build: vendor bcur

CMakeLists.txt

@@ -98,9 +98,10 @@ find_package(QREncode REQUIRED)
 
 # bc-ur
 if(WITH_SCANNER)
-    find_path(BCUR_INCLUDE_DIR "bcur/bc-ur.hpp")
+    find_package(BCUR REQUIRED)
-    find_library(BCUR_LIBRARY bcur)
+    if(BCUR_VENDORED)
-    message(STATUS "bcur: libraries at ${BCUR_INCLUDE_DIR}")
+        add_subdirectory(src/third-party/bcur EXCLUDE_FROM_ALL)
+    endif()
 endif()
 
 # Polyseed

cmake/FindBCUR.cmake

@@ -0,0 +1,12 @@
+find_path(BCUR_INCLUDE_DIR "bcur/bc-ur.hpp")
+find_library(BCUR_LIBRARY bcur)
+
+if (NOT BCUR_INCLUDE_DIR OR NOT BCUR_LIBRARY)
+    MESSAGE(STATUS "Could not find installed BCUR, using vendored library instead")
+    set(BCUR_VENDORED "ON")
+    set(BCUR_INCLUDE_DIR ${CMAKE_SOURCE_DIR}/src/third-party)
+    set(BCUR_LIBRARY bcur_static)
+endif()
+
+message(STATUS "BCUR PATH ${BCUR_INCLUDE_DIR}")
+message(STATUS "BCUR LIBRARY ${BCUR_LIBRARY}")

src/qrcode/scanner/QrCodeScanDialog.h

@@ -13,8 +13,6 @@
 
 #include "QrScanThread.h"
 
-#include <bcur/ur-decoder.hpp>
-
 namespace Ui {
     class QrCodeScanDialog;
 }

src/qrcode/scanner/QrCodeScanWidget.cpp

@@ -9,7 +9,6 @@
 
 #include "utils/config.h"
 #include "utils/Icons.h"
-#include <bcur/bc-ur.hpp>
 
 QrCodeScanWidget::QrCodeScanWidget(QWidget *parent)
         : QWidget(parent)

src/qrcode/scanner/QrCodeScanWidget.h

@@ -13,6 +13,7 @@
 
 #include "QrScanThread.h"
 
+#include <bcur/bc-ur.hpp>
 #include <bcur/ur-decoder.hpp>
 
 namespace Ui {

src/third-party/bcur/CMakeLists.txt

@@ -0,0 +1,21 @@
+cmake_minimum_required(VERSION 3.5)
+
+project(bcur)
+
+set(bcur_sources
+        bytewords.cpp
+        fountain-encoder.cpp
+        fountain-decoder.cpp
+        fountain-utils.cpp
+        xoshiro256.cpp
+        utils.cpp
+        random-sampler.cpp
+        ur-decoder.cpp
+        ur.cpp
+        ur-encoder.cpp
+        memzero.c
+        crc32.c
+        sha2.c)
+
+add_library(bcur_static STATIC ${bcur_sources})
+set_property(TARGET bcur_static PROPERTY POSITION_INDEPENDENT_CODE ON)

src/third-party/bcur/README.md

@@ -0,0 +1,2 @@
+vendored from https://github.com/BlockchainCommons/bc-ur
+2bfc3fd396498c2519273aeaa732abf7ea7d24b8

src/third-party/bcur/bc-ur.hpp

@@ -0,0 +1,28 @@
+//
+//  bc-ur.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_HPP
+#define BC_UR_HPP
+
+#include "ur.hpp"
+#include "ur-encoder.hpp"
+#include "ur-decoder.hpp"
+#include "fountain-encoder.hpp"
+#include "fountain-decoder.hpp"
+#include "fountain-utils.hpp"
+#include "utils.hpp"
+#include "bytewords.hpp"
+#include "xoshiro256.hpp"
+#include "random-sampler.hpp"
+
+namespace ur {
+
+#include "cbor-lite.hpp"
+
+}
+
+#endif // BC_UR_HPP

src/third-party/bcur/bytewords.cpp

@@ -0,0 +1,169 @@
+//
+//  bytewords.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "bytewords.hpp"
+#include "utils.hpp"
+#include <stdexcept>
+#include <algorithm>
+
+namespace ur {
+
+using namespace std;
+
+static const char* bytewords = "ableacidalsoapexaquaarchatomauntawayaxisbackbaldbarnbeltbetabiasbluebodybragbrewbulbbuzzcalmcashcatschefcityclawcodecolacookcostcruxcurlcuspcyandarkdatadaysdelidicedietdoordowndrawdropdrumdulldutyeacheasyechoedgeepicevenexamexiteyesfactfairfernfigsfilmfishfizzflapflewfluxfoxyfreefrogfuelfundgalagamegeargemsgiftgirlglowgoodgraygrimgurugushgyrohalfhanghardhawkheathelphighhillholyhopehornhutsicedideaidleinchinkyintoirisironitemjadejazzjoinjoltjowljudojugsjumpjunkjurykeepkenokeptkeyskickkilnkingkitekiwiknoblamblavalazyleaflegsliarlimplionlistlogoloudloveluaulucklungmainmanymathmazememomenumeowmildmintmissmonknailnavyneednewsnextnoonnotenumbobeyoboeomitonyxopenovalowlspaidpartpeckplaypluspoempoolposepuffpumapurrquadquizraceramprealredorichroadrockroofrubyruinrunsrustsafesagascarsetssilkskewslotsoapsolosongstubsurfswantacotasktaxitenttiedtimetinytoiltombtoystriptunatwinuglyundouniturgeuservastveryvetovialvibeviewvisavoidvowswallwandwarmwaspwavewaxywebswhatwhenwhizwolfworkyankyawnyellyogayurtzapszerozestzinczonezoom";
+
+uint8_t decode_word(const string& word, size_t word_len) {
+    if(word.length() != word_len) {
+        throw runtime_error("Invalid Bytewords.");
+    }
+
+    static int16_t* array = NULL;
+    const size_t dim = 26;
+
+    // Since the first and last letters of each Byteword are unique,
+    // we can use them as indexes into a two-dimensional lookup table.
+    // This table is generated lazily.
+    if(array == NULL) {
+        const size_t array_len = dim * dim;
+        array = (int16_t*)malloc(array_len * sizeof(int16_t));
+        for(size_t i = 0; i < array_len; i++) {
+            array[i] = -1;
+        }
+        for(size_t i = 0; i < 256; i++) {
+            const char* byteword = bytewords + i * 4;
+            size_t x = byteword[0] - 'a';
+            size_t y = byteword[3] - 'a';
+            size_t offset = y * dim + x;
+            array[offset] = i;
+        }
+    }
+
+    // If the coordinates generated by the first and last letters are out of bounds,
+    // or the lookup table contains -1 at the coordinates, then the word is not valid.
+    int x = tolower(word[0]) - 'a';
+    int y = tolower(word[word_len == 4 ? 3 : 1]) - 'a';
+    if(!(0 <= x && x < dim && 0 <= y && y < dim)) {
+        throw runtime_error("Invalid Bytewords.");
+    }
+    size_t offset = y * dim + x;
+    int16_t value = array[offset];
+    if(value == -1) {
+        throw runtime_error("Invalid Bytewords.");
+    }
+
+    // If we're decoding a full four-letter word, verify that the two middle letters are correct.
+    if(word_len == 4) {
+        const char* byteword = bytewords + value * 4;
+        int c1 = tolower(word[1]);
+        int c2 = tolower(word[2]);
+        if(c1 != byteword[1] || c2 != byteword[2]) {
+            throw runtime_error("Invalid Bytewords.");
+        }
+    }
+
+    // Successful decode.
+    return value;
+}
+
+static const string get_word(uint8_t index) {
+    auto p = &bytewords[index * 4];
+    return string(p, p + 4);
+}
+
+static const string get_minimal_word(uint8_t index) {
+    string word;
+    word.reserve(2);
+    auto p = &bytewords[index * 4];
+    word.push_back(*p);
+    word.push_back(*(p + 3));
+    return word;
+}
+
+static const string encode(const ByteVector& buf, const string& separator) {
+    auto len = buf.size();
+    StringVector words;
+    words.reserve(len);
+    for(int i = 0; i < len; i++) {
+        auto byte = buf[i];
+        words.push_back(get_word(byte));
+    }
+    return join(words, separator);
+}
+
+static const ByteVector add_crc(const ByteVector& buf) {
+    auto crc_buf = crc32_bytes(buf);
+    auto result = buf;
+    append(result, crc_buf);
+    return result;
+}
+
+static const string encode_with_separator(const ByteVector& buf, const string& separator) {
+    auto crc_buf = add_crc(buf);
+    return encode(crc_buf, separator);
+}
+
+static const string encode_minimal(const ByteVector& buf) {
+    string result;
+    auto crc_buf = add_crc(buf);
+    auto len = crc_buf.size();
+    for(int i = 0; i < len; i++) {
+        auto byte = crc_buf[i];
+        result.append(get_minimal_word(byte));
+    }
+    return result;
+}
+
+static const ByteVector _decode(const string& s, char separator, size_t word_len) {
+    StringVector words;
+    if(word_len == 4) {
+        words = split(s, separator);
+    } else {
+        words = partition(s, 2);
+    }
+    ByteVector buf;
+    transform(words.begin(), words.end(), back_inserter(buf), [&](auto word) { return decode_word(word, word_len); });
+    if(buf.size() < 5) {
+        throw runtime_error("Invalid Bytewords.");
+    }
+    auto p = split(buf, buf.size() - 4);
+    auto body = p.first;
+    auto body_checksum = p.second;
+    auto checksum = crc32_bytes(body);
+    if(checksum != body_checksum) {
+        throw runtime_error("Invalid Bytewords.");
+    }
+
+    return body;
+}
+
+string Bytewords::encode(style style, const ByteVector& bytes) {
+    switch(style) {
+        case standard:
+            return encode_with_separator(bytes, " ");
+        case uri:
+            return encode_with_separator(bytes, "-");
+        case minimal:
+            return encode_minimal(bytes);
+        default:
+            assert(false);
+    }
+}
+
+ByteVector Bytewords::decode(style style, const string& string) {
+    switch(style) {
+        case standard:
+            return _decode(string, ' ', 4);
+        case uri:
+            return _decode(string, '-', 4);
+        case minimal:
+            return _decode(string, 0, 2);
+        default:
+            assert(false);
+    }
+}
+
+}

src/third-party/bcur/bytewords.hpp

@@ -0,0 +1,30 @@
+//
+//  bytewords.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_BYTEWORDS_HPP
+#define BC_UR_BYTEWORDS_HPP
+
+#include <string>
+#include "utils.hpp"
+
+namespace ur {
+
+class Bytewords final {
+public:
+    enum style {
+        standard,
+        uri,
+        minimal
+    };
+
+    static std::string encode(style style, const ByteVector& bytes);
+    static ByteVector decode(style style, const std::string& string);
+};
+
+}
+
+#endif // BC_UR_BYTEWORDS_HPP

