drinkingtea/nostalgia
drinkingtea/nostalgia
2
0
Fork 0
Code Issues 6 Pull Requests Actions Releases 6 Activity

[ox/mc] Fix decoding of int64s

Browse Source
This commit is contained in:
Gary Talent 2022-08-13 01:35:17 -05:00
parent 714d9fe433
commit 84d54ba340
2 changed files with 33 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
deps/ox/src/ox/mc/intops.hpp vendored
View File

@ -8,6 +8,7 @@
#pragma once
#include <ox/std/array.hpp>
#include <ox/std/assert.hpp>
#include <ox/std/bit.hpp>
#include <ox/std/byteswap.hpp>
@ -55,7 +56,7 @@ static_assert(highestBit(uint64_t(1) << 31) == 31);
static_assert(highestBit(uint64_t(1) << 63) == 63);
struct McInt {
uint8_t data[9] = {0};
uint8_t data[9] = {};
// length of integer in bytes
std::size_t length = 0;
};
@ -113,7 +114,7 @@ constexpr McInt encodeInteger(I input) noexcept {
* length integer.
*/
[[nodiscard]]
static constexpr std::size_t countBytes(uint8_t b) noexcept {
static constexpr std::size_t countBytes(unsigned b) noexcept {
std::size_t i = 0;
while ((b >> i) & 1) ++i;
return i + 1;
@ -130,13 +131,13 @@ static_assert(countBytes(0b0111'1111) == 8);
static_assert(countBytes(0b1111'1111) == 9);
template<typename I>
Result<I> decodeInteger(const uint8_t buff[9], std::size_t buffLen, std::size_t *bytesRead) noexcept {
constexpr Result<I> decodeInteger(const uint8_t buff[9], std::size_t buffLen, std::size_t *bytesRead) noexcept {
const auto bytes = countBytes(buff[0]);
if (bytes == 9) {
*bytesRead = bytes;
I out = 0;
ox_memcpy(&out, &buff[1], sizeof(I));
return static_cast<I>(LittleEndian<I>(out));
return fromLittleEndian<I>(out);
} else if (buffLen >= bytes) {
*bytesRead = bytes;
uint64_t decoded = 0;
@ -150,28 +151,33 @@ Result<I> decodeInteger(const uint8_t buff[9], std::size_t buffLen, std::size_t
if (negative) {
// fill in all bits between encoded sign and real sign with 1s
// split it up because the 32-bit ARM can't shift more than 32 bits
uint32_t *d = reinterpret_cast<uint32_t*>(&decoded);
ox::Array<uint32_t, 2> d = {};
ox_memcpy(d.data(), &decoded, sizeof(decoded));
auto bit = negBit;
for (; bit < ox::min<std::size_t>(Bits<I>, 32); ++bit) {
d[0] |= 1 << bit;
}
bit -= 32;
for (; bit < Bits<I>; ++bit) {
d[1] |= 1 << bit;
}
I out = 0;
if constexpr(ox::defines::BigEndian) {
const auto d0Tmp = d[0];
d[0] = d[1];
d[1] = d0Tmp;
}
ox_memcpy(&out, d.data(), sizeof(out));
return out;
}
I out = 0;
ox_memcpy(&out, &decoded, sizeof(out));
return out;
} else {
auto out = static_cast<I>(decoded);
return out;
}
return static_cast<I>(decoded);
}
return OxError(1);
}
template<typename I>
Result<I> decodeInteger(McInt m) noexcept {
constexpr Result<I> decodeInteger(McInt m) noexcept {
std::size_t bytesRead;
return decodeInteger<I>(m.data, 9, &bytesRead);
}

16
deps/ox/src/ox/std/byteswap.hpp vendored
View File

@ -64,13 +64,27 @@ constexpr T conditionalByteSwap(T i) noexcept {
}
template<typename T>
[[nodiscard]]
constexpr T fromLittleEndian(T i) noexcept {
return conditionalByteSwap<T, defines::BigEndian>(i);
}
template<typename T>
[[nodiscard]]
constexpr T fromBigEndian(T i) noexcept {
return conditionalByteSwap<T, defines::LittleEndian>(i);
}
template<typename T>
[[nodiscard]]
constexpr T toLittleEndian(T i) noexcept {
return conditionalByteSwap<T, defines::BigEndian>(i);
}
template<typename T>
[[nodiscard]]
constexpr T toBigEndian(T i) noexcept {
return conditionalByteSwap<T, defines::BigEndian>(i);
return conditionalByteSwap<T, defines::LittleEndian>(i);
}
template<typename T, bool byteSwap>