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 /*
 ** $Id: llimits.h $
 ** Limits, basic types, and some other 'installation-dependent' definitions
 ** See Copyright Notice in lua.h
 */
 
 #ifndef llimits_h
 #define llimits_h
 
 
 #include <limits.h>
 #include <stddef.h>
 
 
 #include "lua.h"
 
 
 /*
 ** 'lu_mem' and 'l_mem' are unsigned/signed integers big enough to count
 ** the total memory used by Lua (in bytes). Usually, 'size_t' and
 ** 'ptrdiff_t' should work, but we use 'long' for 16-bit machines.
 */
 #if defined(LUAI_MEM)       /* { external definitions? */
 typedef LUAI_UMEM lu_mem;
 typedef LUAI_MEM l_mem;
 #elif LUAI_IS32INT  /* }{ */
 typedef size_t lu_mem;
 typedef ptrdiff_t l_mem;
 #else  /* 16-bit ints */    /* }{ */
 typedef unsigned long lu_mem;
 typedef long l_mem;
 #endif              /* } */
 
 
 /* chars used as small naturals (so that 'char' is reserved for characters) */
 typedef unsigned char lu_byte;
 typedef signed char ls_byte;
 
 
 /* maximum value for size_t */
 #define MAX_SIZET   ((size_t)(~(size_t)0))
 
 /* maximum size visible for Lua (must be representable in a lua_Integer) */
 #define MAX_SIZE    (sizeof(size_t) < sizeof(lua_Integer) ? MAX_SIZET \
                           : (size_t)(LUA_MAXINTEGER))
 
 
 #define MAX_LUMEM   ((lu_mem)(~(lu_mem)0))
 
 #define MAX_LMEM    ((l_mem)(MAX_LUMEM >> 1))
 
 
 #define MAX_INT     INT_MAX  /* maximum value of an int */
 
 
 /*
 ** floor of the log2 of the maximum signed value for integral type 't'.
 ** (That is, maximum 'n' such that '2^n' fits in the given signed type.)
 */
 #define log2maxs(t) (sizeof(t) * 8 - 2)
 
 
 /*
 ** test whether an unsigned value is a power of 2 (or zero)
 */
 #define ispow2(x)   (((x) & ((x) - 1)) == 0)
 
 
 /* number of chars of a literal string without the ending \0 */
 #define LL(x)   (sizeof(x)/sizeof(char) - 1)
 
 
 /*
 ** conversion of pointer to unsigned integer: this is for hashing only;
 ** there is no problem if the integer cannot hold the whole pointer
 ** value. (In strict ISO C this may cause undefined behavior, but no
 ** actual machine seems to bother.)
 */
 #if !defined(LUA_USE_C89) && defined(__STDC_VERSION__) && \
     __STDC_VERSION__ >= 199901L
 #include <stdint.h>
 #if defined(UINTPTR_MAX)  /* even in C99 this type is optional */
 #define L_P2I   uintptr_t
 #else  /* no 'intptr'? */
 #define L_P2I   uintmax_t  /* use the largest available integer */
 #endif
 #else  /* C89 option */
 #define L_P2I   size_t
 #endif
 
 #define point2uint(p)   ((unsigned int)((L_P2I)(p) & UINT_MAX))
 
 
 
 /* types of 'usual argument conversions' for lua_Number and lua_Integer */
 typedef LUAI_UACNUMBER l_uacNumber;
 typedef LUAI_UACINT l_uacInt;
 
 
 /*
 ** Internal assertions for in-house debugging
 */
 #if defined LUAI_ASSERT
 #undef NDEBUG
 #include <assert.h>
 #define lua_assert(c)           assert(c)
 #endif
 
 #if defined(lua_assert)
 #define check_exp(c,e)      (lua_assert(c), (e))
 /* to avoid problems with conditions too long */
 #define lua_longassert(c)   ((c) ? (void)0 : lua_assert(0))
 #else
 #define lua_assert(c)       ((void)0)
 #define check_exp(c,e)      (e)
 #define lua_longassert(c)   ((void)0)
 #endif
 
 /*
 ** assertion for checking API calls
 */
 #if !defined(luai_apicheck)
 #define luai_apicheck(l,e)  ((void)l, lua_assert(e))
 #endif
 