src/third-party/bcur/cbor-lite.hpp

@@ -0,0 +1,558 @@
+#ifndef BC_UR_CBOR_LITE_HPP
+#define BC_UR_CBOR_LITE_HPP
+
+// From: https://bitbucket.org/isode/cbor-lite/raw/6c770624a97e3229e3f200be092c1b9c70a60ef1/include/cbor-lite/codec.h
+
+// This file is part of CBOR-lite which is copyright Isode Limited
+// and others and released under a MIT license. For details, see the
+// COPYRIGHT.md file in the top-level folder of the CBOR-lite software
+// distribution.
+
+#include <exception>
+#include <iterator>
+#include <string>
+#include <type_traits>
+#include <cstdint>
+
+#ifndef __BYTE_ORDER__
+#error __BYTE_ORDER__ not defined
+#elif (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__) && (__BYTE_ORDER__ != __ORDER_BIG_ENDIAN__)
+#error __BYTE_ORDER__ neither __ORDER_BIG_ENDIAN__ nor __ORDER_LITTLE_ENDIAN__
+#endif
+
+namespace CborLite {
+
+class Exception : public std::exception {
+public:
+    Exception() noexcept {
+    }
+    virtual ~Exception() noexcept = default;
+
+    explicit Exception(const char* d) noexcept {
+        what_ += std::string(": ") + d;
+    }
+
+    explicit Exception(const std::string& d) noexcept {
+        what_ += ": " + d;
+    }
+
+    Exception(const Exception& e) noexcept : what_(e.what_) {
+    }
+
+    Exception(Exception&& e) noexcept : what_(std::move(e.what_)) {
+        // Note that e.what_ is not re-initialized to "CBOR Exception" as
+        // the moved-from object is not expected to ever be reused.
+    }
+
+    Exception& operator=(const Exception&) = delete;
+    Exception& operator=(Exception&&) = delete;
+
+    virtual const char* what() const noexcept {
+        return what_.c_str();
+    }
+
+private:
+    std::string what_ = "CBOR Exception";
+};
+
+using Tag = std::uint_fast64_t;
+
+namespace Major {
+constexpr Tag unsignedInteger = 0u;
+constexpr Tag negativeInteger = 1u << 5;
+constexpr Tag byteString = 2u << 5;
+constexpr Tag textString = 3u << 5;
+constexpr Tag array = 4u << 5;
+constexpr Tag map = 5u << 5;
+constexpr Tag semantic = 6u << 5;
+constexpr Tag floatingPoint = 7u << 5;
+constexpr Tag simple = 7u << 5;
+constexpr Tag mask = 0xe0u;
+} // namespace Major
+
+namespace Minor {
+constexpr Tag length1 = 24u;
+constexpr Tag length2 = 25u;
+constexpr Tag length4 = 26u;
+constexpr Tag length8 = 27u;
+
+constexpr Tag False = 20u;
+constexpr Tag True = 21u;
+constexpr Tag null = 22u;
+constexpr Tag undefined = 23u;
+constexpr Tag halfFloat = 25u; // not implemented
+constexpr Tag singleFloat = 26u;
+constexpr Tag doubleFloat = 27u;
+
+constexpr Tag dataTime = 0u;
+constexpr Tag epochDataTime = 1u;
+constexpr Tag positiveBignum = 2u;
+constexpr Tag negativeBignum = 3u;
+constexpr Tag decimalFraction = 4u;
+constexpr Tag bigfloat = 5u;
+constexpr Tag convertBase64Url = 21u;
+constexpr Tag convertBase64 = 22u;
+constexpr Tag convertBase16 = 23u;
+constexpr Tag cborEncodedData = 24u;
+constexpr Tag uri = 32u;
+constexpr Tag base64Url = 33u;
+constexpr Tag base64 = 34u;
+constexpr Tag regex = 35u;
+constexpr Tag mimeMessage = 36u;
+constexpr Tag selfDescribeCbor = 55799u;
+
+constexpr Tag mask = 0x1fu;
+} // namespace Minor
+
+constexpr Tag undefined = Major::semantic + Minor::undefined;
+
+using Flags = unsigned;
+namespace Flag {
+constexpr Flags none = 0;
+constexpr Flags requireMinimalEncoding = 1 << 0;
+} // namespace Flag
+
+template <typename Type>
+typename std::enable_if<std::is_unsigned<Type>::value, std::size_t>::type length(Type val) {
+    if (val < 24) return 0;
+    for (std::size_t i = 1; i <= ((sizeof val) >> 1); i <<= 1) {
+        if (!(val >> (i << 3))) return i;
+    }
+    return sizeof val;
+}
+
+template <typename Buffer>
+typename std::enable_if<std::is_class<Buffer>::value, std::size_t>::type encodeTagAndAdditional(
+    Buffer& buffer, Tag tag, Tag additional) {
+    buffer.push_back(static_cast<char>(tag + additional));
+    return 1;
+}
+
+template <typename InputIterator>
+typename std::enable_if<std::is_class<InputIterator>::value, std::size_t>::type decodeTagAndAdditional(
+    InputIterator& pos, InputIterator end, Tag& tag, Tag& additional, Flags = Flag::none) {
+    if (pos == end) throw Exception("not enough input");
+    auto octet = *(pos++);
+    tag = octet & Major::mask;
+    additional = octet & Minor::mask;
+    return 1;
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value && std::is_unsigned<Type>::value, std::size_t>::type encodeTagAndValue(
+    Buffer& buffer, Tag tag, const Type t) {
+    auto len = length(t);
+    buffer.reserve(buffer.size() + len + 1);
+
+    switch (len) {
+    case 8:
+        encodeTagAndAdditional(buffer, tag, Minor::length8);
+        break;
+    case 4:
+        encodeTagAndAdditional(buffer, tag, Minor::length4);
+        break;
+    case 2:
+        encodeTagAndAdditional(buffer, tag, Minor::length2);
+        break;
+    case 1:
+        encodeTagAndAdditional(buffer, tag, Minor::length1);
+        break;
+    case 0:
+        return encodeTagAndAdditional(buffer, tag, t);
+    default:
+        throw Exception("too long");
+    }
+
+    switch (len) {
+    case 8:
+        buffer.push_back((t >> 56) & 0xffU);
+        buffer.push_back((t >> 48) & 0xffU);
+        buffer.push_back((t >> 40) & 0xffU);
+        buffer.push_back((t >> 32) & 0xffU);
+    case 4:
+        buffer.push_back((t >> 24) & 0xffU);
+        buffer.push_back((t >> 16) & 0xffU);
+    case 2:
+        buffer.push_back((t >> 8) & 0xffU);
+    case 1:
+        buffer.push_back(t & 0xffU);
+    }
+
+    return 1 + len;
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && std::is_unsigned<Type>::value, std::size_t>::type decodeTagAndValue(
+    InputIterator& pos, InputIterator end, Tag& tag, Type& t, Flags flags = Flag::none) {
+    if (pos == end) throw Exception("not enough input");
+    auto additional = Minor::undefined;
+    auto len = decodeTagAndAdditional(pos, end, tag, additional, flags);
+    if (additional < Minor::length1) {
+        t = additional;
+        return len;
+    }
+    t = 0u;
+    switch (additional) {
+    case Minor::length8:
+        if (std::distance(pos, end) < 8) throw Exception("not enough input");
+        t |= static_cast<Type>(reinterpret_cast<const unsigned char&>(*(pos++))) << 56;
+        t |= static_cast<Type>(reinterpret_cast<const unsigned char&>(*(pos++))) << 48;
+        t |= static_cast<Type>(reinterpret_cast<const unsigned char&>(*(pos++))) << 40;
+        t |= static_cast<Type>(reinterpret_cast<const unsigned char&>(*(pos++))) << 32;
+        len += 4;
+        if ((flags & Flag::requireMinimalEncoding) && !t) throw Exception("encoding not minimal");
+    case Minor::length4:
+        if (std::distance(pos, end) < 4) throw Exception("not enough input");
+        t |= static_cast<Type>(reinterpret_cast<const unsigned char&>(*(pos++))) << 24;
+        t |= static_cast<Type>(reinterpret_cast<const unsigned char&>(*(pos++))) << 16;
+        len += 2;
+        if ((flags & Flag::requireMinimalEncoding) && !t) throw Exception("encoding not minimal");
+    case Minor::length2:
+        if (std::distance(pos, end) < 2) throw Exception("not enough input");
+        t |= static_cast<Type>(reinterpret_cast<const unsigned char&>(*(pos++))) << 8;
+        len++;
+        if ((flags & Flag::requireMinimalEncoding) && !t) throw Exception("encoding not minimal");
+    case Minor::length1:
+        if (std::distance(pos, end) < 1) throw Exception("not enough input");
+        t |= static_cast<Type>(reinterpret_cast<const unsigned char&>(*(pos++)));
+        len++;
+        if ((flags & Flag::requireMinimalEncoding) && t < 24) throw Exception("encoding not minimal");
+        return len;
+    }
+    throw Exception("bad additional value");
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value, std::size_t>::type encodeUnsigned(Buffer& buffer, const Type& t) {
+    return encodeTagAndValue(buffer, Major::unsignedInteger, t);
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && std::is_unsigned<Type>::value && !std::is_const<Type>::value,
+    std::size_t>::type
+decodeUnsigned(InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    auto len = decodeTagAndValue(pos, end, tag, t, flags);
+    if (tag != Major::unsignedInteger) throw Exception("not Unsigned");
+    return len;
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value, std::size_t>::type encodeNegative(Buffer& buffer, const Type& t) {
+    return encodeTagAndValue(buffer, Major::negativeInteger, t);
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && std::is_unsigned<Type>::value && !std::is_const<Type>::value,
+    std::size_t>::type
+decodeNegative(InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    auto len = decodeTagAndValue(pos, end, tag, t, flags);
+    if (tag != Major::negativeInteger) throw Exception("not Unsigned");
+    return len;
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value, std::size_t>::type encodeInteger(Buffer& buffer, const Type& t) {
+    if (t >= 0) {
+        unsigned long long val = t;
+        return encodeUnsigned(buffer, val);
+    } else {
+        unsigned long long val = -t - 1;
+        return encodeNegative(buffer, val);
+    }
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && std::is_signed<Type>::value && !std::is_const<Type>::value,
+    std::size_t>::type
+decodeInteger(InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    unsigned long long val;
+    auto len = decodeTagAndValue(pos, end, tag, val, flags);
+    switch (tag) {
+    case Major::unsignedInteger:
+        t = val;
+        break;
+    case Major::negativeInteger:
+        t = -1 - static_cast<long long>(val);
+        break;
+    default:
+        throw Exception("not integer");
+    }
+    return len;
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value && std::is_same<bool, Type>::value, std::size_t>::type encodeBool(
+    Buffer& buffer, const Type& t) {
+    return encodeTagAndAdditional(buffer, Major::simple, t ? Minor::True : Minor::False);
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && std::is_same<bool, Type>::value && !std::is_const<Type>::value,
+    std::size_t>::type
+decodeBool(InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    auto value = undefined;
+    auto len = decodeTagAndValue(pos, end, tag, value, flags);
+    if (tag == Major::simple) {
+        if (value == Minor::True) {
+            t = true;
+            return len;
+        } else if (value == Minor::False) {
+            t = false;
+            return len;
+        }
+        throw Exception("not Boolean");
+    }
+    throw Exception("not Simple");
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value, std::size_t>::type encodeBytes(Buffer& buffer, const Type& t) {
+    auto len = encodeTagAndValue(buffer, Major::byteString, t.size());
+    buffer.insert(std::end(buffer), std::begin(t), std::end(t));
+    return len + t.size();
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && !std::is_const<Type>::value, std::size_t>::type decodeBytes(
+    InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    auto value = undefined;
+    auto len = decodeTagAndValue(pos, end, tag, value, flags);
+    if (tag != Major::byteString) throw Exception("not ByteString");
+
+    auto dist = std::distance(pos, end);
+    if (dist < static_cast<decltype(dist)>(value)) throw Exception("not enough input");
+    t.insert(std::end(t), pos, pos + value);
+    std::advance(pos, value);
+    return len + value;
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value && std::is_unsigned<Type>::value, std::size_t>::type encodeEncodedBytesPrefix(
+    Buffer& buffer, const Type& t) {
+    auto len = encodeTagAndValue(buffer, Major::semantic, Minor::cborEncodedData);
+    return len + encodeTagAndValue(buffer, Major::byteString, t);
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && !std::is_const<Type>::value, std::size_t>::type
+decodeEncodedBytesPrefix(InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    auto value = undefined;
+    auto len = decodeTagAndValue(pos, end, tag, value, flags);
+    if (tag != Major::semantic || value != Minor::cborEncodedData) {
+        throw Exception("not CBOR Encoded Data");
+    }
+    tag = undefined;
+    len += decodeTagAndValue(pos, end, tag, value, flags);
+    if (tag != Major::byteString) throw Exception("not ByteString");
+    t = value;
+    return len;
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value, std::size_t>::type encodeEncodedBytes(Buffer& buffer, const Type& t) {
+    auto len = encodeTagAndValue(buffer, Major::semantic, Minor::cborEncodedData);
+    return len + encodeBytes(buffer, t);
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && !std::is_const<Type>::value, std::size_t>::type decodeEncodedBytes(
+    InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    auto value = undefined;
+    auto len = decodeTagAndValue(pos, end, tag, value, flags);
+    if (tag != Major::semantic || value != Minor::cborEncodedData) {
+        throw Exception("not CBOR Encoded Data");
+    }
+    return len + decodeBytes(pos, end, t, flags);
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value, std::size_t>::type encodeText(Buffer& buffer, const Type& t) {
+    auto len = encodeTagAndValue(buffer, Major::textString, t.size());
+    buffer.insert(std::end(buffer), std::begin(t), std::end(t));
+    return len + t.size();
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && !std::is_const<Type>::value, std::size_t>::type decodeText(
+    InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    auto value = undefined;
+    auto len = decodeTagAndValue(pos, end, tag, value, flags);
+    if (tag != Major::textString) throw Exception("not TextString");
+
+    auto dist = std::distance(pos, end);
+    if (dist < static_cast<decltype(dist)>(value)) throw Exception("not enough input");
+    t.insert(std::end(t), pos, pos + value);
+    std::advance(pos, value);
+    return len + value;
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value && std::is_unsigned<Type>::value, std::size_t>::type encodeArraySize(
+    Buffer& buffer, const Type& t) {
+    return encodeTagAndValue(buffer, Major::array, t);
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && !std::is_const<Type>::value && std::is_unsigned<Type>::value,
+    std::size_t>::type
+decodeArraySize(InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    auto value = undefined;
+    auto len = decodeTagAndValue(pos, end, tag, value, flags);
+    if (tag != Major::array) throw Exception("not Array");
+    t = value;
+    return len;
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value && std::is_unsigned<Type>::value, std::size_t>::type encodeMapSize(
+    Buffer& buffer, const Type& t) {
+    return encodeTagAndValue(buffer, Major::map, t);
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && !std::is_const<Type>::value && std::is_unsigned<Type>::value,
+    std::size_t>::type
+decodeMapSize(InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    auto tag = undefined;
+    auto value = undefined;
+    auto len = decodeTagAndValue(pos, end, tag, value, flags);
+    if (tag != Major::map) throw Exception("not Map");
+    t = value;
+    return len;
+}
+
+//
+// codec-fp.h
+//
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value && std::is_floating_point<Type>::value, std::size_t>::type encodeSingleFloat(
+    Buffer& buffer, const Type& t) {
+    static_assert(sizeof(float) == 4, "sizeof(float) expected to be 4");
+    auto len = encodeTagAndAdditional(buffer, Major::floatingPoint, Minor::singleFloat);
+    const char* p;
+    float ft;
+    if (sizeof(t) == sizeof(ft)) {
+        p = reinterpret_cast<const char*>(&t);
+    } else {
+        ft = static_cast<decltype(ft)>(t);
+        p = reinterpret_cast<char*>(&ft);
+    }
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    for (auto i = 0u; i < sizeof(ft); ++i) {
+        buffer.push_back(p[i]);
+    }
+#else
+    for (auto i = 1u; i <= sizeof(ft); ++i) {
+        buffer.push_back(p[sizeof(ft) - i]);
+    }
+#endif
+    return len + sizeof(ft);
+}
+
+template <typename Buffer, typename Type>
+typename std::enable_if<std::is_class<Buffer>::value && std::is_floating_point<Type>::value, std::size_t>::type encodeDoubleFloat(
+    Buffer& buffer, const Type& t) {
+    static_assert(sizeof(double) == 8, "sizeof(double) expected to be 8");
+    auto len = encodeTagAndAdditional(buffer, Major::floatingPoint, Minor::doubleFloat);
+    const char* p;
+    double ft;
+    if (sizeof(t) == sizeof(ft)) {
+        p = reinterpret_cast<const char*>(&t);
+    } else {
+        ft = t;
+        p = reinterpret_cast<char*>(&ft);
+    }
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    for (auto i = 0u; i < sizeof(ft); ++i) {
+        buffer.push_back(p[i]);
+    }
+#else
+    for (auto i = 1u; i <= sizeof(ft); ++i) {
+        buffer.push_back(p[sizeof(ft) - i]);
+    }
+#endif
+    return len + sizeof(ft);
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && std::is_floating_point<Type>::value && !std::is_const<Type>::value,
+    std::size_t>::type
+decodeSingleFloat(InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    static_assert(sizeof(float) == 4, "sizeof(float) expected to be 4");
+    auto tag = undefined;
+    auto value = undefined;
+    auto len = decodeTagAndAdditional(pos, end, tag, value, flags);
+    if (tag != Major::floatingPoint) throw Exception("not floating-point");
+    if (value != Minor::singleFloat) throw Exception("not single-precision floating-point");
+    if (std::distance(pos, end) < static_cast<int>(sizeof(float))) throw Exception("not enough input");
+
+    char* p;
+    float ft;
+    if (sizeof(t) == sizeof(ft)) {
+        p = reinterpret_cast<char*>(&t);
+    } else {
+        ft = static_cast<decltype(ft)>(t);
+        p = reinterpret_cast<char*>(&ft);
+    }
+
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    for (auto i = 0u; i < sizeof(ft); ++i) {
+        p[i] = *(pos++);
+    }
+#else
+    for (auto i = 1u; i <= sizeof(ft); ++i) {
+        p[sizeof(ft) - i] = *(pos++);
+    }
+#endif
+    if (sizeof(t) != sizeof(ft)) t = ft;
+    return len + sizeof(ft);
+}
+
+template <typename InputIterator, typename Type>
+typename std::enable_if<std::is_class<InputIterator>::value && std::is_floating_point<Type>::value && !std::is_const<Type>::value,
+    std::size_t>::type
+decodeDoubleFloat(InputIterator& pos, InputIterator end, Type& t, Flags flags = Flag::none) {
+    static_assert(sizeof(double) == 8, "sizeof(double) expected to be 8");
+    auto tag = undefined;
+    auto value = undefined;
+    auto len = decodeTagAndAdditional(pos, end, tag, value, flags);
+    if (tag != Major::floatingPoint) throw Exception("not floating-point");
+    if (value != Minor::doubleFloat) throw Exception("not double-precision floating-point");
+    if (std::distance(pos, end) < static_cast<int>(sizeof(double))) throw Exception("not enough input");
+
+    char* p;
+    double ft;
+    if (sizeof(t) == sizeof(ft)) {
+        p = reinterpret_cast<char*>(&t);
+    } else {
+        ft = t;
+        p = reinterpret_cast<char*>(&ft);
+    }
+
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    for (auto i = 0u; i < sizeof(ft); ++i) {
+        p[i] = *(pos++);
+    }
+#else
+    for (auto i = 1u; i <= sizeof(ft); ++i) {
+        p[sizeof(ft) - i] = *(pos++);
+    }
+#endif
+
+    if (sizeof(t) != sizeof(ft)) t = ft;
+    return len + sizeof(ft);
+}
+
+} // namespace CborLite
+
+#endif // BC_UR_CBOR_LITE_HPP

src/third-party/bcur/crc32.c

@@ -0,0 +1,43 @@
+//
+//  crc32.c
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "crc32.h"
+#include <memory.h>
+
+#ifdef ARDUINO
+#define htonl(x) __builtin_bswap32((uint32_t) (x))
+#elif _WIN32
+#include <winsock2.h>
+#else
+#include <arpa/inet.h>
+#endif
+
+uint32_t ur_crc32(const uint8_t* bytes, size_t len) {
+    static uint32_t* table = NULL;
+
+    if(table == NULL) {
+        table = malloc(256 * sizeof(uint32_t));
+        for(int i = 0; i < 256; i++) {
+            uint32_t c = i;
+            for(int j = 0; j < 8; j++) {
+                c = (c % 2 == 0) ? (c >> 1) : (0xEDB88320 ^ (c >> 1));
+            }
+            table[i] = c;
+        }
+    }
+
+    uint32_t crc = ~0;
+    for(int i = 0; i < len; i++) {
+        uint32_t byte = bytes[i];
+        crc = (crc >> 8) ^ table[(crc ^ byte) & 0xFF];
+    }
+    return ~crc;
+}
+
+uint32_t ur_crc32n(const uint8_t* bytes, size_t len) {
+    return htonl(ur_crc32(bytes, len));
+}

