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Member "memcached-1.6.15/vendor/lua/src/lfunc.c" (1 Oct 2021, 8367 Bytes) of package /linux/www/memcached-1.6.15.tar.gz:


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    1 /*
    2 ** $Id: lfunc.c $
    3 ** Auxiliary functions to manipulate prototypes and closures
    4 ** See Copyright Notice in lua.h
    5 */
    6 
    7 #define lfunc_c
    8 #define LUA_CORE
    9 
   10 #include "lprefix.h"
   11 
   12 
   13 #include <stddef.h>
   14 
   15 #include "lua.h"
   16 
   17 #include "ldebug.h"
   18 #include "ldo.h"
   19 #include "lfunc.h"
   20 #include "lgc.h"
   21 #include "lmem.h"
   22 #include "lobject.h"
   23 #include "lstate.h"
   24 
   25 
   26 
   27 CClosure *luaF_newCclosure (lua_State *L, int nupvals) {
   28   GCObject *o = luaC_newobj(L, LUA_VCCL, sizeCclosure(nupvals));
   29   CClosure *c = gco2ccl(o);
   30   c->nupvalues = cast_byte(nupvals);
   31   return c;
   32 }
   33 
   34 
   35 LClosure *luaF_newLclosure (lua_State *L, int nupvals) {
   36   GCObject *o = luaC_newobj(L, LUA_VLCL, sizeLclosure(nupvals));
   37   LClosure *c = gco2lcl(o);
   38   c->p = NULL;
   39   c->nupvalues = cast_byte(nupvals);
   40   while (nupvals--) c->upvals[nupvals] = NULL;
   41   return c;
   42 }
   43 
   44 
   45 /*
   46 ** fill a closure with new closed upvalues
   47 */
   48 void luaF_initupvals (lua_State *L, LClosure *cl) {
   49   int i;
   50   for (i = 0; i < cl->nupvalues; i++) {
   51     GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
   52     UpVal *uv = gco2upv(o);
   53     uv->v = &uv->u.value;  /* make it closed */
   54     setnilvalue(uv->v);
   55     cl->upvals[i] = uv;
   56     luaC_objbarrier(L, cl, uv);
   57   }
   58 }
   59 
   60 
   61 /*
   62 ** Create a new upvalue at the given level, and link it to the list of
   63 ** open upvalues of 'L' after entry 'prev'.
   64 **/
   65 static UpVal *newupval (lua_State *L, int tbc, StkId level, UpVal **prev) {
   66   GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
   67   UpVal *uv = gco2upv(o);
   68   UpVal *next = *prev;
   69   uv->v = s2v(level);  /* current value lives in the stack */
   70   uv->tbc = tbc;
   71   uv->u.open.next = next;  /* link it to list of open upvalues */
   72   uv->u.open.previous = prev;
   73   if (next)
   74     next->u.open.previous = &uv->u.open.next;
   75   *prev = uv;
   76   if (!isintwups(L)) {  /* thread not in list of threads with upvalues? */
   77     L->twups = G(L)->twups;  /* link it to the list */
   78     G(L)->twups = L;
   79   }
   80   return uv;
   81 }
   82 
   83 
   84 /*
   85 ** Find and reuse, or create if it does not exist, an upvalue
   86 ** at the given level.
   87 */
   88 UpVal *luaF_findupval (lua_State *L, StkId level) {
   89   UpVal **pp = &L->openupval;
   90   UpVal *p;
   91   lua_assert(isintwups(L) || L->openupval == NULL);
   92   while ((p = *pp) != NULL && uplevel(p) >= level) {  /* search for it */
   93     lua_assert(!isdead(G(L), p));
   94     if (uplevel(p) == level)  /* corresponding upvalue? */
   95       return p;  /* return it */
   96     pp = &p->u.open.next;
   97   }
   98   /* not found: create a new upvalue after 'pp' */
   99   return newupval(L, 0, level, pp);
  100 }
  101 
  102 
  103 /*
  104 ** Call closing method for object 'obj' with error message 'err'. The
  105 ** boolean 'yy' controls whether the call is yieldable.
