tdlight/tdutils/td/utils/tl_storers.h

161 lines
3.8 KiB
C++

//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2023
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#pragma once
#include "td/utils/common.h"
#include "td/utils/logging.h"
#include "td/utils/Slice.h"
#include "td/utils/StorerBase.h"
#include <cstring>
namespace td {
class TlStorerUnsafe {
unsigned char *buf_;
public:
explicit TlStorerUnsafe(unsigned char *buf) : buf_(buf) {
}
TlStorerUnsafe(const TlStorerUnsafe &) = delete;
TlStorerUnsafe &operator=(const TlStorerUnsafe &) = delete;
template <class T>
void store_binary(const T &x) {
std::memcpy(buf_, &x, sizeof(T));
buf_ += sizeof(T);
}
void store_int(int32 x) {
store_binary<int32>(x);
}
void store_long(int64 x) {
store_binary<int64>(x);
}
void store_slice(Slice slice) {
std::memcpy(buf_, slice.begin(), slice.size());
buf_ += slice.size();
}
void store_storer(const Storer &storer) {
size_t size = storer.store(buf_);
buf_ += size;
}
template <class T>
void store_string(const T &str) {
size_t len = str.size();
if (len < 254) {
*buf_++ = static_cast<unsigned char>(len);
len++;
} else if (len < (1 << 24)) {
*buf_++ = static_cast<unsigned char>(254);
*buf_++ = static_cast<unsigned char>(len & 255);
*buf_++ = static_cast<unsigned char>((len >> 8) & 255);
*buf_++ = static_cast<unsigned char>(len >> 16);
} else if (static_cast<uint64>(len) < (static_cast<uint64>(1) << 32)) {
*buf_++ = static_cast<unsigned char>(255);
*buf_++ = static_cast<unsigned char>(len & 255);
*buf_++ = static_cast<unsigned char>((len >> 8) & 255);
*buf_++ = static_cast<unsigned char>((len >> 16) & 255);
*buf_++ = static_cast<unsigned char>((len >> 24) & 255);
*buf_++ = static_cast<unsigned char>(0);
*buf_++ = static_cast<unsigned char>(0);
*buf_++ = static_cast<unsigned char>(0);
} else {
LOG(FATAL) << "String size " << len << " is too big to be stored";
}
std::memcpy(buf_, str.data(), str.size());
buf_ += str.size();
switch (len & 3) {
case 1:
*buf_++ = 0;
// fallthrough
case 2:
*buf_++ = 0;
// fallthrough
case 3:
*buf_++ = 0;
}
}
unsigned char *get_buf() const {
return buf_;
}
};
class TlStorerCalcLength {
size_t length = 0;
public:
TlStorerCalcLength() = default;
TlStorerCalcLength(const TlStorerCalcLength &) = delete;
TlStorerCalcLength &operator=(const TlStorerCalcLength &) = delete;
template <class T>
void store_binary(const T &x) {
length += sizeof(T);
}
void store_int(int32 x) {
store_binary<int32>(x);
}
void store_long(int64 x) {
store_binary<int64>(x);
}
void store_slice(Slice slice) {
length += slice.size();
}
void store_storer(const Storer &storer) {
length += storer.size();
}
template <class T>
void store_string(const T &str) {
size_t add = str.size();
if (add < 254) {
add += 1;
} else if (add < (1 << 24)) {
add += 4;
} else {
add += 8;
}
add = (add + 3) & -4;
length += add;
}
size_t get_length() const {
return length;
}
};
template <class T>
size_t tl_calc_length(const T &data) {
TlStorerCalcLength storer_calc_length;
data.store(storer_calc_length);
return storer_calc_length.get_length();
}
template <class T>
size_t tl_store_unsafe(const T &data, unsigned char *dst) TD_WARN_UNUSED_RESULT;
template <class T>
size_t tl_store_unsafe(const T &data, unsigned char *dst) {
TlStorerUnsafe storer_unsafe(dst);
data.store(storer_unsafe);
return static_cast<size_t>(storer_unsafe.get_buf() - dst);
}
} // namespace td