src/third-party/bcur/crc32.h

@@ -0,0 +1,28 @@
+//
+//  crc32.h
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_CRC32_H
+#define BC_UR_CRC32_H
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Returns the CRC-32 checksum of the input buffer.
+uint32_t ur_crc32(const uint8_t* bytes, size_t len);
+
+// Returns the CRC-32 checksum of the input buffer in network byte order (big endian).
+uint32_t ur_crc32n(const uint8_t* bytes, size_t len);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // BC_UR_CRC32_H

src/third-party/bcur/fountain-decoder.cpp

@@ -0,0 +1,253 @@
+//
+//  fountain-decoder.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "fountain-decoder.hpp"
+#include <utility>
+#include <algorithm>
+#include <iostream>
+#include <string>
+#include <cmath>
+#include <numeric>
+
+using namespace std;
+
+namespace ur {
+
+FountainDecoder::FountainDecoder() { }
+
+FountainDecoder::Part::Part(const FountainEncoder::Part& p)
+    : indexes_(choose_fragments(p.seq_num(), p.seq_len(), p.checksum()))
+    , data_(p.data())
+{
+}
+
+FountainDecoder::Part::Part(PartIndexes& indexes, ByteVector& data)
+    : indexes_(indexes)
+    , data_(data)
+{
+}
+
+const ByteVector FountainDecoder::join_fragments(const vector<ByteVector>& fragments, size_t message_len) {
+    auto message = join(fragments);
+    return take_first(message, message_len);
+}
+
+double FountainDecoder::estimated_percent_complete() const {
+    if(is_complete()) return 1;
+    if(!_expected_part_indexes.has_value()) return 0;
+    auto estimated_input_parts = expected_part_count() * 1.75;
+    return min(0.99, processed_parts_count_ / estimated_input_parts);
+}
+
+bool FountainDecoder::receive_part(FountainEncoder::Part& encoder_part) {
+    // Don't process the part if we're already done
+    if(is_complete()) return false;
+
+    // Don't continue if this part doesn't validate
+    if(!validate_part(encoder_part)) return false;
+
+    // Add this part to the queue
+    auto p = Part(encoder_part);
+    last_part_indexes_ = p.indexes();
+    enqueue(p);
+
+    // Process the queue until we're done or the queue is empty
+    while(!is_complete() && !_queued_parts.empty()) {
+        process_queue_item();
+    }
+
+    // Keep track of how many parts we've processed
+    processed_parts_count_ += 1;
+
+    //print_part_end();
+
+    return true;
+}
+
+void FountainDecoder::enqueue(Part &&p) {
+    _queued_parts.push_back(p);
+}
+
+void FountainDecoder::enqueue(const Part &p) {
+    _queued_parts.push_back(p);
+}
+
+void FountainDecoder::process_queue_item() {
+    auto part = _queued_parts.front();
+    //print_part(part);
+    _queued_parts.pop_front();
+    if(part.is_simple()) {
+        process_simple_part(part);
+    } else {
+        process_mixed_part(part);
+    }
+    //print_state();
+}
+
+void FountainDecoder::reduce_mixed_by(const Part& p) {
+    // Reduce all the current mixed parts by the given part
+    vector<Part> reduced_parts;
+    for(auto i = _mixed_parts.begin(); i != _mixed_parts.end(); i++) {
+        reduced_parts.push_back(reduce_part_by_part(i->second, p));
+    }
+
+    // Collect all the remaining mixed parts
+    PartDict new_mixed;
+    for(auto reduced_part: reduced_parts) {
+        // If this reduced part is now simple
+        if(reduced_part.is_simple()) {
+            // Add it to the queue
+            enqueue(reduced_part);
+        } else {
+            // Otherwise, add it to the list of current mixed parts
+            new_mixed.insert(pair(reduced_part.indexes(), reduced_part));
+        }
+    }
+    _mixed_parts = new_mixed;
+}
+
+FountainDecoder::Part FountainDecoder::reduce_part_by_part(const Part& a, const Part& b) const {
+    // If the fragments mixed into `b` are a strict (proper) subset of those in `a`...
+    if(is_strict_subset(b.indexes(), a.indexes())) {
+        // The new fragments in the revised part are `a` - `b`.
+        auto new_indexes = set_difference(a.indexes(), b.indexes());
+        // The new data in the revised part are `a` XOR `b`
+        auto new_data = xor_with(a.data(), b.data());
+        return Part(new_indexes, new_data);
+    } else {
+        // `a` is not reducable by `b`, so return a
+        return a;
+    }
+}
+
+void FountainDecoder::process_simple_part(Part& p) {
+    // Don't process duplicate parts
+    auto fragment_index = p.index();
+    if(contains(received_part_indexes_, fragment_index)) return;
+
+    // Record this part
+    _simple_parts.insert(pair(p.indexes(), p));
+    received_part_indexes_.insert(fragment_index);
+
+    // If we've received all the parts
+    if(received_part_indexes_ == _expected_part_indexes) {
+        // Reassemble the message from its fragments
+        vector<Part> sorted_parts;
+        transform(_simple_parts.begin(), _simple_parts.end(), back_inserter(sorted_parts), [&](auto elem) { return elem.second; });
+        sort(sorted_parts.begin(), sorted_parts.end(),
+            [](const Part& a, const Part& b) -> bool {
+                return a.index() < b.index();
+            }
+        );
+        vector<ByteVector> fragments;
+        transform(sorted_parts.begin(), sorted_parts.end(), back_inserter(fragments), [&](auto part) { return part.data(); });
+        auto message = join_fragments(fragments, *_expected_message_len);
+
+        // Verify the message checksum and note success or failure
+        auto checksum = crc32_int(message);
+        if(checksum == _expected_checksum) {
+            result_ = message;
+        } else {
+            result_ = InvalidChecksum();
+        }
+    } else {
+        // Reduce all the mixed parts by this part
+        reduce_mixed_by(p);
+    }
+}
+
+void FountainDecoder::process_mixed_part(const Part& p) {
+    // Don't process duplicate parts
+    if(any_of(_mixed_parts.begin(), _mixed_parts.end(), [&](auto r) { return r.first == p.indexes(); })) {
+        return;
+    }
+
+    // Reduce this part by all the others
+    auto p2 = accumulate(_simple_parts.begin(), _simple_parts.end(), p, [&](auto p, auto r) { return reduce_part_by_part(p, r.second); });
+    p2 = accumulate(_mixed_parts.begin(), _mixed_parts.end(), p2, [&](auto p, auto r) { return reduce_part_by_part(p, r.second); });
+
+    // If the part is now simple
+    if(p2.is_simple()) {
+        // Add it to the queue
+        enqueue(p2);
+    } else {
+        // Reduce all the mixed parts by this one
+        reduce_mixed_by(p2);
+        // Record this new mixed part
+        _mixed_parts.insert(pair(p2.indexes(), p2));
+    }
+}
+
+bool FountainDecoder::validate_part(const FountainEncoder::Part& p) {
+    // If this is the first part we've seen
+    if(!_expected_part_indexes.has_value()) {
+        // Record the things that all the other parts we see will have to match to be valid.
+        _expected_part_indexes = PartIndexes();
+        for(size_t i = 0; i < p.seq_len(); i++) { _expected_part_indexes->insert(i); }
+        _expected_message_len = p.message_len();
+        _expected_checksum = p.checksum();
+        _expected_fragment_len = p.data().size();
+    } else {
+        // If this part's values don't match the first part's values, throw away the part
+        if(expected_part_count() != p.seq_len()) return false;
+        if(_expected_message_len != p.message_len()) return false;
+        if(_expected_checksum != p.checksum()) return false;
+        if(_expected_fragment_len != p.data().size()) return false;
+    }
+    // This part should be processed
+    return true;
+}
+
+string FountainDecoder::indexes_to_string(const PartIndexes& indexes) {
+    auto i = vector<size_t>(indexes.begin(), indexes.end());
+    sort(i.begin(), i.end());
+    StringVector s;
+    transform(i.begin(), i.end(), back_inserter(s), [](size_t a) { return to_string(a); });
+    return "[" + join(s, ", ") + "]";
+}
+
+void FountainDecoder::print_part(const Part& p) const {
+    cout << "part indexes: " << indexes_to_string(p.indexes()) << endl;
+}
+
+void FountainDecoder::print_part_end() const {
+    auto expected = _expected_part_indexes.has_value() ? to_string(expected_part_count()) : "nil";
+    auto percent = int(round(estimated_percent_complete() * 100));
+    cout << "processed: " << processed_parts_count_ << ", expected: " << expected << ", received: " << received_part_indexes_.size() << ", percent: " << percent << "%" << endl;
+}
+
+string FountainDecoder::result_description() const {
+    string desc;
+    if(!result_.has_value()) {
+        desc = "nil";
+    } else {
+        auto r = *result_;
+        if(holds_alternative<ByteVector>(r)) {
+            desc = to_string(get<ByteVector>(r).size()) + " bytes";
+        } else if(holds_alternative<exception>(r)) {
+            desc = get<exception>(r).what();
+        } else {
+            assert(false);
+        }
+    }
+    return desc;
+}
+
+void FountainDecoder::print_state() const {
+    auto parts = _expected_part_indexes.has_value() ? to_string(expected_part_count()) : "nil";
+    auto received = indexes_to_string(received_part_indexes_);
+    StringVector mixed;
+    transform(_mixed_parts.begin(), _mixed_parts.end(), back_inserter(mixed), [](const pair<const PartIndexes, Part>& p) { 
+        return indexes_to_string(p.first);
+    });
+    auto mixed_s = "[" + join(mixed, ", ") + "]";
+    auto queued = _queued_parts.size();
+    auto res = result_description();
+    cout << "parts: " << parts << ", received: " << received << ", mixed: " << mixed_s << ", queued: " << queued << ", result: " << res << endl;
+}
+
+}

src/third-party/bcur/fountain-decoder.hpp

@@ -0,0 +1,103 @@
+//
+//  fountain-decoder.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_FOUNTAIN_DECODER_HPP
+#define BC_UR_FOUNTAIN_DECODER_HPP
+
+#include "utils.hpp"
+#include "fountain-encoder.hpp"
+#include <map>
+#include <exception>
+#include <deque>
+#include <optional>
+#include <variant>
+
+namespace ur {
+
+class FountainDecoder final {
+public:
+    typedef std::optional<std::variant<ByteVector, std::exception> > Result;
+
+    class InvalidPart: public std::exception { };
+    class InvalidChecksum: public std::exception { };
+
+    FountainDecoder();
+
+    size_t expected_part_count() const { return _expected_part_indexes.value().size(); }
+    const PartIndexes& received_part_indexes() const { return received_part_indexes_; }
+    const PartIndexes& last_part_indexes() const { return last_part_indexes_.value(); }
+    size_t processed_parts_count() const { return processed_parts_count_; }
+    const Result& result() const { return result_; }
+    bool is_success() const { return result() && std::holds_alternative<ByteVector>(result().value()); }
+    bool is_failure() const { return result() && std::holds_alternative<std::exception>(result().value()); }
+    bool is_complete() const { return result().has_value(); }
+    const ByteVector& result_message() const { return std::get<ByteVector>(result().value()); }
+    const std::exception& result_error() const { return std::get<std::exception>(result().value()); }
+
+    double estimated_percent_complete() const;
+    bool receive_part(FountainEncoder::Part& encoder_part);
+
+    // Join all the fragments of a message together, throwing away any padding
+    static const ByteVector join_fragments(const std::vector<ByteVector>& fragments, size_t message_len);
+
+private:
+    class Part {
+    private:
+        PartIndexes indexes_;
+        ByteVector data_;
+
+    public:
+        explicit Part(const FountainEncoder::Part& p);
+        Part(PartIndexes& indexes, ByteVector& data);
+
+        const PartIndexes& indexes() const { return indexes_; }
+        const ByteVector& data() const { return data_; }
+        bool is_simple() const { return indexes_.size() == 1; }
+        size_t index() const { return *indexes_.begin(); }
+    };
+
+    PartIndexes received_part_indexes_;
+    std::optional<PartIndexes> last_part_indexes_;
+    size_t processed_parts_count_ = 0;
+
+    Result result_;
+
+    typedef std::map<PartIndexes, Part> PartDict;
+
+    std::optional<PartIndexes> _expected_part_indexes;
+    std::optional<size_t> _expected_fragment_len;
+    std::optional<size_t> _expected_message_len;
+    std::optional<uint32_t> _expected_checksum;
+
+    PartDict _simple_parts;
+    PartDict _mixed_parts;
+    std::deque<Part> _queued_parts;
+
+    void enqueue(const Part &p);
+    void enqueue(Part &&p);
+    void process_queue_item();
+    void reduce_mixed_by(const Part& p);
+    Part reduce_part_by_part(const Part& a, const Part& b) const;
+    void process_simple_part(Part& p);
+    void process_mixed_part(const Part& p);
+    bool validate_part(const FountainEncoder::Part& p);
+
+    // debugging
+    static std::string indexes_to_string(const PartIndexes& indexes);
+    std::string result_description() const;
+
+    // cppcheck-suppress unusedPrivateFunction
+    void print_part(const Part& p) const;
+    // cppcheck-suppress unusedPrivateFunction
+    void print_part_end() const;
+    // cppcheck-suppress unusedPrivateFunction
+    void print_state() const;
+};
+
+}
+
+#endif // BC_UR_FOUNTAIN_DECODER_HPP

