/*
** $Id: lbaselib.c,v 1.276 2013/02/21 13:44:53 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"


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;
        size_t l;
        lua_pushvalue(L, -1);  /* function to be called */
        lua_pushvalue(L, i);   /* value to print */
        lua_call(L, 1, 1);
        s = lua_tolstring(L, -1, &l);  /* get result */
        if (s == NULL)
            return luaL_error(L,
                              LUA_QL("tostring") " must return a string to " LUA_QL("print"));
        if (i > 1) luai_writestring("\t", 1);
        luai_writestring(s, l);
        lua_pop(L, 1);  /* pop result */
    }
    luai_writeline();
    return 0;
}


#define SPACECHARS " \f\n\r\t\v"

static int luaB_tonumber(lua_State *L) {
    if (lua_isnoneornil(L, 2)) {  /* standard conversion */
        int isnum;
        lua_Number n = lua_tonumberx(L, 1, &isnum);
        if (isnum) {
            lua_pushnumber(L, n);
            return 1;
        }  /* else not a number; must be something */
        luaL_checkany(L, 1);
    } else {
        size_t l;
        const char *s = luaL_checklstring(L, 1, &l);
        const char *e = s + l;  /* end point for 's' */
        int base = luaL_checkint(L, 2);
        int neg = 0;
        luaL_argcheck(L, 2 <= base && base <= 36, 2, "base out of range");
        s += strspn(s, SPACECHARS);  /* skip initial spaces */
        if (*s == '-') { s++; neg = 1; }  /* handle signal */
        else if (*s == '+') s++;
        if (isalnum((unsigned char)*s)) {
            lua_Number n = 0;
            do {
                int digit = (isdigit((unsigned char) * s)) ? *s - '0'
                            : toupper((unsigned char) * s) - 'A' + 10;
                if (digit >= base) break;  /* invalid numeral; force a fail */
                n = n * (lua_Number)base + (lua_Number)digit;
                s++;
            } while (isalnum((unsigned char)*s));
            s += strspn(s, SPACECHARS);  /* skip trailing spaces */
            if (s == e) {  /* no invalid trailing characters? */
                lua_pushnumber(L, (neg) ? -n : n);
                return 1;
            }  /* else not a number */
        }  /* else not a number */
    }
    lua_pushnil(L);  /* 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"))
        return luaL_error(L, "cannot change a protected metatable");
    lua_settop(L, 2);
    lua_setmetatable(L, 1);
    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_rawlen(lua_State *L) {
    int t = lua_type(L, 1);
    luaL_argcheck(L, t == LUA_TTABLE || t == LUA_TSTRING, 1,
                  "table or string expected");
    lua_pushinteger(L, lua_rawlen(L, 1));
    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_collectgarbage(lua_State *L) {
    static const char *const opts[] = {"stop", "restart", "collect",
                                       "count", "step", "setpause", "setstepmul",
                                       "setmajorinc", "isrunning", "generational", "incremental", NULL
                                      };
    static const int optsnum[] = {LUA_GCSTOP, LUA_GCRESTART, LUA_GCCOLLECT,
                                  LUA_GCCOUNT, LUA_GCSTEP, LUA_GCSETPAUSE, LUA_GCSETSTEPMUL,
                                  LUA_GCSETMAJORINC, LUA_GCISRUNNING, LUA_GCGEN, LUA_GCINC
                                 };
    int o = optsnum[luaL_checkoption(L, 1, "collect", opts)];
    int ex = luaL_optint(L, 2, 0);
    int res = lua_gc(L, o, ex);
    switch (o) {
        case LUA_GCCOUNT: {
            int b = lua_gc(L, LUA_GCCOUNTB, 0);
            lua_pushnumber(L, res + ((lua_Number)b / 1024));
            lua_pushinteger(L, b);
            return 2;
        }
        case LUA_GCSTEP:
        case LUA_GCISRUNNING: {
            lua_pushboolean(L, res);
            return 1;
        }
        default: {
            lua_pushinteger(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 pairsmeta(lua_State *L, const char *method, int iszero,
                     lua_CFunction iter) {
    if (!luaL_getmetafield(L, 1, method)) {  /* no metamethod? */
        luaL_checktype(L, 1, LUA_TTABLE);  /* argument must be a table */
        lua_pushcfunction(L, iter);  /* will return generator, */
        lua_pushvalue(L, 1);  /* state, */
        if (iszero) lua_pushinteger(L, 0);  /* and initial value */
        else lua_pushnil(L);
    } else {
        lua_pushvalue(L, 1);  /* argument 'self' to metamethod */
        lua_call(L, 1, 3);  /* get 3 values from metamethod */
    }
    return 3;
}


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) {
    return pairsmeta(L, "__pairs", 0, luaB_next);
}


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)) ? 1 : 2;
}


static int luaB_ipairs(lua_State *L) {
    return pairsmeta(L, "__ipairs", 1, ipairsaux);
}


static int load_aux(lua_State *L, int status, int envidx) {
    if (status == LUA_OK) {
        if (envidx != 0) {  /* 'env' parameter? */
            lua_pushvalue(L, envidx);  /* environment for loaded function */
            if (!lua_setupvalue(L, -2, 1))  /* set it as 1st upvalue */
                lua_pop(L, 1);  /* remove 'env' if not used by previous call */
        }
        return 1;
    } else { /* error (message is on top of the stack) */
        lua_pushnil(L);
        lua_insert(L, -2);  /* put before error message */
        return 2;  /* return nil plus error message */
    }
}


static int luaB_loadfile(lua_State *L) {
    const char *fname = luaL_optstring(L, 1, NULL);
    const char *mode = luaL_optstring(L, 2, NULL);
    int env = (!lua_isnone(L, 3) ? 3 : 0);  /* 'env' index or 0 if no 'env' */
    int status = luaL_loadfilex(L, fname, mode);
    return load_aux(L, status, env);
}


