/*
** $Id: lbaselib.c,v 1.191.1.6 2008/02/14 16:46:22 roberto Exp $
** Basic library
** See Copyright Notice in lua.h
*/

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define lbaselib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

/*
** If your system does not support `stdout', you can just remove this function.
** If you need, you can define your own `print' function, following this
** model but changing `fputs' to put the strings at a proper place
** (a console window or a log file, for instance).
*/
static int luaB_print(lua_State *L)
{
    int n = lua_gettop(L); /* number of arguments */
    int i;
    lua_getglobal(L, "tostring");
    for (i = 1; i <= n; i++) {
        const char *s;
        lua_pushvalue(L, -1); /* function to be called */
        lua_pushvalue(L, i);  /* value to print */
        lua_call(L, 1, 1);
        s = lua_tostring(L, -1); /* get result */
        if (s == NULL)
            return luaL_error(
                L,
                LUA_QL("tostring") " must return a string to " LUA_QL("print"));
        if (i > 1)
            fputs("\t", stdout);
        fputs(s, stdout);
        lua_pop(L, 1); /* pop result */
    }
    fputs("\n", stdout);
    return 0;
}

static int luaB_tonumber(lua_State *L)
{
    int base = luaL_optint(L, 2, 10);
    if (base == 10) { /* standard conversion */
        luaL_checkany(L, 1);
        if (lua_isnumber(L, 1)) {
            lua_pushnumber(L, lua_tonumber(L, 1));
            return 1;
        }
    }
    else {
        const char *s1 = luaL_checkstring(L, 1);
        char *s2;
        unsigned long n;
        luaL_argcheck(L, 2 <= base && base <= 36, 2, "base out of range");
        n = strtoul(s1, &s2, base);
        if (s1 != s2) { /* at least one valid digit? */
            while (isspace((unsigned char)(*s2)))
                s2++;          /* skip trailing spaces */
            if (*s2 == '\0') { /* no invalid trailing characters? */
                lua_pushnumber(L, (lua_Number)n);
                return 1;
            }
        }
    }
    lua_pushnil(L); /* else not a number */
    return 1;
}

static int luaB_error(lua_State *L)
{
    int level = luaL_optint(L, 2, 1);
    lua_settop(L, 1);
    if (lua_isstring(L, 1) && level > 0) { /* add extra information? */
        luaL_where(L, level);
        lua_pushvalue(L, 1);
        lua_concat(L, 2);
    }
    return lua_error(L);
}

static int luaB_getmetatable(lua_State *L)
{
    luaL_checkany(L, 1);
    if (!lua_getmetatable(L, 1)) {
        lua_pushnil(L);
        return 1; /* no metatable */
    }
    luaL_getmetafield(L, 1, "__metatable");
    return 1; /* returns either __metatable field (if present) or metatable */
}

static int luaB_setmetatable(lua_State *L)
{
    int t = lua_type(L, 2);
    luaL_checktype(L, 1, LUA_TTABLE);
    luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
                  "nil or table expected");
    if (luaL_getmetafield(L, 1, "__metatable"))
        luaL_error(L, "cannot change a protected metatable");
    lua_settop(L, 2);
    lua_setmetatable(L, 1);
    return 1;
}

static void getfunc(lua_State *L, int opt)
{
    if (lua_isfunction(L, 1))
        lua_pushvalue(L, 1);
    else {
        lua_Debug ar;
        int level = opt ? luaL_optint(L, 1, 1) : luaL_checkint(L, 1);
        luaL_argcheck(L, level >= 0, 1, "level must be non-negative");
        if (lua_getstack(L, level, &ar) == 0)
            luaL_argerror(L, 1, "invalid level");
        lua_getinfo(L, "f", &ar);
        if (lua_isnil(L, -1))
            luaL_error(L, "no function environment for tail call at level %d",
                       level);
    }
}

static int luaB_getfenv(lua_State *L)
{
    getfunc(L, 1);
    if (lua_iscfunction(L, -1)) /* is a C function? */
        lua_pushvalue(L,
                      LUA_GLOBALSINDEX); /* return the thread's global env. */
    else
        lua_getfenv(L, -1);
    return 1;
}

