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  1. /*
  2. ** $Id: liolib.c,v 2.151.1.1 2017/04/19 17:29:57 roberto Exp $
  3. ** Standard I/O (and system) library
  4. ** See Copyright Notice in lua.h
  5. */
  6.  
  7. #define liolib_c
  8. #define LUA_LIB
  9.  
  10. #include "lprefix.h"
  11.  
  12.  
  13. #include <ctype.h>
  14. #include <errno.h>
  15. #include <locale.h>
  16. #include <stdio.h>
  17. #include <stdlib.h>
  18. #include <string.h>
  19.  
  20. #include "lua.h"
  21.  
  22. #include "lauxlib.h"
  23. #include "lualib.h"
  24.  
  25.  
  26.  
  27.  
  28. /*
  29. ** Change this macro to accept other modes for 'fopen' besides
  30. ** the standard ones.
  31. */
  32. #if !defined(l_checkmode)
  33.  
  34. /* accepted extensions to 'mode' in 'fopen' */
  35. #if !defined(L_MODEEXT)
  36. #define L_MODEEXT       "b"
  37. #endif
  38.  
  39. /* Check whether 'mode' matches '[rwa]%+?[L_MODEEXT]*' */
  40. static int l_checkmode (const char *mode) {
  41.   return (*mode != '\0' && strchr("rwa", *(mode++)) != NULL &&
  42.          (*mode != '+' || (++mode, 1)) &&  /* skip if char is '+' */
  43.          (strspn(mode, L_MODEEXT) == strlen(mode)));  /* check extensions */
  44. }
  45.  
  46. #endif
  47.  
  48. /*
  49. ** {======================================================
  50. ** l_popen spawns a new process connected to the current
  51. ** one through the file streams.
  52. ** =======================================================
  53. */
  54.  
  55. #if !defined(l_popen)           /* { */
  56.  
  57. #if defined(LUA_USE_POSIX)      /* { */
  58.  
  59. #define l_popen(L,c,m)          (fflush(NULL), popen(c,m))
  60. #define l_pclose(L,file)        (pclose(file))
  61.  
  62. #elif defined(LUA_USE_WINDOWS)  /* }{ */
  63.  
  64. #define l_popen(L,c,m)          (_popen(c,m))
  65. #define l_pclose(L,file)        (_pclose(file))
  66.  
  67. #else                           /* }{ */
  68.  
  69. /* ISO C definitions */
  70. #define l_popen(L,c,m)  \
  71.           ((void)((void)c, m), \
  72.           luaL_error(L, "'popen' not supported"), \
  73.           (FILE*)0)
  74. #define l_pclose(L,file)                ((void)L, (void)file, -1)
  75.  
  76. #endif                          /* } */
  77.  
  78. #endif                          /* } */
  79.  
  80. /* }====================================================== */
  81.  
  82.  
  83. #if !defined(l_getc)            /* { */
  84.  
  85. #if defined(LUA_USE_POSIX)
  86. #define l_getc(f)               getc_unlocked(f)
  87. #define l_lockfile(f)           flockfile(f)
  88. #define l_unlockfile(f)         funlockfile(f)
  89. #else
  90. #define l_getc(f)               getc(f)
  91. #define l_lockfile(f)           ((void)0)
  92. #define l_unlockfile(f)         ((void)0)
  93. #endif
  94.  
  95. #endif                          /* } */
  96.  
  97.  
  98. /*
  99. ** {======================================================
  100. ** l_fseek: configuration for longer offsets
  101. ** =======================================================
  102. */
  103.  
  104. #if !defined(l_fseek)           /* { */
  105.  
  106. #if defined(LUA_USE_POSIX)      /* { */
  107.  
  108. #include <sys/types.h>
  109.  
  110. #define l_fseek(f,o,w)          fseeko(f,o,w)
  111. #define l_ftell(f)              ftello(f)
  112. #define l_seeknum               off_t
  113.  