/*
** {======================================================
** Generic Read function
** =======================================================
*/


/*
** reserved slot, above all arguments, to hold a copy of the returned
** string to avoid it being collected while parsed. 'load' has four
** optional arguments (chunk, source name, mode, and environment).
*/
#define RESERVEDSLOT 5


/*
** 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);  /* not used */
    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)) {
        lua_pop(L, 1);  /* pop result */
        *size = 0;
        return NULL;
    } else if (!lua_isstring(L, -1))
        luaL_error(L, "reader function must return a string");
    lua_replace(L, RESERVEDSLOT);  /* save string in reserved slot */
    return lua_tolstring(L, RESERVEDSLOT, size);
}


static int luaB_load(lua_State *L) {
    int status;
    size_t l;
    const char *s = lua_tolstring(L, 1, &l);
    const char *mode = luaL_optstring(L, 3, "bt");
    int env = (!lua_isnone(L, 4) ? 4 : 0);  /* 'env' index or 0 if no 'env' */
    if (s != NULL) {  /* loading a string? */
        const char *chunkname = luaL_optstring(L, 2, s);
        status = luaL_loadbufferx(L, s, l, chunkname, mode);
    } else { /* loading from a reader function */
        const char *chunkname = luaL_optstring(L, 2, "=(load)");
        luaL_checktype(L, 1, LUA_TFUNCTION);
        lua_settop(L, RESERVEDSLOT);  /* create reserved slot */
        status = lua_load(L, generic_reader, NULL, chunkname, mode);
    }
    return load_aux(L, status, env);
}

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


static int dofilecont(lua_State *L) {
    return lua_gettop(L) - 1;
}


static int luaB_dofile(lua_State *L) {
    const char *fname = luaL_optstring(L, 1, NULL);
    lua_settop(L, 1);
    if (luaL_loadfile(L, fname) != LUA_OK)
        return lua_error(L);
    lua_callk(L, 0, LUA_MULTRET, 0, dofilecont);
    return dofilecont(L);
}


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


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 finishpcall(lua_State *L, int status) {
    if (!lua_checkstack(L, 1)) {  /* no space for extra boolean? */
        lua_settop(L, 0);  /* create space for return values */
        lua_pushboolean(L, 0);
        lua_pushstring(L, "stack overflow");
        return 2;  /* return false, msg */
    }
    lua_pushboolean(L, status);  /* first result (status) */
    lua_replace(L, 1);  /* put first result in first slot */
    return lua_gettop(L);
}


static int pcallcont(lua_State *L) {
    int status = lua_getctx(L, NULL);
    return finishpcall(L, (status == LUA_YIELD));
}


static int luaB_pcall(lua_State *L) {
    int status;
    luaL_checkany(L, 1);
    lua_pushnil(L);
    lua_insert(L, 1);  /* create space for status result */
    status = lua_pcallk(L, lua_gettop(L) - 2, LUA_MULTRET, 0, 0, pcallcont);
    return finishpcall(L, (status == LUA_OK));
}


static int luaB_xpcall(lua_State *L) {
    int status;
    int n = lua_gettop(L);
    luaL_argcheck(L, n >= 2, 2, "value expected");
    lua_pushvalue(L, 1);  /* exchange function... */
    lua_copy(L, 2, 1);  /* ...and error handler */
    lua_replace(L, 2);
    status = lua_pcallk(L, n - 2, LUA_MULTRET, 1, 0, pcallcont);
    return finishpcall(L, (status == LUA_OK));
}


static int luaB_tostring(lua_State *L) {
    luaL_checkany(L, 1);
    luaL_tolstring(L, 1, NULL);
    return 1;
}


static const luaL_Reg base_funcs[] = {
    {"assert", luaB_assert},
    {"collectgarbage", luaB_collectgarbage},
    {"dofile", luaB_dofile},
    {"error", luaB_error},
    {"getmetatable", luaB_getmetatable},
    {"ipairs", luaB_ipairs},
    {"loadfile", luaB_loadfile},
    {"load", luaB_load},
#if defined(LUA_COMPAT_LOADSTRING)
    {"loadstring", luaB_load},
#endif
    {"next", luaB_next},
    {"pairs", luaB_pairs},
    {"pcall", luaB_pcall},
    {"print", luaB_print},
    {"rawequal", luaB_rawequal},
    {"rawlen", luaB_rawlen},
    {"rawget", luaB_rawget},
    {"rawset", luaB_rawset},
    {"select", luaB_select},
    {"setmetatable", luaB_setmetatable},
    {"tonumber", luaB_tonumber},
    {"tostring", luaB_tostring},
    {"type", luaB_type},
    {"xpcall", luaB_xpcall},
    {NULL, NULL}
};


LUAMOD_API int luaopen_base(lua_State *L) {
    /* set global _G */
    lua_pushglobaltable(L);
    lua_pushglobaltable(L);
    lua_setfield(L, -2, "_G");
    /* open lib into global table */
    luaL_setfuncs(L, base_funcs, 0);
    lua_pushliteral(L, LUA_VERSION);
    lua_setfield(L, -2, "_VERSION");  /* set global _VERSION */
    return 1;
}

