General Purpose library for Freestanding C++ and POSIX systems
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#pragma once
#include <gp/algorithm/repeat.hpp>
#include <gp/bitops.hpp>
#include <gp/optional.hpp>
#include <gp/pair.hpp>
#include <gp/variant.hpp>
#include <gp/vector.hpp>
namespace gp {
enum class cbor_type : uint8_t {
uint = 0,
nint = 1,
bstr = 2,
tstr = 3,
list = 4,
hmap = 5,
tags = 6,
oths = 7
};
enum class cbor_oths : uint8_t {
value_false = 20,
value_true = 21,
value_null = 22,
value_undefined = 23,
byte = 24,
word = 25,
dword = 26,
qword = 27,
terminator = 31
};
enum class cbor_tags {
datetime = 0,
unix_time = 1,
ubignum = 2,
nbignum = 3,
decimal = 4,
bigfloat = 5,
cose_encrypt0 = 16,
cose_mac0 = 17,
cose_sign1 = 18,
expected_base64url = 21,
expected_base64 = 22,
expected_base16 = 23,
encoded_cbor = 24,
url = 32,
base64url = 33,
base64 = 34,
regexp = 35,
mime = 36,
cose_encrypt = 96,
cose_mac = 97,
cose_sign = 98,
signature = 55799
};
struct cbor_number final {
bool sign;
uint64_t value;
bool is_negative() {
return sign;
}
cbor_number(int64_t v)
: sign{v < 0}
, value{uint64_t((sign ? -1 : 1) * v)}
{}
cbor_number(bool s, uint64_t v)
: sign{s}
, value{v}
{}
};
struct ieee754_hf final {
uint16_t sign : 1;
uint16_t exponent : 5;
uint16_t mantissa : 10;
// TODO: support for denormalized values and NaNs
operator float() {
auto a = (uint32_t)((sign<<16) | ((exponent+0x1C000)<<13) | (mantissa<<13));
return *(float*)&a;
}
operator double() {
return (float)*this;
}
};
struct cbor_floating_point final {
using backing = gp::fixed_variant<
ieee754_hf,
float,
double
>;
backing contents;
cbor_floating_point(backing& p)
: contents{p}{}
cbor_floating_point(ieee754_hf p)
: contents{p}{}
cbor_floating_point(float p)
: contents{p}{}
cbor_floating_point(double p)
: contents{p}{}
operator ieee754_hf() {
return contents.value<ieee754_hf>();
}
operator float() {
switch(contents.type()) {
case backing::alt<ieee754_hf>():
return contents.value<ieee754_hf>();
case backing::alt<float>():
return contents.value<float>();
default:
gp_config::assertion(false,"this code should never be reached");
return std::numeric_limits<float>::quiet_NaN();
}
}
operator double() {
switch(contents.type()) {
case backing::alt<ieee754_hf>():
return contents.value<ieee754_hf>();
case backing::alt<float>():
return contents.value<float>();
case backing::alt<double>():
return contents.value<double>();
default:
gp_config::assertion(false,"this code should never be reached");
return std::numeric_limits<double>::quiet_NaN();
}
}
};
struct undefined_t final {};
template<typename T>
using cbor_composite = gp::fixed_variant<
gp::undefined_t,
cbor_number,
gp::vector<std::byte>,
bool,
gp::vector<T>,
gp::vector<gp::pair<T, T>>,
gp::nullopt_t,
cbor_floating_point
>;
class cbor_value {
cbor_composite<cbor_value> contents;
gp::reference_wrapper<allocator> alloc;
public:
cbor_value(allocator& alloc_v)
: contents()
, alloc(alloc_v)
{}
cbor_value(cbor_number number, allocator& alloc_v)
: contents(number)
, alloc(alloc_v)
{}
cbor_value(cbor_composite<cbor_value> val, allocator& alloc_v)
: contents(val)
, alloc(alloc_v)
{}
cbor_value(const cbor_value& oth)
: contents(oth.contents)
, alloc(oth.alloc)
{}
cbor_value(cbor_value&& oth)
: contents(gp::move(oth.contents))
, alloc(gp::move(oth.alloc))
{}
cbor_value& operator=(cbor_value& value) {
contents = value.contents;
alloc = value.alloc;
return *this;
}
cbor_value& operator=(cbor_value&& value) {
gp::swap(contents, value.contents);
gp::swap(alloc, value.alloc);
return *this;
}
cbor_value& operator=(cbor_composite<cbor_value>& value) {
contents = value;
return *this;
}
template<typename T>
cbor_value& operator=(T& value) {
contents = value;
return *this;
}
template<typename T>
cbor_value& operator=(T&& value) {
contents = gp::move(value);
return *this;
}
auto new_array() {
return gp::vector<cbor_value>{alloc};
}
auto new_object() {