src/third-party/bcur/fountain-encoder.cpp

@@ -0,0 +1,126 @@
+//
+//  fountain-encoder.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "fountain-encoder.hpp"
+#include <assert.h>
+#include <cmath>
+#include <optional>
+#include <vector>
+#include <limits>
+#include "cbor-lite.hpp"
+
+using namespace std;
+
+namespace ur {
+
+size_t FountainEncoder::find_nominal_fragment_length(size_t message_len, size_t min_fragment_len, size_t max_fragment_len) {
+    assert(message_len > 0);
+    assert(min_fragment_len > 0);
+    assert(max_fragment_len >= min_fragment_len);
+    auto max_fragment_count = message_len / min_fragment_len;
+    optional<size_t> fragment_len;
+    for(size_t fragment_count = 1; fragment_count <= max_fragment_count; fragment_count++) {
+        fragment_len = size_t(ceil(double(message_len) / fragment_count));
+        if(fragment_len <= max_fragment_len) {
+            break;
+        }
+    }
+    assert(fragment_len.has_value());
+    return *fragment_len;
+}
+
+vector<ByteVector> FountainEncoder::partition_message(const ByteVector &message, size_t fragment_len) {
+    auto remaining = message;
+    vector<ByteVector> fragments;
+    while(!remaining.empty()) {
+        auto a = split(remaining, fragment_len);
+        auto fragment = a.first;
+        remaining = a.second;
+        auto padding = fragment_len - fragment.size();
+        while(padding > 0) {
+            fragment.push_back(0);
+            padding--;
+        }
+        fragments.push_back(fragment);
+    }
+    return fragments;
+}
+
+FountainEncoder::Part::Part(const ByteVector& cbor) {
+    try {
+        auto i = cbor.begin();
+        auto end = cbor.end();
+        size_t array_size;
+        CborLite::decodeArraySize(i, end, array_size);
+        if(array_size != 5) { throw InvalidHeader(); }
+        
+        uint64_t n;
+        
+        CborLite::decodeUnsigned(i, end, n);
+        if(n > std::numeric_limits<decltype(seq_num_)>::max()) { throw InvalidHeader(); }
+        seq_num_ = n;
+        
+        CborLite::decodeUnsigned(i, end, n);
+        if(n > std::numeric_limits<decltype(seq_len_)>::max()) { throw InvalidHeader(); }
+        seq_len_ = n;
+        
+        CborLite::decodeUnsigned(i, end, n);
+        if(n > std::numeric_limits<decltype(message_len_)>::max()) { throw InvalidHeader(); }
+        message_len_ = n;
+        
+        CborLite::decodeUnsigned(i, end, n);
+        if(n > std::numeric_limits<decltype(checksum_)>::max()) { throw InvalidHeader(); }
+        checksum_ = n;
+
+        CborLite::decodeBytes(i, end, data_);
+    } catch(...) {
+        throw InvalidHeader();
+    }
+}
+
+ByteVector FountainEncoder::Part::cbor() const {
+    using namespace CborLite;
+
+    ByteVector result;
+
+    encodeArraySize(result, (size_t)5);
+    encodeInteger(result, seq_num());
+    encodeInteger(result, seq_len());
+    encodeInteger(result, message_len());
+    encodeInteger(result, checksum());
+    encodeBytes(result, data());
+
+    return result;
+}
+
+FountainEncoder::FountainEncoder(const ByteVector& message, size_t max_fragment_len, uint32_t first_seq_num, size_t min_fragment_len) {
+    assert(message.size() <= std::numeric_limits<uint32_t>::max());
+    message_len_ = message.size();
+    checksum_ = crc32_int(message);
+    fragment_len_ = find_nominal_fragment_length(message_len_, min_fragment_len, max_fragment_len);
+    fragments_ = partition_message(message, fragment_len_);
+    seq_num_ = first_seq_num;
+}
+
+ByteVector FountainEncoder::mix(const PartIndexes& indexes) const {
+    ByteVector result(fragment_len_, 0);
+    for(auto index: indexes) { xor_into(result, fragments_[index]); }
+    return result;
+}
+
+FountainEncoder::Part FountainEncoder::next_part() {
+    seq_num_ += 1; // wrap at period 2^32
+    auto indexes = choose_fragments(seq_num_, seq_len(), checksum_);
+    auto mixed = mix(indexes);
+    return Part(seq_num_, seq_len(), message_len_, checksum_, mixed); 
+}
+
+string FountainEncoder::Part::description() const {
+    return "seqNum:" + to_string(seq_num_) + ", seqLen:" + to_string(seq_len_) + ", messageLen:" + to_string(message_len_) + ", checksum:" + to_string(checksum_) + ", data:" + data_to_hex(data_);
+}
+
+}

src/third-party/bcur/fountain-encoder.hpp

@@ -0,0 +1,81 @@
+//
+//  fountain-encoder.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_FOUNTAIN_ENCODER_HPP
+#define BC_UR_FOUNTAIN_ENCODER_HPP
+
+#include <stddef.h>
+#include <vector>
+#include <exception>
+#include "utils.hpp"
+#include "fountain-utils.hpp"
+
+namespace ur {
+
+// Implements Luby transform code rateless coding
+// https://en.wikipedia.org/wiki/Luby_transform_code
+
+class FountainEncoder final {
+public:
+    class Part {
+    public:
+        class InvalidHeader: public std::exception { };
+
+        Part(uint32_t seq_num, size_t seq_len, size_t message_len, uint32_t checksum, const ByteVector& data) 
+            : seq_num_(seq_num), seq_len_(seq_len), message_len_(message_len), checksum_(checksum), data_(data)
+        { }
+        explicit Part(const ByteVector& cbor);
+
+        uint32_t seq_num() const { return seq_num_; }
+        size_t seq_len() const { return seq_len_; }
+        size_t message_len() const { return message_len_; }
+        uint32_t checksum() const { return checksum_; }
+        const ByteVector& data() const { return data_; }
+
+        ByteVector cbor() const;
+        std::string description() const;
+
+    private:
+        uint32_t seq_num_;
+        size_t seq_len_;
+        size_t message_len_;
+        uint32_t checksum_;
+        ByteVector data_;
+    };
+
+    FountainEncoder(const ByteVector& message, size_t max_fragment_len, uint32_t first_seq_num = 0, size_t min_fragment_len = 10);
+    
+    static size_t find_nominal_fragment_length(size_t message_len, size_t min_fragment_len, size_t max_fragment_len);
+    static std::vector<ByteVector> partition_message(const ByteVector &message, size_t fragment_len);
+
+    uint32_t seq_num() const { return seq_num_; }
+    const PartIndexes& last_part_indexes() const { return last_part_indexes_; }
+    size_t seq_len() const { return fragments_.size(); }
+
+    // This becomes `true` when the minimum number of parts
+    // to relay the complete message have been generated
+    bool is_complete() const { return seq_num_ >= seq_len(); }
+
+    /// True if only a single part will be generated.
+    bool is_single_part() const { return seq_len() == 1; }
+
+    Part next_part();
+
+private:
+    size_t message_len_;
+    uint32_t checksum_;
+    size_t fragment_len_;
+    std::vector<ByteVector> fragments_;
+    uint32_t seq_num_;
+    PartIndexes last_part_indexes_;
+
+    ByteVector mix(const PartIndexes& indexes) const;
+};
+
+}
+
+#endif // BC_UR_FOUNTAIN_ENCODER_HPP

src/third-party/bcur/fountain-utils.cpp

@@ -0,0 +1,43 @@
+//
+//  fountain-utils.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "fountain-utils.hpp"
+#include "random-sampler.hpp"
+#include "utils.hpp"
+
+using namespace std;
+
+namespace ur {
+
+size_t choose_degree(size_t seq_len, Xoshiro256& rng) {
+    vector<double> degree_probabilities;
+    for(int i = 1; i <= seq_len; i++) {
+        degree_probabilities.push_back(1.0 / i);
+    }
+    auto degree_chooser = RandomSampler(degree_probabilities);
+    return degree_chooser.next([&]() { return rng.next_double(); }) + 1;
+}
+
+set<size_t> choose_fragments(uint32_t seq_num, size_t seq_len, uint32_t checksum) {
+    // The first `seq_len` parts are the "pure" fragments, not mixed with any
+    // others. This means that if you only generate the first `seq_len` parts,
+    // then you have all the parts you need to decode the message.
+    if(seq_num <= seq_len) {
+        return set<size_t>({seq_num - 1});
+    } else {
+        auto seed = join(vector({int_to_bytes(seq_num), int_to_bytes(checksum)}));
+        auto rng = Xoshiro256(seed);
+        auto degree = choose_degree(seq_len, rng);
+        vector<size_t> indexes;
+        indexes.reserve(seq_len);
+        for(int i = 0; i < seq_len; i++) { indexes.push_back(i); }
+        auto shuffled_indexes = shuffled(indexes, rng);
+        return set<size_t>(shuffled_indexes.begin(), shuffled_indexes.begin() + degree);
+    }
+}
+
+}

src/third-party/bcur/fountain-utils.hpp

@@ -0,0 +1,61 @@
+//
+//  fountain-utils.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_FOUNTAIN_UTILS_HPP
+#define BC_UR_FOUNTAIN_UTILS_HPP
+
+#include <functional>
+#include <vector>
+#include <set>
+#include <algorithm>
+#include <iterator>
+#include <stdint.h>
+#include "xoshiro256.hpp"
+
+namespace ur {
+
+typedef std::set<size_t> PartIndexes;
+
+// Fisher-Yates shuffle
+template<typename T>
+std::vector<T> shuffled(const std::vector<T>& items, Xoshiro256& rng) {
+    auto remaining = items;
+    std::vector<T> result;
+    while(!remaining.empty()) {
+        auto index = rng.next_int(0, remaining.size() - 1);
+        auto item = remaining[index];
+        remaining.erase(remaining.begin() + index);
+        result.push_back(item);
+    }
+    return result;
+}
+
+// Return `true` if `a` is a strict subset of `b`.
+template<typename T>
+bool is_strict_subset(const std::set<T>& a, const std::set<T>& b) {
+    if(a == b) { return false; }
+    return std::includes(b.begin(), b.end(), a.begin(), a.end());
+}
+
+template<typename T>
+std::set<T> set_difference(const std::set<T>& a, const std::set<T>& b) {
+    std::set<T> result;
+    std::set_difference(a.begin(), a.end(), b.begin(), b.end(), std::inserter(result, result.begin()));
+    return result;
+}
+
+template<typename T>
+bool contains(const std::set<T>& s, const T& v) {
+    return s.find(v) != s.end();
+}
+
+size_t choose_degree(size_t seq_len, Xoshiro256& rng);
+std::set<size_t> choose_fragments(uint32_t seq_num, size_t seq_len, uint32_t checksum);
+
+}
+
+#endif // BC_UR_FOUNTAIN_UTILS_HPP

src/third-party/bcur/memzero.c

@@ -0,0 +1,84 @@
+#include "memzero.h"
+
+#ifndef __STDC_WANT_LIB_EXT1__
+#define __STDC_WANT_LIB_EXT1__ 1  // C11's bounds-checking interface.
+#endif
+#include <string.h>
+
+#ifdef _WIN32
+#include <Windows.h>
+#endif
+
+#ifdef __unix__
+#include <strings.h>
+#include <sys/param.h>
+#endif
+
+// C11's bounds-checking interface.
+#if defined(__STDC_LIB_EXT1__)
+#define HAVE_MEMSET_S 1
+#endif
+
+// GNU C Library version 2.25 or later.
+#if defined(__GLIBC__) && \
+    (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 25))
+#define HAVE_EXPLICIT_BZERO 1
+#endif
+
+// Newlib
+#if defined(__NEWLIB__)
+#define HAVE_EXPLICIT_BZERO 1
+#endif
+
+// FreeBSD version 11.0 or later.
+#if defined(__FreeBSD__) && __FreeBSD_version >= 1100037
+#define HAVE_EXPLICIT_BZERO 1
+#endif
+
+// OpenBSD version 5.5 or later.
+#if defined(__OpenBSD__) && OpenBSD >= 201405
+#define HAVE_EXPLICIT_BZERO 1
+#endif
+
+// NetBSD version 7.2 or later.
+#if defined(__NetBSD__) && __NetBSD_Version__ >= 702000000
+#define HAVE_EXPLICIT_MEMSET 1
+#endif
+
+// Adapted from
+// https://github.com/jedisct1/libsodium/blob/1647f0d53ae0e370378a9195477e3df0a792408f/src/libsodium/sodium/utils.c#L102-L130
+
+void memzero(void *const pnt, const size_t len) {
+#ifdef _WIN32
+  SecureZeroMemory(pnt, len);
+#elif defined(HAVE_MEMSET_S)
+  memset_s(pnt, (rsize_t)len, 0, (rsize_t)len);
+#elif defined(HAVE_EXPLICIT_BZERO)
+  bzero(pnt, len);
+#elif defined(HAVE_EXPLICIT_MEMSET)
+  explicit_memset(pnt, 0, len);
+#else
+  volatile unsigned char *volatile pnt_ = (volatile unsigned char *volatile)pnt;
+  size_t i = (size_t)0U;
+
+  while (i < len) {
+    pnt_[i++] = 0U;
+  }
+
+  /* Memory barrier that scares the compiler away from optimizing out
+   * the above loop.
+   *
+   * Quoting Adam Langley <agl@google.com> in commit
+   * ad1907fe73334d6c696c8539646c21b11178f20f of BoringSSL (ISC License):
+   *
+   *    As best as we can tell, this is sufficient to break any optimisations
+   *    that might try to eliminate "superfluous" memsets.  This method is used
+   *    in memzero_explicit() the Linux kernel, too.  Its advantage is that it
+   *    is pretty efficient because the compiler can still implement the
+   *    memset() efficiently, just not remove it entirely.  See "Dead Store
+   *    Elimination (Still) Considered Harmful" by Yang et al. (USENIX Security
+   *    2017) for more background.
+   */
+  __asm__ __volatile__("" : : "r"(pnt_) : "memory");
+#endif
+}

src/third-party/bcur/memzero.h

@@ -0,0 +1,8 @@
+#ifndef BC_UR_MEMZERO_H
+#define BC_UR_MEMZERO_H
+
+#include <stddef.h>
+
+void memzero(void* const pnt, const size_t len);
+
+#endif // BC_UR_MEMZERO_H

src/third-party/bcur/random-sampler.cpp

@@ -0,0 +1,84 @@
+//
+//  random-sampler.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "random-sampler.hpp"
+#include <numeric>
+#include <algorithm>
+#include <assert.h>
+
+using namespace std;
+
+namespace ur {
+
+RandomSampler::RandomSampler(std::vector<double> probs) {
+    for(auto p: probs) { assert(p >= 0); }
+
+    // Normalize given probabilities
+    auto sum = accumulate(probs.begin(), probs.end(), 0.0);
+    assert(sum > 0);
+
+    auto n = probs.size();
+
+    vector<double> P;
+    P.reserve(n);
+    transform(probs.begin(), probs.end(), back_inserter(P), [&](double d) { return d * double(n) / sum; });
+
+    vector<int> S;
+    S.reserve(n);
+    vector<int> L;
+    L.reserve(n);
+
+    // Set separate index lists for small and large probabilities:
+    for(int i = n - 1; i >= 0; i--) {
+        // at variance from Schwarz, we reverse the index order
+        if(P[i] < 1) {
+            S.push_back(i);
+        } else {
+            L.push_back(i);
+        }
+    }
+
+    // Work through index lists
+    vector<double> _probs(n, 0);
+    vector<int> _aliases(n, 0);
+    while(!S.empty() && !L.empty()) {
+        auto a = S.back(); S.pop_back(); // Schwarz's l
+        auto g = L.back(); L.pop_back(); // Schwarz's g
+        _probs[a] = P[a];
+        _aliases[a] = g;
+        P[g] += P[a] - 1;
+        if(P[g] < 1) {
+            S.push_back(g);
+        } else {
+            L.push_back(g);
+        }
+    }
+
+    while(!L.empty()) {
+        _probs[L.back()] = 1;
+        L.pop_back();
+    }
+
+    while(!S.empty()) {
+        // can only happen through numeric instability
+        _probs[S.back()] = 1;
+        S.pop_back();
+    }
+
+    this->probs_ = _probs;
+    this->aliases_ = _aliases;
+}
+
+int RandomSampler::next(std::function<double()> rng) {
+    auto r1 = rng();
+    auto r2 = rng();
+    auto n = probs_.size();
+    auto i = int(double(n) * r1);
+    return r2 < probs_[i] ? i : aliases_[i];
+}
+
+}

src/third-party/bcur/random-sampler.hpp

@@ -0,0 +1,38 @@
+//
+//  random-sampler.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_RANDOM_SAMPLER_HPP
+#define BC_UR_RANDOM_SAMPLER_HPP
+
+#include <vector>
+#include <functional>
+
+// Random-number sampling using the Walker-Vose alias method,
+// as described by Keith Schwarz (2011)
+// http://www.keithschwarz.com/darts-dice-coins
+
+// Based on C implementation:
+// https://jugit.fz-juelich.de/mlz/ransampl
+
+// Translated to C++ by Wolf McNally
+
+namespace ur {
+
+class RandomSampler final {
+public:
+    explicit RandomSampler(std::vector<double> probs);
+
+    int next(std::function<double()> rng);
+
+private:
+    std::vector<double> probs_;
+    std::vector<int> aliases_;
+};
+
+}
+
+#endif // BC_UR_RANDOM_SAMPLER_HPP

