lua/llimits.h

186 lines
4.1 KiB
C

/*
** $Id: $
** Limits, basic types, and some other "instalation-dependent" definitions
** See Copyright Notice in lua.h
*/
#ifndef llims_h
#define llims_h
#include <limits.h>
/*
** Define the type `number' of Lua
** GREP LUA_NUMBER to change that
*/
#ifndef LUA_NUM_TYPE
#define LUA_NUM_TYPE double
#endif
typedef LUA_NUM_TYPE Number;
#define MAX_INT (INT_MAX-2) /* maximum value of an int (-2 for safety) */
/*
** conversion of pointer to int (for hashing only)
** (the shift removes bits that are usually 0 because of alignment)
*/
#define IntPoint(L, p) (((unsigned long)(p)) >> 3)
/*
** number of `blocks' for garbage collection: each reference to other
** objects count 1, and each 32 bytes of `raw' memory count 1; we add
** 2 to the total as a minimum (and also to count the overhead of malloc)
*/
#define numblocks(L, o,b) ((o)+((b)>>5)+2)
#define MINPOWER2 4 /* minimum size for "growing" vectors */
/*
** type for virtual-machine instructions
** must be an unsigned with 4 bytes (see details in lopcodes.h)
** For a very small machine, you may change that to 2 bytes (and adjust
** the following limits accordingly)
*/
typedef unsigned long Instruction;
/*
** limits for opcode arguments.
** For an instruction with 2 bytes, size is 16, and size_b can be 5
*/
#define SIZE_INSTRUCTION 32
#define SIZE_OP 6
#define SIZE_B 9
#define SIZE_U (SIZE_INSTRUCTION-SIZE_OP)
#define POS_U SIZE_OP
#define SIZE_S (SIZE_INSTRUCTION-SIZE_OP)
#define POS_S SIZE_OP
#define POS_B SIZE_OP
#define SIZE_A (SIZE_INSTRUCTION-(SIZE_OP+SIZE_B))
#define POS_A (SIZE_OP+SIZE_B)
#define MAXARG_U ((1<<SIZE_U)-1)
#define MAXARG_S ((1<<(SIZE_S-1))-1) /* `S' is signed */
#define MAXARG_A ((1<<SIZE_A)-1)
#define MAXARG_B ((1<<SIZE_B)-1)
/*
** we use int to manipulate most arguments, so they must fit
*/
#if MAXARG_U > MAX_INT
#undef MAXARG_U
#define MAXARG_U MAX_INT
#endif
#if MAXARG_S > MAX_INT
#undef MAXARG_S
#define MAXARG_S MAX_INT
#endif
#if MAXARG_A > MAX_INT
#undef MAXARG_A
#define MAXARG_A MAX_INT
#endif
#if MAXARG_B > MAX_INT
#undef MAXARG_B
#define MAXARG_B MAX_INT
#endif
/* maximum stack size in a function */
#define MAXSTACK MAXARG_B
/* maximum number of local variables */
#ifndef MAXLOCALS
#define MAXLOCALS 200 /* arbitrary limit (<MAXSTACK) */
#endif
#if MAXLOCALS>=MAXSTACK
#undef MAXLOCALS
#define MAXLOCALS (MAXSTACK-1)
#endif
/* maximum number of upvalues */
#ifndef MAXUPVALUES
#define MAXUPVALUES 32 /* arbitrary limit (<=MAXARG_B) */
#endif
#if MAXUPVALUES>MAXARG_B
#undef MAXUPVALUES
#define MAXUPVALUES MAXARG_B
#endif
/* special code for multiple returns */
#define MULT_RET 255 /* (<=MAXARG_B) */
#if MULT_RET>MAXARG_B
#undef MULT_RET
#define MULT_RET MAXARG_B
#endif
/* maximum number of variables in the left side of an assignment */
#ifndef MAXVARSLH
#define MAXVARSLH 100 /* arbitrary limit (<MULT_RET) */
#endif
#if MAXVARSLH>=MULT_RET
#undef MAXVARSLH
#define MAXVARSLH (MULT_RET-1)
#endif
/* maximum number of parameters in a function */
#ifndef MAXPARAMS
#define MAXPARAMS 100 /* arbitrary limit (<MAXLOCALS) */
#endif
#if MAXPARAMS>=MAXLOCALS
#undef MAXPARAMS
#define MAXPARAMS (MAXLOCALS-1)
#endif
/* number of list items to accumulate before a SETLIST instruction */
#define LFIELDS_PER_FLUSH (MAXSTACK/4)
/* number of record items to accumulate before a SETMAP instruction */
/* (each item counts 2 elements on the stack: an index and a value) */
#define RFIELDS_PER_FLUSH (LFIELDS_PER_FLUSH/2)
/* maximum number of values printed in one call to `print' */
#ifndef MAXPRINT
#define MAXPRINT 40 /* arbitrary limit */
#endif
/* maximum depth of nested $ifs */
#ifndef MAX_IFS
#define MAX_IFS 5 /* arbitrary limit */
#endif
/* maximum size of a pragma line */
#ifndef PRAGMASIZE
#define PRAGMASIZE 80 /* arbitrary limit */
#endif
/* maximum lookback to find a real constant (for code generation) */
#ifndef LOOKBACKNUMS
#define LOOKBACKNUMS 20 /* arbitrary limit */
#endif
#endif