  114. #elif defined(LUA_USE_WINDOWS) && !defined(_CRTIMP_TYPEINFO) \
  115.    && defined(_MSC_VER) && (_MSC_VER >= 1400)   /* }{ */
  116.  
  117. /* Windows (but not DDK) and Visual C++ 2005 or higher */
  118. #define l_fseek(f,o,w)          _fseeki64(f,o,w)
  119. #define l_ftell(f)              _ftelli64(f)
  120. #define l_seeknum               __int64
  121.  
  122. #else                           /* }{ */
  123.  
  124. /* ISO C definitions */
  125. #define l_fseek(f,o,w)          fseek(f,o,w)
  126. #define l_ftell(f)              ftell(f)
  127. #define l_seeknum               long
  128.  
  129. #endif                          /* } */
  130.  
  131. #endif                          /* } */
  132.  
  133. /* }====================================================== */
  134.  
  135.  
  136. #define IO_PREFIX       "_IO_"
  137. #define IOPREF_LEN      (sizeof(IO_PREFIX)/sizeof(char) - 1)
  138. #define IO_INPUT        (IO_PREFIX "input")
  139. #define IO_OUTPUT       (IO_PREFIX "output")
  140.  
  141.  
  142. typedef luaL_Stream LStream;
  143.  
  144.  
  145. #define tolstream(L)    ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))
  146.  
  147. #define isclosed(p)     ((p)->closef == NULL)
  148.  
  149.  
  150. static int io_type (lua_State *L) {
  151.   LStream *p;
  152.   luaL_checkany(L, 1);
  153.   p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE);
  154.   if (p == NULL)
  155.     lua_pushnil(L);  /* not a file */
  156.   else if (isclosed(p))
  157.     lua_pushliteral(L, "closed file");
  158.   else
  159.     lua_pushliteral(L, "file");
  160.   return 1;
  161. }
  162.  
  163.  
  164. static int f_tostring (lua_State *L) {
  165.   LStream *p = tolstream(L);
  166.   if (isclosed(p))
  167.     lua_pushliteral(L, "file (closed)");
  168.   else
  169.     lua_pushfstring(L, "file (%p)", p->f);
  170.   return 1;
  171. }
  172.  
  173.  
  174. static FILE *tofile (lua_State *L) {
  175.   LStream *p = tolstream(L);
  176.   if (isclosed(p))
  177.     luaL_error(L, "attempt to use a closed file");
  178.   lua_assert(p->f);
  179.   return p->f;
  180. }
  181.  
  182.  
  183. /*
  184. ** When creating file handles, always creates a 'closed' file handle
  185. ** before opening the actual file; so, if there is a memory error, the
  186. ** handle is in a consistent state.
  187. */
  188. static LStream *newprefile (lua_State *L) {
  189.   LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream));
  190.   p->closef = NULL;  /* mark file handle as 'closed' */
  191.   luaL_setmetatable(L, LUA_FILEHANDLE);
  192.   return p;
  193. }
  194.  
  195.  
  196. /*
  197. ** Calls the 'close' function from a file handle. The 'volatile' avoids
  198. ** a bug in some versions of the Clang compiler (e.g., clang 3.0 for
  199. ** 32 bits).
  200. */
  201. static int aux_close (lua_State *L) {
  202.   LStream *p = tolstream(L);
  203.   volatile lua_CFunction cf = p->closef;
  204.   p->closef = NULL;  /* mark stream as closed */
  205.   return (*cf)(L);  /* close it */
  206. }
  207.  
  208.  
  209. static int f_close (lua_State *L) {
  210.   tofile(L);  /* make sure argument is an open stream */
  211.   return aux_close(L);
  212. }
  213.  
  214.  
  215. static int io_close (lua_State *L) {
  216.   if (lua_isnone(L, 1))  /* no argument? */
  217.     lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT);  /* use standard output */
  218.   return f_close(L);
  219. }
  220.  
  221.  
