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tdlib-fork/tdutils/td/utils/misc.h
levlam 4910a36a13 Add narrow_cast debug.
GitOrigin-RevId: e088bc1d01f880d1126000f3ecea0be70c2dbcb7
2018-04-10 20:21:17 +03:00

339 lines
8.4 KiB
C++

//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
//
// 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/Status.h"
#include "td/utils/StringBuilder.h"
#include <cstdint>
#include <limits>
#include <tuple>
#include <type_traits>
#include <utility>
namespace td {
char *str_dup(Slice str);
template <class T>
std::pair<T, T> split(T s, char delimiter = ' ') {
auto delimiter_pos = s.find(delimiter);
if (delimiter_pos == string::npos) {
return {std::move(s), T()};
} else {
return {s.substr(0, delimiter_pos), s.substr(delimiter_pos + 1)};
}
}
template <class T>
vector<T> full_split(T s, char delimiter = ' ') {
T next;
vector<T> result;
while (!s.empty()) {
std::tie(next, s) = split(s, delimiter);
result.push_back(next);
}
return result;
}
string implode(vector<string> v, char delimiter = ' ');
namespace detail {
template <typename T>
struct transform_helper {
template <class Func>
auto transform(const T &v, const Func &f) {
vector<decltype(f(*v.begin()))> result;
result.reserve(v.size());
for (auto &x : v) {
result.push_back(f(x));
}
return result;
}
template <class Func>
auto transform(T &&v, const Func &f) {
vector<decltype(f(std::move(*v.begin())))> result;
result.reserve(v.size());
for (auto &x : v) {
result.push_back(f(std::move(x)));
}
return result;
}
};
} // namespace detail
template <class T, class Func>
auto transform(T &&v, const Func &f) {
return detail::transform_helper<std::decay_t<T>>().transform(std::forward<T>(v), f);
}
template <class T>
void reset_to_empty(T &value) {
using std::swap;
std::decay_t<T> tmp;
swap(tmp, value);
}
template <class T>
auto append(vector<T> &destination, const vector<T> &source) {
destination.insert(destination.end(), source.begin(), source.end());
}
template <class T>
auto append(vector<T> &destination, vector<T> &&source) {
if (destination.empty()) {
destination.swap(source);
return;
}
destination.reserve(destination.size() + source.size());
for (auto &elem : source) {
destination.push_back(std::move(elem));
}
reset_to_empty(source);
}
inline bool begins_with(Slice str, Slice prefix) {
return prefix.size() <= str.size() && prefix == Slice(str.data(), prefix.size());
}
inline bool ends_with(Slice str, Slice suffix) {
return suffix.size() <= str.size() && suffix == Slice(str.data() + str.size() - suffix.size(), suffix.size());
}
inline char to_lower(char c) {
if ('A' <= c && c <= 'Z') {
return static_cast<char>(c - 'A' + 'a');
}
return c;
}
inline void to_lower_inplace(MutableSlice slice) {
for (auto &c : slice) {
c = to_lower(c);
}
}
inline string to_lower(Slice slice) {
auto result = slice.str();
to_lower_inplace(result);
return result;
}
inline char to_upper(char c) {
if ('a' <= c && c <= 'z') {
return static_cast<char>(c - 'a' + 'A');
}
return c;
}
inline void to_upper_inplace(MutableSlice slice) {
for (auto &c : slice) {
c = to_upper(c);
}
}
inline string to_upper(Slice slice) {
auto result = slice.str();
to_upper_inplace(result);
return result;
}
inline bool is_space(char c) {
return c == ' ' || c == '\t' || c == '\r' || c == '\n' || c == '\0' || c == '\v';
}
inline bool is_alpha(char c) {
c |= 0x20;
return 'a' <= c && c <= 'z';
}
inline bool is_digit(char c) {
return '0' <= c && c <= '9';
}
inline bool is_alnum(char c) {
return is_alpha(c) || is_digit(c);
}
inline bool is_hex_digit(char c) {
if (is_digit(c)) {
return true;
}
c |= 0x20;
return 'a' <= c && c <= 'f';
}
template <class T>
T trim(T str) {
auto begin = str.data();
auto end = begin + str.size();
while (begin < end && is_space(*begin)) {
begin++;
}
while (begin < end && is_space(end[-1])) {
end--;
}
if (static_cast<size_t>(end - begin) == str.size()) {
return std::move(str);
}
return T(begin, end);
}
string oneline(Slice str);
template <class T>
std::enable_if_t<std::is_signed<T>::value, T> to_integer(Slice str) {
using unsigned_T = typename std::make_unsigned<T>::type;
unsigned_T integer_value = 0;
auto begin = str.begin();
auto end = str.end();
bool is_negative = false;
if (begin != end && *begin == '-') {
is_negative = true;
begin++;
}
while (begin != end && is_digit(*begin)) {
integer_value = static_cast<unsigned_T>(integer_value * 10 + (*begin++ - '0'));
}
if (integer_value > static_cast<unsigned_T>(std::numeric_limits<T>::max())) {
static_assert(~0 + 1 == 0, "Two's complement");
// Use ~x + 1 instead of -x to suppress Visual Studio warning.