return gp::vector<gp::pair<cbor_value, cbor_value>>{alloc};
}
static gp::pair<uint64_t, gp::buffer<std::byte>::associated_iterator> decode_integer(gp::buffer<std::byte> src) {
#define ERROR return {0, src.begin()}
auto local = (uint8_t)0b00011111 & (uint8_t)src[0];
if(local <= 23) {
return {local, src.begin()+1};
} else {
switch((cbor_oths)local) {
case cbor_oths::byte: {
if(src.size()<2) ERROR;
return {
(uint8_t)*(src.begin()+1),
src.begin()+2
};
}
case cbor_oths::word: {
if(src.size()<3) ERROR;
return {
uint16_t(*(src.slice_start(3).slice_end(2).cast<gp::endian_wrapper<uint16_t, endian::big>>().begin().data)),
src.begin()+3
};
}
case cbor_oths::dword: {
if(src.size()<5) ERROR;
return {
uint32_t(*(src.slice_start(5).slice_end(4).cast<gp::endian_wrapper<uint32_t, endian::big>>().begin().data)),
src.begin()+5
};
}
case cbor_oths::qword: {
if(src.size()<9) ERROR;
return {
uint64_t(*(src.slice_start(9).slice_end(8).cast<gp::endian_wrapper<uint64_t, endian::big>>().begin().data)),
src.begin()+9
};
}
default: {
ERROR;
}
}
}
#undef ERROR
}
template<typename U>
bool is_a() {
if constexpr (
std::is_same_v<U, uint8_t>
|| std::is_same_v<U, uint16_t>
|| std::is_same_v<U, uint32_t>
|| std::is_same_v<U, uint64_t>
|| std::is_same_v<U, int8_t>
|| std::is_same_v<U, int16_t>
|| std::is_same_v<U, int32_t>
|| std::is_same_v<U, int64_t>
) {
if(contents.is_a<cbor_number>())
{
auto& v = contents.value<cbor_number>();
if(!std::is_signed_v<U> && v.is_negative()) return false;
if(
std::numeric_limits<int64_t>::max()<v.value
&& (
!std::is_same_v<U, uint64_t>
|| v.is_negative()
)
) return false;
int64_t signed_v = (v.is_negative() ? -1 : 1 ) * v.value;
if(
std::numeric_limits<U>::min() <= signed_v
&& std::numeric_limits<U>::max() >= signed_v
) return true;
return false;
} else return false;
} else if constexpr (
std::is_same_v<U, ieee754_hf>
|| std::is_same_v<U, float>
|| std::is_same_v<U, double>
) {
auto& v = contents.value<cbor_floating_point>();
switch(v.contents.type()) {
case cbor_floating_point::backing::alt<ieee754_hf>():
return std::is_same_v<U, ieee754_hf>;
case cbor_floating_point::backing::alt<float>():
return std::is_same_v<U, float> || std::is_same_v<U, ieee754_hf>;
case cbor_floating_point::backing::alt<double>():
return std::is_same_v<U, double> || std::is_same_v<U, float> || std::is_same_v<U, ieee754_hf>;
default:
return false;
}
} else {
return contents.is_a<U>();
}
}
template<typename U>
U get_value() {
gp_config::assertion(is_a<U>(), "can't convert value legally");
if constexpr (
std::is_same_v<U, uint8_t>
|| std::is_same_v<U, uint16_t>
|| std::is_same_v<U, uint32_t>
|| std::is_same_v<U, uint64_t>
|| std::is_same_v<U, int8_t>
|| std::is_same_v<U, int16_t>
|| std::is_same_v<U, int32_t>
|| std::is_same_v<U, int64_t>
) {
auto& v = contents.value<cbor_number>();
return (v.is_negative() ? -1 : 1 ) * v.value;
} else if constexpr (
std::is_same_v<U, ieee754_hf>
|| std::is_same_v<U, float>
|| std::is_same_v<U, double>
) {
auto& v = contents.value<cbor_floating_point>();
return v;
} else {
return contents.value<U>();
}
}
static gp::pair<cbor_value, gp::buffer<std::byte>::associated_iterator> decode(allocator& alloc, gp::buffer<std::byte> src) {
#define ERROR return {cbor_value{alloc}, src.begin()}
if(src.size()==0) ERROR;
auto discriminant = (cbor_type)(((uint8_t)*src.begin()) >> 5);
auto local = uint8_t(((uint8_t)*src.begin()) & 0b00011111);
switch(discriminant) {
case cbor_type::uint:
case cbor_type::nint: {
auto nb = decode_integer(src);
return {cbor_value{cbor_number{(bool)discriminant, nb.first}, alloc}, nb.second};
}
case cbor_type::bstr: {
gp::vector<std::byte> str{alloc};
if(local == 31) {
auto sub = src.slice_end(src.size() - 1);
if(!sub.size()) ERROR;
while((uint8_t)sub[0] && 0b00011111 != 31) {
auto len = decode_integer(sub);
if(len.second == sub.begin()) ERROR;
str.reserve(str.size() + len.first);
auto end = (len.second + len.first);