  222. static int f_gc (lua_State *L) {
  223.   LStream *p = tolstream(L);
  224.   if (!isclosed(p) && p->f != NULL)
  225.     aux_close(L);  /* ignore closed and incompletely open files */
  226.   return 0;
  227. }
  228.  
  229.  
  230. /*
  231. ** function to close regular files
  232. */
  233. static int io_fclose (lua_State *L) {
  234.   LStream *p = tolstream(L);
  235.   int res = fclose(p->f);
  236.   return luaL_fileresult(L, (res == 0), NULL);
  237. }
  238.  
  239.  
  240. static LStream *newfile (lua_State *L) {
  241.   LStream *p = newprefile(L);
  242.   p->f = NULL;
  243.   p->closef = &io_fclose;
  244.   return p;
  245. }
  246.  
  247.  
  248. static void opencheck (lua_State *L, const char *fname, const char *mode) {
  249.   LStream *p = newfile(L);
  250.   p->f = fopen(fname, mode);
  251.   if (p->f == NULL)
  252.     luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno));
  253. }
  254.  
  255.  
  256. static int io_open (lua_State *L) {
  257.   const char *filename = luaL_checkstring(L, 1);
  258.   const char *mode = luaL_optstring(L, 2, "r");
  259.   LStream *p = newfile(L);
  260.   const char *md = mode;  /* to traverse/check mode */
  261.   luaL_argcheck(L, l_checkmode(md), 2, "invalid mode");
  262.   p->f = fopen(filename, mode);
  263.   return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
  264. }
  265.  
  266.  
  267. /*
  268. ** function to close 'popen' files
  269. */
  270. static int io_pclose (lua_State *L) {
  271.   LStream *p = tolstream(L);
  272.   return luaL_execresult(L, l_pclose(L, p->f));
  273. }
  274.  
  275.  
  276. static int io_popen (lua_State *L) {
  277.   const char *filename = luaL_checkstring(L, 1);
  278.   const char *mode = luaL_optstring(L, 2, "r");
  279.   LStream *p = newprefile(L);
  280.   luaL_argcheck(L, ((mode[0] == 'r' || mode[0] == 'w') && mode[1] == '\0'),
  281.                    2, "invalid mode");
  282.   p->f = l_popen(L, filename, mode);
  283.   p->closef = &io_pclose;
  284.   return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
  285. }
  286.  
  287.  
  288. static int io_tmpfile (lua_State *L) {
  289.   LStream *p = newfile(L);
  290.   p->f = tmpfile();
  291.   return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1;
  292. }
  293.  
  294.  
  295. static FILE *getiofile (lua_State *L, const char *findex) {
  296.   LStream *p;
  297.   lua_getfield(L, LUA_REGISTRYINDEX, findex);
  298.   p = (LStream *)lua_touserdata(L, -1);
  299.   if (isclosed(p))
  300.     luaL_error(L, "standard %s file is closed", findex + IOPREF_LEN);
  301.   return p->f;
  302. }
  303.  
  304.  
  305. static int g_iofile (lua_State *L, const char *f, const char *mode) {
  306.   if (!lua_isnoneornil(L, 1)) {
  307.     const char *filename = lua_tostring(L, 1);
  308.     if (filename)
  309.       opencheck(L, filename, mode);
  310.     else {
  311.       tofile(L);  /* check that it's a valid file handle */
  312.       lua_pushvalue(L, 1);
  313.     }
  314.     lua_setfield(L, LUA_REGISTRYINDEX, f);
  315.   }
  316.   /* return current value */
  317.   lua_getfield(L, LUA_REGISTRYINDEX, f);
  318.   return 1;
  319. }
  320.  
  321.  
  322. static int io_input (lua_State *L) {
  323.   return g_iofile(L, IO_INPUT, "r");
  324. }
  325.  
  326.  
  327. static int io_output (lua_State *L) {
  328.   return g_iofile(L, IO_OUTPUT, "w");
  329. }
  330.  
  331.  
