From a9af12bbe765dd2c60fa3d9d43013042fd3361a8 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Wed, 16 Jul 2014 09:44:52 -0300 Subject: Table library now respects '__index'/'__newindex' metamethods --- ltablib.c | 139 +++++++++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 96 insertions(+), 43 deletions(-) (limited to 'ltablib.c') diff --git a/ltablib.c b/ltablib.c index e61f3323..dca2bc8e 100644 --- a/ltablib.c +++ b/ltablib.c @@ -1,5 +1,5 @@ /* -** $Id: ltablib.c,v 1.69 2014/04/12 14:43:50 roberto Exp roberto $ +** $Id: ltablib.c,v 1.70 2014/05/16 18:53:25 roberto Exp roberto $ ** Library for Table Manipulation ** See Copyright Notice in lua.h */ @@ -17,8 +17,56 @@ #include "lualib.h" -#define aux_getn(L,n) (luaL_checktype(L, n, LUA_TTABLE), luaL_len(L, n)) +/* +** Structure with table-access functions +*/ +typedef struct { + int (*geti) (lua_State *L, int idx, lua_Integer n); + void (*seti) (lua_State *L, int idx, lua_Integer n); +} TabA; + + +/* +** equivalent to 'lua_rawgeti', but not raw +*/ +static int geti (lua_State *L, int idx, lua_Integer n) { + lua_pushinteger(L, n); + return lua_gettable(L, idx); /* assume 'idx' is not negative */ +} + + +/* +** equivalent to 'lua_rawseti', but not raw +*/ +static void seti (lua_State *L, int idx, lua_Integer n) { + lua_pushinteger(L, n); + lua_rotate(L, -2, 1); /* exchange key and value */ + lua_settable(L, idx); /* assume 'idx' is not negative */ +} + + +/* +** Check that 'arg' has a table and set access functions in 'ta' to raw +** or non-raw according to the presence of corresponding metamethods. +*/ +static void checktab (lua_State *L, int arg, TabA *ta) { + luaL_checktype(L, arg, LUA_TTABLE); + if (!lua_getmetatable(L, arg)) { /* fast track */ + ta->geti = lua_rawgeti; /* with no metatable, all is raw */ + ta->seti = lua_rawseti; + } + else { + lua_pushliteral(L, "__index"); /* 'index' metamethod */ + ta->geti = (lua_rawget(L, -2) == LUA_TNIL) ? lua_rawgeti : geti; + lua_pushliteral(L, "__newindex"); /* 'newindex' metamethod */ + ta->seti = (lua_rawget(L, -3) == LUA_TNIL) ? lua_rawseti : seti; + lua_pop(L, 3); /* pop metatable plus both metamethods */ + } +} + + +#define aux_getn(L,n,ta) (checktab(L, n, ta), luaL_len(L, n)) #if defined(LUA_COMPAT_MAXN) @@ -40,7 +88,8 @@ static int maxn (lua_State *L) { static int tinsert (lua_State *L) { - lua_Integer e = aux_getn(L, 1) + 1; /* first empty element */ + TabA ta; + lua_Integer e = aux_getn(L, 1, &ta) + 1; /* first empty element */ lua_Integer pos; /* where to insert new element */ switch (lua_gettop(L)) { case 2: { /* called with only 2 arguments */ @@ -52,8 +101,8 @@ static int tinsert (lua_State *L) { pos = luaL_checkinteger(L, 2); /* 2nd argument is the position */ luaL_argcheck(L, 1 <= pos && pos <= e, 2, "position out of bounds"); for (i = e; i > pos; i--) { /* move up elements */ - lua_rawgeti(L, 1, i-1); - lua_rawseti(L, 