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  1. /*
  2. ** $Id: liolib.c,v 2.112.1.1 2013/04/12 18:48:47 roberto Exp $
  3. ** Standard I/O (and system) library
  4. ** See Copyright Notice in lua.h
  5. */
  6.  
  7.  
  8. /*
  9. ** This definition must come before the inclusion of 'stdio.h'; it
  10. ** should not affect non-POSIX systems
  11. */
  12. #if !defined(_FILE_OFFSET_BITS)
  13. #define _LARGEFILE_SOURCE       1
  14. #define _FILE_OFFSET_BITS       64
  15. #endif
  16.  
  17.  
  18. #include <errno.h>
  19. #include <stdio.h>
  20. #include <stdlib.h>
  21. #include <string.h>
  22.  
  23. #define liolib_c
  24. #define LUA_LIB
  25.  
  26. #include "lua.h"
  27.  
  28. #include "lauxlib.h"
  29. #include "lualib.h"
  30.  
  31.  
  32. #if !defined(lua_checkmode)
  33.  
  34. /*
  35. ** Check whether 'mode' matches '[rwa]%+?b?'.
  36. ** Change this macro to accept other modes for 'fopen' besides
  37. ** the standard ones.
  38. */
  39. #define lua_checkmode(mode) \
  40.         (*mode != '\0' && strchr("rwa", *(mode++)) != NULL &&   \
  41.         (*mode != '+' || ++mode) &&  /* skip if char is '+' */  \
  42.         (*mode != 'b' || ++mode) &&  /* skip if char is 'b' */  \
  43.         (*mode == '\0'))
  44.  
  45. #endif
  46.  
  47. /*
  48. ** {======================================================
  49. ** lua_popen spawns a new process connected to the current
  50. ** one through the file streams.
  51. ** =======================================================
  52. */
  53.  
  54. #if !defined(lua_popen) /* { */
  55.  
  56. #if defined(LUA_USE_POPEN)      /* { */
  57.  
  58. #define lua_popen(L,c,m)        ((void)L, fflush(NULL), popen(c,m))
  59. #define lua_pclose(L,file)      ((void)L, pclose(file))
  60.  
  61. #elif defined(LUA_WIN)          /* }{ */
  62.  
  63. #define lua_popen(L,c,m)                ((void)L, _popen(c,m))
  64. #define lua_pclose(L,file)              ((void)L, _pclose(file))
  65.  
  66.  
  67. #else                           /* }{ */
  68.  
  69. #define lua_popen(L,c,m)                ((void)((void)c, m),  \
  70.                 luaL_error(L, LUA_QL("popen") " not supported"), (FILE*)0)
  71. #define lua_pclose(L,file)              ((void)((void)L, file), -1)
  72.  
  73.  
  74. #endif                          /* } */
  75.  
  76. #endif                  /* } */
  77.  
  78. /* }====================================================== */
  79.  
  80.  
  81. /*
  82. ** {======================================================
  83. ** lua_fseek: configuration for longer offsets
  84. ** =======================================================
  85. */
  86.  
  87. #if !defined(lua_fseek) && !defined(LUA_ANSI)   /* { */
  88.  
  89. #if defined(LUA_USE_POSIX)      /* { */
  90.  
  91. #define l_fseek(f,o,w)          fseeko(f,o,w)
  92. #define l_ftell(f)              ftello(f)
  93. #define l_seeknum               off_t
  94.  
  95. #elif defined(LUA_WIN) && !defined(_CRTIMP_TYPEINFO) \
  96.    && defined(_MSC_VER) && (_MSC_VER >= 1400)   /* }{ */
  97. /* Windows (but not DDK) and Visual C++ 2005 or higher */
  98.  
  99. #define l_fseek(f,o,w)          _fseeki64(f,o,w)
  100. #define l_ftell(f)              _ftelli64(f)
  101. #define l_seeknum               __int64
  102.  
  103. #endif  /* } */
  104.  
  105. #endif                  /* } */
  106.  
  107.  
  108. #if !defined(l_fseek)           /* default definitions */
  109. #define l_fseek(f,o,w)          fseek(f,o,w)
  110. #define l_ftell(f)              ftell(f)
  111. #define l_seeknum               long
  112. #endif
  113.  