static int luaB_setfenv(lua_State *L)
{
    luaL_checktype(L, 2, LUA_TTABLE);
    getfunc(L, 0);
    lua_pushvalue(L, 2);
    if (lua_isnumber(L, 1) && lua_tonumber(L, 1) == 0) {
        /* change environment of current thread */
        lua_pushthread(L);
        lua_insert(L, -2);
        lua_setfenv(L, -2);
        return 0;
    }
    else if (lua_iscfunction(L, -2) || lua_setfenv(L, -2) == 0)
        luaL_error(
            L, LUA_QL("setfenv") " cannot change environment of given object");
    return 1;
}

static int luaB_rawequal(lua_State *L)
{
    luaL_checkany(L, 1);
    luaL_checkany(L, 2);
    lua_pushboolean(L, lua_rawequal(L, 1, 2));
    return 1;
}

static int luaB_rawget(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    luaL_checkany(L, 2);
    lua_settop(L, 2);
    lua_rawget(L, 1);
    return 1;
}

static int luaB_rawset(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    luaL_checkany(L, 2);
    luaL_checkany(L, 3);
    lua_settop(L, 3);
    lua_rawset(L, 1);
    return 1;
}

static int luaB_gcinfo(lua_State *L)
{
    lua_pushinteger(L, lua_getgccount(L));
    return 1;
}

static int luaB_collectgarbage(lua_State *L)
{
    static const char *const opts[] = {"stop",       "restart", "collect",
                                       "count",      "step",    "setpause",
                                       "setstepmul", NULL};
    static const int optsnum[] = {
        LUA_GCSTOP, LUA_GCRESTART,  LUA_GCCOLLECT,   LUA_GCCOUNT,
        LUA_GCSTEP, LUA_GCSETPAUSE, LUA_GCSETSTEPMUL};
    int o = luaL_checkoption(L, 1, "collect", opts);
    int ex = luaL_optint(L, 2, 0);
    int res = lua_gc(L, optsnum[o], ex);
    switch (optsnum[o]) {
    case LUA_GCCOUNT: {
        int b = lua_gc(L, LUA_GCCOUNTB, 0);
        lua_pushnumber(L, res + ((lua_Number)b / 1024));
        return 1;
    }
    case LUA_GCSTEP: {
        lua_pushboolean(L, res);
        return 1;
    }
    default: {
        lua_pushnumber(L, res);
        return 1;
    }
    }
}

static int luaB_type(lua_State *L)
{
    luaL_checkany(L, 1);
    lua_pushstring(L, luaL_typename(L, 1));
    return 1;
}

static int luaB_next(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    lua_settop(L, 2); /* create a 2nd argument if there isn't one */
    if (lua_next(L, 1))
        return 2;
    else {
        lua_pushnil(L);
        return 1;
    }
}

static int luaB_pairs(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    lua_pushvalue(L, lua_upvalueindex(1)); /* return generator, */
    lua_pushvalue(L, 1);                   /* state, */
    lua_pushnil(L);                        /* and initial value */
    return 3;
}

static int ipairsaux(lua_State *L)
{
    int i = luaL_checkint(L, 2);
    luaL_checktype(L, 1, LUA_TTABLE);
    i++; /* next value */
    lua_pushinteger(L, i);
    lua_rawgeti(L, 1, i);
    return (lua_isnil(L, -1)) ? 0 : 2;
}

static int luaB_ipairs(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    lua_pushvalue(L, lua_upvalueindex(1)); /* return generator, */
    lua_pushvalue(L, 1);                   /* state, */
    lua_pushinteger(L, 0);                 /* and initial value */
    return 3;
}

static int load_aux(lua_State *L, int status)
{
    if (status == 0) /* OK? */
        return 1;
    else {
        lua_pushnil(L);
        lua_insert(L, -2); /* put before error message */
        return 2;          /* return nil plus error message */
    }
}

static int luaB_loadstring(lua_State *L)
{
    size_t l;
    const char *s = luaL_checklstring(L, 1, &l);
    const char *chunkname = luaL_optstring(L, 2, s);
    return load_aux(L, luaL_loadbuffer(L, s, l, chunkname));
}

static int luaB_loadfile(lua_State *L)
{
    const char *fname = luaL_optstring(L, 1, NULL);
    return load_aux(L, luaL_loadfile(L, fname));
}

