/*

** $Id: loslib.c $

** Standard Operating System library

** See Copyright Notice in lua.h

*/

#define loslib_c

#define LUA_LIB

#include "lprefix.h"

#include <errno.h>

#include <locale.h>

#include <stdlib.h>

#include <string.h>

#include <time.h>

#include "lua.h"

#include "lauxlib.h"

#include "lualib.h"

/*

** {==================================================================

** List of valid conversion specifiers for the 'strftime' function;

** options are grouped by length; group of length 2 start with '||'.

** ===================================================================

*/

#if !defined(LUA_STRFTIMEOPTIONS) /* { */

#if defined(LUA_USE_WINDOWS)

#define LUA_STRFTIMEOPTIONS  "aAbBcdHIjmMpSUwWxXyYzZ%" \

    "||" "#c#x#d#H#I#j#m#M#S#U#w#W#y#Y"  /* two-char options */

#elif defined(LUA_USE_C89)  /* ANSI C 89 (only 1-char options) */

#define LUA_STRFTIMEOPTIONS  "aAbBcdHIjmMpSUwWxXyYZ%"

#else  /* C99 specification */

#define LUA_STRFTIMEOPTIONS  "aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%" \

    "||" "EcECExEXEyEY" "OdOeOHOIOmOMOSOuOUOVOwOWOy"  /* two-char options */

#endif

#endif          /* } */

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

/*

** {==================================================================

** Configuration for time-related stuff

** ===================================================================

*/

/*

** type to represent time_t in Lua

*/

#if !defined(LUA_NUMTIME) /* { */

#define l_timet     lua_Integer

#define l_pushtime(L,t)   lua_pushinteger(L,(lua_Integer)(t))

#define l_gettime(L,arg)  luaL_checkinteger(L, arg)

#else       /* }{ */

#define l_timet     lua_Number

#define l_pushtime(L,t)   lua_pushnumber(L,(lua_Number)(t))

#define l_gettime(L,arg)  luaL_checknumber(L, arg)

#endif        /* } */

#if !defined(l_gmtime)    /* { */

/*

** By default, Lua uses gmtime/localtime, except when POSIX is available,

** where it uses gmtime_r/localtime_r

*/

#if defined(LUA_USE_POSIX)  /* { */

#define l_gmtime(t,r)   gmtime_r(t,r)

#define l_localtime(t,r)  localtime_r(t,r)

#else       /* }{ */

/* ISO C definitions */

#define l_gmtime(t,r)   ((void)(r)->tm_sec, gmtime(t))

#define l_localtime(t,r)  ((void)(r)->tm_sec, localtime(t))

#endif        /* } */

#endif        /* } */

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

/*

** {==================================================================

** Configuration for 'tmpnam':

** By default, Lua uses tmpnam except when POSIX is available, where

** it uses mkstemp.

** ===================================================================

*/

#if !defined(lua_tmpnam)  /* { */

#if defined(LUA_USE_POSIX)  /* { */

#include <unistd.h>

#define LUA_TMPNAMBUFSIZE 32

#if !defined(LUA_TMPNAMTEMPLATE)

#define LUA_TMPNAMTEMPLATE  "/tmp/lua_XXXXXX"

#endif

#define lua_tmpnam(b,e) { \

        strcpy(b, LUA_TMPNAMTEMPLATE); \

        e = mkstemp(b); \

        if (e != -1) close(e); \

        e = (e == -1); }

#else       /* }{ */

/* ISO C definitions */

#define LUA_TMPNAMBUFSIZE L_tmpnam

#define lua_tmpnam(b,e)   { e = (tmpnam(b) == NULL); }

#endif        /* } */

#endif        /* } */

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

#if !defined(l_system)

#if defined(LUA_USE_IOS)

/* Despite claiming to be ISO C, iOS does not implement 'system'. */

#define l_system(cmd) ((cmd) == NULL ? 0 : -1)

#else

#define l_system(cmd) system(cmd)  /* default definition */

#endif

#endif

static int os_execute (lua_State *L) {

  const char *cmd = luaL_optstring(L, 1, NULL);

  int stat;

  errno = 0;

  stat = l_system(cmd);

  if (cmd != NULL)

    return luaL_execresult(L, stat);

  else {

    lua_pushboolean(L, stat);  /* true if there is a shell */

    return 1;

  }

}

static int os_remove (lua_State *L) {

  const char *filename = luaL_checkstring(L, 1);

  return luaL_fileresult(L, remove(filename) == 0, filename);

}

static int os_rename (lua_State *L) {

  const char *fromname = luaL_checkstring(L, 1);

  const char *toname = luaL_checkstring(L, 2);

  return luaL_fileresult(L, rename(fromname, toname) == 0, NULL);

