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construct/include/ircd/fmt.h
2016-09-22 16:18:32 -07:00

119 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
#ifdef __cplusplus
namespace ircd {
namespace fmt {
IRCD_EXCEPTION(ircd::error, error);
IRCD_EXCEPTION(error, invalid_format);
IRCD_EXCEPTION(error, invalid_type);
IRCD_EXCEPTION(error, illegal);
//
// Module API
//
extern const char SPECIFIER;
extern const char SPECIFIER_TERMINATOR;
using ptrs = std::vector<const void *>;
using types = std::vector<std::type_index>;
using arg = std::tuple<const void *const &, const std::type_index &>;
// Structural representation of a format specifier
struct spec
{
char sign;
int width;
std::string name;
spec();
};
// A format specifier handler module.
// This allows a new "%foo" to be defined with custom handling.
class specifier
{
std::vector<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;
};
const std::map<std::string, specifier *> &specifiers();
//
// 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 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 ptrs &, const types &);
public:
operator ssize_t() const { return consumed(); }
template<class... A>
snprintf(char *const &buf, const size_t &max, const char *const &fmt, A&&... args);
};
template<class... Args>
snprintf::snprintf(char *const &buf,
const size_t &max,
const char *const &fmt,
Args&&... args)
:snprintf
{
internal, buf, max, fmt, ptrs{std::addressof(args)...}, types{typeid(Args)...}
}
{
}
} // namespace fmt
} // namespace ircd
#endif // __cplusplus