'tablib' does not try to use raw operations when possible: fast

track should make standard operations fast enough to forgo
raw accesses
This commit is contained in:
Roberto Ierusalimschy 2015-09-09 12:42:30 -03:00
parent 364cdbdbdb
commit bda83e22c0

167
ltablib.c
View File

@ -1,5 +1,5 @@
/*
** $Id: ltablib.c,v 1.80 2015/01/13 16:27:29 roberto Exp roberto $
** $Id: ltablib.c,v 1.81 2015/07/04 16:31:42 roberto Exp roberto $
** Library for Table Manipulation
** See Copyright Notice in lua.h
*/
@ -19,40 +19,42 @@
#include "lualib.h"
/*
** Structure with table-access functions
** Operations that an object must define to mimic a table
** (some functions only need some of them)
*/
typedef struct {
int (*geti) (lua_State *L, int idx, lua_Integer n);
void (*seti) (lua_State *L, int idx, lua_Integer n);
} TabA;
#define TAB_R 1
#define TAB_W 2
#define TAB_L 4
#define TAB_RW (TAB_R | TAB_W)
/*
** 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) {
ta->geti = NULL; ta->seti = NULL;
if (lua_getmetatable(L, arg)) {
lua_pushliteral(L, "__index"); /* 'index' metamethod */
if (lua_rawget(L, -2) != LUA_TNIL)
ta->geti = lua_geti;
lua_pushliteral(L, "__newindex"); /* 'newindex' metamethod */
if (lua_rawget(L, -3) != LUA_TNIL)
ta->seti = lua_seti;
lua_pop(L, 3); /* pop metatable plus both metamethods */
}
if (ta->geti == NULL || ta->seti == NULL) {
luaL_checktype(L, arg, LUA_TTABLE); /* must be table for raw methods */
if (ta->geti == NULL) ta->geti = lua_rawgeti;
if (ta->seti == NULL) ta->seti = lua_rawseti;
}
#define aux_getn(L,n,w) (checktab(L, n, (w) | TAB_L), luaL_len(L, n))
static int checkfield (lua_State *L, const char *key, int n) {
lua_pushstring(L, key);
return (lua_rawget(L, -n) != LUA_TNIL);
}
#define aux_getn(L,n,ta) (checktab(L, n, ta), luaL_len(L, n))
/*
** Check that 'arg' either is a table or can behave like one (that is,
** has a metatable with the required metamethods)
*/
static void checktab (lua_State *L, int arg, int what) {
if (lua_type(L, arg) != LUA_TTABLE) { /* is it not a table? */
int n = 1; /* number of elements to pop */
if (lua_getmetatable(L, arg) && /* must have metatable */
(!(what & TAB_R) || checkfield(L, "__index", ++n)) &&
(!(what & TAB_W) || checkfield(L, "__newindex", ++n)) &&
(!(what & TAB_L) || checkfield(L, "__len", ++n))) {
lua_pop(L, n); /* pop metatable and tested metamethods */
}
else
luaL_argerror(L, arg, "table expected"); /* force an error */
}
}
#if defined(LUA_COMPAT_MAXN)
@ -74,8 +76,7 @@ static int maxn (lua_State *L) {
static int tinsert (lua_State *L) {
TabA ta;
lua_Integer e = aux_getn(L, 1, &ta) + 1; /* first empty element */
lua_Integer e = aux_getn(L, 1, TAB_RW) + 1; /* first empty element */
lua_Integer pos; /* where to insert new element */
switch (lua_gettop(L)) {
case 2: { /* called with only 2 arguments */
@ -87,8 +88,8 @@ 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 */
(*ta.geti)(L, 1, i - 1);
(*ta.seti)(L, 1, i); /* t[i] = t[i - 1] */
lua_geti(L, 1, i - 1);
lua_seti(L, 1, i); /* t[i] = t[i - 1] */
}
break;
}
@ -96,42 +97,36 @@ static int tinsert (lua_State *L) {
return luaL_error(L, "wrong number of arguments to 'insert'");
