mirror of
https://github.com/lua/lua
synced 2024-11-22 04:41:23 +03:00
55ac40f859
Several definitions that don't need to be "global" (that is, that concerns only specific parts of the code) moved out of llimits.h, to more appropriate places.
82 lines
2.2 KiB
C
82 lines
2.2 KiB
C
/*
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** $Id: lapi.h $
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** Auxiliary functions from Lua API
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** See Copyright Notice in lua.h
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*/
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#ifndef lapi_h
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#define lapi_h
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#include "llimits.h"
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#include "lstate.h"
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#if defined(LUA_USE_APICHECK)
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#include <assert.h>
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#define api_check(l,e,msg) assert(e)
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#else /* for testing */
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#define api_check(l,e,msg) ((void)(l), lua_assert((e) && msg))
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#endif
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/* Increments 'L->top.p', checking for stack overflows */
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#define api_incr_top(L) \
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(L->top.p++, api_check(L, L->top.p <= L->ci->top.p, "stack overflow"))
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/*
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** macros that are executed whenever program enters the Lua core
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** ('lua_lock') and leaves the core ('lua_unlock')
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*/
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#if !defined(lua_lock)
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#define lua_lock(L) ((void) 0)
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#define lua_unlock(L) ((void) 0)
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#endif
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/*
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** If a call returns too many multiple returns, the callee may not have
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** stack space to accommodate all results. In this case, this macro
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** increases its stack space ('L->ci->top.p').
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*/
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#define adjustresults(L,nres) \
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{ if ((nres) <= LUA_MULTRET && L->ci->top.p < L->top.p) \
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L->ci->top.p = L->top.p; }
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/* Ensure the stack has at least 'n' elements */
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#define api_checknelems(L,n) \
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api_check(L, (n) < (L->top.p - L->ci->func.p), \
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"not enough elements in the stack")
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/* Ensure the stack has at least 'n' elements to be popped. (Some
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** functions only update a slot after checking it for popping, but that
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** is only an optimization for a pop followed by a push.)
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*/
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#define api_checkpop(L,n) \
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api_check(L, (n) < L->top.p - L->ci->func.p && \
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L->tbclist.p < L->top.p - (n), \
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"not enough free elements in the stack")
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/*
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** To reduce the overhead of returning from C functions, the presence of
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** to-be-closed variables in these functions is coded in the CallInfo's
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** field 'nresults', in a way that functions with no to-be-closed variables
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** with zero, one, or "all" wanted results have no overhead. Functions
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** with other number of wanted results, as well as functions with
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** variables to be closed, have an extra check.
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*/
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#define hastocloseCfunc(n) ((n) < LUA_MULTRET)
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/* Map [-1, inf) (range of 'nresults') into (-inf, -2] */
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#define codeNresults(n) (-(n) - 3)
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#define decodeNresults(n) (-(n) - 3)
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#endif
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