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make 'hashfloat' configurable

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This commit is contained in:
Roberto Ierusalimschy 2015-02-20 12:05:01 -02:00
parent 97f2aa5a44
commit 397ce11996
1 changed files with 8 additions and 8 deletions
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16
ltable.c
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@ -1,5 +1,5 @@
/*
** $Id: ltable.c,v 2.102 2015/02/13 13:05:34 roberto Exp roberto $
** $Id: ltable.c,v 2.103 2015/02/16 13:15:00 roberto Exp roberto $
** Lua tables (hash)
** See Copyright Notice in lua.h
*/
@ -97,7 +97,7 @@ static int numisinteger (lua_Number x, lua_Integer *p) {
/*
** Hash for floating-point numbers.
** The main computation should be just
** n = frepx(n, &i); hash = (n * INT_MAX) + i
** n = frepx(n, &i); return (n * INT_MAX) + i
** but there are some numerical subtleties.
** In a two-complement representation, INT_MAX does not has an exact
** representation as a float, but INT_MIN does; because the absolute
@ -107,21 +107,21 @@ static int numisinteger (lua_Number x, lua_Integer *p) {
** adding 'i'; the use of '~u' (instead of '-u') avoids problems with
** INT_MIN.
*/
static Node *hashfloat (const Table *t, lua_Number n) {
#if !defined(l_hashfloat)
static int l_hashfloat (lua_Number n) {
int i;
lua_Integer ni;
n = l_mathop(frexp)(n, &i) * -cast_num(INT_MIN);
if (!lua_numbertointeger(n, &ni)) { /* is 'n' inf/-inf/NaN? */
lua_assert(luai_numisnan(n) || l_mathop(fabs)(n) == HUGE_VAL);
i = 0;
return 0;
}
else { /* normal case */
unsigned int u = cast(unsigned int, i) + cast(unsigned int, ni);
i = (u <= cast(unsigned int, INT_MAX) ? u : ~u);
return cast_int(u <= cast(unsigned int, INT_MAX) ? u : ~u);
}
return hashmod(t, i);
}
#endif
/*
@ -133,7 +133,7 @@ static Node *mainposition (const Table *t, const TValue *key) {
case LUA_TNUMINT:
return hashint(t, ivalue(key));
case LUA_TNUMFLT:
return hashfloat(t, fltvalue(key));
return hashmod(t, l_hashfloat(fltvalue(key)));
case LUA_TSHRSTR:
return hashstr(t, tsvalue(key));
case LUA_TLNGSTR: {