  332. static int io_readline (lua_State *L);
  333.  
  334.  
  335. /*
  336. ** maximum number of arguments to 'f:lines'/'io.lines' (it + 3 must fit
  337. ** in the limit for upvalues of a closure)
  338. */
  339. #define MAXARGLINE      250
  340.  
  341. static void aux_lines (lua_State *L, int toclose) {
  342.   int n = lua_gettop(L) - 1;  /* number of arguments to read */
  343.   luaL_argcheck(L, n <= MAXARGLINE, MAXARGLINE + 2, "too many arguments");
  344.   lua_pushinteger(L, n);  /* number of arguments to read */
  345.   lua_pushboolean(L, toclose);  /* close/not close file when finished */
  346.   lua_rotate(L, 2, 2);  /* move 'n' and 'toclose' to their positions */
  347.   lua_pushcclosure(L, io_readline, 3 + n);
  348. }
  349.  
  350.  
  351. static int f_lines (lua_State *L) {
  352.   tofile(L);  /* check that it's a valid file handle */
  353.   aux_lines(L, 0);
  354.   return 1;
  355. }
  356.  
  357.  
  358. static int io_lines (lua_State *L) {
  359.   int toclose;
  360.   if (lua_isnone(L, 1)) lua_pushnil(L);  /* at least one argument */
  361.   if (lua_isnil(L, 1)) {  /* no file name? */
  362.     lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT);  /* get default input */
  363.     lua_replace(L, 1);  /* put it at index 1 */
  364.     tofile(L);  /* check that it's a valid file handle */
  365.     toclose = 0;  /* do not close it after iteration */
  366.   }
  367.   else {  /* open a new file */
  368.     const char *filename = luaL_checkstring(L, 1);
  369.     opencheck(L, filename, "r");
  370.     lua_replace(L, 1);  /* put file at index 1 */
  371.     toclose = 1;  /* close it after iteration */
  372.   }
  373.   aux_lines(L, toclose);
  374.   return 1;
  375. }
  376.  
  377.  
  378. /*
  379. ** {======================================================
  380. ** READ
  381. ** =======================================================
  382. */
  383.  
  384.  
  385. /* maximum length of a numeral */
  386. #if !defined (L_MAXLENNUM)
  387. #define L_MAXLENNUM     200
  388. #endif
  389.  
  390.  
  391. /* auxiliary structure used by 'read_number' */
  392. typedef struct {
  393.   FILE *f;  /* file being read */
  394.   int c;  /* current character (look ahead) */
  395.   int n;  /* number of elements in buffer 'buff' */
  396.   char buff[L_MAXLENNUM + 1];  /* +1 for ending '\0' */
  397. } RN;
  398.  
  399.  
  400. /*
  401. ** Add current char to buffer (if not out of space) and read next one
  402. */
  403. static int nextc (RN *rn) {
  404.   if (rn->n >= L_MAXLENNUM) {  /* buffer overflow? */
  405.     rn->buff[0] = '\0';  /* invalidate result */
  406.     return 0;  /* fail */
  407.   }
  408.   else {
  409.     rn->buff[rn->n++] = rn->c;  /* save current char */
  410.     rn->c = l_getc(rn->f);  /* read next one */
  411.     return 1;
  412.   }
  413. }
  414.  
  415.  
  416. /*
  417. ** Accept current char if it is in 'set' (of size 2)
  418. */
  419. static int test2 (RN *rn, const char *set) {
  420.   if (rn->c == set[0] || rn->c == set[1])
  421.     return nextc(rn);
  422.   else return 0;
  423. }
  424.  
  425.  
  426. /*
  427. ** Read a sequence of (hex)digits
  428. */
  429. static int readdigits (RN *rn, int hex) {
  430.   int count = 0;
  431.   while ((hex ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn))
  432.     count++;
  433.   return count;
  434. }
  435.  
  436.  
  437. /*
  438. ** Read a number: first reads a valid prefix of a numeral into a buffer.