 #define api_check(l,e,msg)  luai_apicheck(l,(e) && msg)
 
 
 /* macro to avoid warnings about unused variables */
 #if !defined(UNUSED)
 #define UNUSED(x)   ((void)(x))
 #endif
 
 
 /* type casts (a macro highlights casts in the code) */
 #define cast(t, exp)    ((t)(exp))
 
 #define cast_void(i)    cast(void, (i))
 #define cast_voidp(i)   cast(void *, (i))
 #define cast_num(i) cast(lua_Number, (i))
 #define cast_int(i) cast(int, (i))
 #define cast_uint(i)    cast(unsigned int, (i))
 #define cast_byte(i)    cast(lu_byte, (i))
 #define cast_uchar(i)   cast(unsigned char, (i))
 #define cast_char(i)    cast(char, (i))
 #define cast_charp(i)   cast(char *, (i))
 #define cast_sizet(i)   cast(size_t, (i))
 
 
 /* cast a signed lua_Integer to lua_Unsigned */
 #if !defined(l_castS2U)
 #define l_castS2U(i)    ((lua_Unsigned)(i))
 #endif
 
 /*
 ** cast a lua_Unsigned to a signed lua_Integer; this cast is
 ** not strict ISO C, but two-complement architectures should
 ** work fine.
 */
 #if !defined(l_castU2S)
 #define l_castU2S(i)    ((lua_Integer)(i))
 #endif
 
 
 /*
 ** non-return type
 */
 #if !defined(l_noret)
 
 #if defined(__GNUC__)
 #define l_noret     void __attribute__((noreturn))
 #elif defined(_MSC_VER) && _MSC_VER >= 1200
 #define l_noret     void __declspec(noreturn)
 #else
 #define l_noret     void
 #endif
 
 #endif
 
 
 /*
 ** Inline functions
 */
 #if !defined(LUA_USE_C89)
 #define l_inline    inline
 #elif defined(__GNUC__)
 #define l_inline    __inline__
 #else
 #define l_inline    /* empty */
 #endif
 
 #define l_sinline   static l_inline
 
 
 /*
 ** type for virtual-machine instructions;
 ** must be an unsigned with (at least) 4 bytes (see details in lopcodes.h)
 */
 #if LUAI_IS32INT
 typedef unsigned int l_uint32;
 #else
 typedef unsigned long l_uint32;
 #endif
 
 typedef l_uint32 Instruction;
 
 
 
 /*
 ** Maximum length for short strings, that is, strings that are
 ** internalized. (Cannot be smaller than reserved words or tags for
 ** metamethods, as these strings must be internalized;
 ** #("function") = 8, #("__newindex") = 10.)
 */
 #if !defined(LUAI_MAXSHORTLEN)
 #define LUAI_MAXSHORTLEN    40
 #endif
 
 
 /*
 ** Initial size for the string table (must be power of 2).
 ** The Lua core alone registers ~50 strings (reserved words +
 ** metaevent keys + a few others). Libraries would typically add
 ** a few dozens more.
 */
 #if !defined(MINSTRTABSIZE)
 #define MINSTRTABSIZE   128
 #endif
 
 
 /*
 ** Size of cache for strings in the API. 'N' is the number of
 ** sets (better be a prime) and "M" is the size of each set (M == 1
 ** makes a direct cache.)
 */
 #if !defined(STRCACHE_N)
 #define STRCACHE_N      53
 #define STRCACHE_M      2
 #endif
 
 
 /* minimum size for string buffer */
 #if !defined(LUA_MINBUFFER)
 #define LUA_MINBUFFER   32
 #endif
 
 
 /*
 ** Maximum depth for nested C calls, syntactical nested non-terminals,
 ** and other features implemented through recursion in C. (Value must
 ** fit in a 16-bit unsigned integer. It must also be compatible with
 ** the size of the C stack.)
 */
 #if !defined(LUAI_MAXCCALLS)
 #define LUAI_MAXCCALLS      200
 #endif
 
 
 /*
 ** macros that are executed whenever program enters the Lua core
 ** ('lua_lock') and leaves the core ('lua_unlock')
 */
 #if !defined(lua_lock)
 #define lua_lock(L) ((void) 0)
 #define lua_unlock(L)   ((void) 0)
 #endif
 