  114. /* }====================================================== */
  115.  
  116.  
  117. #define IO_PREFIX       "_IO_"
  118. #define IO_INPUT        (IO_PREFIX "input")
  119. #define IO_OUTPUT       (IO_PREFIX "output")
  120.  
  121.  
  122. typedef luaL_Stream LStream;
  123.  
  124.  
  125. #define tolstream(L)    ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))
  126.  
  127. #define isclosed(p)     ((p)->closef == NULL)
  128.  
  129.  
  130. static int io_type (lua_State *L) {
  131.   LStream *p;
  132.   luaL_checkany(L, 1);
  133.   p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE);
  134.   if (p == NULL)
  135.     lua_pushnil(L);  /* not a file */
  136.   else if (isclosed(p))
  137.     lua_pushliteral(L, "closed file");
  138.   else
  139.     lua_pushliteral(L, "file");
  140.   return 1;
  141. }
  142.  
  143.  
  144. static int f_tostring (lua_State *L) {
  145.   LStream *p = tolstream(L);
  146.   if (isclosed(p))
  147.     lua_pushliteral(L, "file (closed)");
  148.   else
  149.     lua_pushfstring(L, "file (%p)", p->f);
  150.   return 1;
  151. }
  152.  
  153.  
  154. static FILE *tofile (lua_State *L) {
  155.   LStream *p = tolstream(L);
  156.   if (isclosed(p))
  157.     luaL_error(L, "attempt to use a closed file");
  158.   lua_assert(p->f);
  159.   return p->f;
  160. }
  161.  
  162.  
  163. /*
  164. ** When creating file handles, always creates a `closed' file handle
  165. ** before opening the actual file; so, if there is a memory error, the
  166. ** file is not left opened.
  167. */
  168. static LStream *newprefile (lua_State *L) {
  169.   LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream));
  170.   p->closef = NULL;  /* mark file handle as 'closed' */
  171.   luaL_setmetatable(L, LUA_FILEHANDLE);
  172.   return p;
  173. }
  174.  
  175.  
  176. static int aux_close (lua_State *L) {
  177.   LStream *p = tolstream(L);
  178.   lua_CFunction cf = p->closef;
  179.   p->closef = NULL;  /* mark stream as closed */
  180.   return (*cf)(L);  /* close it */
  181. }
  182.  
  183.  
  184. static int io_close (lua_State *L) {
  185.   if (lua_isnone(L, 1))  /* no argument? */
  186.     lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT);  /* use standard output */
  187.   tofile(L);  /* make sure argument is an open stream */
  188.   return aux_close(L);
  189. }
  190.  
  191.  
  192. static int f_gc (lua_State *L) {
  193.   LStream *p = tolstream(L);
  194.   if (!isclosed(p) && p->f != NULL)
  195.     aux_close(L);  /* ignore closed and incompletely open files */
  196.   return 0;
  197. }
  198.  
  199.  
  200. /*
  201. ** function to close regular files
  202. */
  203. static int io_fclose (lua_State *L) {
  204.   LStream *p = tolstream(L);
  205.   int res = fclose(p->f);
  206.   return luaL_fileresult(L, (res == 0), NULL);
  207. }
  208.  
  209.  
  210. static LStream *newfile (lua_State *L) {
  211.   LStream *p = newprefile(L);
  212.   p->f = NULL;
  213.   p->closef = &io_fclose;
  214.   return p;
  215. }
  216.  
  217.  
  218. static void opencheck (lua_State *L, const char *fname, const char *mode) {
  219.   LStream *p = newfile(L);
  220.   p->f = fopen(fname, mode);
  221.   if (p->f == NULL)
  222.     luaL_error(L, "cannot open file " LUA_QS " (%s)", fname, strerror(errno));
  223. }
  224.  
  225.  
  226. static int io_open (lua_State *L) {
  227.   const char *filename = luaL_checkstring(L, 1);
  228.   const char *mode = luaL_optstring(L, 2, "r");
  229.   LStream *p = newfile(L);
  230.   const char *md = mode;  /* to traverse/check mode */
  231.   luaL_argcheck(L, lua_checkmode(md), 2, "invalid mode");
  232.   p->f = fopen(filename, mode);
  233.   return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
  234. }
  235.  
