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/* MIT (BSD) license - see LICENSE file for details */
#ifndef CCAN_CPPMAGIC_H
#define CCAN_CPPMAGIC_H
/**
* CPPMAGIC_NOTHING - expands to nothing
*/
#define CPPMAGIC_NOTHING()
/**
* CPPMAGIC_STRINGIFY - convert arguments to a string literal
*/
#define _CPPMAGIC_STRINGIFY(...) #__VA_ARGS__
#define CPPMAGIC_STRINGIFY(...) _CPPMAGIC_STRINGIFY(__VA_ARGS__)
/**
* CPPMAGIC_GLUE2 - glue arguments together
*
* CPPMAGIC_GLUE2(@a_, @b_)
* expands to the expansion of @a_ followed immediately
* (combining tokens) by the expansion of @b_
*/
#define _CPPMAGIC_GLUE2(a_, b_) a_##b_
#define CPPMAGIC_GLUE2(a_, b_) _CPPMAGIC_GLUE2(a_, b_)
/**
* CPPMAGIC_1ST - return 1st argument
*
* CPPMAGIC_1ST(@a_, ...)
* expands to the expansion of @a_
*/
#define CPPMAGIC_1ST(a_, ...) a_
/**
* CPPMAGIC_2ND - return 2nd argument
*
* CPPMAGIC_2ST(@a_, @b_, ...)
* expands to the expansion of @b_
*/
#define CPPMAGIC_2ND(a_, b_, ...) b_
/**
* CPPMAGIC_ISZERO - is argument '0'
*
* CPPMAGIC_ISZERO(@a)
* expands to '1' if @a is '0', otherwise expands to '0'.
*/
#define _CPPMAGIC_ISPROBE(...) CPPMAGIC_2ND(__VA_ARGS__, 0)
#define _CPPMAGIC_PROBE() $, 1
#define _CPPMAGIC_ISZERO_0 _CPPMAGIC_PROBE()
#define CPPMAGIC_ISZERO(a_) \
_CPPMAGIC_ISPROBE(CPPMAGIC_GLUE2(_CPPMAGIC_ISZERO_, a_))
/**
* CPPMAGIC_NONZERO - is argument not '0'
*
* CPPMAGIC_NONZERO(@a)
* expands to '0' if @a is '0', otherwise expands to '1'.
*/
#define CPPMAGIC_NONZERO(a_) CPPMAGIC_ISZERO(CPPMAGIC_ISZERO(a_))
/**
* CPPMAGIC_NONEMPTY - does the macro have any arguments?
*
* CPPMAGIC_NONEMPTY()
* expands to '0'
* CPPMAGIC_NONEMPTY(@a)
* CPPMAGIC_NONEMPTY(@a, ...)
* expand to '1'
*/
#define _CPPMAGIC_EOA() 0
#define CPPMAGIC_NONEMPTY(...) \
CPPMAGIC_NONZERO(CPPMAGIC_1ST(_CPPMAGIC_EOA __VA_ARGS__)())
/**
* CPPMAGIC_ISEMPTY - does the macro have no arguments?
*
* CPPMAGIC_ISEMPTY()
* expands to '1'
* CPPMAGIC_ISEMPTY(@a)
* CPPMAGIC_ISEMPTY(@a, ...)
* expand to '0'
*/
#define CPPMAGIC_ISEMPTY(...) \
CPPMAGIC_ISZERO(CPPMAGIC_NONEMPTY(__VA_ARGS__))
/*
* CPPMAGIC_IFELSE - preprocessor conditional
*
* CPPMAGIC_IFELSE(@cond)(@if)(@else)
* expands to @else if @cond is '0', otherwise expands to @if
*/
#define _CPPMAGIC_IF_0(...) _CPPMAGIC_IF_0_ELSE
#define _CPPMAGIC_IF_1(...) __VA_ARGS__ _CPPMAGIC_IF_1_ELSE
#define _CPPMAGIC_IF_0_ELSE(...) __VA_ARGS__
#define _CPPMAGIC_IF_1_ELSE(...)
#define _CPPMAGIC_IFELSE(cond_) CPPMAGIC_GLUE2(_CPPMAGIC_IF_, cond_)
#define CPPMAGIC_IFELSE(cond_) \
_CPPMAGIC_IFELSE(CPPMAGIC_NONZERO(cond_))
/**
* CPPMAGIC_EVAL - force multiple expansion passes
*
* Forces macros in the arguments to be expanded repeatedly (up to
* 1024 times) even when CPP would usually stop expanding.
