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Encoding of table indices (hres) must use C indices

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As the encoding of array indices is (~index), 0 is encoded as -1 and
INT_MAX is encoded as INT_MIN.
This commit is contained in:
Roberto Ierusalimschy
2024-06-10 12:09:35 -03:00
parent bdc85357aa
commit 94b503d95e
4 changed files with 30 additions and 24 deletions
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36
ltable.h
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@@ -47,20 +47,20 @@
#define luaH_fastgeti(t,k,res,tag) \
{ Table *h = t; lua_Unsigned u = l_castS2U(k); \
if ((u - 1u < h->alimit)) { \
tag = *getArrTag(h,(u)-1u); \
{ Table *h = t; lua_Unsigned u = l_castS2U(k) - 1u; \
if ((u < h->alimit)) { \
tag = *getArrTag(h, u); \
if (!tagisempty(tag)) { farr2val(h, u, tag, res); }} \
else { tag = luaH_getint(h, u, res); }}
else { tag = luaH_getint(h, (k), res); }}
#define luaH_fastseti(t,k,val,hres) \
{ Table *h = t; lua_Unsigned u = l_castS2U(k); \
if ((u - 1u < h->alimit)) { \
lu_byte *tag = getArrTag(h,(u)-1u); \
{ Table *h = t; lua_Unsigned u = l_castS2U(k) - 1u; \
if ((u < h->alimit)) { \
lu_byte *tag = getArrTag(h, u); \
if (tagisempty(*tag)) hres = ~cast_int(u); \
else { fval2arr(h, u, tag, val); hres = HOK; }} \
else { hres = luaH_psetint(h, u, val); }}
else { hres = luaH_psetint(h, k, val); }}
/* results from pset */
@@ -82,6 +82,12 @@
** in the array part, the encoding is (~array index), a negative value.
** The value HNOTATABLE is used by the fast macros to signal that the
** value being indexed is not a table.
** (The size for the array part is limited by the maximum power of two
** that fits in an unsigned integer; that is INT_MAX+1. So, the C-index
** ranges from 0, which encodes to -1, to INT_MAX, which encodes to
** INT_MIN. The size of the hash part is limited by the maximum power of
** two that fits in a signed integer; that is (INT_MAX+1)/2. So, it is
** safe to add HFIRSTNODE to any index there.)
*/
@@ -102,21 +108,21 @@
** and 'getArrVal'.
*/
/* Computes the address of the tag for the abstract index 'k' */
/* Computes the address of the tag for the abstract C-index 'k' */
#define getArrTag(t,k) (cast(lu_byte*, (t)->array) + (k))
/* Computes the address of the value for the abstract index 'k' */
/* Computes the address of the value for the abstract C-index 'k' */
#define getArrVal(t,k) ((t)->array - 1 - (k))
/*
** Move TValues to/from arrays, using Lua indices
** Move TValues to/from arrays, using C indices
*/
#define arr2obj(h,k,val) \
((val)->tt_ = *getArrTag(h,(k)-1u), (val)->value_ = *getArrVal(h,(k)-1u))
((val)->tt_ = *getArrTag(h,(k)), (val)->value_ = *getArrVal(h,(k)))
#define obj2arr(h,k,val) \
(*getArrTag(h,(k)-1u) = (val)->tt_, *getArrVal(h,(k)-1u) = (val)->value_)
(*getArrTag(h,(k)) = (val)->tt_, *getArrVal(h,(k)) = (val)->value_)
/*
@@ -125,10 +131,10 @@
** precomputed tag value or address as an extra argument.
*/
#define farr2val(h,k,tag,res) \
((res)->tt_ = tag, (res)->value_ = *getArrVal(h,(k)-1u))
((res)->tt_ = tag, (res)->value_ = *getArrVal(h,(k)))
#define fval2arr(h,k,tag,val) \
(*tag = (val)->tt_, *getArrVal(h,(k)-1u) = (val)->value_)
(*tag = (val)->tt_, *getArrVal(h,(k)) = (val)->value_)
LUAI_FUNC int luaH_get (Table *t, const TValue *key, TValue *res);