/*

** $Id: ltablib.c,v 1.65.1.1 2013/04/12 18:48:47 roberto Exp $

** Library for Table Manipulation

** See Copyright Notice in lua.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, 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 = e - i + 1; /* number of elements */

if (n <= 0 || !lua_checkstack(L, n)) /* n <= 0 means arith. overflow */

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;

}