/*
** Reader for generic `load' function: `lua_load' uses the
** stack for internal stuff, so the reader cannot change the
** stack top. Instead, it keeps its resulting string in a
** reserved slot inside the stack.
*/
static const char *generic_reader(lua_State *L, void *ud, size_t *size)
{
    (void)ud; /* to avoid warnings */
    luaL_checkstack(L, 2, "too many nested functions");
    lua_pushvalue(L, 1); /* get function */
    lua_call(L, 0, 1);   /* call it */
    if (lua_isnil(L, -1)) {
        *size = 0;
        return NULL;
    }
    else if (lua_isstring(L, -1)) {
        lua_replace(L, 3); /* save string in a reserved stack slot */
        return lua_tolstring(L, 3, size);
    }
    else
        luaL_error(L, "reader function must return a string");
    return NULL; /* to avoid warnings */
}

static int luaB_load(lua_State *L)
{
    int status;
    const char *cname = luaL_optstring(L, 2, "=(load)");
    luaL_checktype(L, 1, LUA_TFUNCTION);
    lua_settop(L, 3); /* function, eventual name, plus one reserved slot */
    status = lua_load(L, generic_reader, NULL, cname);
    return load_aux(L, status);
}

static int luaB_dofile(lua_State *L)
{
    const char *fname = luaL_optstring(L, 1, NULL);
    int n = lua_gettop(L);
    if (luaL_loadfile(L, fname) != 0)
        lua_error(L);
    lua_call(L, 0, LUA_MULTRET);
    return lua_gettop(L) - n;
}

static int luaB_assert(lua_State *L)
{
    luaL_checkany(L, 1);
    if (!lua_toboolean(L, 1))
        return luaL_error(L, "%s", luaL_optstring(L, 2, "assertion failed!"));
    return lua_gettop(L);
}

static int luaB_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_getn(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;
}

static int luaB_select(lua_State *L)
{
    int n = lua_gettop(L);
    if (lua_type(L, 1) == LUA_TSTRING && *lua_tostring(L, 1) == '#') {
        lua_pushinteger(L, n - 1);
        return 1;
    }
    else {
        int i = luaL_checkint(L, 1);
        if (i < 0)
            i = n + i;
        else if (i > n)
            i = n;
        luaL_argcheck(L, 1 <= i, 1, "index out of range");
        return n - i;
    }
}

static int luaB_pcall(lua_State *L)
{
    int status;
    luaL_checkany(L, 1);
    status = lua_pcall(L, lua_gettop(L) - 1, LUA_MULTRET, 0);
    lua_pushboolean(L, (status == 0));
    lua_insert(L, 1);
    return lua_gettop(L); /* return status + all results */
}

static int luaB_xpcall(lua_State *L)
{
    int status;
    luaL_checkany(L, 2);
    lua_settop(L, 2);
    lua_insert(L, 1); /* put error function under function to be called */
    status = lua_pcall(L, 0, LUA_MULTRET, 1);
    lua_pushboolean(L, (status == 0));
    lua_replace(L, 1);
    return lua_gettop(L); /* return status + all results */
}

static int luaB_tostring(lua_State *L)
{
    luaL_checkany(L, 1);
    if (luaL_callmeta(L, 1, "__tostring")) /* is there a metafield? */
        return 1;                          /* use its value */
    switch (lua_type(L, 1)) {
    case LUA_TNUMBER:
        lua_pushstring(L, lua_tostring(L, 1));
        break;
    case LUA_TSTRING:
        lua_pushvalue(L, 1);
        break;
    case LUA_TBOOLEAN:
        lua_pushstring(L, (lua_toboolean(L, 1) ? "true" : "false"));
        break;
    case LUA_TNIL:
        lua_pushliteral(L, "nil");
        break;
    default:
        lua_pushfstring(L, "%s: %p", luaL_typename(L, 1), lua_topointer(L, 1));
        break;
    }
    return 1;
}