src/third-party/bcur/sha2.c

@@ -0,0 +1,889 @@
+/**
+ * Copyright (c) 2000-2001 Aaron D. Gifford
+ * Copyright (c) 2013-2014 Pavol Rusnak
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holder nor the names of contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTOR(S) ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTOR(S) BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <string.h>
+#include <stdint.h>
+#include "sha2.h"
+#include "memzero.h"
+
+/*
+ * ASSERT NOTE:
+ * Some sanity checking code is included using assert().  On my FreeBSD
+ * system, this additional code can be removed by compiling with NDEBUG
+ * defined.  Check your own systems manpage on assert() to see how to
+ * compile WITHOUT the sanity checking code on your system.
+ *
+ * UNROLLED TRANSFORM LOOP NOTE:
+ * You can define SHA2_UNROLL_TRANSFORM to use the unrolled transform
+ * loop version for the hash transform rounds (defined using macros
+ * later in this file).  Either define on the command line, for example:
+ *
+ *   cc -DSHA2_UNROLL_TRANSFORM -o sha2 sha2.c sha2prog.c
+ *
+ * or define below:
+ *
+ *   #define SHA2_UNROLL_TRANSFORM
+ *
+ */
+
+
+/*** SHA-256/384/512 Machine Architecture Definitions *****************/
+/*
+ * BYTE_ORDER NOTE:
+ *
+ * Please make sure that your system defines BYTE_ORDER.  If your
+ * architecture is little-endian, make sure it also defines
+ * LITTLE_ENDIAN and that the two (BYTE_ORDER and LITTLE_ENDIAN) are
+ * equivilent.
+ *
+ * If your system does not define the above, then you can do so by
+ * hand like this:
+ *
+ *   #define LITTLE_ENDIAN 1234
+ *   #define BIG_ENDIAN    4321
+ *
+ * And for little-endian machines, add:
+ *
+ *   #define BYTE_ORDER LITTLE_ENDIAN 
+ *
+ * Or for big-endian machines:
+ *
+ *   #define BYTE_ORDER BIG_ENDIAN
+ *
+ * The FreeBSD machine this was written on defines BYTE_ORDER
+ * appropriately by including <sys/types.h> (which in turn includes
+ * <machine/endian.h> where the appropriate definitions are actually
+ * made).
+ */
+
+#if !defined(BYTE_ORDER) || (BYTE_ORDER != LITTLE_ENDIAN && BYTE_ORDER != BIG_ENDIAN)
+#error Define BYTE_ORDER to be equal to either LITTLE_ENDIAN or BIG_ENDIAN
+#endif
+
+typedef uint8_t  sha2_byte;	/* Exactly 1 byte */
+typedef uint32_t sha2_word32;	/* Exactly 4 bytes */
+typedef uint64_t sha2_word64;	/* Exactly 8 bytes */
+
+/*** SHA-256/384/512 Various Length Definitions ***********************/
+/* NOTE: Most of these are in sha2.h */
+#define SHA256_SHORT_BLOCK_LENGTH	(SHA256_BLOCK_LENGTH - 8)
+#define SHA512_SHORT_BLOCK_LENGTH	(SHA512_BLOCK_LENGTH - 16)
+
+/*
+ * Macro for incrementally adding the unsigned 64-bit integer n to the
+ * unsigned 128-bit integer (represented using a two-element array of
+ * 64-bit words):
+ */
+#define ADDINC128(w,n)	{ \
+	(w)[0] += (sha2_word64)(n); \
+	if ((w)[0] < (n)) { \
+		(w)[1]++; \
+	} \
+}
+
+#define MEMCPY_BCOPY(d,s,l)	memcpy((d), (s), (l))
+
+/*** THE SIX LOGICAL FUNCTIONS ****************************************/
+/*
+ * Bit shifting and rotation (used by the six SHA-XYZ logical functions:
+ *
+ *   NOTE:  In the original SHA-256/384/512 document, the shift-right
+ *   function was named R and the rotate-right function was called S.
+ *   (See: http://csrc.nist.gov/cryptval/shs/sha256-384-512.pdf on the
+ *   web.)
+ *
+ *   The newer NIST FIPS 180-2 document uses a much clearer naming
+ *   scheme, SHR for shift-right, ROTR for rotate-right, and ROTL for
+ *   rotate-left.  (See:
+ *   http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
+ *   on the web.)
+ *
+ *   WARNING: These macros must be used cautiously, since they reference
+ *   supplied parameters sometimes more than once, and thus could have
+ *   unexpected side-effects if used without taking this into account.
+ */
+
+/* Shift-right (used in SHA-256, SHA-384, and SHA-512): */
+#define SHR(b,x) 		((x) >> (b))
+/* 32-bit Rotate-right (used in SHA-256): */
+#define ROTR32(b,x)	(((x) >> (b)) | ((x) << (32 - (b))))
+/* 64-bit Rotate-right (used in SHA-384 and SHA-512): */
+#define ROTR64(b,x)	(((x) >> (b)) | ((x) << (64 - (b))))
+/* 32-bit Rotate-left (used in SHA-1): */
+#define ROTL32(b,x)	(((x) << (b)) | ((x) >> (32 - (b))))
+
+/* Two of six logical functions used in SHA-1, SHA-256, SHA-384, and SHA-512: */
+#define Ch(x,y,z)	(((x) & (y)) ^ ((~(x)) & (z)))
+#define Maj(x,y,z)	(((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
+
+/* Function used in SHA-1: */
+#define Parity(x,y,z)	((x) ^ (y) ^ (z))
+
+/* Four of six logical functions used in SHA-256: */
+#define Sigma0_256(x)	(ROTR32(2,  (x)) ^ ROTR32(13, (x)) ^ ROTR32(22, (x)))
+#define Sigma1_256(x)	(ROTR32(6,  (x)) ^ ROTR32(11, (x)) ^ ROTR32(25, (x)))
+#define sigma0_256(x)	(ROTR32(7,  (x)) ^ ROTR32(18, (x)) ^ SHR(3 ,   (x)))
+#define sigma1_256(x)	(ROTR32(17, (x)) ^ ROTR32(19, (x)) ^ SHR(10,   (x)))
+
+/* Four of six logical functions used in SHA-384 and SHA-512: */
+#define Sigma0_512(x)	(ROTR64(28, (x)) ^ ROTR64(34, (x)) ^ ROTR64(39, (x)))
+#define Sigma1_512(x)	(ROTR64(14, (x)) ^ ROTR64(18, (x)) ^ ROTR64(41, (x)))
+#define sigma0_512(x)	(ROTR64( 1, (x)) ^ ROTR64( 8, (x)) ^ SHR( 7,   (x)))
+#define sigma1_512(x)	(ROTR64(19, (x)) ^ ROTR64(61, (x)) ^ SHR( 6,   (x)))
+
+/*** INTERNAL FUNCTION PROTOTYPES *************************************/
+/* NOTE: These should not be accessed directly from outside this
+ * library -- they are intended for private internal visibility/use
+ * only.
+ */
+static void sha512_Last(SHA512_CTX*);
+
+
+/*** SHA-XYZ INITIAL HASH VALUES AND CONSTANTS ************************/
+
+/* Hash constant words K for SHA-256: */
+static const sha2_word32 K256[64] = {
+	0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL,
+	0x3956c25bUL, 0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL,
+	0xd807aa98UL, 0x12835b01UL, 0x243185beUL, 0x550c7dc3UL,
+	0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL, 0xc19bf174UL,
+	0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
+	0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL,
+	0x983e5152UL, 0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL,
+	0xc6e00bf3UL, 0xd5a79147UL, 0x06ca6351UL, 0x14292967UL,
+	0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL, 0x53380d13UL,
+	0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
+	0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL,
+	0xd192e819UL, 0xd6990624UL, 0xf40e3585UL, 0x106aa070UL,
+	0x19a4c116UL, 0x1e376c08UL, 0x2748774cUL, 0x34b0bcb5UL,
+	0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL, 0x682e6ff3UL,
+	0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
+	0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL
+};
+
+/* Initial hash value H for SHA-256: */
+const sha2_word32 sha256_initial_hash_value[8] = {
+	0x6a09e667UL,
+	0xbb67ae85UL,
+	0x3c6ef372UL,
+	0xa54ff53aUL,
+	0x510e527fUL,
+	0x9b05688cUL,
+	0x1f83d9abUL,
+	0x5be0cd19UL
+};
+
+/* Hash constant words K for SHA-384 and SHA-512: */
+static const sha2_word64 K512[80] = {
+	0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL,
+	0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL,
+	0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
+	0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
+	0xd807aa98a3030242ULL, 0x12835b0145706fbeULL,
+	0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
+	0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL,
+	0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
+	0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
+	0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL,
+	0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL,
+	0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
+	0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL,
+	0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL,
+	0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
+	0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
+	0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL,
+	0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
+	0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL,
+	0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
+	0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
+	0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL,
+	0xd192e819d6ef5218ULL, 0xd69906245565a910ULL,
+	0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
+	0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL,
+	0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL,
+	0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
+	0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
+	0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL,
+	0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
+	0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL,
+	0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
+	0xca273eceea26619cULL, 0xd186b8c721c0c207ULL,
+	0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL,
+	0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL,
+	0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
+	0x28db77f523047d84ULL, 0x32caab7b40c72493ULL,
+	0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL,
+	0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
+	0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL
+};
+
+/* Initial hash value H for SHA-512 */
+const sha2_word64 sha512_initial_hash_value[8] = {
+	0x6a09e667f3bcc908ULL,
+	0xbb67ae8584caa73bULL,
+	0x3c6ef372fe94f82bULL,
+	0xa54ff53a5f1d36f1ULL,
+	0x510e527fade682d1ULL,
+	0x9b05688c2b3e6c1fULL,
+	0x1f83d9abfb41bd6bULL,
+	0x5be0cd19137e2179ULL
+};
+
+/*
+ * Constant used by SHA256/384/512_End() functions for converting the
+ * digest to a readable hexadecimal character string:
+ */
+static const char *sha2_hex_digits = "0123456789abcdef";
+
+
+/*** SHA-256: *********************************************************/
+void sha256_Init(SHA256_CTX* context) {
+	if (context == (SHA256_CTX*)0) {
+		return;
+	}
+	MEMCPY_BCOPY(context->state, sha256_initial_hash_value, SHA256_DIGEST_LENGTH);
+	memzero(context->buffer, SHA256_BLOCK_LENGTH);
+	context->bitcount = 0;
+}
+
+#ifdef SHA2_UNROLL_TRANSFORM
+
+/* Unrolled SHA-256 round macros: */
+
+#define ROUND256_0_TO_15(a,b,c,d,e,f,g,h)	\
+	T1 = (h) + Sigma1_256(e) + Ch((e), (f), (g)) + \
+	     K256[j] + (W256[j] = *data++); \
+	(d) += T1; \
+	(h) = T1 + Sigma0_256(a) + Maj((a), (b), (c)); \
+	j++
+
+#define ROUND256(a,b,c,d,e,f,g,h)	\
+	s0 = W256[(j+1)&0x0f]; \
+	s0 = sigma0_256(s0); \
+	s1 = W256[(j+14)&0x0f]; \
+	s1 = sigma1_256(s1); \
+	T1 = (h) + Sigma1_256(e) + Ch((e), (f), (g)) + K256[j] + \
+	     (W256[j&0x0f] += s1 + W256[(j+9)&0x0f] + s0); \
+	(d) += T1; \
+	(h) = T1 + Sigma0_256(a) + Maj((a), (b), (c)); \
+	j++
+
+void sha256_Transform(const sha2_word32* state_in, const sha2_word32* data, sha2_word32* state_out) {
+	sha2_word32	a = 0, b = 0, c = 0, d = 0, e = 0, f = 0, g = 0, h = 0;
+	sha2_word32	T1 = 0;
+	sha2_word32 W256[16] = {0};
+	int		j = 0;
+
+	/* Initialize registers with the prev. intermediate value */
+	a = state_in[0];
+	b = state_in[1];
+	c = state_in[2];
+	d = state_in[3];
+	e = state_in[4];
+	f = state_in[5];
+	g = state_in[6];
+	h = state_in[7];
+
+	j = 0;
+	do {
+		/* Rounds 0 to 15 (unrolled): */
+		ROUND256_0_TO_15(a,b,c,d,e,f,g,h);
+		ROUND256_0_TO_15(h,a,b,c,d,e,f,g);
+		ROUND256_0_TO_15(g,h,a,b,c,d,e,f);
+		ROUND256_0_TO_15(f,g,h,a,b,c,d,e);
+		ROUND256_0_TO_15(e,f,g,h,a,b,c,d);
+		ROUND256_0_TO_15(d,e,f,g,h,a,b,c);
+		ROUND256_0_TO_15(c,d,e,f,g,h,a,b);
+		ROUND256_0_TO_15(b,c,d,e,f,g,h,a);
+	} while (j < 16);
+
+	/* Now for the remaining rounds to 64: */
+	do {
+		ROUND256(a,b,c,d,e,f,g,h);
+		ROUND256(h,a,b,c,d,e,f,g);
+		ROUND256(g,h,a,b,c,d,e,f);
+		ROUND256(f,g,h,a,b,c,d,e);
+		ROUND256(e,f,g,h,a,b,c,d);
+		ROUND256(d,e,f,g,h,a,b,c);
+		ROUND256(c,d,e,f,g,h,a,b);
+		ROUND256(b,c,d,e,f,g,h,a);
+	} while (j < 64);
+
+	/* Compute the current intermediate hash value */
+	state_out[0] = state_in[0] + a;
+	state_out[1] = state_in[1] + b;
+	state_out[2] = state_in[2] + c;
+	state_out[3] = state_in[3] + d;
+	state_out[4] = state_in[4] + e;
+	state_out[5] = state_in[5] + f;
+	state_out[6] = state_in[6] + g;
+	state_out[7] = state_in[7] + h;
+
+	/* Clean up */
+	// cppcheck-suppress unreadVariable
+	a = b = c = d = e = f = g = h = T1 = 0;
+}
+
+#else /* SHA2_UNROLL_TRANSFORM */
+
+void sha256_Transform(const sha2_word32* state_in, const sha2_word32* data, sha2_word32* state_out) {
+	sha2_word32	a = 0, b = 0, c = 0, d = 0, e = 0, f = 0, g = 0, h = 0;
+	sha2_word32	T1 = 0, T2 = 0 , W256[16] = {0};
+	int		j = 0;
+
+	/* Initialize registers with the prev. intermediate value */
+	a = state_in[0];
+	b = state_in[1];
+	c = state_in[2];
+	d = state_in[3];
+	e = state_in[4];
+	f = state_in[5];
+	g = state_in[6];
+	h = state_in[7];
+
+	j = 0;
+	do {
+		/* Apply the SHA-256 compression function to update a..h with copy */
+		T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] + (W256[j] = *data++);
+		T2 = Sigma0_256(a) + Maj(a, b, c);
+		h = g;
+		g = f;
+		f = e;
+		e = d + T1;
+		d = c;
+		c = b;
+		b = a;
+		a = T1 + T2;
+
+		j++;
+	} while (j < 16);
+
+	do {
+		/* Part of the message block expansion: */
+		sha2_word32 s0 = 0, s1 = 0;
+		s0 = W256[(j+1)&0x0f];
+		s0 = sigma0_256(s0);
+		s1 = W256[(j+14)&0x0f];
+		s1 = sigma1_256(s1);
+
+		/* Apply the SHA-256 compression function to update a..h */
+		T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] + 
+		     (W256[j&0x0f] += s1 + W256[(j+9)&0x0f] + s0);
+		T2 = Sigma0_256(a) + Maj(a, b, c);
+		h = g;
+		g = f;
+		f = e;
+		e = d + T1;
+		d = c;
+		c = b;
+		b = a;
+		a = T1 + T2;
+
+		j++;
+	} while (j < 64);
+
+	/* Compute the current intermediate hash value */
+	state_out[0] = state_in[0] + a;
+	state_out[1] = state_in[1] + b;
+	state_out[2] = state_in[2] + c;
+	state_out[3] = state_in[3] + d;
+	state_out[4] = state_in[4] + e;
+	state_out[5] = state_in[5] + f;
