/*
** $Id: ltablib.c,v 1.38.1.3 2008/02/14 16:46:58 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_getn(L, n))

static int foreachi(lua_State *L)
{
    int i;
    int n = aux_getn(L, 1);
    luaL_checktype(L, 2, LUA_TFUNCTION);
    for (i = 1; i <= n; i++) {
        lua_pushvalue(L, 2);   /* function */
        lua_pushinteger(L, i); /* 1st argument */
        lua_rawgeti(L, 1, i);  /* 2nd argument */
        lua_call(L, 2, 1);
        if (!lua_isnil(L, -1))
            return 1;
        lua_pop(L, 1); /* remove nil result */
    }
    return 0;
}

static int foreach (lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    luaL_checktype(L, 2, LUA_TFUNCTION);
    lua_pushnil(L); /* first key */
    while (lua_next(L, 1)) {
        lua_pushvalue(L, 2);  /* function */
        lua_pushvalue(L, -3); /* key */
        lua_pushvalue(L, -3); /* value */
        lua_call(L, 2, 1);
        if (!lua_isnil(L, -1))
            return 1;
        lua_pop(L, 2); /* remove value and result */
    }
    return 0;
}

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;
}

static int getn(lua_State *L)
{
    lua_pushinteger(L, aux_getn(L, 1));
    return 1;
}

static int setn(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
#ifndef luaL_setn
    luaL_setn(L, 1, luaL_checkint(L, 2));
#else
    luaL_error(L, LUA_QL("setn") " is obsolete");
#endif
    lua_pushvalue(L, 1);
    return 1;
}

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 */
        if (pos > e)
            e = pos;                /* `grow' array if necessary */
        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"));
    }
    }
    luaL_setn(L, 1, e);     /* new size */
    lua_rawseti(L, 1, pos); /* t[pos] = v */
    return 0;
}

static int tremove(lua_State *L)
{
    int e = aux_getn(L, 1);
    int pos = luaL_optint(L, 2, e);
    if (!(1 <= pos && pos <= e)) /* position is outside bounds? */
        return 0;                /* nothing to remove */
    luaL_setn(L, 1, e - 1);      /* t.n = n-1 */
    lua_rawgeti(L, 1, pos);      /* result = t[pos] */
    for (; pos < e; pos++) {
        lua_rawgeti(L, 1, pos + 1);
        lua_rawseti(L, 1, pos); /* t[pos] = t[pos+1] */
    }
    lua_pushnil(L);
    lua_rawseti(L, 1, e); /* t[e] = 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_getn(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;
}

/*
** {======================================================
** 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_lessthan(L, a, b);
}

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}, {"foreach", foreach}, {"foreachi", foreachi},
    {"getn", getn},      {"maxn", maxn},       {"insert", tinsert},
    {"remove", tremove}, {"setn", setn},       {"sort", sort},
    {NULL, NULL}};

LUALIB_API int luaopen_table(lua_State *L)
{
    luaL_register(L, LUA_TABLIBNAME, tab_funcs);
    return 1;
}