integer_value = static_cast<unsigned_T>(~integer_value + 1);
is_negative = !is_negative;
if (integer_value > static_cast<unsigned_T>(std::numeric_limits<T>::max())) {
return std::numeric_limits<T>::min();
}
}
return is_negative ? static_cast<T>(-static_cast<T>(integer_value)) : static_cast<T>(integer_value);
}
template <class T>
std::enable_if_t<std::is_unsigned<T>::value, T> to_integer(Slice str) {
T integer_value = 0;
auto begin = str.begin();
auto end = str.end();
while (begin != end && is_digit(*begin)) {
integer_value = static_cast<T>(integer_value * 10 + (*begin++ - '0'));
}
return integer_value;
}
template <class T>
Result<T> to_integer_safe(Slice str) {
auto res = to_integer<T>(str);
if (to_string(res) != str) {
return Status::Error(PSLICE() << "Can't parse \"" << str << "\" as number");
}
return res;
}
inline int hex_to_int(char c) {
if (is_digit(c)) {
return c - '0';
}
c |= 0x20;
if ('a' <= c && c <= 'f') {
return c - 'a' + 10;
}
return 16;
}
template <class T>
typename std::enable_if<std::is_unsigned<T>::value, T>::type hex_to_integer(Slice str) {
T integer_value = 0;
auto begin = str.begin();
auto end = str.end();
while (begin != end && is_hex_digit(*begin)) {
integer_value = static_cast<T>(integer_value * 16 + hex_to_int(*begin++));
}
return integer_value;
}
double to_double(Slice str);
template <class T>
T clamp(T value, T min_value, T max_value) {
if (value < min_value) {
return min_value;
}
if (value > max_value) {
return max_value;
}
return value;
}
// run-time checked narrowing cast (type conversion):
namespace detail {
template <class T, class U>
struct is_same_signedness
: public std::integral_constant<bool, std::is_signed<T>::value == std::is_signed<U>::value> {};
template <class T, class Enable = void>
struct safe_undeflying_type {
using type = T;
};
template <class T>
struct safe_undeflying_type<T, std::enable_if_t<std::is_enum<T>::value>> {
using type = std::underlying_type_t<T>;
};
} // namespace detail
template <class R, class A>
R narrow_cast(const A &a) {
using RT = typename detail::safe_undeflying_type<R>::type;
using AT = typename detail::safe_undeflying_type<A>::type;
static_assert(std::is_integral<RT>::value, "expected integral type to cast to");
static_assert(std::is_integral<AT>::value, "expected integral type to cast from");
auto r = R(a);
CHECK(A(r) == a) << static_cast<AT>(a) << " " << static_cast<RT>(r);
CHECK((detail::is_same_signedness<RT, AT>::value) || ((static_cast<RT>(r) < RT{}) == (static_cast<AT>(a) < AT{})))
<< static_cast<AT>(a) << " " << static_cast<RT>(r);
return r;
}
template <class R, class A>
Result<R> narrow_cast_safe(const A &a) {
using RT = typename detail::safe_undeflying_type<R>::type;
using AT = typename detail::safe_undeflying_type<A>::type;
static_assert(std::is_integral<RT>::value, "expected integral type to cast to");
static_assert(std::is_integral<AT>::value, "expected integral type to cast from");
auto r = R(a);
if (!(A(r) == a)) {
return Status::Error("Narrow cast failed");
}
if (!((detail::is_same_signedness<RT, AT>::value) || ((static_cast<RT>(r) < RT{}) == (static_cast<AT>(a) < AT{})))) {
return Status::Error("Narrow cast failed");
}
return r;
}
template <int Alignment, class T>
bool is_aligned_pointer(const T *pointer) {
static_assert(Alignment > 0 && (Alignment & (Alignment - 1)) == 0, "Wrong alignment");
return (reinterpret_cast<std::uintptr_t>(static_cast<const void *>(pointer)) & (Alignment - 1)) == 0;
}
} // namespace td