  106 ** (This function assumes EXTRA_STACK.)
  107 */
  108 static void callclosemethod (lua_State *L, TValue *obj, TValue *err, int yy) {
  109   StkId top = L->top;
  110   const TValue *tm = luaT_gettmbyobj(L, obj, TM_CLOSE);
  111   setobj2s(L, top, tm);  /* will call metamethod... */
  112   setobj2s(L, top + 1, obj);  /* with 'self' as the 1st argument */
  113   setobj2s(L, top + 2, err);  /* and error msg. as 2nd argument */
  114   L->top = top + 3;  /* add function and arguments */
  115   if (yy)
  116     luaD_call(L, top, 0);
  117   else
  118     luaD_callnoyield(L, top, 0);
  119 }
  120 
  121 
  122 /*
  123 ** Check whether object at given level has a close metamethod and raise
  124 ** an error if not.
  125 */
  126 static void checkclosemth (lua_State *L, StkId level) {
  127   const TValue *tm = luaT_gettmbyobj(L, s2v(level), TM_CLOSE);
  128   if (ttisnil(tm)) {  /* no metamethod? */
  129     int idx = cast_int(level - L->ci->func);  /* variable index */
  130     const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
  131     if (vname == NULL) vname = "?";
  132     luaG_runerror(L, "variable '%s' got a non-closable value", vname);
  133   }
  134 }
  135 
  136 
  137 /*
  138 ** Prepare and call a closing method.
  139 ** If status is CLOSEKTOP, the call to the closing method will be pushed
  140 ** at the top of the stack. Otherwise, values can be pushed right after
  141 ** the 'level' of the upvalue being closed, as everything after that
  142 ** won't be used again.
  143 */
  144 static void prepcallclosemth (lua_State *L, StkId level, int status, int yy) {
  145   TValue *uv = s2v(level);  /* value being closed */
  146   TValue *errobj;
  147   if (status == CLOSEKTOP)
  148     errobj = &G(L)->nilvalue;  /* error object is nil */
  149   else {  /* 'luaD_seterrorobj' will set top to level + 2 */
  150     errobj = s2v(level + 1);  /* error object goes after 'uv' */
  151     luaD_seterrorobj(L, status, level + 1);  /* set error object */
  152   }
  153   callclosemethod(L, uv, errobj, yy);
  154 }
  155 
  156 
  157 /*
  158 ** Maximum value for deltas in 'tbclist', dependent on the type
  159 ** of delta. (This macro assumes that an 'L' is in scope where it
  160 ** is used.)
  161 */
  162 #define MAXDELTA  \
  163     ((256ul << ((sizeof(L->stack->tbclist.delta) - 1) * 8)) - 1)
  164 
  165 
  166 /*
  167 ** Insert a variable in the list of to-be-closed variables.
  168 */
  169 void luaF_newtbcupval (lua_State *L, StkId level) {
  170   lua_assert(level > L->tbclist);
  171   if (l_isfalse(s2v(level)))
  172     return;  /* false doesn't need to be closed */
  173   checkclosemth(L, level);  /* value must have a close method */
  174   while (cast_uint(level - L->tbclist) > MAXDELTA) {
  175     L->tbclist += MAXDELTA;  /* create a dummy node at maximum delta */
  176     L->tbclist->tbclist.delta = 0;
  177   }
  178   level->tbclist.delta = cast(unsigned short, level - L->tbclist);
  179   L->tbclist = level;
  180 }
  181 
  182 
  183 void luaF_unlinkupval (UpVal *uv) {
  184   lua_assert(upisopen(uv));
  185   *uv->u.open.previous = uv->u.open.next;
  186   if (uv->u.open.next)
  187     uv->u.open.next->u.open.previous = uv->u.open.previous;
  188 }
  189 
  190 
  191 /*
  192 ** Close all upvalues up to the given stack level.