}
}
(*ta.seti)(L, 1, pos); /* t[pos] = v */
lua_seti(L, 1, pos); /* t[pos] = v */
return 0;
}
static int tremove (lua_State *L) {
TabA ta;
lua_Integer size = aux_getn(L, 1, &ta);
lua_Integer size = aux_getn(L, 1, TAB_RW);
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");
(*ta.geti)(L, 1, pos); /* result = t[pos] */
lua_geti(L, 1, pos); /* result = t[pos] */
for ( ; pos < size; pos++) {
(*ta.geti)(L, 1, pos + 1);
(*ta.seti)(L, 1, pos); /* t[pos] = t[pos + 1] */
lua_geti(L, 1, pos + 1);
lua_seti(L, 1, pos); /* t[pos] = t[pos + 1] */
}
lua_pushnil(L);
(*ta.seti)(L, 1, pos); /* t[pos] = nil */
lua_seti(L, 1, pos); /* t[pos] = nil */
return 1;
}
static int tmove (lua_State *L) {
TabA ta;
lua_Integer f = luaL_checkinteger(L, 2);
lua_Integer e = luaL_checkinteger(L, 3);
lua_Integer t = luaL_checkinteger(L, 4);
int tt = !lua_isnoneornil(L, 5) ? 5 : 1; /* destination table */
checktab(L, 1, TAB_R);
checktab(L, tt, TAB_W);
if (e >= f) { /* otherwise, nothing to move */
lua_Integer n, i;
ta.geti = (luaL_getmetafield(L, 1, "__index") == LUA_TNIL)
? (luaL_checktype(L, 1, LUA_TTABLE), lua_rawgeti)
: lua_geti;
ta.seti = (luaL_getmetafield(L, tt, "__newindex") == LUA_TNIL)
? (luaL_checktype(L, tt, LUA_TTABLE), lua_rawseti)
: lua_seti;
luaL_argcheck(L, f > 0 || e < LUA_MAXINTEGER + f, 3,
"too many elements to move");
n = e - f + 1; /* number of elements to move */
@ -139,14 +134,14 @@ static int tmove (lua_State *L) {
"destination wrap around");
if (t > f) {
for (i = n - 1; i >= 0; i--) {
(*ta.geti)(L, 1, f + i);
(*ta.seti)(L, tt, t + i);
lua_geti(L, 1, f + i);
lua_seti(L, tt, t + i);
}
}
else {
for (i = 0; i < n; i++) {
(*ta.geti)(L, 1, f + i);
(*ta.seti)(L, tt, t + i);
lua_geti(L, 1, f + i);
lua_seti(L, tt, t + i);
}
}
}
@ -155,8 +150,8 @@ static int tmove (lua_State *L) {
}
static void addfield (lua_State *L, luaL_Buffer *b, TabA *ta, lua_Integer i) {
(*ta->geti)(L, 1, i);
static void addfield (lua_State *L, luaL_Buffer *b, lua_Integer i) {
lua_geti(L, 1, i);
if (!lua_isstring(L, -1))
luaL_error(L, "invalid value (%s) at index %d in table for 'concat'",
luaL_typename(L, -1), i);
@ -165,21 +160,20 @@ static void addfield (lua_State *L, luaL_Buffer *b, TabA *ta, lua_Integer i) {
static int tconcat (lua_State *L) {
TabA ta;
luaL_Buffer b;
size_t lsep;
lua_Integer i, last;
lua_Integer i;
lua_Integer last = aux_getn(L, 1, TAB_R);
const char *sep = luaL_optlstring(L, 2, "", &lsep);
checktab(L, 1, &ta);
i = luaL_optinteger(L, 3, 1);
last = luaL_opt(L, luaL_checkinteger, 4, luaL_len(L, 1));
last = luaL_opt(L, luaL_checkinteger, 4, last);
luaL_buffinit(L, &b);
for (; i < last; i++) {
addfield(L, &b, &ta, i);
addfield(L, &b, i);
luaL_addlstring(&b, sep, lsep);
}
if (i == last) /* add last value (if interval was not empty) */
addfield(L, &b, &ta, i);
addfield(L, &b, i);
luaL_pushresult(&b);
return 1;
}
@ -197,7 +191,7 @@ static int pack (lua_State *L) {
lua_createtable(L, n, 1); /* create result table */
lua_insert(L, 1); /* put it at index 1 */
for (i = n; i >= 1; i--) /* assign elements */
lua_rawseti(L, 1, i);
lua_seti(L, 1, i);
lua_pushinteger(L, n);
lua_setfield(L, 1, "n"); /* t.n = number of elements */
