mirror of
https://github.com/lua/lua.git
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233 lines
5.8 KiB
C
233 lines
5.8 KiB
C
/*
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** $Id: ltablib.c,v 1.7 2002/06/18 15:16:18 roberto Exp roberto $
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** Library for Table Manipulation
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** See Copyright Notice in lua.h
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*/
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#include <stddef.h>
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#include "lua.h"
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#include "lauxlib.h"
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#include "luadebug.h"
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#include "lualib.h"
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static int luaB_foreachi (lua_State *L) {
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int n, i;
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luaL_check_type(L, 1, LUA_TTABLE);
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luaL_check_type(L, 2, LUA_TFUNCTION);
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n = lua_getn(L, 1);
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for (i=1; i<=n; i++) {
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lua_pushvalue(L, 2); /* function */
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lua_pushnumber(L, i); /* 1st argument */
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lua_rawgeti(L, 1, i); /* 2nd argument */
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lua_call(L, 2, 1);
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if (!lua_isnil(L, -1))
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return 1;
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lua_pop(L, 1); /* remove nil result */
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}
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return 0;
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}
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static int luaB_foreach (lua_State *L) {
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luaL_check_type(L, 1, LUA_TTABLE);
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luaL_check_type(L, 2, LUA_TFUNCTION);
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lua_pushnil(L); /* first key */
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for (;;) {
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if (lua_next(L, 1) == 0)
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return 0;
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lua_pushvalue(L, 2); /* function */
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lua_pushvalue(L, -3); /* key */
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lua_pushvalue(L, -3); /* value */
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lua_call(L, 2, 1);
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if (!lua_isnil(L, -1))
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return 1;
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lua_pop(L, 2); /* remove value and result */
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}
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}
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static void aux_setn (lua_State *L, int t, int n) {
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lua_pushliteral(L, "n");
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lua_pushnumber(L, n);
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lua_rawset(L, t);
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}
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static int luaB_getn (lua_State *L) {
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luaL_check_type(L, 1, LUA_TTABLE);
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lua_pushnumber(L, lua_getn(L, 1));
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return 1;
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}
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static int luaB_tinsert (lua_State *L) {
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int v = lua_gettop(L); /* number of arguments */
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int n, pos;
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luaL_check_type(L, 1, LUA_TTABLE);
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n = lua_getn(L, 1);
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if (v == 2) /* called with only 2 arguments */
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pos = n+1;
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else {
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v = 3; /* function may be called with more than 3 args */
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pos = luaL_check_int(L, 2); /* 2nd argument is the position */
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}
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if (pos > n+1) n = pos-1;
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aux_setn(L, 1, n+1); /* t.n = n+1 */
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for (; n>=pos; n--) {
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lua_rawgeti(L, 1, n);
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lua_rawseti(L, 1, n+1); /* t[n+1] = t[n] */
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}
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lua_pushvalue(L, v);
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lua_rawseti(L, 1, pos); /* t[pos] = v */
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return 0;
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}
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static int luaB_tremove (lua_State *L) {
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int pos, n;
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luaL_check_type(L, 1, LUA_TTABLE);
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n = lua_getn(L, 1);
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pos = luaL_opt_int(L, 2, n);
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if (n <= 0) return 0; /* table is `empty' */
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aux_setn(L, 1, n-1); /* t.n = n-1 */
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lua_rawgeti(L, 1, pos); /* result = t[pos] */
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for ( ;pos<n; pos++) {
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lua_rawgeti(L, 1, pos+1);
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lua_rawseti(L, 1, pos); /* a[pos] = a[pos+1] */
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}
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lua_pushnil(L);
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lua_rawseti(L, 1, n); /* t[n] = nil */
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return 1;
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}
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/*
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** {======================================================
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** Quicksort
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** (based on `Algorithms in MODULA-3', Robert Sedgewick;
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** Addison-Wesley, 1993.)