*/
#define CPPMAGIC_EVAL1(...) __VA_ARGS__
#define CPPMAGIC_EVAL2(...) \
CPPMAGIC_EVAL1(CPPMAGIC_EVAL1(__VA_ARGS__))
#define CPPMAGIC_EVAL4(...) \
CPPMAGIC_EVAL2(CPPMAGIC_EVAL2(__VA_ARGS__))
#define CPPMAGIC_EVAL8(...) \
CPPMAGIC_EVAL4(CPPMAGIC_EVAL4(__VA_ARGS__))
#define CPPMAGIC_EVAL16(...) \
CPPMAGIC_EVAL8(CPPMAGIC_EVAL8(__VA_ARGS__))
#define CPPMAGIC_EVAL32(...) \
CPPMAGIC_EVAL16(CPPMAGIC_EVAL16(__VA_ARGS__))
#define CPPMAGIC_EVAL64(...) \
CPPMAGIC_EVAL32(CPPMAGIC_EVAL32(__VA_ARGS__))
#define CPPMAGIC_EVAL128(...) \
CPPMAGIC_EVAL64(CPPMAGIC_EVAL64(__VA_ARGS__))
#define CPPMAGIC_EVAL256(...) \
CPPMAGIC_EVAL128(CPPMAGIC_EVAL128(__VA_ARGS__))
#define CPPMAGIC_EVAL512(...) \
CPPMAGIC_EVAL256(CPPMAGIC_EVAL256(__VA_ARGS__))
#define CPPMAGIC_EVAL1024(...) \
CPPMAGIC_EVAL512(CPPMAGIC_EVAL512(__VA_ARGS__))
#define CPPMAGIC_EVAL(...) CPPMAGIC_EVAL1024(__VA_ARGS__)
/**
* CPPMAGIC_DEFER1, CPPMAGIC_DEFER2 - defer expansion
*/
#define CPPMAGIC_DEFER1(a_) a_ CPPMAGIC_NOTHING()
#define CPPMAGIC_DEFER2(a_) a_ CPPMAGIC_NOTHING CPPMAGIC_NOTHING()()
/**
* CPPMAGIC_MAP - iterate another macro across arguments
* @m: name of a one argument macro
*
* CPPMAGIC_MAP(@m, @a1, @a2, ... @an)
* expands to the expansion of @m(@a1) , @m(@a2) , ... , @m(@an)
*/
#define _CPPMAGIC_MAP_() _CPPMAGIC_MAP
#define _CPPMAGIC_MAP(m_, a_, ...) \
m_(a_) \
CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__)) \
(, CPPMAGIC_DEFER2(_CPPMAGIC_MAP_)()(m_, __VA_ARGS__)) \
()
#define CPPMAGIC_MAP(m_, ...) \
CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__)) \
(CPPMAGIC_EVAL(_CPPMAGIC_MAP(m_, __VA_ARGS__))) \
()
/**
* CPPMAGIC_2MAP - iterate another macro across pairs of arguments
* @m: name of a two argument macro
*
* CPPMAGIC_2MAP(@m, @a1, @b1, @a2, @b2, ..., @an, @bn)
* expands to the expansion of
* @m(@a1, @b1) , @m(@a2, @b2) , ... , @m(@an, @bn)
*/
#define _CPPMAGIC_2MAP_() _CPPMAGIC_2MAP
#define _CPPMAGIC_2MAP(m_, a_, b_, ...) \
m_(a_, b_) \
CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__)) \
(, CPPMAGIC_DEFER2(_CPPMAGIC_2MAP_)()(m_, __VA_ARGS__)) \
()
#define CPPMAGIC_2MAP(m_, ...) \
CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__)) \
(CPPMAGIC_EVAL(_CPPMAGIC_2MAP(m_, __VA_ARGS__))) \
()
/**
* CPPMAGIC_JOIN - separate arguments with given delimiter
* @d: delimiter
*
* CPPMAGIC_JOIN(@d, @a1, @a2, ..., @an)
* expands to the expansion of @a1 @d @a2 @d ... @d @an
*/
#define _CPPMAGIC_JOIN_() _CPPMAGIC_JOIN
#define _CPPMAGIC_JOIN(d_, a_, ...) \
a_ \
CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__)) \
(d_ CPPMAGIC_DEFER2(_CPPMAGIC_JOIN_)()(d_, __VA_ARGS__)) \
()
#define CPPMAGIC_JOIN(d_, ...) \
CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__)) \
(CPPMAGIC_EVAL(_CPPMAGIC_JOIN(d_, __VA_ARGS__))) \
()
#endif /* CCAN_CPPMAGIC_H */