+	state_out[6] = state_in[6] + g;
+	state_out[7] = state_in[7] + h;
+
+	/* Clean up */
+	// cppcheck-suppress unreadVariable
+	a = b = c = d = e = f = g = h = T1 = T2 = 0;
+}
+
+#endif /* SHA2_UNROLL_TRANSFORM */
+
+void sha256_Update(SHA256_CTX* context, const sha2_byte *data, size_t len) {
+	unsigned int	freespace = 0, usedspace = 0;
+
+	if (len == 0) {
+		/* Calling with no data is valid - we do nothing */
+		return;
+	}
+
+	usedspace = (context->bitcount >> 3) % SHA256_BLOCK_LENGTH;
+	if (usedspace > 0) {
+		/* Calculate how much free space is available in the buffer */
+		freespace = SHA256_BLOCK_LENGTH - usedspace;
+
+		if (len >= freespace) {
+			/* Fill the buffer completely and process it */
+			MEMCPY_BCOPY(((uint8_t*)context->buffer) + usedspace, data, freespace);
+			context->bitcount += freespace << 3;
+			len -= freespace;
+			data += freespace;
+#if BYTE_ORDER == LITTLE_ENDIAN
+			/* Convert TO host byte order */
+			for (int j = 0; j < 16; j++) {
+				REVERSE32(context->buffer[j],context->buffer[j]);
+			}
+#endif
+			sha256_Transform(context->state, context->buffer, context->state);
+		} else {
+			/* The buffer is not yet full */
+			MEMCPY_BCOPY(((uint8_t*)context->buffer) + usedspace, data, len);
+			context->bitcount += len << 3;
+			/* Clean up: */
+			// cppcheck-suppress unreadVariable
+			usedspace = freespace = 0;
+			return;
+		}
+	}
+	while (len >= SHA256_BLOCK_LENGTH) {
+		/* Process as many complete blocks as we can */
+		MEMCPY_BCOPY(context->buffer, data, SHA256_BLOCK_LENGTH);
+#if BYTE_ORDER == LITTLE_ENDIAN
+		/* Convert TO host byte order */
+		for (int j = 0; j < 16; j++) {
+			REVERSE32(context->buffer[j],context->buffer[j]);
+		}
+#endif
+		sha256_Transform(context->state, context->buffer, context->state);
+		context->bitcount += SHA256_BLOCK_LENGTH << 3;
+		len -= SHA256_BLOCK_LENGTH;
+		data += SHA256_BLOCK_LENGTH;
+	}
+	if (len > 0) {
+		/* There's left-overs, so save 'em */
+		MEMCPY_BCOPY(context->buffer, data, len);
+		context->bitcount += len << 3;
+	}
+	/* Clean up: */
+	// cppcheck-suppress unreadVariable
+	usedspace = freespace = 0;
+}
+
+void sha256_Final(SHA256_CTX* context, sha2_byte digest[]) {
+	unsigned int	usedspace = 0;
+
+	/* If no digest buffer is passed, we don't bother doing this: */
+	if (digest != (sha2_byte*)0) {
+		usedspace = (context->bitcount >> 3) % SHA256_BLOCK_LENGTH;
+		/* Begin padding with a 1 bit: */
+		((uint8_t*)context->buffer)[usedspace++] = 0x80;
+
+		if (usedspace > SHA256_SHORT_BLOCK_LENGTH) {
+			memzero(((uint8_t*)context->buffer) + usedspace, SHA256_BLOCK_LENGTH - usedspace);
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+			/* Convert TO host byte order */
+			for (int j = 0; j < 16; j++) {
+				REVERSE32(context->buffer[j],context->buffer[j]);
+			}
+#endif
+			/* Do second-to-last transform: */
+			sha256_Transform(context->state, context->buffer, context->state);
+
+			/* And prepare the last transform: */
+			usedspace = 0;
+		}
+		/* Set-up for the last transform: */
+		memzero(((uint8_t*)context->buffer) + usedspace, SHA256_SHORT_BLOCK_LENGTH - usedspace);
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+		/* Convert TO host byte order */
+		for (int j = 0; j < 14; j++) {
+			REVERSE32(context->buffer[j],context->buffer[j]);
+		}
+#endif
+		/* Set the bit count: */
+		context->buffer[14] = context->bitcount >> 32;
+		context->buffer[15] = context->bitcount & 0xffffffff;
+
+		/* Final transform: */
+		sha256_Transform(context->state, context->buffer, context->state);
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+		/* Convert FROM host byte order */
+		for (int j = 0; j < 8; j++) {
+			REVERSE32(context->state[j],context->state[j]);
+		}
+#endif
+		MEMCPY_BCOPY(digest, context->state, SHA256_DIGEST_LENGTH);
+	}
+
+	/* Clean up state data: */
+	memzero(context, sizeof(SHA256_CTX));
+	// cppcheck-suppress unreadVariable
+	usedspace = 0;
+}
+
+char *sha256_End(SHA256_CTX* context, char buffer[]) {
+	sha2_byte	digest[SHA256_DIGEST_LENGTH] = {0}, *d = digest;
+
+	if (buffer != (char*)0) {
+		sha256_Final(context, digest);
+
+		for (int i = 0; i < SHA256_DIGEST_LENGTH; i++) {
+			*buffer++ = sha2_hex_digits[(*d & 0xf0) >> 4];
+			*buffer++ = sha2_hex_digits[*d & 0x0f];
+			d++;
+		}
+		*buffer = (char)0;
+	} else {
+		memzero(context, sizeof(SHA256_CTX));
+	}
+	memzero(digest, SHA256_DIGEST_LENGTH);
+	return buffer;
+}
+
+void sha256_Raw(const sha2_byte* data, size_t len, uint8_t digest[SHA256_DIGEST_LENGTH]) {
+	SHA256_CTX	context = {0};
+	sha256_Init(&context);
+	sha256_Update(&context, data, len);
+	sha256_Final(&context, digest);
+}
+
+char* sha256_Data(const sha2_byte* data, size_t len, char digest[SHA256_DIGEST_STRING_LENGTH]) {
+	SHA256_CTX	context = {0};
+
+	sha256_Init(&context);
+	sha256_Update(&context, data, len);
+	return sha256_End(&context, digest);
+}
+
+
+/*** SHA-512: *********************************************************/
+void sha512_Init(SHA512_CTX* context) {
+	if (context == (SHA512_CTX*)0) {
+		return;
+	}
+	MEMCPY_BCOPY(context->state, sha512_initial_hash_value, SHA512_DIGEST_LENGTH);
+	memzero(context->buffer, SHA512_BLOCK_LENGTH);
+	context->bitcount[0] = context->bitcount[1] =  0;
+}
+
+#ifdef SHA2_UNROLL_TRANSFORM
+
+/* Unrolled SHA-512 round macros: */
+#define ROUND512_0_TO_15(a,b,c,d,e,f,g,h)	\
+	T1 = (h) + Sigma1_512(e) + Ch((e), (f), (g)) + \
+             K512[j] + (W512[j] = *data++); \
+	(d) += T1; \
+	(h) = T1 + Sigma0_512(a) + Maj((a), (b), (c)); \
+	j++
+
+#define ROUND512(a,b,c,d,e,f,g,h)	\
+	s0 = W512[(j+1)&0x0f]; \
+	s0 = sigma0_512(s0); \
+	s1 = W512[(j+14)&0x0f]; \
+	s1 = sigma1_512(s1); \
+	T1 = (h) + Sigma1_512(e) + Ch((e), (f), (g)) + K512[j] + \
+             (W512[j&0x0f] += s1 + W512[(j+9)&0x0f] + s0); \
+	(d) += T1; \
+	(h) = T1 + Sigma0_512(a) + Maj((a), (b), (c)); \
+	j++
+
+void sha512_Transform(const sha2_word64* state_in, const sha2_word64* data, sha2_word64* state_out) {
+	sha2_word64	a = 0, b = 0, c = 0, d = 0, e = 0, f = 0, g = 0, h = 0;
+	sha2_word64	T1 = 0, W512[16] = {0};
+	int		j = 0;
+
+	/* Initialize registers with the prev. intermediate value */
+	a = state_in[0];
+	b = state_in[1];
+	c = state_in[2];
+	d = state_in[3];
+	e = state_in[4];
+	f = state_in[5];
+	g = state_in[6];
+	h = state_in[7];
+
+	j = 0;
+	do {
+		ROUND512_0_TO_15(a,b,c,d,e,f,g,h);
+		ROUND512_0_TO_15(h,a,b,c,d,e,f,g);
+		ROUND512_0_TO_15(g,h,a,b,c,d,e,f);
+		ROUND512_0_TO_15(f,g,h,a,b,c,d,e);
+		ROUND512_0_TO_15(e,f,g,h,a,b,c,d);
+		ROUND512_0_TO_15(d,e,f,g,h,a,b,c);
+		ROUND512_0_TO_15(c,d,e,f,g,h,a,b);
+		ROUND512_0_TO_15(b,c,d,e,f,g,h,a);
+	} while (j < 16);
+
+	/* Now for the remaining rounds up to 79: */
+	do {
+		ROUND512(a,b,c,d,e,f,g,h);
+		ROUND512(h,a,b,c,d,e,f,g);
+		ROUND512(g,h,a,b,c,d,e,f);
+		ROUND512(f,g,h,a,b,c,d,e);
+		ROUND512(e,f,g,h,a,b,c,d);
+		ROUND512(d,e,f,g,h,a,b,c);
+		ROUND512(c,d,e,f,g,h,a,b);
+		ROUND512(b,c,d,e,f,g,h,a);
+	} while (j < 80);
+
+	/* Compute the current intermediate hash value */
+	state_out[0] = state_in[0] + a;
+	state_out[1] = state_in[1] + b;
+	state_out[2] = state_in[2] + c;
+	state_out[3] = state_in[3] + d;
+	state_out[4] = state_in[4] + e;
+	state_out[5] = state_in[5] + f;
+	state_out[6] = state_in[6] + g;
+	state_out[7] = state_in[7] + h;
+
+	/* Clean up */
+	// cppcheck-suppress unreadVariable
+	a = b = c = d = e = f = g = h = T1 = 0;
+}
+
+#else /* SHA2_UNROLL_TRANSFORM */
+
+void sha512_Transform(const sha2_word64* state_in, const sha2_word64* data, sha2_word64* state_out) {
+	sha2_word64	a = 0, b = 0, c = 0, d = 0, e = 0, f = 0, g = 0, h = 0;
+	sha2_word64	T1 = 0, T2 = 0, W512[16] = {0};
+	int		j = 0;
+
+	/* Initialize registers with the prev. intermediate value */
+	a = state_in[0];
+	b = state_in[1];
+	c = state_in[2];
+	d = state_in[3];
+	e = state_in[4];
+	f = state_in[5];
+	g = state_in[6];
+	h = state_in[7];
+
+	j = 0;
+	do {
+		/* Apply the SHA-512 compression function to update a..h with copy */
+		T1 = h + Sigma1_512(e) + Ch(e, f, g) + K512[j] + (W512[j] = *data++);
+		T2 = Sigma0_512(a) + Maj(a, b, c);
+		h = g;
+		g = f;
+		f = e;
+		e = d + T1;
+		d = c;
+		c = b;
+		b = a;
+		a = T1 + T2;
+
+		j++;
+	} while (j < 16);
+
+	do {
+		/* Part of the message block expansion: */
+		sha2_word64 s0 = 0, s1 = 0;
+		s0 = W512[(j+1)&0x0f];
+		s0 = sigma0_512(s0);
+		s1 = W512[(j+14)&0x0f];
+		s1 =  sigma1_512(s1);
+
+		/* Apply the SHA-512 compression function to update a..h */
+		T1 = h + Sigma1_512(e) + Ch(e, f, g) + K512[j] +
+		     (W512[j&0x0f] += s1 + W512[(j+9)&0x0f] + s0);
+		T2 = Sigma0_512(a) + Maj(a, b, c);
+		h = g;
+		g = f;
+		f = e;
+		e = d + T1;
+		d = c;
+		c = b;
+		b = a;
+		a = T1 + T2;
+
+		j++;
+	} while (j < 80);
+
+	/* Compute the current intermediate hash value */
+	state_out[0] = state_in[0] + a;
+	state_out[1] = state_in[1] + b;
+	state_out[2] = state_in[2] + c;
+	state_out[3] = state_in[3] + d;
+	state_out[4] = state_in[4] + e;
+	state_out[5] = state_in[5] + f;
+	state_out[6] = state_in[6] + g;
+	state_out[7] = state_in[7] + h;
+
+	/* Clean up */
+	// cppcheck-suppress unreadVariable
+	a = b = c = d = e = f = g = h = T1 = T2 = 0;
+}
+
+#endif /* SHA2_UNROLL_TRANSFORM */
+
+void sha512_Update(SHA512_CTX* context, const sha2_byte *data, size_t len) {
+	unsigned int	freespace = 0, usedspace = 0;
+
+	if (len == 0) {
+		/* Calling with no data is valid - we do nothing */
+		return;
+	}
+
+	usedspace = (context->bitcount[0] >> 3) % SHA512_BLOCK_LENGTH;
+	if (usedspace > 0) {
+		/* Calculate how much free space is available in the buffer */
+		freespace = SHA512_BLOCK_LENGTH - usedspace;
+
+		if (len >= freespace) {
+			/* Fill the buffer completely and process it */
+			MEMCPY_BCOPY(((uint8_t*)context->buffer) + usedspace, data, freespace);
+			ADDINC128(context->bitcount, freespace << 3);
+			len -= freespace;
+			data += freespace;
+#if BYTE_ORDER == LITTLE_ENDIAN
+			/* Convert TO host byte order */
+			for (int j = 0; j < 16; j++) {
+				REVERSE64(context->buffer[j],context->buffer[j]);
+			}
+#endif
+			sha512_Transform(context->state, context->buffer, context->state);
+		} else {
+			/* The buffer is not yet full */
+			MEMCPY_BCOPY(((uint8_t*)context->buffer) + usedspace, data, len);
+			ADDINC128(context->bitcount, len << 3);
+			/* Clean up: */
+			// cppcheck-suppress unreadVariable
+			usedspace = freespace = 0;
+			return;
+		}
+	}
+	while (len >= SHA512_BLOCK_LENGTH) {
+		/* Process as many complete blocks as we can */
+		MEMCPY_BCOPY(context->buffer, data, SHA512_BLOCK_LENGTH);
+#if BYTE_ORDER == LITTLE_ENDIAN
+		/* Convert TO host byte order */
+		for (int j = 0; j < 16; j++) {
+			REVERSE64(context->buffer[j],context->buffer[j]);
+		}
+#endif
+		sha512_Transform(context->state, context->buffer, context->state);
+		ADDINC128(context->bitcount, SHA512_BLOCK_LENGTH << 3);
+		len -= SHA512_BLOCK_LENGTH;
+		data += SHA512_BLOCK_LENGTH;
+	}
+	if (len > 0) {
+		/* There's left-overs, so save 'em */
+		MEMCPY_BCOPY(context->buffer, data, len);
+		ADDINC128(context->bitcount, len << 3);
+	}
+	/* Clean up: */
+	// cppcheck-suppress unreadVariable
+	usedspace = freespace = 0;
+}
+
+static void sha512_Last(SHA512_CTX* context) {
+	unsigned int	usedspace = 0;
+
+	usedspace = (context->bitcount[0] >> 3) % SHA512_BLOCK_LENGTH;
+	/* Begin padding with a 1 bit: */
+	((uint8_t*)context->buffer)[usedspace++] = 0x80;
+
+	if (usedspace > SHA512_SHORT_BLOCK_LENGTH) {
+		memzero(((uint8_t*)context->buffer) + usedspace, SHA512_BLOCK_LENGTH - usedspace);
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+		/* Convert TO host byte order */
+		for (int j = 0; j < 16; j++) {
+			REVERSE64(context->buffer[j],context->buffer[j]);
+		}
+#endif
+		/* Do second-to-last transform: */
+		sha512_Transform(context->state, context->buffer, context->state);
+
+		/* And prepare the last transform: */
+		usedspace = 0;
+	}
+	/* Set-up for the last transform: */
+	memzero(((uint8_t*)context->buffer) + usedspace, SHA512_SHORT_BLOCK_LENGTH - usedspace);
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+	/* Convert TO host byte order */
+	for (int j = 0; j < 14; j++) {
+		REVERSE64(context->buffer[j],context->buffer[j]);
+	}
+#endif
+	/* Store the length of input data (in bits): */
+	context->buffer[14] = context->bitcount[1];
+	context->buffer[15] = context->bitcount[0];
+
+	/* Final transform: */
+	sha512_Transform(context->state, context->buffer, context->state);
+}
+
+void sha512_Final(SHA512_CTX* context, sha2_byte digest[]) {
+	/* If no digest buffer is passed, we don't bother doing this: */
+	if (digest != (sha2_byte*)0) {
+		sha512_Last(context);
+
+		/* Save the hash data for output: */
+#if BYTE_ORDER == LITTLE_ENDIAN
+		/* Convert FROM host byte order */
+		for (int j = 0; j < 8; j++) {
+			REVERSE64(context->state[j],context->state[j]);
+		}
+#endif
+		MEMCPY_BCOPY(digest, context->state, SHA512_DIGEST_LENGTH);
+	}
+
+	/* Zero out state data */
+	memzero(context, sizeof(SHA512_CTX));
+}
+
+char *sha512_End(SHA512_CTX* context, char buffer[]) {
+	sha2_byte	digest[SHA512_DIGEST_LENGTH] = {0}, *d = digest;
+
+	if (buffer != (char*)0) {
+		sha512_Final(context, digest);
+
+		for (int i = 0; i < SHA512_DIGEST_LENGTH; i++) {
+			*buffer++ = sha2_hex_digits[(*d & 0xf0) >> 4];
+			*buffer++ = sha2_hex_digits[*d & 0x0f];
+			d++;
+		}
+		*buffer = (char)0;
+	} else {
+		memzero(context, sizeof(SHA512_CTX));
+	}
+	memzero(digest, SHA512_DIGEST_LENGTH);
+	return buffer;
+}
+
+void sha512_Raw(const sha2_byte* data, size_t len, uint8_t digest[SHA512_DIGEST_LENGTH]) {
+	SHA512_CTX	context = {0};
+	sha512_Init(&context);
+	sha512_Update(&context, data, len);
+	sha512_Final(&context, digest);
+}
+
+char* sha512_Data(const sha2_byte* data, size_t len, char digest[SHA512_DIGEST_STRING_LENGTH]) {
+	SHA512_CTX	context = {0};
+
+	sha512_Init(&context);
+	sha512_Update(&context, data, len);
+	return sha512_End(&context, digest);
+}