static int luaB_newproxy(lua_State *L)
{
    lua_settop(L, 1);
    lua_newuserdata(L, 0); /* create proxy */
    if (lua_toboolean(L, 1) == 0)
        return 1; /* no metatable */
    else if (lua_isboolean(L, 1)) {
        lua_newtable(L);      /* create a new metatable `m' ... */
        lua_pushvalue(L, -1); /* ... and mark `m' as a valid metatable */
        lua_pushboolean(L, 1);
        lua_rawset(L, lua_upvalueindex(1)); /* weaktable[m] = true */
    }
    else {
        int validproxy = 0; /* to check if weaktable[metatable(u)] == true */
        if (lua_getmetatable(L, 1)) {
            lua_rawget(L, lua_upvalueindex(1));
            validproxy = lua_toboolean(L, -1);
            lua_pop(L, 1); /* remove value */
        }
        luaL_argcheck(L, validproxy, 1, "boolean or proxy expected");
        lua_getmetatable(L, 1); /* metatable is valid; get it */
    }
    lua_setmetatable(L, 2);
    return 1;
}

static const luaL_Reg base_funcs[] = {{"assert", luaB_assert},
                                      {"collectgarbage", luaB_collectgarbage},
                                      {"dofile", luaB_dofile},
                                      {"error", luaB_error},
                                      {"gcinfo", luaB_gcinfo},
                                      {"getfenv", luaB_getfenv},
                                      {"getmetatable", luaB_getmetatable},
                                      {"loadfile", luaB_loadfile},
                                      {"load", luaB_load},
                                      {"loadstring", luaB_loadstring},
                                      {"next", luaB_next},
                                      {"pcall", luaB_pcall},
                                      {"print", luaB_print},
                                      {"rawequal", luaB_rawequal},
                                      {"rawget", luaB_rawget},
                                      {"rawset", luaB_rawset},
                                      {"select", luaB_select},
                                      {"setfenv", luaB_setfenv},
                                      {"setmetatable", luaB_setmetatable},
                                      {"tonumber", luaB_tonumber},
                                      {"tostring", luaB_tostring},
                                      {"type", luaB_type},
                                      {"unpack", luaB_unpack},
                                      {"xpcall", luaB_xpcall},
                                      {NULL, NULL}};

/*
** {======================================================
** Coroutine library
** =======================================================
*/

#define CO_RUN 0 /* running */
#define CO_SUS 1 /* suspended */
#define CO_NOR 2 /* 'normal' (it resumed another coroutine) */
#define CO_DEAD 3

static const char *const statnames[] = {"running", "suspended", "normal",
                                        "dead"};

static int costatus(lua_State *L, lua_State *co)
{
    if (L == co)
        return CO_RUN;
    switch (lua_status(co)) {
    case LUA_YIELD:
        return CO_SUS;
    case 0: {
        lua_Debug ar;
        if (lua_getstack(co, 0, &ar) > 0) /* does it have frames? */
            return CO_NOR;                /* it is running */
        else if (lua_gettop(co) == 0)
            return CO_DEAD;
        else
            return CO_SUS; /* initial state */
    }
    default: /* some error occured */
        return CO_DEAD;
    }
}

static int luaB_costatus(lua_State *L)
{
    lua_State *co = lua_tothread(L, 1);
    luaL_argcheck(L, co, 1, "coroutine expected");
    lua_pushstring(L, statnames[costatus(L, co)]);
    return 1;
}

static int auxresume(lua_State *L, lua_State *co, int narg)
{
    int status = costatus(L, co);
    if (!lua_checkstack(co, narg))
        luaL_error(L, "too many arguments to resume");
    if (status != CO_SUS) {
        lua_pushfstring(L, "cannot resume %s coroutine", statnames[status]);
        return -1; /* error flag */
    }
    lua_xmove(L, co, narg);
    lua_setlevel(L, co);
    status = lua_resume(co, narg);
    if (status == 0 || status == LUA_YIELD) {
        int nres = lua_gettop(co);
        if (!lua_checkstack(L, nres + 1))
            luaL_error(L, "too many results to resume");
        lua_xmove(co, L, nres); /* move yielded values */
        return nres;
    }
    else {
        lua_xmove(co, L, 1); /* move error message */
        return -1;           /* error flag */
    }
}