  236.  
  237. /*
  238. ** function to close 'popen' files
  239. */
  240. static int io_pclose (lua_State *L) {
  241.   LStream *p = tolstream(L);
  242.   return luaL_execresult(L, lua_pclose(L, p->f));
  243. }
  244.  
  245.  
  246. static int io_popen (lua_State *L) {
  247.   const char *filename = luaL_checkstring(L, 1);
  248.   const char *mode = luaL_optstring(L, 2, "r");
  249.   LStream *p = newprefile(L);
  250.   p->f = lua_popen(L, filename, mode);
  251.   p->closef = &io_pclose;
  252.   return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
  253. }
  254.  
  255.  
  256. static int io_tmpfile (lua_State *L) {
  257.   LStream *p = newfile(L);
  258.   p->f = tmpfile();
  259.   return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1;
  260. }
  261.  
  262.  
  263. static FILE *getiofile (lua_State *L, const char *findex) {
  264.   LStream *p;
  265.   lua_getfield(L, LUA_REGISTRYINDEX, findex);
  266.   p = (LStream *)lua_touserdata(L, -1);
  267.   if (isclosed(p))
  268.     luaL_error(L, "standard %s file is closed", findex + strlen(IO_PREFIX));
  269.   return p->f;
  270. }
  271.  
  272.  
  273. static int g_iofile (lua_State *L, const char *f, const char *mode) {
  274.   if (!lua_isnoneornil(L, 1)) {
  275.     const char *filename = lua_tostring(L, 1);
  276.     if (filename)
  277.       opencheck(L, filename, mode);
  278.     else {
  279.       tofile(L);  /* check that it's a valid file handle */
  280.       lua_pushvalue(L, 1);
  281.     }
  282.     lua_setfield(L, LUA_REGISTRYINDEX, f);
  283.   }
  284.   /* return current value */
  285.   lua_getfield(L, LUA_REGISTRYINDEX, f);
  286.   return 1;
  287. }
  288.  
  289.  
  290. static int io_input (lua_State *L) {
  291.   return g_iofile(L, IO_INPUT, "r");
  292. }
  293.  
  294.  
  295. static int io_output (lua_State *L) {
  296.   return g_iofile(L, IO_OUTPUT, "w");
  297. }
  298.  
  299.  
  300. static int io_readline (lua_State *L);
  301.  
  302.  
  303. static void aux_lines (lua_State *L, int toclose) {
  304.   int i;
  305.   int n = lua_gettop(L) - 1;  /* number of arguments to read */
  306.   /* ensure that arguments will fit here and into 'io_readline' stack */
  307.   luaL_argcheck(L, n <= LUA_MINSTACK - 3, LUA_MINSTACK - 3, "too many options");
  308.   lua_pushvalue(L, 1);  /* file handle */
  309.   lua_pushinteger(L, n);  /* number of arguments to read */
  310.   lua_pushboolean(L, toclose);  /* close/not close file when finished */
  311.   for (i = 1; i <= n; i++) lua_pushvalue(L, i + 1);  /* copy arguments */
  312.   lua_pushcclosure(L, io_readline, 3 + n);
  313. }
  314.  
  315.  
  316. static int f_lines (lua_State *L) {
  317.   tofile(L);  /* check that it's a valid file handle */
  318.   aux_lines(L, 0);
  319.   return 1;
  320. }
  321.  
  322.  
  323. static int io_lines (lua_State *L) {
  324.   int toclose;
  325.   if (lua_isnone(L, 1)) lua_pushnil(L);  /* at least one argument */
  326.   if (lua_isnil(L, 1)) {  /* no file name? */
  327.     lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT);  /* get default input */
  328.     lua_replace(L, 1);  /* put it at index 1 */
  329.     tofile(L);  /* check that it's a valid file handle */
  330.     toclose = 0;  /* do not close it after iteration */
  331.   }
  332.   else {  /* open a new file */
  333.     const char *filename = luaL_checkstring(L, 1);
  334.     opencheck(L, filename, "r");
  335.     lua_replace(L, 1);  /* put file at index 1 */
  336.     toclose = 1;  /* close it after iteration */
  337.   }
  338.   aux_lines(L, toclose);
  339.   return 1;
  340. }
  341.  