 /*
 ** macro executed during Lua functions at points where the
 ** function can yield.
 */
 #if !defined(luai_threadyield)
 #define luai_threadyield(L) {lua_unlock(L); lua_lock(L);}
 #endif
 
 
 /*
 ** these macros allow user-specific actions when a thread is
 ** created/deleted/resumed/yielded.
 */
 #if !defined(luai_userstateopen)
 #define luai_userstateopen(L)       ((void)L)
 #endif
 
 #if !defined(luai_userstateclose)
 #define luai_userstateclose(L)      ((void)L)
 #endif
 
 #if !defined(luai_userstatethread)
 #define luai_userstatethread(L,L1)  ((void)L)
 #endif
 
 #if !defined(luai_userstatefree)
 #define luai_userstatefree(L,L1)    ((void)L)
 #endif
 
 #if !defined(luai_userstateresume)
 #define luai_userstateresume(L,n)   ((void)L)
 #endif
 
 #if !defined(luai_userstateyield)
 #define luai_userstateyield(L,n)    ((void)L)
 #endif
 
 
 
 /*
 ** The luai_num* macros define the primitive operations over numbers.
 */
 
 /* floor division (defined as 'floor(a/b)') */
 #if !defined(luai_numidiv)
 #define luai_numidiv(L,a,b)     ((void)L, l_floor(luai_numdiv(L,a,b)))
 #endif
 
 /* float division */
 #if !defined(luai_numdiv)
 #define luai_numdiv(L,a,b)      ((a)/(b))
 #endif
 
 /*
 ** modulo: defined as 'a - floor(a/b)*b'; the direct computation
 ** using this definition has several problems with rounding errors,
 ** so it is better to use 'fmod'. 'fmod' gives the result of
 ** 'a - trunc(a/b)*b', and therefore must be corrected when
 ** 'trunc(a/b) ~= floor(a/b)'. That happens when the division has a
 ** non-integer negative result: non-integer result is equivalent to
 ** a non-zero remainder 'm'; negative result is equivalent to 'a' and
 ** 'b' with different signs, or 'm' and 'b' with different signs
 ** (as the result 'm' of 'fmod' has the same sign of 'a').
 */
 #if !defined(luai_nummod)
 #define luai_nummod(L,a,b,m)  \
   { (void)L; (m) = l_mathop(fmod)(a,b); \
     if (((m) > 0) ? (b) < 0 : ((m) < 0 && (b) > 0)) (m) += (b); }
 #endif
 
 /* exponentiation */
 #if !defined(luai_numpow)
 #define luai_numpow(L,a,b)  \
   ((void)L, (b == 2) ? (a)*(a) : l_mathop(pow)(a,b))
 #endif
 
 /* the others are quite standard operations */
 #if !defined(luai_numadd)
 #define luai_numadd(L,a,b)      ((a)+(b))
 #define luai_numsub(L,a,b)      ((a)-(b))
 #define luai_nummul(L,a,b)      ((a)*(b))
 #define luai_numunm(L,a)        (-(a))
 #define luai_numeq(a,b)         ((a)==(b))
 #define luai_numlt(a,b)         ((a)<(b))
 #define luai_numle(a,b)         ((a)<=(b))
 #define luai_numgt(a,b)         ((a)>(b))
 #define luai_numge(a,b)         ((a)>=(b))
 #define luai_numisnan(a)        (!luai_numeq((a), (a)))
 #endif
 
 
 
 
 
 /*
 ** macro to control inclusion of some hard tests on stack reallocation
 */
 #if !defined(HARDSTACKTESTS)
 #define condmovestack(L,pre,pos)    ((void)0)
 #else
 /* realloc stack keeping its size */
 #define condmovestack(L,pre,pos)  \
   { int sz_ = stacksize(L); pre; luaD_reallocstack((L), sz_, 0); pos; }
 #endif
 
 #if !defined(HARDMEMTESTS)
 #define condchangemem(L,pre,pos)    ((void)0)
 #else
 #define condchangemem(L,pre,pos)  \
     { if (gcrunning(G(L))) { pre; luaC_fullgc(L, 0); pos; } }
 #endif
 
 #endif

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