8_t* position, const std::string& errorMessage) = 0;
+};
+
+}  // namespace cppbor