}

static int os_tmpname (lua_State *L) {

  char buff[LUA_TMPNAMBUFSIZE];

  int err;

  lua_tmpnam(buff, err);

  if (l_unlikely(err))

    return luaL_error(L, "unable to generate a unique filename");

  lua_pushstring(L, buff);

  return 1;

}

static int os_getenv (lua_State *L) {

  lua_pushstring(L, getenv(luaL_checkstring(L, 1)));  /* if NULL push nil */

  return 1;

}

static int os_clock (lua_State *L) {

  lua_pushnumber(L, ((lua_Number)clock())/(lua_Number)CLOCKS_PER_SEC);

  return 1;

}

/*

** {======================================================

** Time/Date operations

** { year=%Y, month=%m, day=%d, hour=%H, min=%M, sec=%S,

**   wday=%w+1, yday=%j, isdst=? }

** =======================================================

*/

/*

** About the overflow check: an overflow cannot occur when time

** is represented by a lua_Integer, because either lua_Integer is

** large enough to represent all int fields or it is not large enough

** to represent a time that cause a field to overflow.  However, if

** times are represented as doubles and lua_Integer is int, then the

** time 0x1.e1853b0d184f6p+55 would cause an overflow when adding 1900

** to compute the year.

*/

static void setfield (lua_State *L, const char *key, int value, int delta) {

  #if (defined(LUA_NUMTIME) && LUA_MAXINTEGER <= INT_MAX)

    if (l_unlikely(value > LUA_MAXINTEGER - delta))

      luaL_error(L, "field '%s' is out-of-bound", key);

  #endif

  lua_pushinteger(L, (lua_Integer)value + delta);

  lua_setfield(L, -2, key);

}

static void setboolfield (lua_State *L, const char *key, int value) {

  if (value < 0)  /* undefined? */

    return;  /* does not set field */

  lua_pushboolean(L, value);

  lua_setfield(L, -2, key);

}

/*

** Set all fields from structure 'tm' in the table on top of the stack

*/

static void setallfields (lua_State *L, struct tm *stm) {

  setfield(L, "year", stm->tm_year, 1900);

  setfield(L, "month", stm->tm_mon, 1);

  setfield(L, "day", stm->tm_mday, 0);

  setfield(L, "hour", stm->tm_hour, 0);

  setfield(L, "min", stm->tm_min, 0);

  setfield(L, "sec", stm->tm_sec, 0);

  setfield(L, "yday", stm->tm_yday, 1);

  setfield(L, "wday", stm->tm_wday, 1);

  setboolfield(L, "isdst", stm->tm_isdst);

}

static int getboolfield (lua_State *L, const char *key) {

  int res;

  res = (lua_getfield(L, -1, key) == LUA_TNIL) ? -1 : lua_toboolean(L, -1);

  lua_pop(L, 1);

  return res;

}

static int getfield (lua_State *L, const char *key, int d, int delta) {

  int isnum;

  int t = lua_getfield(L, -1, key);  /* get field and its type */

  lua_Integer res = lua_tointegerx(L, -1, &isnum);

  if (!isnum) {  /* field is not an integer? */

    if (l_unlikely(t != LUA_TNIL))  /* some other value? */

      return luaL_error(L, "field '%s' is not an integer", key);

    else if (l_unlikely(d < 0))  /* absent field; no default? */

      return luaL_error(L, "field '%s' missing in date table", key);

    res = d;

  }

  else {

    if (!(res >= 0 ? res - delta <= INT_MAX : INT_MIN + delta <= res))

      return luaL_error(L, "field '%s' is out-of-bound", key);

    res -= delta;

  }

  lua_pop(L, 1);

  return (int)res;

}

static const char *checkoption (lua_State *L, const char *conv,

                                ptrdiff_t convlen, char *buff) {

  const char *option = LUA_STRFTIMEOPTIONS;

  int oplen = 1;  /* length of options being checked */

  for (; *option != '\0' && oplen <= convlen; option += oplen) {

    if (*option == '|')  /* next block? */

      oplen++;  /* will check options with next length (+1) */

    else if (memcmp(conv, option, oplen) == 0) {  /* match? */

      memcpy(buff, conv, oplen);  /* copy valid option to buffer */

      buff[oplen] = '\0';

      return conv + oplen;  /* return next item */

    }

  }

  luaL_argerror(L, 1,

    lua_pushfstring(L, "invalid conversion specifier '%%%s'", conv));

  return conv;  /* to avoid warnings */

}

static time_t l_checktime (lua_State *L, int arg) {

  l_timet t = l_gettime(L, arg);

  luaL_argcheck(L, (time_t)t == t, arg, "time out-of-bounds");

  return (time_t)t;

