/* ** $Id: ltablib.c,v 1.75 2014/08/21 20:07:56 roberto Exp roberto $ ** Library for Table Manipulation ** See Copyright Notice in lua.h */ #include #include #define ltablib_c #define LUA_LIB #include "lua.h" #include "lauxlib.h" #include "lualib.h" /* ** 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; /* ** 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,ta) (checktab(L, n, ta), luaL_len(L, n)) #if defined(LUA_COMPAT_MAXN) static int maxn (lua_State *L) { lua_Number max = 0; luaL_checktype(L, 1, LUA_TTABLE); lua_pushnil(L); /* first key */ while (lua_next(L, 1)) { lua_pop(L, 1); /* remove value */ if (lua_type(L, -1) == LUA_TNUMBER) { lua_Number v = lua_tonumber(L, -1); if (v > max) max = v; } } lua_pushnumber(L, max); return 1; } #endif static int tinsert (lua_State *L) { 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 */ pos = e; /* insert new element at the end */ break; } case 3: { lua_Integer i; 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] */ } break; } default: { return luaL_error(L, "wrong number of arguments to " LUA_QL("insert")); } } (*ta.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 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] */ for ( ; pos < size; pos++) { (*ta.geti)(L, 1, pos + 1); (*ta.seti)(L, 1, pos); /* t[pos] = t[pos + 1] */ } lua_pushnil(L); (*ta.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 */ /* the following restriction avoids several problems with overflows */ luaL_argcheck(L, f > 0, 2, "initial position must be positive"); 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; n = e - f + 1; /* number of elements to move */ if (t > f) { for (i = n - 1; i >= 0; i--) { (*ta.geti)(L, 1, f + i); (*ta.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_pushvalue(L, tt); /* return "to table" */ return 1; } 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); luaL_addvalue(b); } 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); 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, &ta, i); luaL_addlstring(&b, sep, lsep); } if (i == last) /* add last value (if interval was not empty) */ addfield(L, &b, &ta, i); luaL_pushresult(&b); return 1; } /* ** {====================================================== ** Pack/unpack ** ======================================================= */ static int pack (lua_State *L) { int i; int n = lua_gettop(L); /* number of elements to pack */ 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_pushinteger(L, n); lua_setfield(L, 1, "n"); /* t.n = number of elements */ return 1; /* return table */ } 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 */ n = (lua_Unsigned)e - i; /* number of elements minus 1 (avoid overflows) */ if (n >= (unsigned int)INT_MAX || !lua_checkstack(L, (int)(++n))) return luaL_error(L, "too many results to unpack"); do { /* must have at least one element */ (*ta.geti)(L, 1, i); /* push arg[i..e] */ } while (i++ < e); return (int)n; } /* }====================================================== */ /* ** {====================================================== ** Quicksort ** (based on `Algorithms in MODULA-3', Robert Sedgewick; ** Addison-Wesley, 1993.) ** ======================================================= */ 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) { if (!lua_isnil(L, 2)) { /* function? */ int res; lua_pushvalue(L, 2); lua_pushvalue(L, a-1); /* -1 to compensate function */ lua_pushvalue(L, b-2); /* -2 to compensate function and `a' */ lua_call(L, 2, 1); res = lua_toboolean(L, -1); lua_pop(L, 1); return res; } else /* a < b? */ return lua_compare(L, a, b, LUA_OPLT); } 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] */ (*ta->geti)(L, 1, l); (*ta->geti)(L, 1, u); if (sort_comp(L, -1, -2)) /* a[u] < a[l]? */ 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; (*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); (*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 ((*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 ((*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] */ } if (jgeti)(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) { j=l; i=i-1; l=i+2; } else { j=i+1; i=u; u=j-2; } auxsort(L, ta, 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); 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); return 0; } /* }====================================================== */ static const luaL_Reg tab_funcs[] = { {"concat", tconcat}, #if defined(LUA_COMPAT_MAXN) {"maxn", maxn}, #endif {"insert", tinsert}, {"pack", pack}, {"unpack", unpack}, {"remove", tremove}, {"move", tmove}, {"sort", sort}, {NULL, NULL} }; LUAMOD_API int luaopen_table (lua_State *L) { luaL_newlib(L, tab_funcs); #if defined(LUA_COMPAT_UNPACK) /* _G.unpack = table.unpack */ lua_getfield(L, -1, "unpack"); lua_setglobal(L, "unpack"); #endif return 1; }