149 lines
3.4 KiB
C++
149 lines
3.4 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2020
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#pragma once
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#include "td/utils/common.h"
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#include "td/utils/Slice.h"
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#include "td/utils/StackAllocator.h"
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#include <cstdlib>
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#include <memory>
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#include <type_traits>
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namespace td {
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class StringBuilder {
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public:
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explicit StringBuilder(MutableSlice slice, bool use_buffer = false);
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StringBuilder() : StringBuilder({}, true) {
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}
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void clear() {
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current_ptr_ = begin_ptr_;
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error_flag_ = false;
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}
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MutableCSlice as_cslice() {
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if (current_ptr_ >= end_ptr_ + RESERVED_SIZE) {
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std::abort(); // shouldn't happen
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}
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*current_ptr_ = 0;
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return MutableCSlice(begin_ptr_, current_ptr_);
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}
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bool is_error() const {
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return error_flag_;
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}
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template <class T>
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std::enable_if_t<std::is_same<char *, std::remove_const_t<T>>::value, StringBuilder> &operator<<(T str) {
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return *this << Slice(str);
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}
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template <class T>
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std::enable_if_t<std::is_same<const char *, std::remove_const_t<T>>::value, StringBuilder> &operator<<(T str) {
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return *this << Slice(str);
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}
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template <size_t N>
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StringBuilder &operator<<(char (&str)[N]) = delete;
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template <size_t N>
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StringBuilder &operator<<(const char (&str)[N]) {
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return *this << Slice(str, N - 1);
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}
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StringBuilder &operator<<(const wchar_t *str) = delete;
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StringBuilder &operator<<(Slice slice);
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StringBuilder &operator<<(bool b) {
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return *this << (b ? Slice("true") : Slice("false"));
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}
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StringBuilder &operator<<(char c) {
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if (unlikely(!reserve())) {
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return on_error();
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}
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*current_ptr_++ = c;
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return *this;
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}
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StringBuilder &operator<<(unsigned char c) {
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return *this << static_cast<unsigned int>(c);
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}
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StringBuilder &operator<<(signed char c) {
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return *this << static_cast<int>(c);
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}
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StringBuilder &operator<<(int x);
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StringBuilder &operator<<(unsigned int x);
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StringBuilder &operator<<(long int x);
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StringBuilder &operator<<(long unsigned int x);
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StringBuilder &operator<<(long long int x);
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StringBuilder &operator<<(long long unsigned int x);
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struct FixedDouble {
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double d;
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int precision;
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FixedDouble(double d, int precision) : d(d), precision(precision) {
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}
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};
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StringBuilder &operator<<(FixedDouble x);
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StringBuilder &operator<<(double x) {
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return *this << FixedDouble(x, 6);
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}
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StringBuilder &operator<<(const void *ptr);
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private:
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char *begin_ptr_;
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char *current_ptr_;
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char *end_ptr_;
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bool error_flag_ = false;
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bool use_buffer_ = false;
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std::unique_ptr<char[]> buffer_;
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static constexpr size_t RESERVED_SIZE = 30;
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StringBuilder &on_error() {
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error_flag_ = true;
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return *this;
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}
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bool reserve() {
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if (end_ptr_ > current_ptr_) {
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return true;
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}
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return reserve_inner(RESERVED_SIZE);
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}
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bool reserve(size_t size) {
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if (end_ptr_ > current_ptr_ && static_cast<size_t>(end_ptr_ - current_ptr_) >= size) {
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return true;
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}
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return reserve_inner(size);
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}
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bool reserve_inner(size_t size);
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};
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template <class T>
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std::enable_if_t<std::is_arithmetic<T>::value, string> to_string(const T &x) {
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const size_t buf_size = 1000;
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auto buf = StackAllocator::alloc(buf_size);
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StringBuilder sb(buf.as_slice());
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sb << x;
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return sb.as_cslice().str();
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}
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} // namespace td
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