src/third-party/bcur/sha2.h

@@ -0,0 +1,100 @@
+/**
+ * Copyright (c) 2000-2001 Aaron D. Gifford
+ * Copyright (c) 2013-2014 Pavol Rusnak
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holder nor the names of contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTOR(S) ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTOR(S) BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef BC_UR_SHA2_H
+#define BC_UR_SHA2_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+#define SHA256_BLOCK_LENGTH		64
+#define SHA256_DIGEST_LENGTH		32
+#define SHA256_DIGEST_STRING_LENGTH	(SHA256_DIGEST_LENGTH * 2 + 1)
+#define SHA512_BLOCK_LENGTH		128
+#define SHA512_DIGEST_LENGTH		64
+#define SHA512_DIGEST_STRING_LENGTH	(SHA512_DIGEST_LENGTH * 2 + 1)
+
+typedef struct _SHA256_CTX {
+	uint32_t	state[8];
+	uint64_t	bitcount;
+	uint32_t	buffer[SHA256_BLOCK_LENGTH/sizeof(uint32_t)];
+} SHA256_CTX;
+typedef struct _SHA512_CTX {
+	uint64_t	state[8];
+	uint64_t	bitcount[2];
+	uint64_t	buffer[SHA512_BLOCK_LENGTH/sizeof(uint64_t)];
+} SHA512_CTX;
+
+/*** ENDIAN REVERSAL MACROS *******************************************/
+#ifndef LITTLE_ENDIAN
+#define LITTLE_ENDIAN 1234
+#define BIG_ENDIAN    4321
+#endif
+
+#ifndef BYTE_ORDER
+#define BYTE_ORDER LITTLE_ENDIAN
+#endif
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define REVERSE32(w,x)	{ \
+	uint32_t tmp = (w); \
+	tmp = (tmp >> 16) | (tmp << 16); \
+	(x) = ((tmp & 0xff00ff00UL) >> 8) | ((tmp & 0x00ff00ffUL) << 8); \
+}
+#define REVERSE64(w,x)	{ \
+	uint64_t tmp = (w); \
+	tmp = (tmp >> 32) | (tmp << 32); \
+	tmp = ((tmp & 0xff00ff00ff00ff00ULL) >> 8) | \
+	      ((tmp & 0x00ff00ff00ff00ffULL) << 8); \
+	(x) = ((tmp & 0xffff0000ffff0000ULL) >> 16) | \
+	      ((tmp & 0x0000ffff0000ffffULL) << 16); \
+}
+#endif /* BYTE_ORDER == LITTLE_ENDIAN */
+
+extern const uint32_t sha256_initial_hash_value[8];
+extern const uint64_t sha512_initial_hash_value[8];
+
+void sha256_Transform(const uint32_t* state_in, const uint32_t* data, uint32_t* state_out);
+void sha256_Init(SHA256_CTX *);
+void sha256_Update(SHA256_CTX*, const uint8_t*, size_t);
+void sha256_Final(SHA256_CTX*, uint8_t[SHA256_DIGEST_LENGTH]);
+char* sha256_End(SHA256_CTX*, char[SHA256_DIGEST_STRING_LENGTH]);
+void sha256_Raw(const uint8_t*, size_t, uint8_t[SHA256_DIGEST_LENGTH]);
+char* sha256_Data(const uint8_t*, size_t, char[SHA256_DIGEST_STRING_LENGTH]);
+
+void sha512_Transform(const uint64_t* state_in, const uint64_t* data, uint64_t* state_out);
+void sha512_Init(SHA512_CTX*);
+void sha512_Update(SHA512_CTX*, const uint8_t*, size_t);
+void sha512_Final(SHA512_CTX*, uint8_t[SHA512_DIGEST_LENGTH]);
+char* sha512_End(SHA512_CTX*, char[SHA512_DIGEST_STRING_LENGTH]);
+void sha512_Raw(const uint8_t*, size_t, uint8_t[SHA512_DIGEST_LENGTH]);
+char* sha512_Data(const uint8_t*, size_t, char[SHA512_DIGEST_STRING_LENGTH]);
+
+#endif // BC_UR_SHA2_H

src/third-party/bcur/ur-decoder.cpp

@@ -0,0 +1,119 @@
+//
+//  ur-decoder.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "ur-decoder.hpp"
+#include "bytewords.hpp"
+
+using namespace std;
+
+namespace ur {
+
+UR URDecoder::decode(const string& s) {
+    auto [type, components] = parse(s);
+
+    if(components.empty()) throw InvalidPathLength();
+    auto body = components.front();
+
+    return decode(type, body);
+}
+
+URDecoder::URDecoder() { }
+
+UR URDecoder::decode(const std::string& type, const std::string& body) {
+    auto cbor = Bytewords::decode(Bytewords::style::minimal, body);
+    return UR(type, cbor);
+}
+
+pair<string, StringVector> URDecoder::parse(const string& s) {
+    // Don't consider case
+    auto lowered = to_lowercase(s);
+
+    // Validate URI scheme
+    if(!has_prefix(lowered, "ur:")) throw InvalidScheme();
+    auto path = drop_first(lowered, 3);
+
+    // Split the remainder into path components
+    auto components = split(path, '/');
+
+    // Make sure there are at least two path components
+    if(components.size() < 2) throw InvalidPathLength();
+
+    // Validate the type
+    auto type = components.front();
+    if(!is_ur_type(type)) throw InvalidType();
+
+    auto comps = StringVector(components.begin() + 1, components.end());
+    return pair(type, comps);
+}
+
+pair<uint32_t, size_t> URDecoder::parse_sequence_component(const string& s) {
+    try {
+        auto comps = split(s, '-');
+        if(comps.size() != 2) throw InvalidSequenceComponent();
+        uint32_t seq_num = stoul(comps[0]);
+        size_t seq_len = stoul(comps[1]);
+        if(seq_num < 1 || seq_len < 1) throw InvalidSequenceComponent();
+        return pair(seq_num, seq_len);
+    } catch(...) {
+        throw InvalidSequenceComponent();
+    }
+}
+
+bool URDecoder::validate_part(const std::string& type) {
+    if(!expected_type_.has_value()) {
+        if(!is_ur_type(type)) return false;
+        expected_type_ = type;
+        return true;
+    } else {
+        return type == expected_type_;
+    }
+}
+
+bool URDecoder::receive_part(const std::string& s) {
+    try {
+        // Don't process the part if we're already done
+        if(result_.has_value()) return false;
+
+        // Don't continue if this part doesn't validate
+        auto [type, components] = parse(s);
+        if(!validate_part(type)) return false;
+
+        // If this is a single-part UR then we're done
+        if(components.size() == 1) {
+            auto body = components.front();
+            result_ = decode(type, body);
+            return true;
+        }
+
+        // Multi-part URs must have two path components: seq/fragment
+        if(components.size() != 2) throw InvalidPathLength();
+        auto seq = components[0];
+        auto fragment = components[1];
+
+        // Parse the sequence component and the fragment, and
+        // make sure they agree.
+        auto [seq_num, seq_len] = parse_sequence_component(seq);
+        auto cbor = Bytewords::decode(Bytewords::style::minimal, fragment);
+        auto part = FountainEncoder::Part(cbor);
+        if(seq_num != part.seq_num() || seq_len != part.seq_len()) return false;
+
+        // Process the part
+        if(!fountain_decoder.receive_part(part)) return false;
+
+        if(fountain_decoder.is_success()) {
+            result_ = UR(type, fountain_decoder.result_message());
+        } else if(fountain_decoder.is_failure()) {
+            result_ = fountain_decoder.result_error();
+        }
+
+        return true;
+    } catch(...) {
+        return false;
+    }
+}
+
+}

src/third-party/bcur/ur-decoder.hpp

@@ -0,0 +1,66 @@
+//
+//  ur-decoder.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_DECODER_HPP
+#define BC_UR_DECODER_HPP
+
+#include <string>
+#include <exception>
+#include <utility>
+#include <optional>
+
+#include "ur.hpp"
+#include "fountain-decoder.hpp"
+
+namespace ur {
+
+class URDecoder final {
+public:
+    typedef std::optional<std::variant<UR, std::exception> > Result;
+
+    class InvalidScheme: public std::exception { };
+    class InvalidType: public std::exception { };
+    class InvalidPathLength: public std::exception { };
+    class InvalidSequenceComponent: public std::exception { };
+    class InvalidFragment: public std::exception { };
+
+    // Decode a single-part UR.
+    static UR decode(const std::string& string);
+
+    // Start decoding a (possibly) multi-part UR.
+    URDecoder();
+
+    const std::optional<std::string>& expected_type() const { return expected_type_; }
+    size_t expected_part_count() const { return fountain_decoder.expected_part_count(); }
+    const PartIndexes& received_part_indexes() const { return fountain_decoder.received_part_indexes(); }
+    const PartIndexes& last_part_indexes() const { return fountain_decoder.last_part_indexes(); }
+    size_t processed_parts_count() const { return fountain_decoder.processed_parts_count(); }
+    double estimated_percent_complete() const { return fountain_decoder.estimated_percent_complete(); }
+    const Result& result() const { return result_; }
+    bool is_success() const { return result() && std::holds_alternative<UR>(result().value()); }
+    bool is_failure() const { return result() && std::holds_alternative<std::exception>(result().value()); }
+    bool is_complete() const { return result().has_value(); }
+    const UR& result_ur() const { return std::get<UR>(result().value()); }
+    const std::exception& result_error() const { return std::get<std::exception>(result().value()); }
+
+    bool receive_part(const std::string& s);
+
+private:
+    FountainDecoder fountain_decoder;
+
+    std::optional<std::string> expected_type_;
+    Result result_;
+
+    static std::pair<std::string, StringVector> parse(const std::string& string);
+    static std::pair<uint32_t, size_t> parse_sequence_component(const std::string& string);
+    static UR decode(const std::string& type, const std::string& body);
+    bool validate_part(const std::string& type);
+};
+
+}
+
+#endif // BC_UR_DECODER_HPP

src/third-party/bcur/ur-encoder.cpp

@@ -0,0 +1,50 @@
+//
+//  ur-encoder.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "ur-encoder.hpp"
+#include "bytewords.hpp"
+
+using namespace std;
+
+namespace ur {
+
+string UREncoder::encode(const UR& ur) {
+    auto body = Bytewords::encode(Bytewords::style::minimal, ur.cbor());
+    return encode_ur({ur.type(), body});
+}
+
+UREncoder::UREncoder(const UR& ur, size_t max_fragment_len, uint32_t first_seq_num, size_t min_fragment_len)
+    : ur_(ur),
+    fountain_encoder_(FountainEncoder(ur.cbor(), max_fragment_len, first_seq_num, min_fragment_len))
+{
+}
+
+std::string UREncoder::next_part() {
+    auto part = fountain_encoder_.next_part();
+    if(is_single_part()) {
+        return encode(ur_);
+    } else {
+        return encode_part(ur_.type(), part);
+    }
+}
+
+string UREncoder::encode_part(const string& type, const FountainEncoder::Part& part) {
+    auto seq = to_string(part.seq_num()) + "-" + to_string(part.seq_len());
+    auto body = Bytewords::encode(Bytewords::style::minimal, part.cbor());
+    return encode_ur({type, seq, body});
+}
+
+string UREncoder::encode_uri(const string& scheme, const StringVector& path_components) {
+    auto path = join(path_components, "/");
+    return join({scheme, path}, ":");
+}
+
+string UREncoder::encode_ur(const StringVector& path_components) {
+    return encode_uri("ur", path_components);
+}
+
+}

src/third-party/bcur/ur-encoder.hpp

@@ -0,0 +1,52 @@
+//
+//  ur-encoder.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_ENCODER_HPP
+#define BC_UR_ENCODER_HPP
+
+#include <string>
+#include "ur.hpp"
+#include "utils.hpp"
+#include "fountain-encoder.hpp"
+
+namespace ur {
+
+class UREncoder final {
+public:
+    // Encode a single-part UR.
+    static std::string encode(const UR& ur);
+
+    // Start encoding a (possibly) multi-part UR.
+    UREncoder(const UR& ur, size_t max_fragment_len, uint32_t first_seq_num = 0, size_t min_fragment_len = 10);
+
+    uint32_t seq_num() const { return fountain_encoder_.seq_num(); }
+    size_t seq_len() const { return fountain_encoder_.seq_len(); }
+    PartIndexes last_part_indexes() const { return fountain_encoder_.last_part_indexes(); }
+
+    // `true` if the minimal number of parts to transmit the message have been
+    // generated. Parts generated when this is `true` will be fountain codes
+    // containing various mixes of the part data.
+    bool is_complete() const { return fountain_encoder_.is_complete(); }
+
+    // `true` if this UR can be contained in a single part. If `true`, repeated
+    // calls to `next_part()` will all return the same single-part UR.
+    bool is_single_part() const { return fountain_encoder_.is_single_part(); }
+
+    std::string next_part();
+    
+private:
+    UR ur_;
+    FountainEncoder fountain_encoder_;
+
+    static std::string encode_part(const std::string& type, const FountainEncoder::Part& part);
+    static std::string encode_uri(const std::string& scheme, const StringVector& path_components);
+    static std::string encode_ur(const StringVector& path_components);
+};
+
+}
+
+#endif // BC_UR_ENCODER_HPP