  193 */
  194 void luaF_closeupval (lua_State *L, StkId level) {
  195   UpVal *uv;
  196   StkId upl;  /* stack index pointed by 'uv' */
  197   while ((uv = L->openupval) != NULL && (upl = uplevel(uv)) >= level) {
  198     TValue *slot = &uv->u.value;  /* new position for value */
  199     lua_assert(uplevel(uv) < L->top);
  200     luaF_unlinkupval(uv);  /* remove upvalue from 'openupval' list */
  201     setobj(L, slot, uv->v);  /* move value to upvalue slot */
  202     uv->v = slot;  /* now current value lives here */
  203     if (!iswhite(uv)) {  /* neither white nor dead? */
  204       nw2black(uv);  /* closed upvalues cannot be gray */
  205       luaC_barrier(L, uv, slot);
  206     }
  207   }
  208 }
  209 
  210 
  211 /*
  212 ** Remove firt element from the tbclist plus its dummy nodes.
  213 */
  214 static void poptbclist (lua_State *L) {
  215   StkId tbc = L->tbclist;
  216   lua_assert(tbc->tbclist.delta > 0);  /* first element cannot be dummy */
  217   tbc -= tbc->tbclist.delta;
  218   while (tbc > L->stack && tbc->tbclist.delta == 0)
  219     tbc -= MAXDELTA;  /* remove dummy nodes */
  220   L->tbclist = tbc;
  221 }
  222 
  223 
  224 /*
  225 ** Close all upvalues and to-be-closed variables up to the given stack
  226 ** level.
  227 */
  228 void luaF_close (lua_State *L, StkId level, int status, int yy) {
  229   ptrdiff_t levelrel = savestack(L, level);
  230   luaF_closeupval(L, level);  /* first, close the upvalues */
  231   while (L->tbclist >= level) {  /* traverse tbc's down to that level */
  232     StkId tbc = L->tbclist;  /* get variable index */
  233     poptbclist(L);  /* remove it from list */
  234     prepcallclosemth(L, tbc, status, yy);  /* close variable */
  235     level = restorestack(L, levelrel);
  236   }
  237 }
  238 
  239 
  240 Proto *luaF_newproto (lua_State *L) {
  241   GCObject *o = luaC_newobj(L, LUA_VPROTO, sizeof(Proto));
  242   Proto *f = gco2p(o);
  243   f->k = NULL;
  244   f->sizek = 0;
  245   f->p = NULL;
  246   f->sizep = 0;
  247   f->code = NULL;
  248   f->sizecode = 0;
  249   f->lineinfo = NULL;
  250   f->sizelineinfo = 0;
  251   f->abslineinfo = NULL;
  252   f->sizeabslineinfo = 0;
  253   f->upvalues = NULL;
  254   f->sizeupvalues = 0;
  255   f->numparams = 0;
  256   f->is_vararg = 0;
  257   f->maxstacksize = 0;
  258   f->locvars = NULL;
  259   f->sizelocvars = 0;
  260   f->linedefined = 0;
  261   f->lastlinedefined = 0;
  262   f->source = NULL;
  263   return f;
  264 }
  265 
  266 
  267 void luaF_freeproto (lua_State *L, Proto *f) {
  268   luaM_freearray(L, f->code, f->sizecode);
  269   luaM_freearray(L, f->p, f->sizep);
  270   luaM_freearray(L, f->k, f->sizek);
  271   luaM_freearray(L, f->lineinfo, f->sizelineinfo);
  272   luaM_freearray(L, f->abslineinfo, f->sizeabslineinfo);
  273   luaM_freearray(L, f->locvars, f->sizelocvars);
  274   luaM_freearray(L, f->upvalues, f->sizeupvalues);
  275   luaM_free(L, f);
  276 }
  277 
  278 
  279 /*
  280 ** Look for n-th local variable at line 'line' in function 'func'.
  281 ** Returns NULL if not found.
  282 */
  283 const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
  284   int i;
  285   for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
  286     if (pc < f->locvars[i].endpc) {  /* is variable active? */
  287       local_number--;
  288       if (local_number == 0)
  289         return getstr(f->locvars[i].varname);
  290     }
  291   }
  292   return NULL;  /* not found */
  293 }
  294