static int luaB_coresume(lua_State *L)
{
    lua_State *co = lua_tothread(L, 1);
    int r;
    luaL_argcheck(L, co, 1, "coroutine expected");
    r = auxresume(L, co, lua_gettop(L) - 1);
    if (r < 0) {
        lua_pushboolean(L, 0);
        lua_insert(L, -2);
        return 2; /* return false + error message */
    }
    else {
        lua_pushboolean(L, 1);
        lua_insert(L, -(r + 1));
        return r + 1; /* return true + `resume' returns */
    }
}

static int luaB_auxwrap(lua_State *L)
{
    lua_State *co = lua_tothread(L, lua_upvalueindex(1));
    int r = auxresume(L, co, lua_gettop(L));
    if (r < 0) {
        if (lua_isstring(L, -1)) { /* error object is a string? */
            luaL_where(L, 1);      /* add extra info */
            lua_insert(L, -2);
            lua_concat(L, 2);
        }
        lua_error(L); /* propagate error */
    }
    return r;
}

static int luaB_cocreate(lua_State *L)
{
    lua_State *NL = lua_newthread(L);
    luaL_argcheck(L, lua_isfunction(L, 1) && !lua_iscfunction(L, 1), 1,
                  "Lua function expected");
    lua_pushvalue(L, 1); /* move function to top */
    lua_xmove(L, NL, 1); /* move function from L to NL */
    return 1;
}

static int luaB_cowrap(lua_State *L)
{
    luaB_cocreate(L);
    lua_pushcclosure(L, luaB_auxwrap, 1);
    return 1;
}

static int luaB_yield(lua_State *L) { return lua_yield(L, lua_gettop(L)); }

static int luaB_corunning(lua_State *L)
{
    if (lua_pushthread(L))
        lua_pushnil(L); /* main thread is not a coroutine */
    return 1;
}

static const luaL_Reg co_funcs[] = {{"create", luaB_cocreate},
                                    {"resume", luaB_coresume},
                                    {"running", luaB_corunning},
                                    {"status", luaB_costatus},
                                    {"wrap", luaB_cowrap},
                                    {"yield", luaB_yield},
                                    {NULL, NULL}};

/* }====================================================== */

static void auxopen(lua_State *L, const char *name, lua_CFunction f,
                    lua_CFunction u)
{
    lua_pushcfunction(L, u);
    lua_pushcclosure(L, f, 1);
    lua_setfield(L, -2, name);
}

static void base_open(lua_State *L)
{
    /* set global _G */
    lua_pushvalue(L, LUA_GLOBALSINDEX);
    lua_setglobal(L, "_G");
    /* open lib into global table */
    luaL_register(L, "_G", base_funcs);
    lua_pushliteral(L, LUA_VERSION);
    lua_setglobal(L, "_VERSION"); /* set global _VERSION */
    /* `ipairs' and `pairs' need auxiliary functions as upvalues */
    auxopen(L, "ipairs", luaB_ipairs, ipairsaux);
    auxopen(L, "pairs", luaB_pairs, luaB_next);
    /* `newproxy' needs a weaktable as upvalue */
    lua_createtable(L, 0, 1); /* new table `w' */
    lua_pushvalue(L, -1);     /* `w' will be its own metatable */
    lua_setmetatable(L, -2);
    lua_pushliteral(L, "kv");
    lua_setfield(L, -2, "__mode"); /* metatable(w).__mode = "kv" */
    lua_pushcclosure(L, luaB_newproxy, 1);
    lua_setglobal(L, "newproxy"); /* set global `newproxy' */
}

LUALIB_API int luaopen_base(lua_State *L)
{
    base_open(L);
    luaL_register(L, LUA_COLIBNAME, co_funcs);
    return 2;
}
