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move around to bytes and make it faster

v1
Brett 2023-10-24 21:43:22 -04:00
parent 5a07594e42
commit 63ae93c6e6
2 changed files with 78 additions and 29 deletions
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32
include/blt/nbt/nbt.h
View File

@ -12,10 +12,12 @@
#include <cstring>
#include <type_traits>
#include <unordered_map>
#include <algorithm>
#include "blt/std/format.h"
#include "blt/std/filesystem.h"
#include "blt/std/logging.h"
#include "blt/std/memory.h"
#include <blt/std/hashmap.h>
@ -25,36 +27,10 @@ namespace blt::nbt {
std::string readUTF8String(blt::fs::block_reader& stream);
// Used to grab the byte-data of any T element. Defaults to Big Endian, however can be configured to use little endian
template <typename T>
inline static int toBytes(const T& in, char* out) {
std::memcpy(out, (void*) &in, sizeof(T));
if constexpr (std::endian::native == std::endian::little) {
for (size_t i = 0; i < sizeof(T) / 2; i++)
std::swap(out[i], out[sizeof(T) - 1 - i]);
}
return 0;
}
// Used to cast the binary data of any T object, into a T object.
template <typename T>
inline static int fromBytes(const char* in, T* out) {
memcpy(out, in, sizeof(T));
if constexpr (std::endian::native == std::endian::little) {
for (size_t i = 0; i < sizeof(T) / 2; i++)
std::swap(((char*) (out))[i], ((char*) (out))[sizeof(T) - 1 - i]);
}
return 0;
}
template<typename T>
inline static void writeData(blt::fs::block_writer& out, const T& d){
char data[sizeof(T)];
toBytes(d, data);
mem::toBytes(d, data);
out.write(data, sizeof(T));
}
@ -62,7 +38,7 @@ namespace blt::nbt {
inline static void readData(blt::fs::block_reader& in, T& d) {
char data[sizeof(T)];
in.read(data, sizeof(T));
fromBytes(data, &d);
mem::fromBytes(data, &d);
}
enum class nbt_tag : char {

75
include/blt/std/memory.h
View File

@ -10,12 +10,85 @@
#include <initializer_list>
#include <iterator>
#include <cstring>
#include <type_traits>
#include "queue.h"
#include <cstdint>
#include <bit>
#include <type_traits>
#include <algorithm>
#include <utility>
#include <cstring>
#include <array>
#if defined(__clang__) || defined(__llvm__) || defined(__GNUC__) || defined(__GNUG__)
#include <byteswap.h>
#define SWAP16(val) bswap_16(val)
#define SWAP32(val) bswap_32(val)
#define SWAP64(val) bswap_64(val)
#define ENDIAN_LOOKUP(little_endian) (std::endian::native == std::endian::little && !little_endian) || \
(std::endian::native == std::endian::big && little_endian)
#elif defined(_MSC_VER)
#include <intrin.h>
#define SWAP16(val) _byteswap_ushort(val)
#define SWAP32(val) _byteswap_ulong(val)
#define SWAP64(val) _byteswap_uint64(val)
#define ENDIAN_LOOKUP(little_endian) !little_endian
#endif
namespace blt
{
namespace mem
{
// Used to grab the byte-data of any T element. Defaults to Big Endian, however can be configured to use little endian
template<bool little_endian = false, typename BYTE_TYPE, typename T>
inline static int toBytes(const T& in, BYTE_TYPE* out)
{
if constexpr (!(std::is_same_v<BYTE_TYPE, std::int8_t> || std::is_same_v<BYTE_TYPE, std::uint8_t>))
static_assert("Must provide a signed/unsigned int8 type");
std::memcpy(out, (void*) &in, sizeof(T));
if constexpr (ENDIAN_LOOKUP(little_endian))
{
// TODO: this but better.
for (size_t i = 0; i < sizeof(T) / 2; i++)
std::swap(out[i], out[sizeof(T) - 1 - i]);
}
return 0;
}
// Used to cast the binary data of any T object, into a T object. Assumes data is in big ending (configurable)
template<bool little_endian = false, typename BYTE_TYPE, typename T>
inline static int fromBytes(const BYTE_TYPE* in, T& out)
{
if constexpr (!(std::is_same_v<BYTE_TYPE, std::int8_t> || std::is_same_v<BYTE_TYPE, std::uint8_t>))
static_assert("Must provide a signed/unsigned int8 type");
std::array<BYTE_TYPE, sizeof(T)> data;
std::memcpy(data.data(), in, sizeof(T));
if constexpr (ENDIAN_LOOKUP(little_endian))
{
// if we need to swap find the best way to do so
if constexpr (std::is_same_v<T, int16_t> || std::is_same_v<T, uint16_t>)
out = SWAP16(*reinterpret_cast<T*>(data.data()));
else if constexpr (std::is_same_v<T, int32_t> || std::is_same_v<T, uint32_t>)
out = SWAP32(*reinterpret_cast<T*>(data.data()));
else if constexpr (std::is_same_v<T, int64_t> || std::is_same_v<T, uint64_t>)
out = SWAP64(*reinterpret_cast<T*>(data.data()));
else
{
std::reverse(data.begin(), data.end());
out = *reinterpret_cast<T*>(data.data());
}
}
return 0;
}
}
template<typename V>
struct ptr_iterator
{