}

/* maximum size for an individual 'strftime' item */

#define SIZETIMEFMT 250

static int os_date (lua_State *L) {

  size_t slen;

  const char *s = luaL_optlstring(L, 1, "%c", &slen);

  time_t t = luaL_opt(L, l_checktime, 2, time(NULL));

  const char *se = s + slen;  /* 's' end */

  struct tm tmr, *stm;

  if (*s == '!') {  /* UTC? */

    stm = l_gmtime(&t, &tmr);

    s++;  /* skip '!' */

  }

  else

    stm = l_localtime(&t, &tmr);

  if (stm == NULL)  /* invalid date? */

    return luaL_error(L,

                 "date result cannot be represented in this installation");

  if (strcmp(s, "*t") == 0) {

    lua_createtable(L, 0, 9);  /* 9 = number of fields */

    setallfields(L, stm);

  }

  else {

    char cc[4];  /* buffer for individual conversion specifiers */

    luaL_Buffer b;

    cc[0] = '%';

    luaL_buffinit(L, &b);

    while (s < se) {

      if (*s != '%')  /* not a conversion specifier? */

        luaL_addchar(&b, *s++);

      else {

        size_t reslen;

        char *buff = luaL_prepbuffsize(&b, SIZETIMEFMT);

        s++;  /* skip '%' */

        s = checkoption(L, s, se - s, cc + 1);  /* copy specifier to 'cc' */

        reslen = strftime(buff, SIZETIMEFMT, cc, stm);

        luaL_addsize(&b, reslen);

      }

    }

    luaL_pushresult(&b);

  }

  return 1;

}

static int os_time (lua_State *L) {

  time_t t;

  if (lua_isnoneornil(L, 1))  /* called without args? */

    t = time(NULL);  /* get current time */

  else {

    struct tm ts;

    luaL_checktype(L, 1, LUA_TTABLE);

    lua_settop(L, 1);  /* make sure table is at the top */

    ts.tm_year = getfield(L, "year", -1, 1900);

    ts.tm_mon = getfield(L, "month", -1, 1);

    ts.tm_mday = getfield(L, "day", -1, 0);

    ts.tm_hour = getfield(L, "hour", 12, 0);

    ts.tm_min = getfield(L, "min", 0, 0);

    ts.tm_sec = getfield(L, "sec", 0, 0);

    ts.tm_isdst = getboolfield(L, "isdst");

    t = mktime(&ts);

    setallfields(L, &ts);  /* update fields with normalized values */

  }

  if (t != (time_t)(l_timet)t || t == (time_t)(-1))

    return luaL_error(L,

                  "time result cannot be represented in this installation");

  l_pushtime(L, t);

  return 1;

}

static int os_difftime (lua_State *L) {

  time_t t1 = l_checktime(L, 1);

  time_t t2 = l_checktime(L, 2);

  lua_pushnumber(L, (lua_Number)difftime(t1, t2));

  return 1;

}

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

static int os_setlocale (lua_State *L) {

  static const int cat[] = {LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY,

                      LC_NUMERIC, LC_TIME};

  static const char *const catnames[] = {"all", "collate", "ctype", "monetary",

     "numeric", "time", NULL};

  const char *l = luaL_optstring(L, 1, NULL);

  int op = luaL_checkoption(L, 2, "all", catnames);

  lua_pushstring(L, setlocale(cat[op], l));

  return 1;

}

static int os_exit (lua_State *L) {

  int status;

  if (lua_isboolean(L, 1))

    status = (lua_toboolean(L, 1) ? EXIT_SUCCESS : EXIT_FAILURE);

  else

    status = (int)luaL_optinteger(L, 1, EXIT_SUCCESS);

  if (lua_toboolean(L, 2))

    lua_close(L);

  if (L) exit(status);  /* 'if' to avoid warnings for unreachable 'return' */

  return 0;

}

static const luaL_Reg syslib[] = {

  {"clock",     os_clock},

  {"date",      os_date},

  {"difftime",  os_difftime},

  {"execute",   os_execute},

  {"exit",      os_exit},

  {"getenv",    os_getenv},

  {"remove",    os_remove},

  {"rename",    os_rename},

  {"setlocale", os_setlocale},

  {"time",      os_time},

  {"tmpname",   os_tmpname},

  {NULL, NULL}

};

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

LUAMOD_API int luaopen_os (lua_State *L) {

  luaL_newlib(L, syslib);

  return 1;

}