src/third-party/bcur/ur.cpp

@@ -0,0 +1,28 @@
+//
+//  ur.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "ur.hpp"
+
+#include <iostream>
+
+using namespace std;
+
+namespace ur {
+
+UR::UR(const std::string &type, const ByteVector &cbor)
+    : type_(type), cbor_(cbor)
+{
+    if (!is_ur_type(type)) {
+        throw invalid_type();
+    }
+}
+
+bool operator==(const UR& lhs, const UR& rhs) {
+    return lhs.type() == rhs.type() && lhs.cbor() == rhs.cbor();
+}
+
+} // namespace ur

src/third-party/bcur/ur.hpp

@@ -0,0 +1,34 @@
+//
+//  ur.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef BC_UR_UR_HPP
+#define BC_UR_UR_HPP
+
+#include <string>
+#include <exception>
+#include "utils.hpp"
+
+namespace ur {
+
+class UR final {
+private:
+    std::string type_;
+    ByteVector cbor_;
+public:
+    class invalid_type: public std::exception { };
+
+    const std::string& type() const { return type_; }
+    const ByteVector& cbor() const { return cbor_; }
+
+    UR(const std::string& type, const ByteVector& cbor);
+};
+
+bool operator==(const UR& lhs, const UR& rhs);
+
+}
+
+#endif // BC_UR_UR_HPP

src/third-party/bcur/utils.cpp

@@ -0,0 +1,171 @@
+//
+//  utils.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "utils.hpp"
+
+extern "C" {
+
+#include "sha2.h"
+#include "crc32.h"
+
+}
+
+#include <vector>
+#include <sstream>
+#include <algorithm>
+#include <cctype>
+
+using namespace std;
+
+namespace ur {
+
+ByteVector sha256(const ByteVector &buf) {
+    uint8_t digest[SHA256_DIGEST_LENGTH];
+    sha256_Raw(&buf[0], buf.size(), digest);
+    return ByteVector(digest, digest + SHA256_DIGEST_LENGTH);
+}
+
+ByteVector crc32_bytes(const ByteVector &buf) {
+    uint32_t checksum = ur_crc32n(&buf[0], buf.size());
+    auto cbegin = (uint8_t*)&checksum;
+    auto cend = cbegin + sizeof(uint32_t);
+    return ByteVector(cbegin, cend);
+}
+
+uint32_t crc32_int(const ByteVector &buf) {
+    return ur_crc32(&buf[0], buf.size());
+}
+
+ByteVector string_to_bytes(const string& s) {
+    return ByteVector(s.begin(), s.end());
+}
+
+string data_to_hex(const ByteVector& in) {
+    auto hex = "0123456789abcdef";
+    string result;
+    for(auto c: in) {
+        result.append(1, hex[(c >> 4) & 0xF]);
+        result.append(1, hex[c & 0xF]);
+    }
+    return result;
+}
+
+string data_to_hex(uint32_t n) {
+    return data_to_hex(int_to_bytes(n));
+}
+
+ByteVector int_to_bytes(uint32_t n) {
+    ByteVector b;
+    b.reserve(4);
+    b.push_back((n >> 24 & 0xff));
+    b.push_back((n >> 16) & 0xff);
+    b.push_back((n >> 8) & 0xff);
+    b.push_back(n & 0xff);
+    return b;
+}
+
+uint32_t bytes_to_int(const ByteVector& in) {
+    assert(in.size() >= 4);
+    uint32_t result = 0;
+    result |= in[0] << 24;
+    result |= in[1] << 16;
+    result |= in[2] << 8;
+    result |= in[3];
+    return result;
+}
+
+string join(const StringVector &strings, const string &separator) {
+    ostringstream result;
+    bool first = true;
+    for(auto s: strings) {
+        if(!first) {
+            result << separator;
+        }
+        result << s;
+        first = false;
+    }
+    return result.str();
+}
+
+StringVector split(const string& s, char separator) {
+	StringVector result;
+	string buf;
+
+	for(auto c: s) {
+		if(c != separator) {
+            buf += c;
+        } else if(c == separator && buf.length() > 0) {
+            result.push_back(buf);
+            buf = "";
+        }
+	}
+
+	if(buf != "") {
+        result.push_back(buf);
+    }
+
+	return result;
+}
+
+StringVector partition(const string& s, size_t size) {
+    StringVector result;
+    auto remaining = s;
+    while(remaining.length() > 0) {
+        result.push_back(take_first(remaining, size));
+        remaining = drop_first(remaining, size);
+    }
+    return result;
+}
+
+string take_first(const string &s, size_t count) {
+    auto first = s.begin();
+    auto c = min(s.size(), count);
+    auto last = first + c;
+    return string(first, last);
+}
+
+string drop_first(const string& s, size_t count) {
+    if(count >= s.length()) { return ""; }
+    return string(s.begin() + count, s.end());
+}
+
+void xor_into(ByteVector& target, const ByteVector& source) {
+    auto count = target.size();
+    assert(count == source.size());
+    for(int i = 0; i < count; i++) {
+        target[i] ^= source[i];
+    }
+}
+
+ByteVector xor_with(const ByteVector& a, const ByteVector& b) {
+    auto target = a;
+    xor_into(target, b);
+    return target;
+}
+
+bool is_ur_type(char c) {
+    if('a' <= c && c <= 'z') return true;
+    if('0' <= c && c <= '9') return true;
+    if(c == '-') return true;
+    return false;
+}
+
+bool is_ur_type(const string& s) {
+    return none_of(s.begin(), s.end(), [](auto c) { return !is_ur_type(c); });
+}
+
+string to_lowercase(const string& s) {
+    string result;
+    transform(s.begin(), s.end(), back_inserter(result), [](char c){ return tolower(c); });
+    return result;
+}
+
+bool has_prefix(const string& s, const string& prefix) {
+    return s.rfind(prefix, 0) == 0;
+}
+
+}

src/third-party/bcur/utils.hpp

@@ -0,0 +1,89 @@
+//
+//  utils.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef UTILS_HPP
+#define UTILS_HPP
+
+#include <stdint.h>
+#include <vector>
+#include <utility>
+#include <string>
+#include <array>
+#include <assert.h>
+
+namespace ur {
+
+typedef std::vector<uint8_t> ByteVector;
+typedef std::vector<std::string> StringVector;
+
+ByteVector sha256(const ByteVector &buf);
+ByteVector crc32_bytes(const ByteVector &buf);
+uint32_t crc32_int(const ByteVector &buf);
+
+ByteVector string_to_bytes(const std::string& s);
+
+std::string data_to_hex(const ByteVector& in);
+std::string data_to_hex(uint32_t n);
+
+ByteVector int_to_bytes(uint32_t n);
+uint32_t bytes_to_int(const ByteVector& in);
+
+std::string join(const StringVector &strings, const std::string &separator);
+StringVector split(const std::string& s, char separator);
+
+StringVector partition(const std::string& string, size_t size);
+
+std::string take_first(const std::string &s, size_t count);
+std::string drop_first(const std::string &s, size_t count);
+
+template<typename T>
+void append(std::vector<T>& target, const std::vector<T>& source) {
+    target.insert(target.end(), source.begin(), source.end());
+}
+
+template<typename T, size_t N>
+void append(std::vector<T>& target, const std::array<T, N>& source) {
+    target.insert(target.end(), source.begin(), source.end());
+}
+
+template<typename T>
+std::vector<T> join(const std::vector<std::vector<T>>& parts) {
+    std::vector<T> result;
+    for(auto part: parts) { append(result, part); }
+    return result;
+}
+
+template<typename T>
+std::pair<std::vector<T>, std::vector<T>> split(const std::vector<T>& buf, size_t count) {
+    auto first = buf.begin();
+    auto c = std::min(buf.size(), count);
+    auto last = first + c;
+    auto a = std::vector(first, last);
+    auto b = std::vector(last, buf.end());
+    return std::make_pair(a, b);
+}
+
+template<typename T>
+std::vector<T> take_first(const std::vector<T> &buf, size_t count) {
+    auto first = buf.begin();
+    auto c = std::min(buf.size(), count);
+    auto last = first + c;
+    return std::vector(first, last);
+}
+
+void xor_into(ByteVector& target, const ByteVector& source);
+ByteVector xor_with(const ByteVector& a, const ByteVector& b);
+
+bool is_ur_type(char c);
+bool is_ur_type(const std::string& s);
+
+std::string to_lowercase(const std::string& s);
+bool has_prefix(const std::string& s, const std::string& prefix);
+
+}
+
+#endif // UTILS_HPP

src/third-party/bcur/xoshiro256.cpp

@@ -0,0 +1,177 @@
+//
+//  xoshiro256.cpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#include "xoshiro256.hpp"
+#include <limits>
+#include <cstring>
+
+/*  Written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org)
+
+To the extent possible under law, the author has dedicated all copyright
+and related and neighboring rights to this software to the public domain
+worldwide. This software is distributed without any warranty.
+
+See <http://creativecommons.org/publicdomain/zero/1.0/>. */
+
+/* This is xoshiro256** 1.0, one of our all-purpose, rock-solid
+   generators. It has excellent (sub-ns) speed, a state (256 bits) that is
+   large enough for any parallel application, and it passes all tests we
+   are aware of.
+
+   For generating just floating-point numbers, xoshiro256+ is even faster.
+
+   The state must be seeded so that it is not everywhere zero. If you have
+   a 64-bit seed, we suggest to seed a splitmix64 generator and use its
+   output to fill s. */
+
+namespace ur {
+
+static inline uint64_t rotl(const uint64_t x, int k) {
+	return (x << k) | (x >> (64 - k));
+}
+
+Xoshiro256::Xoshiro256(const std::array<uint64_t, 4>& a) {
+    s[0] = a[0];
+    s[1] = a[1];
+    s[2] = a[2];
+    s[3] = a[3];
+}
+
+void Xoshiro256::set_s(const std::array<uint8_t, 32>& a) {
+    for(int i = 0; i < 4; i++) {
+        auto o = i * 8;
+        uint64_t v = 0;
+        for(int n = 0; n < 8; n++) {
+            v <<= 8;
+            v |= a[o + n];
+        }
+        s[i] = v;
+    }
+}
+
+void Xoshiro256::hash_then_set_s(const ByteVector& bytes) {
+    auto digest = sha256(bytes);
+    std::array<uint8_t, 32> a;
+    memcpy(a.data(), &digest[0], 32);
+    set_s(a);
+}
+
+Xoshiro256::Xoshiro256(const std::array<uint8_t, 32>& a) {
+    set_s(a);
+}
+
+Xoshiro256::Xoshiro256(const ByteVector& bytes) {
+    hash_then_set_s(bytes);
+}
+
+Xoshiro256::Xoshiro256(const std::string& s) {
+    ByteVector bytes(s.begin(), s.end());
+    hash_then_set_s(bytes);
+}
+
+Xoshiro256::Xoshiro256(uint32_t crc32) {
+    auto bytes = int_to_bytes(crc32);
+    hash_then_set_s(bytes);
+}
+
+double Xoshiro256::next_double() {
+    auto m = ((double)std::numeric_limits<uint64_t>::max()) + 1;
+    return next() / m;
+}
+
+uint64_t Xoshiro256::next_int(uint64_t low, uint64_t high) {
+    return uint64_t(next_double() * (high - low + 1)) + low;
+}
+
+uint8_t Xoshiro256::next_byte() {
+    return uint8_t(next_int(0, 255));
+}
+
+ByteVector Xoshiro256::next_data(size_t count) {
+    ByteVector result;
+    result.reserve(count);
+    for(int i = 0; i < count; i++) {
+        result.push_back(next_byte());
+    }
+    return result;
+}
+
+uint64_t Xoshiro256::next() {
+	const uint64_t result = rotl(s[1] * 5, 7) * 9;
+
+	const uint64_t t = s[1] << 17;
+
+	s[2] ^= s[0];
+	s[3] ^= s[1];
+	s[1] ^= s[2];
+	s[0] ^= s[3];
+
+	s[2] ^= t;
+
+	s[3] = rotl(s[3], 45);
+
+	return result;
+}
+
+/* This is the jump function for the generator. It is equivalent
+   to 2^128 calls to next(); it can be used to generate 2^128
+   non-overlapping subsequences for parallel computations. */
+
+void Xoshiro256::jump() {
+	static const uint64_t JUMP[] = { 0x180ec6d33cfd0aba, 0xd5a61266f0c9392c, 0xa9582618e03fc9aa, 0x39abdc4529b1661c };
+
+	uint64_t s0 = 0;
+	uint64_t s1 = 0;
+	uint64_t s2 = 0;
+	uint64_t s3 = 0;
+	for(int i = 0; i < sizeof JUMP / sizeof *JUMP; i++)
+		for(int b = 0; b < 64; b++) {
+			if (JUMP[i] & UINT64_C(1) << b) {
+				s0 ^= s[0];
+				s1 ^= s[1];
+				s2 ^= s[2];
+				s3 ^= s[3];
+			}
+			next();
+		}
+
+	s[0] = s0;
+	s[1] = s1;
+	s[2] = s2;
+	s[3] = s3;
+}
+
+/* This is the long-jump function for the generator. It is equivalent to
+   2^192 calls to next(); it can be used to generate 2^64 starting points,
+   from each of which jump() will generate 2^64 non-overlapping
+   subsequences for parallel distributed computations. */
+
+void Xoshiro256::long_jump() {
+	static const uint64_t LONG_JUMP[] = { 0x76e15d3efefdcbbf, 0xc5004e441c522fb3, 0x77710069854ee241, 0x39109bb02acbe635 };
+
+	uint64_t s0 = 0;
+	uint64_t s1 = 0;
+	uint64_t s2 = 0;
+	uint64_t s3 = 0;
+	for(int i = 0; i < sizeof LONG_JUMP / sizeof *LONG_JUMP; i++)
+		for(int b = 0; b < 64; b++) {
+			if (LONG_JUMP[i] & UINT64_C(1) << b) {
+				s0 ^= s[0];
+				s1 ^= s[1];
+				s2 ^= s[2];
+				s3 ^= s[3];
+			}
+			next();
+		}
+
+	s[0] = s0;
+	s[1] = s1;
+	s[2] = s2;
+	s[3] = s3;
+}
+
+}

src/third-party/bcur/xoshiro256.hpp

@@ -0,0 +1,45 @@
+//
+//  xoshiro256.hpp
+//
+//  Copyright © 2020 by Blockchain Commons, LLC
+//  Licensed under the "BSD-2-Clause Plus Patent License"
+//
+
+#ifndef XOSHIRO256_HPP
+#define XOSHIRO256_HPP
+
+#include <stdint.h>
+#include <array>
+#include <string>
+#include "utils.hpp"
+
+namespace ur {
+
+class Xoshiro256 {
+public:
+    explicit Xoshiro256(const std::array<uint64_t, 4>& a);
+    explicit Xoshiro256(const std::array<uint8_t, 32>& a);
+
+    explicit Xoshiro256(const ByteVector& bytes);
+    explicit Xoshiro256(const std::string& s);
+    explicit Xoshiro256(uint32_t crc32);
+
+    uint64_t next();
+    double next_double();
+    uint64_t next_int(uint64_t low, uint64_t high);
+    uint8_t next_byte();
+    ByteVector next_data(size_t count);
+
+    void jump();
+    void long_jump();
+
+private:
+    uint64_t s[4];
+
+    void set_s(const std::array<uint8_t, 32>& a);
+    void hash_then_set_s(const ByteVector& bytes);
+};
+
+}
+
+#endif // XOSHIRO256_HPP