  439. ** Then it calls 'lua_stringtonumber' to check whether the format is
  440. ** correct and to convert it to a Lua number
  441. */
  442. static int read_number (lua_State *L, FILE *f) {
  443.   RN rn;
  444.   int count = 0;
  445.   int hex = 0;
  446.   char decp[2];
  447.   rn.f = f; rn.n = 0;
  448.   decp[0] = lua_getlocaledecpoint();  /* get decimal point from locale */
  449.   decp[1] = '.';  /* always accept a dot */
  450.   l_lockfile(rn.f);
  451.   do { rn.c = l_getc(rn.f); } while (isspace(rn.c));  /* skip spaces */
  452.   test2(&rn, "-+");  /* optional signal */
  453.   if (test2(&rn, "00")) {
  454.     if (test2(&rn, "xX")) hex = 1;  /* numeral is hexadecimal */
  455.     else count = 1;  /* count initial '0' as a valid digit */
  456.   }
  457.   count += readdigits(&rn, hex);  /* integral part */
  458.   if (test2(&rn, decp))  /* decimal point? */
  459.     count += readdigits(&rn, hex);  /* fractional part */
  460.   if (count > 0 && test2(&rn, (hex ? "pP" : "eE"))) {  /* exponent mark? */
  461.     test2(&rn, "-+");  /* exponent signal */
  462.     readdigits(&rn, 0);  /* exponent digits */
  463.   }
  464.   ungetc(rn.c, rn.f);  /* unread look-ahead char */
  465.   l_unlockfile(rn.f);
  466.   rn.buff[rn.n] = '\0';  /* finish string */
  467.   if (lua_stringtonumber(L, rn.buff))  /* is this a valid number? */
  468.     return 1;  /* ok */
  469.   else {  /* invalid format */
  470.    lua_pushnil(L);  /* "result" to be removed */
  471.    return 0;  /* read fails */
  472.   }
  473. }
  474.  
  475.  
  476. static int test_eof (lua_State *L, FILE *f) {
  477.   int c = getc(f);
  478.   ungetc(c, f);  /* no-op when c == EOF */
  479.   lua_pushliteral(L, "");
  480.   return (c != EOF);
  481. }
  482.  
  483.  
  484. static int read_line (lua_State *L, FILE *f, int chop) {
  485.   luaL_Buffer b;
  486.   int c = '\0';
  487.   luaL_buffinit(L, &b);
  488.   while (c != EOF && c != '\n') {  /* repeat until end of line */
  489.     char *buff = luaL_prepbuffer(&b);  /* preallocate buffer */
  490.     int i = 0;
  491.     l_lockfile(f);  /* no memory errors can happen inside the lock */
  492.     while (i < LUAL_BUFFERSIZE && (c = l_getc(f)) != EOF && c != '\n')
  493.       buff[i++] = c;
  494.     l_unlockfile(f);
  495.     luaL_addsize(&b, i);
  496.   }
  497.   if (!chop && c == '\n')  /* want a newline and have one? */
  498.     luaL_addchar(&b, c);  /* add ending newline to result */
  499.   luaL_pushresult(&b);  /* close buffer */
  500.   /* return ok if read something (either a newline or something else) */
  501.   return (c == '\n' || lua_rawlen(L, -1) > 0);
  502. }
  503.  
  504.  
  505. static void read_all (lua_State *L, FILE *f) {
  506.   size_t nr;
  507.   luaL_Buffer b;
  508.   luaL_buffinit(L, &b);
  509.   do {  /* read file in chunks of LUAL_BUFFERSIZE bytes */
  510.     char *p = luaL_prepbuffer(&b);
  511.     nr = fread(p, sizeof(char), LUAL_BUFFERSIZE, f);
  512.     luaL_addsize(&b, nr);
  513.   } while (nr == LUAL_BUFFERSIZE);
  514.   luaL_pushresult(&b);  /* close buffer */
  515. }
  516.  