  342.  
  343. /*
  344. ** {======================================================
  345. ** READ
  346. ** =======================================================
  347. */
  348.  
  349.  
  350. static int read_number (lua_State *L, FILE *f) {
  351.   lua_Number d;
  352.   if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1) {
  353.     lua_pushnumber(L, d);
  354.     return 1;
  355.   }
  356.   else {
  357.    lua_pushnil(L);  /* "result" to be removed */
  358.    return 0;  /* read fails */
  359.   }
  360. }
  361.  
  362.  
  363. static int test_eof (lua_State *L, FILE *f) {
  364.   int c = getc(f);
  365.   ungetc(c, f);
  366.   lua_pushlstring(L, NULL, 0);
  367.   return (c != EOF);
  368. }
  369.  
  370.  
  371. static int read_line (lua_State *L, FILE *f, int chop) {
  372.   luaL_Buffer b;
  373.   luaL_buffinit(L, &b);
  374.   for (;;) {
  375.     size_t l;
  376.     char *p = luaL_prepbuffer(&b);
  377.     if (fgets(p, LUAL_BUFFERSIZE, f) == NULL) {  /* eof? */
  378.       luaL_pushresult(&b);  /* close buffer */
  379.       return (lua_rawlen(L, -1) > 0);  /* check whether read something */
  380.     }
  381.     l = strlen(p);
  382.     if (l == 0 || p[l-1] != '\n')
  383.       luaL_addsize(&b, l);
  384.     else {
  385.       luaL_addsize(&b, l - chop);  /* chop 'eol' if needed */
  386.       luaL_pushresult(&b);  /* close buffer */
  387.       return 1;  /* read at least an `eol' */
  388.     }
  389.   }
  390. }
  391.  
  392.  
  393. #define MAX_SIZE_T      (~(size_t)0)
  394.  
  395. static void read_all (lua_State *L, FILE *f) {
  396.   size_t rlen = LUAL_BUFFERSIZE;  /* how much to read in each cycle */
  397.   luaL_Buffer b;
  398.   luaL_buffinit(L, &b);
  399.   for (;;) {
  400.     char *p = luaL_prepbuffsize(&b, rlen);
  401.     size_t nr = fread(p, sizeof(char), rlen, f);
  402.     luaL_addsize(&b, nr);
  403.     if (nr < rlen) break;  /* eof? */
  404.     else if (rlen <= (MAX_SIZE_T / 4))  /* avoid buffers too large */
  405.       rlen *= 2;  /* double buffer size at each iteration */
  406.   }
  407.   luaL_pushresult(&b);  /* close buffer */
  408. }
  409.  
  410.  
  411. static int read_chars (lua_State *L, FILE *f, size_t n) {
  412.   size_t nr;  /* number of chars actually read */
  413.   char *p;
  414.   luaL_Buffer b;
  415.   luaL_buffinit(L, &b);
  416.   p = luaL_prepbuffsize(&b, n);  /* prepare buffer to read whole block */
  417.   nr = fread(p, sizeof(char), n, f);  /* try to read 'n' chars */
  418.   luaL_addsize(&b, nr);
  419.   luaL_pushresult(&b);  /* close buffer */
  420.   return (nr > 0);  /* true iff read something */
  421. }
  422.  
  423.  