if(len.first + (len.second - src.begin()) > src.size()) ERROR;
for(auto it = len.second; it != end; it++) {
str.push_back(*it);
}
sub = sub.slice_end(sub.size() - (len.first + (len.second - sub.begin())));
}
return {cbor_value{str, alloc}, sub.begin()+1};
} else if(auto len = decode_integer(src); len.second != src.begin()) {
str.reserve(len.first);
auto end = (len.second + len.first);
if(len.first + (len.second - src.begin()) > src.size()) ERROR;
for(auto it = len.second; it != end; it++) {
str.push_back(*it);
}
return {cbor_value{str, alloc}, end};
}
ERROR;
}
case cbor_type::tstr: {
ERROR;
}
case cbor_type::list: {
gp::vector<cbor_value> list{alloc};
if(local == 31) {
// TODO: Add the indefinite length version
} else if(auto len = decode_integer(src); len.second != src.begin()) {
auto sub = src.slice_end(src.size()-(len.second - src.begin()));
while(len.first--) {
auto tmp = decode(alloc, sub);
if(tmp.second == sub.begin()) ERROR;
list.push_back(tmp.first);
sub = sub.slice_end(sub.size() - (tmp.second - sub.begin()));
}
return {cbor_value{list, alloc}, sub.begin()};
}
ERROR;
}
case cbor_type::hmap: {
gp::vector<gp::pair<cbor_value, cbor_value>> list{alloc};
if(local == 31) {
// TODO: Add the indefinite length version
} else if(auto len = decode_integer(src); len.second != src.begin()) {
auto sub = src.slice_end(src.size()-(len.second - src.begin()));
while(len.first--) {
auto tmpl = decode(alloc, sub);
if(tmpl.second == sub.begin()) ERROR;
sub = sub.slice_end(sub.size() - (tmpl.second - sub.begin()));
auto tmpr = decode(alloc, sub);
if(tmpr.second == sub.begin()) ERROR;
list.push_back(gp::make_pair(
tmpl.first,
tmpr.first
));
sub = sub.slice_end(sub.size() - (tmpr.second - sub.begin()));
}
return {cbor_value{list, alloc}, sub.begin()};
}
ERROR;
}
case cbor_type::tags: {
// TODO: add tag decoding methods
}
case cbor_type::oths: {
switch((cbor_oths)local) {
case cbor_oths::value_false: {
return {
cbor_value{
cbor_composite<cbor_value>(false),
alloc
},
src.begin()+1
};
}
case cbor_oths::value_true: {
return {
cbor_value{
cbor_composite<cbor_value>(true),
alloc
},
src.begin()+1
};
}
case cbor_oths::value_null: {
return {
cbor_value{
cbor_composite<cbor_value>(nullopt),
alloc
},
src.begin()+1
};
}
case cbor_oths::value_undefined: {
return {
cbor_value{
cbor_composite<cbor_value>(undefined_t{}),
alloc
},
src.begin()+1
};
}
case cbor_oths::word: {
if(src.size()<3) ERROR;
return {
cbor_value{
cbor_floating_point{ieee754_hf(*(src.slice_start(3).slice_end(2).cast<gp::endian_wrapper<ieee754_hf, endian::big>>().begin().data))},
alloc
},
src.begin()+3
};
}
case cbor_oths::dword: {
if(src.size()<5) ERROR;
return {
cbor_value{
cbor_floating_point{float(*(src.slice_start(5).slice_end(4).cast<gp::endian_wrapper<float, endian::big>>().begin().data))},
alloc
},
src.begin()+5
};
}
case cbor_oths::qword: {
if(src.size()<9) ERROR;
return {
cbor_value{
cbor_floating_point{double(*(src.slice_start(9).slice_end(8).cast<gp::endian_wrapper<double, endian::big>>().begin().data))},
alloc
},
src.begin()+9
};
}
default: {
ERROR;
}
}
}
}
ERROR;
#undef ERROR
}
static auto encode_float(buffer<std::byte> dest, cbor_floating_point& value) {
switch(value.contents.type()) {
case cbor_floating_point::backing::alt<ieee754_hf>():{
if(dest.size() < 3) return dest.begin();
dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::word);
(dest.slice_start(3).slice_end(2).cast<gp::endian_wrapper<ieee754_hf, gp::endian::big>>())[0] = value.contents.value<ieee754_hf>();
return dest.begin()+3;
}
case cbor_floating_point::backing::alt<float>():{
if(dest.size() < 5) return dest.begin();
dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::dword);
(dest.slice_start(5).slice_end(4).cast<gp::endian_wrapper<float, gp::endian::big>>())[0] = value.contents.value<float>();
return dest.begin()+5;
}
case cbor_floating_point::backing::alt<double>():{
if(dest.size() < 9) return dest.begin();
dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::qword);
(dest.slice_start(9).slice_end(8).cast<gp::endian_wrapper<double, gp::endian::big>>())[0] = value.contents.value<double>();
return dest.begin()+9;
}
default: return dest.begin();
}
}
static auto encode_length(buffer<std::byte> dest, cbor_type major, uint64_t value) {
auto num = value;
if(value <= 23) {
if(dest.size() < 1) return dest.begin();
dest[0] = std::byte(((uint8_t)major << 5u) + value);
return dest.begin()+1;
} else if(value <= 255) {
if(dest.size() < 2) return dest.begin();
dest[0] = std::byte(((uint8_t)major << 5u) + (uint8_t)cbor_oths::byte);
dest[1] = std::byte(value);
return dest.begin() + 2;
} else if(value <= 65535) {
if(dest.size() < 3) return dest.begin();
dest[0] = std::byte(((uint8_t)major << 5u) + (uint8_t)cbor_oths::word);
(dest.slice_start(3).slice_end(2).cast<gp::endian_wrapper<uint16_t, gp::endian::big>>())[0] = num;
return dest.begin()+3;
} else if(value <= 4294967295) {
if(dest.size() < 5) return dest.begin();
dest[0] = std::byte(((uint8_t)major << 5u) + (uint8_t)cbor_oths::dword);
(dest.slice_start(5).slice_end(4).cast<gp::endian_wrapper<uint32_t, gp::endian::big>>())[0] = num;
return dest.begin()+5;
} else {
if(dest.size() < 9) return dest.begin();
dest[0] = std::byte(((uint8_t)major << 5u) + (uint8_t)cbor_oths::qword);
(dest.slice_start(9).slice_end(8).cast<gp::endian_wrapper<uint64_t, gp::endian::big>>())[0] = num;
return dest.begin()+9;
}
}
auto encode(buffer<std::byte> dest) {
switch(contents.type()) {
case cbor_composite<cbor_value>::alt<undefined_t>(): {
if(dest.size() < 1) return dest.begin();
dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::value_undefined);
return dest.begin()+1;
}
case cbor_composite<cbor_value>::alt<cbor_number>(): {
auto& ref = contents.value<cbor_number>();
return encode_length(
dest,
ref.is_negative() ? cbor_type::nint : cbor_type::uint,
ref.value
);
}
case cbor_composite<cbor_value>::alt<gp::vector<std::byte>>(): {
auto& ref = contents.value<gp::vector<std::byte>>();
auto it = encode_length(
dest,
cbor_type::bstr,
ref.size()
);
if(it == dest.begin()) return it;
for(auto a : ref) {
*(it++) = a;
}
return it;
}
case cbor_composite<cbor_value>::alt<bool>(): {
if(dest.size() < 1) return dest.begin();
if(contents.value<bool>())
dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::value_true);
else
dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::value_false);
return dest.begin()+1;
}
case cbor_composite<cbor_value>::alt<gp::vector<cbor_value>>(): {
auto& ary = contents.value<gp::vector<cbor_value>>();
auto it_begin = encode_length(dest, cbor_type::list, ary.size());
if(it_begin == dest.begin()) return dest.begin();
for(auto& elem : ary) {
auto slice = dest.slice_end(dest.size() - (it_begin - dest.begin()));
auto it = elem.encode(slice);
if(it == it_begin)
return dest.begin();
it_begin = it;
}
return it_begin;
}
case cbor_composite<cbor_value>::alt<gp::vector<gp::pair<cbor_value, cbor_value>>>(): {
auto& ary = contents.value<gp::vector<gp::pair<cbor_value,cbor_value>>>();
auto it_begin = encode_length(dest, cbor_type::hmap, ary.size());
if(it_begin == dest.begin()) return dest.begin();
for(auto& elem : ary) {
auto slice = dest.slice_end(dest.size() - (it_begin - dest.begin()));
auto it = elem.first.encode(slice);
if(it == it_begin) return dest.begin();
it_begin = it;
slice = dest.slice_end(dest.size() - (it_begin - dest.begin()));
it = elem.second.encode(slice);
if(it == it_begin) return dest.begin();
it_begin = it;
}
return it_begin;
}
case cbor_composite<cbor_value>::alt<gp::nullopt_t>(): {
if(dest.size() < 1) return dest.begin();
dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::value_null);
return dest.begin()+1;
}
case cbor_composite<cbor_value>::alt<cbor_floating_point>(): {
return encode_float(dest, contents.value<cbor_floating_point>());
}
default: return dest.begin();
}
}
};
}