1, i); /* t[i] = t[i-1] */ + (*ta.geti)(L, 1, i - 1); + (*ta.seti)(L, 1, i); /* t[i] = t[i - 1] */ } break; } @@ -61,29 +110,30 @@ static int tinsert (lua_State *L) { return luaL_error(L, "wrong number of arguments to " LUA_QL("insert")); } } - lua_rawseti(L, 1, pos); /* t[pos] = v */ + (*ta.seti)(L, 1, pos); /* t[pos] = v */ return 0; } static int tremove (lua_State *L) { - lua_Integer size = aux_getn(L, 1); + TabA ta; + lua_Integer size = aux_getn(L, 1, &ta); lua_Integer pos = luaL_optinteger(L, 2, size); if (pos != size) /* validate 'pos' if given */ luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds"); - lua_rawgeti(L, 1, pos); /* result = t[pos] */ + (*ta.geti)(L, 1, pos); /* result = t[pos] */ for ( ; pos < size; pos++) { - lua_rawgeti(L, 1, pos+1); - lua_rawseti(L, 1, pos); /* t[pos] = t[pos+1] */ + (*ta.geti)(L, 1, pos + 1); + (*ta.seti)(L, 1, pos); /* t[pos] = t[pos + 1] */ } lua_pushnil(L); - lua_rawseti(L, 1, pos); /* t[pos] = nil */ + (*ta.seti)(L, 1, pos); /* t[pos] = nil */ return 1; } -static void addfield (lua_State *L, luaL_Buffer *b, lua_Integer i) { - lua_rawgeti(L, 1, i); +static void addfield (lua_State *L, luaL_Buffer *b, TabA *ta, lua_Integer i) { + (*ta->geti)(L, 1, i); if (!lua_isstring(L, -1)) luaL_error(L, "invalid value (%s) at index %d in table for " LUA_QL("concat"), luaL_typename(L, -1), i); @@ -92,20 +142,21 @@ static void addfield (lua_State *L, luaL_Buffer *b, lua_Integer i) { static int tconcat (lua_State *L) { + TabA ta; luaL_Buffer b; size_t lsep; lua_Integer i, last; const char *sep = luaL_optlstring(L, 2, "", &lsep); - luaL_checktype(L, 1, LUA_TTABLE); + checktab(L, 1, &ta); i = luaL_optinteger(L, 3, 1); last = luaL_opt(L, luaL_checkinteger, 4, luaL_len(L, 1)); luaL_buffinit(L, &b); for (; i < last; i++) { - addfield(L, &b, i); + addfield(L, &b, &ta, i); luaL_addlstring(&b, sep, lsep); } if (i == last) /* add last value (if interval was not empty) */ - addfield(L, &b, i); + addfield(L, &b, &ta, i); luaL_pushresult(&b); return 1; } @@ -131,9 +182,10 @@ static int pack (lua_State *L) { static int unpack (lua_State *L) { + TabA ta; lua_Integer i, e; lua_Unsigned n; - luaL_checktype(L, 1, LUA_TTABLE); + checktab(L, 1, &ta); i = luaL_optinteger(L, 2, 1); e = luaL_opt(L, luaL_checkinteger, 3, luaL_len(L, 1)); if (i > e) return 0; /* empty range */ @@ -141,7 +193,7 @@ static int unpack (lua_State *L) { if (n >= (unsigned int)INT_MAX || !lua_checkstack(L, ++n)) return luaL_error(L, "too many results to unpack"); do { /* must have at least one element */ - lua_rawgeti(L, 1, i); /* push arg[i..e] */ + (*ta.geti)(L, 1, i); /* push arg[i..e] */ } while (i++ < e); return n; @@ -160,9 +212,9 @@ static int unpack (lua_State *L) { */ -static void set2 (lua_State *L, int i, int j) { - lua_rawseti(L, 1, i); - lua_rawseti(L, 1, j); +static void set2 (lua_State *L, TabA *ta, int i, int j) { + (*ta->seti)(L, 1, i); + (*ta->seti)(L, 