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use a table to find (and reuse) constants when parsing

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Roberto Ierusalimschy
2001-08-27 12:16:28 -03:00
parent 7afc74ff07
commit c3d72096c4
6 changed files with 32 additions and 38 deletions
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44
lcode.c
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@@ -1,5 +1,5 @@
/*
** $Id: lcode.c,v 1.77 2001/07/17 14:30:44 roberto Exp roberto $
** $Id: lcode.c,v 1.78 2001/07/24 17:19:07 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -18,6 +18,7 @@
#include "lobject.h"
#include "lopcodes.h"
#include "lparser.h"
#include "ltable.h"
#define hasjumps(e) ((e)->t != (e)->f)
@@ -222,38 +223,33 @@ static void freeexp (FuncState *fs, expdesc *e) {
static int addk (FuncState *fs, TObject *k) {
Proto *f = fs->f;
luaM_growvector(fs->L, f->k, fs->nk, f->sizek, TObject,
MAXARG_Bc, l_s("constant table overflow"));
setobj(&f->k[fs->nk], k);
return fs->nk++;
const TObject *index = luaH_get(fs->h, k);
if (ttype(index) == LUA_TNUMBER) {
lua_assert(luaO_equalObj(&fs->f->k[(int)nvalue(index)], k));
return (int)nvalue(index);
}
else { /* constant not found; create a new entry */
TObject o;
Proto *f = fs->f;
luaM_growvector(fs->L, f->k, fs->nk, f->sizek, TObject,
MAXARG_Bc, l_s("constant table overflow"));
setobj(&f->k[fs->nk], k);
setnvalue(&o, fs->nk);
setobj(luaH_set(fs->L, fs->h, k), &o);
return fs->nk++;
}
}
int luaK_stringk (FuncState *fs, TString *s) {
Proto *f = fs->f;
int c = s->tsv.constindex;
if (c >= fs->nk || ttype(&f->k[c]) != LUA_TSTRING || tsvalue(&f->k[c]) != s) {
TObject o;
setsvalue(&o, s);
c = addk(fs, &o);
s->tsv.constindex = (unsigned short)c; /* hint for next time */
}
return c;
TObject o;
setsvalue(&o, s);
return addk(fs, &o);
}
static int number_constant (FuncState *fs, lua_Number r) {
/* check whether `r' has appeared within the last LOOKBACKNUMS entries */
TObject o;
Proto *f = fs->f;
int c = fs->nk;
int lim = c < LOOKBACKNUMS ? 0 : c-LOOKBACKNUMS;
while (--c >= lim) {
if (ttype(&f->k[c]) == LUA_TNUMBER && nvalue(&f->k[c]) == r)
return c;
}
/* not found; create a new entry */
setnvalue(&o, r);
return addk(fs, &o);
}