  517.  
  518. static int read_chars (lua_State *L, FILE *f, size_t n) {
  519.   size_t nr;  /* number of chars actually read */
  520.   char *p;
  521.   luaL_Buffer b;
  522.   luaL_buffinit(L, &b);
  523.   p = luaL_prepbuffsize(&b, n);  /* prepare buffer to read whole block */
  524.   nr = fread(p, sizeof(char), n, f);  /* try to read 'n' chars */
  525.   luaL_addsize(&b, nr);
  526.   luaL_pushresult(&b);  /* close buffer */
  527.   return (nr > 0);  /* true iff read something */
  528. }
  529.  
  530.  
  531. static int g_read (lua_State *L, FILE *f, int first) {
  532.   int nargs = lua_gettop(L) - 1;
  533.   int success;
  534.   int n;
  535.   clearerr(f);
  536.   if (nargs == 0) {  /* no arguments? */
  537.     success = read_line(L, f, 1);
  538.     n = first+1;  /* to return 1 result */
  539.   }
  540.   else {  /* ensure stack space for all results and for auxlib's buffer */
  541.     luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");
  542.     success = 1;
  543.     for (n = first; nargs-- && success; n++) {
  544.       if (lua_type(L, n) == LUA_TNUMBER) {
  545.         size_t l = (size_t)luaL_checkinteger(L, n);
  546.         success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
  547.       }
  548.       else {
  549.         const char *p = luaL_checkstring(L, n);
  550.         if (*p == '*') p++;  /* skip optional '*' (for compatibility) */
  551.         switch (*p) {
  552.           case 'n':  /* number */
  553.             success = read_number(L, f);
  554.             break;
  555.           case 'l':  /* line */
  556.             success = read_line(L, f, 1);
  557.             break;
  558.           case 'L':  /* line with end-of-line */
  559.             success = read_line(L, f, 0);
  560.             break;
  561.           case 'a':  /* file */
  562.             read_all(L, f);  /* read entire file */
  563.             success = 1; /* always success */
  564.             break;
  565.           default:
  566.             return luaL_argerror(L, n, "invalid format");
  567.         }
  568.       }
  569.     }
  570.   }
  571.   if (ferror(f))
  572.     return luaL_fileresult(L, 0, NULL);
  573.   if (!success) {
  574.     lua_pop(L, 1);  /* remove last result */
  575.     lua_pushnil(L);  /* push nil instead */
  576.   }
  577.   return n - first;
  578. }
  579.  
  580.  
  581. static int io_read (lua_State *L) {
  582.   return g_read(L, getiofile(L, IO_INPUT), 1);
  583. }
  584.  
  585.  
  586. static int f_read (lua_State *L) {
  587.   return g_read(L, tofile(L), 2);
  588. }
  589.  
  590.  
  591. static int io_readline (lua_State *L) {
  592.   LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1));
  593.   int i;
  594.   int n = (int)lua_tointeger(L, lua_upvalueindex(2));
  595.   if (isclosed(p))  /* file is already closed? */
  596.     return luaL_error(L, "file is already closed");
  597.   lua_settop(L , 1);
  598.   luaL_checkstack(L, n, "too many arguments");
  599.   for (i = 1; i <= n; i++)  /* push arguments to 'g_read' */
  600.     lua_pushvalue(L, lua_upvalueindex(3 + i));
  601.   n = g_read(L, p->f, 2);  /* 'n' is number of results */
  602.   lua_assert(n > 0);  /* should return at least a nil */
  603.   if (lua_toboolean(L, -n))  /* read at least one value? */
  604.     return n;  /* return them */
  605.   else {  /* first result is nil: EOF or error */
  606.     if (n > 1) {  /* is there error information? */
  607.       /* 2nd result is error message */
  608.       return luaL_error(L, "%s", lua_tostring(L, -n + 1));
  609.     }
  610.     if (lua_toboolean(L, lua_upvalueindex(3))) {  /* generator created file? */
  611.       lua_settop(L, 0);
  612.       lua_pushvalue(L, lua_upvalueindex(1));
  613.       aux_close(L);  /* close it */
  614.     }
  615.     return 0;
  616.   }
  617. }
  618.  