return 1; /* return table */
@ -205,10 +199,8 @@ static int pack (lua_State *L) {
static int unpack (lua_State *L) {
TabA ta;
lua_Integer i, e;
lua_Unsigned n;
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 */
@ -216,9 +208,9 @@ static int unpack (lua_State *L) {
if (n >= (unsigned int)INT_MAX || !lua_checkstack(L, (int)(++n)))
return luaL_error(L, "too many results to unpack");
for (; i < e; i++) { /* push arg[i..e - 1] (to avoid overflows) */
(*ta.geti)(L, 1, i);
lua_geti(L, 1, i);
}
(*ta.geti)(L, 1, e); /* push last element */
lua_geti(L, 1, e); /* push last element */
return (int)n;
}
@ -235,9 +227,9 @@ static int unpack (lua_State *L) {
*/
static void set2 (lua_State *L, TabA *ta, int i, int j) {
(*ta->seti)(L, 1, i);
(*ta->seti)(L, 1, j);
static void set2 (lua_State *L, int i, int j) {
lua_seti(L, 1, i);
lua_seti(L, 1, j);
}
static int sort_comp (lua_State *L, int a, int b) {
@ -255,45 +247,45 @@ 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, TabA *ta, int l, int u) {
static void auxsort (lua_State *L, int l, int u) {
while (l < u) { /* for tail recursion */
int i, j;
/* sort elements a[l], a[(l+u)/2] and a[u] */
(*ta->geti)(L, 1, l);
(*ta->geti)(L, 1, u);
lua_geti(L, 1, l);
lua_geti(L, 1, u);
if (sort_comp(L, -1, -2)) /* a[u] < a[l]? */
set2(L, ta, l, u); /* swap a[l] - a[u] */
set2(L, l, u); /* swap a[l] - a[u] */
else
lua_pop(L, 2);
if (u-l == 1) break; /* only 2 elements */
i = (l+u)/2;
(*ta->geti)(L, 1, i);
(*ta->geti)(L, 1, l);
lua_geti(L, 1, i);
lua_geti(L, 1, l);
if (sort_comp(L, -2, -1)) /* a[i]<a[l]? */
set2(L, ta, i, l);
set2(L, i, l);
else {
lua_pop(L, 1); /* remove a[l] */
(*ta->geti)(L, 1, u);
lua_geti(L, 1, u);
if (sort_comp(L, -1, -2)) /* a[u]<a[i]? */
set2(L, ta, i, u);
set2(L, i, u);
else
lua_pop(L, 2);
}
if (u-l == 2) break; /* only 3 elements */
(*ta->geti)(L, 1, i); /* Pivot */
lua_geti(L, 1, i); /* Pivot */
lua_pushvalue(L, -1);
(*ta->geti)(L, 1, u-1);
set2(L, ta, i, u-1);
lua_geti(L, 1, u-1);
set2(L, 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 ((*ta->geti)(L, 1, ++i), sort_comp(L, -1, -2)) {
while (lua_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 ((*ta->geti)(L, 1, --j), sort_comp(L, -3, -1)) {
while (lua_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] */
}
@ -301,11 +293,11 @@ static void auxsort (lua_State *L, TabA *ta, int l, int u) {
lua_pop(L, 3); /* pop pivot, a[i], a[j] */
break;
}
set2(L, ta, i, j);
set2(L, i, j);
}
(*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] */
lua_geti(L, 1, u-1);
lua_geti(L, 1, i);
set2(L, 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) {
@ -314,18 +306,17 @@ static void auxsort (lua_State *L, TabA *ta, int l, int u) {
else {
j=i+1; i=u; u=j-2;
}
auxsort(L, ta, j, i); /* call recursively the smaller one */
auxsort(L, j, i); /* call recursively the smaller one */
} /* repeat the routine for the larger one */
}
static int sort (lua_State *L) {
TabA ta;
int n = (int)aux_getn(L, 1, &ta);
int n = (int)aux_getn(L, 1, TAB_RW);
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 are two arguments */
auxsort(L, &ta, 1, n);
auxsort(L, 1, n);
return 0;
}