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construct/include/ircd/fmt.h
Jason Volk d9a4f06bf6 ircd: Employ namespace scope extensions from c++1z/gnu++14.
This is not a move to c++17. If the compiler happens to have support
for c++17 namespace scope resolution, they have been kind enough to
backport it to gnu++14. This limits our support for really old c++14
compilers, but that was limited anyway. GCC 6.1 and clang 3.6 tested.
2017-09-08 03:47:46 -07:00

132 lines
4 KiB
C++

/**
* Copyright (C) 2016 Charybdis Development Team
* Copyright (C) 2016 Jason Volk
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice is present in all copies.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#define HAVE_IRCD_FMT_H
namespace ircd::fmt
{
IRCD_EXCEPTION(ircd::error, error);
IRCD_EXCEPTION(error, invalid_format);
IRCD_EXCEPTION(error, invalid_type);
IRCD_EXCEPTION(error, illegal);
struct spec;
struct specifier;
struct snprintf;
struct vsnprintf;
//
// Module API
//
constexpr char SPECIFIER
{
'%'
};
constexpr char SPECIFIER_TERMINATOR
{
'$'
};
using arg = std::tuple<const void *, std::type_index>;
const std::map<string_view, specifier *, std::less<>> &specifiers();
}
// Structural representation of a format specifier
struct ircd::fmt::spec
{
char sign {'+'};
ushort width {0};
string_view name;
spec() = default;
};
// A format specifier handler module.
// This allows a new "%foo" to be defined with custom handling.
class ircd::fmt::specifier
{
std::set<std::string> names;
public:
virtual bool operator()(char *&out, const size_t &max, const spec &, const arg &) const = 0;
specifier(const std::initializer_list<std::string> &names);
specifier(const std::string &name);
virtual ~specifier() noexcept;
};
//
// User API
//
// * The arguments are not restricted by stdarg limitations. You can pass a real std::string.
// * The function participates in the custom protocol-safe ruleset.
class ircd::fmt::snprintf
{
const char *fstart; // Current running position in the fmtstr
const char *fstop; // Saved state from the last position
const char *fend; // past-the-end iterator of the fmtstr
const char *obeg; // Saved beginning of the output buffer
const char *oend; // past-the-end iterator of the output buffer
char *out; // Current running position of the output buffer
short idx; // Keeps count of the args for better err msgs
protected:
auto finished() const { return !fstart || fstop >= fend; }
auto remaining() const { return (oend - out) - 1; }
auto consumed() const { return size_t(out - obeg); }
auto &buffer() const { return obeg; }
void append(const char *const &begin, const char *const &end);
void argument(const arg &);
IRCD_OVERLOAD(internal)
snprintf(internal_t, char *const &, const size_t &, const char *const &, const va_rtti &);
public:
operator ssize_t() const { return consumed(); }
template<class... Args>
snprintf(char *const &buf,
const size_t &max,
const char *const &fmt,
Args&&... args)
:snprintf
{
internal, buf, max, fmt, va_rtti{std::forward<Args>(args)...}
}{}
};
struct ircd::fmt::vsnprintf
:snprintf
{
vsnprintf(char *const &buf,
const size_t &max,
const char *const &fmt,
const va_rtti &ap)
:snprintf
{
internal, buf, max, fmt, ap
}{}
};