/*
** $Id: ltablib.c,v 1.65.1.2 2014/05/07 16:32:55 roberto Exp $
** Library for Table Manipulation
** See Copyright Notice in lua.h
*/
#include <limits.h>
#include <stddef.h>
#define ltablib_c
#define LUA_LIB
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
#define aux_getn(L,n) (luaL_checktype(L, n, LUA_TTABLE), 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) {
int e = aux_getn(L, 1) + 1; /* first empty element */
int 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: {
int i;
pos = luaL_checkint(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] */
}
break;
}
default: {
return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
}
}
lua_rawseti(L, 1, pos); /* t[pos] = v */
return 0;
}
static int tremove (lua_State *L) {
int size = aux_getn(L, 1);
int pos = luaL_optint(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] */
for ( ; pos < size; pos++) {
lua_rawgeti(L, 1, pos+1);
lua_rawseti(L, 1, pos); /* t[pos] = t[pos+1] */
}
lua_pushnil(L);
lua_rawseti(L, 1, pos); /* t[pos] = nil */
return 1;
}
static void addfield (lua_State *L, luaL_Buffer *b, int i) {
lua_rawgeti(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) {
luaL_Buffer b;
size_t lsep;
int i, last;
const char *sep = luaL_optlstring(L, 2, "", &lsep);
luaL_checktype(L, 1, LUA_TTABLE);
i = luaL_optint(L, 3, 1);
last = luaL_opt(L, luaL_checkint, 4, luaL_len(L, 1));
luaL_buffinit(L, &b);
for (; i < last; i++) {
addfield(L, &b, i);
luaL_addlstring(&b, sep, lsep);
}
if (i == last) /* add last value (if interval was not empty) */
addfield(L, &b, i);
luaL_pushresult(&b);
return 1;
}
/*
** {======================================================
** Pack/unpack
** =======================================================
*/
static int pack (lua_State *L) {
int n = lua_gettop(L); /* number of elements to pack */
lua_createtable(L, n, 1); /* create result table */
lua_pushinteger(L, n);
lua_setfield(L, -2, "n"); /* t.n = number of elements */
if (n > 0) { /* at least one element? */
int i;
lua_pushvalue(L, 1);
lua_rawseti(L, -2, 1); /* insert first element */
lua_replace(L, 1); /* move table into index 1 */
for (i = n; i >= 2; i--) /* assign other elements */
lua_rawseti(L, 1, i);
}
return 1; /* return table */
}
static int unpack (lua_State *L) {
int i, e;
unsigned int n;
luaL_checktype(L, 1, LUA_TTABLE);
i = luaL_optint(L, 2, 1);
e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1));
if (i > e) return 0; /* empty range */
n = (unsigned int)e - (unsigned int)i; /* number of elements minus 1 */
if (n > (INT_MAX - 10) || !lua_checkstack(L, ++n))
return luaL_error(L, "too many results to unpack");
lua_rawgeti(L, 1, i); /* push arg[i] (avoiding overflow problems) */
while (i++ < e) /* push arg[i + 1...e] */
lua_rawgeti(L, 1, i);
return n;
}
/* }====================================================== */
/*
** {======================================================
** Quicksort
** (based on `Algorithms in MODULA-3', Robert Sedgewick;
** Addison-Wesley, 1993.)
** =======================================================
*/
static void set2 (lua_State *L, int i, int j) {
lua_rawseti(L, 1, i);
lua_rawseti(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, 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);
if (sort_comp(L, -1, -2)) /* a[u] < a[l]? */
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;
lua_rawgeti(L, 1, i);
lua_rawgeti(L, 1, l);
if (sort_comp(L, -2, -1)) /* a[i]<a[l]? */
set2(L, i, l);
else {
lua_pop(L, 1); /* remove a[l] */
lua_rawgeti(L, 1, u);
if (sort_comp(L, -1, -2)) /* a[u]<a[i]? */
set2(L, i, u);
else
lua_pop(L, 2);
}
if (u-l == 2) break; /* only 3 elements */
lua_rawgeti(L, 1, i); /* Pivot */
lua_pushvalue(L, -1);
lua_rawgeti(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 (lua_rawgeti(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)) {
if (j<=l) luaL_error(L, "invalid order function for sorting");
lua_pop(L, 1); /* remove a[j] */
}
if (j<i) {
lua_pop(L, 3); /* pop pivot, a[i], a[j] */
break;
}
set2(L, 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] */
/* 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, 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 */
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);
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},
{"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;
}