Table library now respects '__index'/'__newindex' metamethods

This commit is contained in:
Roberto Ierusalimschy 2014-07-16 09:44:52 -03:00
parent 5bbb4a06a6
commit a9af12bbe7

139
ltablib.c
View File

@ -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]<a[l]? */
set2(L, i, l);
set2(L, ta, i, l);
else {
lua_pop(L, 1); /* remove a[l] */
lua_rawgeti(L, 1, u);
(*ta->geti)(L, 1, u);
if (sort_comp(L, -1, -2)) /* a[u]<a[i]? */
set2(L, i, u);
set2(L, ta, i, u);
else
lua_pop(L, 2);
}
if (u-l == 2) break; /* only 3 elements */
lua_rawgeti(L, 1, i); /* Pivot */
(*ta->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;
}