lua/llimits.h
2001-02-22 14:15:18 -03:00

227 lines
5.1 KiB
C

/*
** $Id: llimits.h,v 1.23 2001/02/20 18:15:33 roberto Exp roberto $
** 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>
/*
** try to find number of bits in an integer
*/
#ifndef BITS_INT
/* avoid overflows in comparison */
#if INT_MAX-20 < 32760
#define BITS_INT 16
#else
#if INT_MAX > 2147483640L
/* machine has at least 32 bits */
#define BITS_INT 32
#else
#error "you must define BITS_INT with number of bits in an integer"
#endif
#endif
#endif
/* function to convert a lua_Number to a string */
#ifndef NUMBER_FMT
#define NUMBER_FMT "%.16g" /* LUA_NUMBER */
#endif
#ifndef lua_number2str
#define lua_number2str(s,n) sprintf((s), NUMBER_FMT, (n))
#endif
/* function to convert a string to a lua_Number */
#ifndef lua_str2number
#define lua_str2number(s,p) strtod((s), (p))
#endif
/*
** the following types define integer types for values that may not
** fit in a "small int" (16 bits), but may waste space in a
** "large long" (64 bits). The current definitions should work in
** any machine, but may not be optimal.
*/
/* an unsigned integer to hold hash values */
typedef unsigned int lu_hash;
/* its signed equivalent */
typedef int ls_hash;
/* an unsigned integer big enough to count the total memory used by Lua */
typedef unsigned long lu_mem;
/* an integer big enough to count the number of strings in use */
typedef long ls_nstr;
/* chars used as small naturals (so that `char' is reserved for characteres) */
typedef unsigned char lu_byte;
/* macro to `unsign' a character */
#define uchar(c) ((unsigned char)(c))
#define MAX_SIZET ((size_t)(~(size_t)0)-2)
#define MAX_INT (INT_MAX-2) /* maximum value of an int (-2 for safety) */
/*
** conversion of pointer to integer
** this is for hashing only; there is no problem if the integer
** cannot hold the whole pointer value
** (the shift removes bits that are usually 0 because of alignment)
*/
#define IntPoint(p) ((((lu_hash)(p)) >> 4) ^ (lu_hash)(p))
#define MINPOWER2 4 /* minimum size for "growing" vectors */
#ifndef DEFAULT_STACK_SIZE
#define DEFAULT_STACK_SIZE 1024
#endif
/* type to ensure maximum alignment */
union L_Umaxalign { double d; void *s; long l; };
/*
** type for virtual-machine instructions
** must be an unsigned with (at least) 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;
/*
** size and position of opcode arguments.
** For an instruction with 2 bytes, size is 16, and size_b can be 5
** (accordingly, size_u will be 10, and size_a will be 5)
*/
#define SIZE_INSTRUCTION 32
#define SIZE_B 8
#define SIZE_OP 6
#define SIZE_U (SIZE_INSTRUCTION-SIZE_OP)
#define POS_U SIZE_OP
#define POS_B SIZE_OP
#define SIZE_A (SIZE_INSTRUCTION-(SIZE_OP+SIZE_B))
#define POS_A (SIZE_OP+SIZE_B)
/*
** limits for opcode arguments.
** we use (signed) int to manipulate most arguments,
** so they must fit in BITS_INT-1 bits (-1 for sign)
*/
#if SIZE_U < BITS_INT-1
#define MAXARG_U ((1<<SIZE_U)-1)
#define MAXARG_S (MAXARG_U>>1) /* `S' is signed */
#else
#define MAXARG_U MAX_INT
#define MAXARG_S MAX_INT
#endif
#if SIZE_A < BITS_INT-1
#define MAXARG_A ((1<<SIZE_A)-1)
#else
#define MAXARG_A MAX_INT
#endif
#if SIZE_B < BITS_INT-1
#define MAXARG_B ((1<<SIZE_B)-1)
#else
#define MAXARG_B MAX_INT
#endif
/* maximum stack size in a function */
#ifndef MAXSTACK
#define MAXSTACK 250
#endif
#if MAXSTACK > MAXARG_B
#undef MAXSTACK
#define MAXSTACK MAXARG_B
#endif
/* 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
/* 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 64
#if LFIELDS_PER_FLUSH>(MAXSTACK/4)
#undef LFIELDS_PER_FLUSH
#define LFIELDS_PER_FLUSH (MAXSTACK/4)
#endif
/* 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 lookback to find a real constant (for code generation) */
#ifndef LOOKBACKNUMS
#define LOOKBACKNUMS 20 /* arbitrary constant */
#endif
#endif