libcruft-util/io.hpp

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/*
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* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
* Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
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*/
#ifndef __UTIL_IO_HPP
#define __UTIL_IO_HPP
#include "platform.hpp"
#include "posix/fd.hpp"
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#include <cstddef>
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#include <cstdint>
#include <cstdio>
#include <filesystem>
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#include <vector>
#include <streambuf>
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#include <functional>
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#ifdef PLATFORM_WIN32
#include "win32/windows.hpp"
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#else
#define O_BINARY 0
#endif
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namespace cruft {
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///////////////////////////////////////////////////////////////////////////
/// Reads an entire file into memory in one operation.
template <typename T = std::byte>
std::vector<T>
slurp (std::filesystem::path const&);
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///------------------------------------------------------------------------
/// Read the entire contents of a FILE object into memory.
///
/// * This may trigger an arbitrary number of read calls.
/// * This may block indefinitely depending on the contents of the fd.
template <typename T = std::byte>
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std::vector<T>
slurp (FILE *);
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///------------------------------------------------------------------------
/// Read the entire contents of a file-descriptor into memory in one
/// operation.
///
/// * This may trigger an arbitrary number of read calls.
/// * This may block indefinitely depending on the contents of the fd.
template <typename T = std::byte>
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std::vector<T>
slurp (cruft::posix::fd&);
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///////////////////////////////////////////////////////////////////////////
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/// Repeatedly calls FunctionT to transfer data from a supplied view to a
/// file-like-object.
///
/// FunctionT must return a view of the consumed data.
///
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/// The operation will iterate until the entire view has been consumed and
/// hence may block for an indefinate period.
///
/// An exception may be throw in the event forward progress is impossible
/// (depending on the supplied FunctionT).
template <
typename DstT,
typename FunctionT,
typename IteratorA,
typename IteratorB,
typename ...Args
>
[[nodiscard]] decltype(auto)
drain (
DstT &&dst,
FunctionT &&func,
cruft::view<IteratorA,IteratorB> const &src,
Args&& ...args
) {
static_assert (std::is_pointer_v<IteratorA>);
static_assert (std::is_pointer_v<IteratorB>);
auto cursor = reinterpret_cast<std::byte const*> (src.data ());
auto remain = src.size ();
while (remain) {
auto count = std::invoke (func, dst, cursor, remain, args...);
cursor += count;
remain -= count;
}
return src;
}
///////////////////////////////////////////////////////////////////////////
/// Drains all data from the supplied view `src` to the file-like-object
/// `dst` by way of repeated calls to `write`.
///
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/// Returns a view over the consumed data. This SHOULD always be identical
/// to `src`.
template <
typename DstT,
typename IteratorA,
typename IteratorB
>
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decltype(auto)
write (DstT &&dst, const cruft::view<IteratorA, IteratorB> &src)
{
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constexpr auto func = &std::decay_t<DstT>::write;
return drain (std::forward<DstT> (dst), func, src);
}
///------------------------------------------------------------------------
/// Drain the supplied data view into the destination object by calling
/// pwrite repeatedly.
///
/// Returns a view over the consumed data. This SHOULD always be identical
/// to `src`.
template <
typename DstT,
typename IteratorA,
typename IteratorB
>
decltype(auto)
pwrite (DstT &&dst, const cruft::view<IteratorA, IteratorB> &src, size_t offset)
{
return drain (std::forward<DstT> (dst), &std::decay_t<DstT>::pwrite, src, offset);
}
///////////////////////////////////////////////////////////////////////////
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class indenter : public std::streambuf {
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protected:
std::streambuf* m_dest;
bool m_line_start;
std::string m_indent;
std::ostream* m_owner;
protected:
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virtual int overflow (int ch) override;
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public:
explicit indenter (std::streambuf* _dest, size_t _indent = 4);
explicit indenter (std::ostream& _dest, size_t _indent = 4);
virtual ~indenter ();
};
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//-------------------------------------------------------------------------
// a wrapper type that implicitly indents a single value when passed to an
// ostream operator.
template <typename ValueT>
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struct indented {
explicit indented (const ValueT &_data):
data (_data)
{ ; }
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const ValueT &data;
};
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//-------------------------------------------------------------------------
template <typename ValueT>
std::ostream&
operator<< (std::ostream &os, const cruft::indented<ValueT> &value)
{
cruft::indenter scoped_indent (os);
return os << value.data;
}
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//-------------------------------------------------------------------------
class scoped_cwd {
public:
scoped_cwd ();
~scoped_cwd ();
protected:
std::string m_original;
};
//-------------------------------------------------------------------------
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class path_error : public std::runtime_error {
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public:
explicit path_error (std::filesystem::path const &path);
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std::filesystem::path const& path (void) const noexcept;
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private:
std::filesystem::path const m_path;
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};
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class stream_error : public std::exception {
public:
virtual const char* what (void) const noexcept
{ return "error on C stream"; }
};
}
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#ifdef PLATFORM_WIN32
#include "io_win32.hpp"
#else
#include "io_posix.hpp"
#endif
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#endif