138 lines
3.5 KiB
C++
138 lines
3.5 KiB
C++
/*
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This file is part of Telegram Desktop,
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the official desktop application for the Telegram messaging service.
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For license and copyright information please follow this link:
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https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
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*/
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#pragma once
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#include <gsl/gsl_byte>
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namespace bytes {
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using span = gsl::span<gsl::byte>;
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using const_span = gsl::span<const gsl::byte>;
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using vector = std::vector<gsl::byte>;
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template <
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typename Container,
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typename = std::enable_if_t<!std::is_const_v<Container>>>
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inline span make_span(Container &container) {
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return gsl::as_writeable_bytes(gsl::make_span(container));
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}
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template <typename Container>
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inline const_span make_span(const Container &container) {
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return gsl::as_bytes(gsl::make_span(container));
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}
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template <typename Type, std::ptrdiff_t Extent>
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inline span make_span(gsl::span<Type, Extent> container) {
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return gsl::as_writeable_bytes(container);
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}
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template <typename Type, std::ptrdiff_t Extent>
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inline const_span make_span(gsl::span<const Type, Extent> container) {
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return gsl::as_bytes(container);
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}
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template <typename Type>
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inline span make_span(Type *value, std::size_t count) {
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return gsl::as_writeable_bytes(gsl::make_span(value, count));
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}
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template <typename Type>
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inline const_span make_span(const Type *value, std::size_t count) {
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return gsl::as_bytes(gsl::make_span(value, count));
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}
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template <typename Container>
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inline vector make_vector(const Container &container) {
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const auto buffer = bytes::make_span(container);
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return { buffer.begin(), buffer.end() };
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}
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inline void copy(span destination, const_span source) {
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Expects(destination.size() >= source.size());
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memcpy(destination.data(), source.data(), source.size());
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}
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inline void move(span destination, const_span source) {
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Expects(destination.size() >= source.size());
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memmove(destination.data(), source.data(), source.size());
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}
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inline void set_with_const(span destination, gsl::byte value) {
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memset(
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destination.data(),
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gsl::to_integer<unsigned char>(value),
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destination.size());
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}
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inline int compare(const_span a, const_span b) {
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const auto aSize = a.size(), bSize = b.size();
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return (aSize > bSize)
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? 1
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: (aSize < bSize)
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? -1
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: memcmp(a.data(), b.data(), aSize);
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}
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namespace details {
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template <typename Arg>
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std::size_t spansLength(Arg &&arg) {
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return bytes::make_span(arg).size();
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}
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template <typename Arg, typename ...Args>
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std::size_t spansLength(Arg &&arg, Args &&...args) {
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return bytes::make_span(arg).size() + spansLength(args...);
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}
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template <typename Arg>
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void spansAppend(span destination, Arg &&arg) {
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bytes::copy(destination, bytes::make_span(arg));
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}
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template <typename Arg, typename ...Args>
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void spansAppend(span destination, Arg &&arg, Args &&...args) {
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const auto data = bytes::make_span(arg);
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bytes::copy(destination, data);
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spansAppend(destination.subspan(data.size()), args...);
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}
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} // namespace details
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template <
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typename ...Args,
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typename = std::enable_if_t<(sizeof...(Args) > 1)>>
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vector concatenate(Args &&...args) {
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const auto size = details::spansLength(args...);
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auto result = vector(size);
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details::spansAppend(make_span(result), args...);
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return result;
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}
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template <
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typename SpanRange>
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vector concatenate(SpanRange args) {
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auto size = std::size_t(0);
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for (const auto &arg : args) {
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size += bytes::make_span(arg).size();
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}
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auto result = vector(size);
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auto buffer = make_span(result);
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for (const auto &arg : args) {
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const auto part = bytes::make_span(arg);
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bytes::copy(buffer, part);
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buffer = buffer.subspan(part.size());
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}
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return result;
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}
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} // namespace bytes
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