  424. static int g_read (lua_State *L, FILE *f, int first) {
  425.   int nargs = lua_gettop(L) - 1;
  426.   int success;
  427.   int n;
  428.   clearerr(f);
  429.   if (nargs == 0) {  /* no arguments? */
  430.     success = read_line(L, f, 1);
  431.     n = first+1;  /* to return 1 result */
  432.   }
  433.   else {  /* ensure stack space for all results and for auxlib's buffer */
  434.     luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");
  435.     success = 1;
  436.     for (n = first; nargs-- && success; n++) {
  437.       if (lua_type(L, n) == LUA_TNUMBER) {
  438.         size_t l = (size_t)lua_tointeger(L, n);
  439.         success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
  440.       }
  441.       else {
  442.         const char *p = lua_tostring(L, n);
  443.         luaL_argcheck(L, p && p[0] == '*', n, "invalid option");
  444.         switch (p[1]) {
  445.           case 'n':  /* number */
  446.             success = read_number(L, f);
  447.             break;
  448.           case 'l':  /* line */
  449.             success = read_line(L, f, 1);
  450.             break;
  451.           case 'L':  /* line with end-of-line */
  452.             success = read_line(L, f, 0);
  453.             break;
  454.           case 'a':  /* file */
  455.             read_all(L, f);  /* read entire file */
  456.             success = 1; /* always success */
  457.             break;
  458.           default:
  459.             return luaL_argerror(L, n, "invalid format");
  460.         }
  461.       }
  462.     }
  463.   }
  464.   if (ferror(f))
  465.     return luaL_fileresult(L, 0, NULL);
  466.   if (!success) {
  467.     lua_pop(L, 1);  /* remove last result */
  468.     lua_pushnil(L);  /* push nil instead */
  469.   }
  470.   return n - first;
  471. }
  472.  
  473.  
  474. static int io_read (lua_State *L) {
  475.   return g_read(L, getiofile(L, IO_INPUT), 1);
  476. }
  477.  
  478.  
  479. static int f_read (lua_State *L) {
  480.   return g_read(L, tofile(L), 2);
  481. }
  482.  
  483.  
  484. static int io_readline (lua_State *L) {
  485.   LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1));
  486.   int i;
  487.   int n = (int)lua_tointeger(L, lua_upvalueindex(2));
  488.   if (isclosed(p))  /* file is already closed? */
  489.     return luaL_error(L, "file is already closed");
  490.   lua_settop(L , 1);
  491.   for (i = 1; i <= n; i++)  /* push arguments to 'g_read' */
  492.     lua_pushvalue(L, lua_upvalueindex(3 + i));
  493.   n = g_read(L, p->f, 2);  /* 'n' is number of results */
  494.   lua_assert(n > 0);  /* should return at least a nil */
  495.   if (!lua_isnil(L, -n))  /* read at least one value? */
  496.     return n;  /* return them */
  497.   else {  /* first result is nil: EOF or error */
  498.     if (n > 1) {  /* is there error information? */
  499.       /* 2nd result is error message */
  500.       return luaL_error(L, "%s", lua_tostring(L, -n + 1));
  501.     }
  502.     if (lua_toboolean(L, lua_upvalueindex(3))) {  /* generator created file? */
  503.       lua_settop(L, 0);
  504.       lua_pushvalue(L, lua_upvalueindex(1));
  505.       aux_close(L);  /* close it */
  506.     }
  507.     return 0;
  508.   }
  509. }
  510.  
  511. /* }====================================================== */
  512.  
  513.  
  514. static int g_write (lua_State *L, FILE *f, int arg) {
  515.   int nargs = lua_gettop(L) - arg;
  516.   int status = 1;
  517.   for (; nargs--; arg++) {
  518.     if (lua_type(L, arg) == LUA_TNUMBER) {
  519.       /* optimization: could be done exactly as for strings */
  520.       status = status &&
  521.           fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
  522.     }
  523.     else {
  524.       size_t l;
  525.       const char *s = luaL_checklstring(L, arg, &l);
  526.       status = status && (fwrite(s, sizeof(char), l, f) == l);
  527.     }
  528.   }
  529.   if (status) return 1;  /* file handle already on stack top */
  530.   else return luaL_fileresult(L, status, NULL);
  531. }
  532.  
  533.  
  534. static int io_write (lua_State *L) {
  535.   return g_write(L, getiofile(L, IO_OUTPUT), 1);
  536. }
  537.  
  538.  
  539. static int f_write (lua_State *L) {
  540.   FILE *f = tofile(L);
  541.   lua_pushvalue(L, 1);  /* push file at the stack top (to be returned) */
  542.   return g_write(L, f, 2);
  543. }
  544.  
  545.  