1, j); } static int sort_comp (lua_State *L, int a, int b) { @@ -180,45 +232,45 @@ static int sort_comp (lua_State *L, int a, int b) { return lua_compare(L, a, b, LUA_OPLT); } -static void auxsort (lua_State *L, int l, int u) { +static void auxsort (lua_State *L, TabA *ta, int l, int u) { while (l < u) { /* for tail recursion */ int i, j; /* sort elements a[l], a[(l+u)/2] and a[u] */ - lua_rawgeti(L, 1, l); - lua_rawgeti(L, 1, u); + (*ta->geti)(L, 1, l); + (*ta->geti)(L, 1, u); if (sort_comp(L, -1, -2)) /* a[u] < a[l]? */ - set2(L, l, u); /* swap a[l] - a[u] */ + set2(L, ta, l, u); /* swap a[l] - a[u] */ else lua_pop(L, 2); if (u-l == 1) break; /* only 2 elements */ i = (l+u)/2; - lua_rawgeti(L, 1, i); - lua_rawgeti(L, 1, l); + (*ta->geti)(L, 1, i); + (*ta->geti)(L, 1, l); if (sort_comp(L, -2, -1)) /* a[i]geti)(L, 1, u); if (sort_comp(L, -1, -2)) /* a[u]geti)(L, 1, i); /* Pivot */ lua_pushvalue(L, -1); - lua_rawgeti(L, 1, u-1); - set2(L, i, u-1); + (*ta->geti)(L, 1, u-1); + set2(L, ta, i, u-1); /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */ i = l; j = u-1; for (;;) { /* invariant: a[l..i] <= P <= a[j..u] */ /* repeat ++i until a[i] >= P */ - while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) { + while ((*ta->geti)(L, 1, ++i), sort_comp(L, -1, -2)) { if (i>=u) luaL_error(L, "invalid order function for sorting"); lua_pop(L, 1); /* remove a[i] */ } /* repeat --j until a[j] <= P */ - while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) { + while ((*ta->geti)(L, 1, --j), sort_comp(L, -3, -1)) { if (j<=l) luaL_error(L, "invalid order function for sorting"); lua_pop(L, 1); /* remove a[j] */ } @@ -226,11 +278,11 @@ static void auxsort (lua_State *L, int l, int u) { lua_pop(L, 3); /* pop pivot, a[i], a[j] */ break; } - set2(L, i, j); + set2(L, ta, i, j); } - lua_rawgeti(L, 1, u-1); - lua_rawgeti(L, 1, i); - set2(L, u-1, i); /* swap pivot (a[u-1]) with a[i] */ + (*ta->geti)(L, 1, u-1); + (*ta->geti)(L, 1, i); + set2(L, ta, u-1, i); /* swap pivot (a[u-1]) with a[i] */ /* a[l..i-1] <= a[i] == P <= a[i+1..u] */ /* adjust so that smaller half is in [j..i] and larger one in [l..u] */ if (i-l < u-i) { @@ -239,17 +291,18 @@ static void auxsort (lua_State *L, int l, int u) { else { j=i+1; i=u; u=j-2; } - auxsort(L, j, i); /* call recursively the smaller one */ + auxsort(L, ta, j, i); /* call recursively the smaller one */ } /* repeat the routine for the larger one */ } static int sort (lua_State *L) { - int n = aux_getn(L, 1); - luaL_checkstack(L, 40, ""); /* assume array is smaller than 2^40 */ + TabA ta; + int n = aux_getn(L, 1, &ta); + luaL_checkstack(L, 50, ""); /* assume array is smaller than 2^50 */ if (!lua_isnoneornil(L, 2)) /* is there a 2nd argument? */ luaL_checktype(L, 2, LUA_TFUNCTION); lua_settop(L, 2); /* make sure there is two arguments */ - auxsort(L, 1, n); + auxsort(L, &ta, 1, n); return 0; } -- cgit v1.2.3-55-g6feb