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*/
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static void set2 (lua_State *L, int i, int j) {
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lua_rawseti(L, 1, i);
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lua_rawseti(L, 1, j);
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}
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static int sort_comp (lua_State *L, int a, int b) {
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/* WARNING: the caller (auxsort) must ensure stack space */
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if (!lua_isnoneornil(L, 2)) { /* function? */
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int res;
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lua_pushvalue(L, 2);
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lua_pushvalue(L, a-1); /* -1 to compensate function */
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lua_pushvalue(L, b-2); /* -2 to compensate function and `a' */
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lua_call(L, 2, 1);
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res = lua_toboolean(L, -1);
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lua_pop(L, 1);
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return res;
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}
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else /* a < b? */
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return lua_lessthan(L, a, b);
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}
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static void auxsort (lua_State *L, int l, int u) {
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while (l < u) { /* for tail recursion */
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int i, j;
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/* sort elements a[l], a[(l+u)/2] and a[u] */
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lua_rawgeti(L, 1, l);
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lua_rawgeti(L, 1, u);
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if (sort_comp(L, -1, -2)) /* a[u] < a[l]? */
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set2(L, l, u); /* swap a[l] - a[u] */
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else
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lua_pop(L, 2);
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if (u-l == 1) break; /* only 2 elements */
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i = (l+u)/2;
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lua_rawgeti(L, 1, i);
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lua_rawgeti(L, 1, l);
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if (sort_comp(L, -2, -1)) /* a[i]<a[l]? */
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set2(L, i, l);
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else {
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lua_pop(L, 1); /* remove a[l] */
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lua_rawgeti(L, 1, u);
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if (sort_comp(L, -1, -2)) /* a[u]<a[i]? */
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set2(L, i, u);
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else
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lua_pop(L, 2);
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}
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if (u-l == 2) break; /* only 3 elements */
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lua_rawgeti(L, 1, i); /* Pivot */
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lua_pushvalue(L, -1);
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lua_rawgeti(L, 1, u-1);
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set2(L, i, u-1);
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/* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
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i = l; j = u-1;
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for (;;) { /* invariant: a[l..i] <= P <= a[j..u] */
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/* repeat ++i until a[i] >= P */
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while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
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if (i>u) luaL_error(L, "invalid order function for sorting");
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lua_pop(L, 1); /* remove a[i] */
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}
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/* repeat --j until a[j] <= P */
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while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
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if (j<l) luaL_error(L, "invalid order function for sorting");
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lua_pop(L, 1); /* remove a[j] */
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}
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if (j<i) {
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lua_pop(L, 3); /* pop pivot, a[i], a[j] */
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break;
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}
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set2(L, i, j);
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}
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lua_rawgeti(L, 1, u-1);
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lua_rawgeti(L, 1, i);
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set2(L, u-1, i); /* swap pivot (a[u-1]) with a[i] */
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/* a[l..i-1] <= a[i] == P <= a[i+1..u] */
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/* adjust so that smaller half is in [j..i] and larger one in [l..u] */
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if (i-l < u-i) {
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j=l; i=i-1; l=i+2;
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}
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else {
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j=i+1; i=u; u=j-2;
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}
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auxsort(L, j, i); /* call recursively the smaller one */
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} /* repeat the routine for the larger one */
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}
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static int luaB_sort (lua_State *L) {
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int n;
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luaL_check_type(L, 1, LUA_TTABLE);
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n = lua_getn(L, 1);
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if (!lua_isnoneornil(L, 2)) /* is there a 2nd argument? */
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luaL_check_type(L, 2, LUA_TFUNCTION);
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lua_settop(L, 2); /* make sure there is two arguments */
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auxsort(L, 1, n);
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return 0;
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}
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/* }====================================================== */
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static const luaL_reg tab_funcs[] = {
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{"foreach", luaB_foreach},
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{"foreachi", luaB_foreachi},
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{"getn", luaB_getn},
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{"sort", luaB_sort},
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{"insert", luaB_tinsert},
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{"remove", luaB_tremove},
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{NULL, NULL}
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};
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LUALIB_API int lua_tablibopen (lua_State *L) {
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luaL_opennamedlib(L, LUA_TABLIBNAME, tab_funcs, 0);
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return 0;
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}
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