  546. static int f_seek (lua_State *L) {
  547.   static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
  548.   static const char *const modenames[] = {"set", "cur", "end", NULL};
  549.   FILE *f = tofile(L);
  550.   int op = luaL_checkoption(L, 2, "cur", modenames);
  551.   lua_Number p3 = luaL_optnumber(L, 3, 0);
  552.   l_seeknum offset = (l_seeknum)p3;
  553.   luaL_argcheck(L, (lua_Number)offset == p3, 3,
  554.                   "not an integer in proper range");
  555.   op = l_fseek(f, offset, mode[op]);
  556.   if (op)
  557.     return luaL_fileresult(L, 0, NULL);  /* error */
  558.   else {
  559.     lua_pushnumber(L, (lua_Number)l_ftell(f));
  560.     return 1;
  561.   }
  562. }
  563.  
  564.  
  565. static int f_setvbuf (lua_State *L) {
  566.   static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
  567.   static const char *const modenames[] = {"no", "full", "line", NULL};
  568.   FILE *f = tofile(L);
  569.   int op = luaL_checkoption(L, 2, NULL, modenames);
  570.   lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
  571.   int res = setvbuf(f, NULL, mode[op], sz);
  572.   return luaL_fileresult(L, res == 0, NULL);
  573. }
  574.  
  575.  
  576.  
  577. static int io_flush (lua_State *L) {
  578.   return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
  579. }
  580.  
  581.  
  582. static int f_flush (lua_State *L) {
  583.   return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL);
  584. }
  585.  
  586.  
  587. /*
  588. ** functions for 'io' library
  589. */
  590. static const luaL_Reg iolib[] = {
  591.   {"close", io_close},
  592.   {"flush", io_flush},
  593.   {"input", io_input},
  594.   {"lines", io_lines},
  595.   {"open", io_open},
  596.   {"output", io_output},
  597.   {"popen", io_popen},
  598.   {"read", io_read},
  599.   {"tmpfile", io_tmpfile},
  600.   {"type", io_type},
  601.   {"write", io_write},
  602.   {NULL, NULL}
  603. };
  604.  
  605.  
  606. /*
  607. ** methods for file handles
  608. */
  609. static const luaL_Reg flib[] = {
  610.   {"close", io_close},
  611.   {"flush", f_flush},
  612.   {"lines", f_lines},
  613.   {"read", f_read},
  614.   {"seek", f_seek},
  615.   {"setvbuf", f_setvbuf},
  616.   {"write", f_write},
  617.   {"__gc", f_gc},
  618.   {"__tostring", f_tostring},
  619.   {NULL, NULL}
  620. };
  621.  
  622.  
  623. static void createmeta (lua_State *L) {
  624.   luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */
  625.   lua_pushvalue(L, -1);  /* push metatable */
  626.   lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
  627.   luaL_setfuncs(L, flib, 0);  /* add file methods to new metatable */
  628.   lua_pop(L, 1);  /* pop new metatable */
  629. }
  630.  
  631.  
  632. /*
  633. ** function to (not) close the standard files stdin, stdout, and stderr
  634. */
  635. static int io_noclose (lua_State *L) {
  636.   LStream *p = tolstream(L);
  637.   p->closef = &io_noclose;  /* keep file opened */
  638.   lua_pushnil(L);
  639.   lua_pushliteral(L, "cannot close standard file");
  640.   return 2;
  641. }
  642.  
  643.  
  644. static void createstdfile (lua_State *L, FILE *f, const char *k,
  645.                            const char *fname) {
  646.   LStream *p = newprefile(L);
  647.   p->f = f;
  648.   p->closef = &io_noclose;
  649.   if (k != NULL) {
  650.     lua_pushvalue(L, -1);
  651.     lua_setfield(L, LUA_REGISTRYINDEX, k);  /* add file to registry */
  652.   }
  653.   lua_setfield(L, -2, fname);  /* add file to module */
  654. }
  655.  
  656.  
  657. LUAMOD_API int luaopen_io (lua_State *L) {
  658.   luaL_newlib(L, iolib);  /* new module */
  659.   createmeta(L);
  660.   /* create (and set) default files */
  661.   createstdfile(L, stdin, IO_INPUT, "stdin");
  662.   createstdfile(L, stdout, IO_OUTPUT, "stdout");
  663.   createstdfile(L, stderr, NULL, "stderr");
  664.   return 1;
  665. }
  666.  
  667.