  619. /* }====================================================== */
  620.  
  621.  
  622. static int g_write (lua_State *L, FILE *f, int arg) {
  623.   int nargs = lua_gettop(L) - arg;
  624.   int status = 1;
  625.   for (; nargs--; arg++) {
  626.     if (lua_type(L, arg) == LUA_TNUMBER) {
  627.       /* optimization: could be done exactly as for strings */
  628.       int len = lua_isinteger(L, arg)
  629.                 ? fprintf(f, LUA_INTEGER_FMT,
  630.                              (LUAI_UACINT)lua_tointeger(L, arg))
  631.                 : fprintf(f, LUA_NUMBER_FMT,
  632.                              (LUAI_UACNUMBER)lua_tonumber(L, arg));
  633.       status = status && (len > 0);
  634.     }
  635.     else {
  636.       size_t l;
  637.       const char *s = luaL_checklstring(L, arg, &l);
  638.       status = status && (fwrite(s, sizeof(char), l, f) == l);
  639.     }
  640.   }
  641.   if (status) return 1;  /* file handle already on stack top */
  642.   else return luaL_fileresult(L, status, NULL);
  643. }
  644.  
  645.  
  646. static int io_write (lua_State *L) {
  647.   return g_write(L, getiofile(L, IO_OUTPUT), 1);
  648. }
  649.  
  650.  
  651. static int f_write (lua_State *L) {
  652.   FILE *f = tofile(L);
  653.   lua_pushvalue(L, 1);  /* push file at the stack top (to be returned) */
  654.   return g_write(L, f, 2);
  655. }
  656.  
  657.  
  658. static int f_seek (lua_State *L) {
  659.   static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
  660.   static const char *const modenames[] = {"set", "cur", "end", NULL};
  661.   FILE *f = tofile(L);
  662.   int op = luaL_checkoption(L, 2, "cur", modenames);
  663.   lua_Integer p3 = luaL_optinteger(L, 3, 0);
  664.   l_seeknum offset = (l_seeknum)p3;
  665.   luaL_argcheck(L, (lua_Integer)offset == p3, 3,
  666.                   "not an integer in proper range");
  667.   op = l_fseek(f, offset, mode[op]);
  668.   if (op)
  669.     return luaL_fileresult(L, 0, NULL);  /* error */
  670.   else {
  671.     lua_pushinteger(L, (lua_Integer)l_ftell(f));
  672.     return 1;
  673.   }
  674. }
  675.  
  676.  
  677. static int f_setvbuf (lua_State *L) {
  678.   static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
  679.   static const char *const modenames[] = {"no", "full", "line", NULL};
  680.   FILE *f = tofile(L);
  681.   int op = luaL_checkoption(L, 2, NULL, modenames);
  682.   lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
  683.   int res = setvbuf(f, NULL, mode[op], (size_t)sz);
  684.   return luaL_fileresult(L, res == 0, NULL);
  685. }
  686.  
  687.  
  688.  
  689. static int io_flush (lua_State *L) {
  690.   return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
  691. }
  692.  
  693.  
  694. static int f_flush (lua_State *L) {
  695.   return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL);
  696. }
  697.  
  698.  
  699. /*
  700. ** functions for 'io' library
  701. */
  702. static const luaL_Reg iolib[] = {
  703.   {"close", io_close},
  704.   {"flush", io_flush},
  705.   {"input", io_input},
  706.   {"lines", io_lines},
  707.   {"open", io_open},
  708.   {"output", io_output},
  709.   {"popen", io_popen},
  710.   {"read", io_read},
  711.   {"tmpfile", io_tmpfile},
  712.   {"type", io_type},
  713.   {"write", io_write},
  714.   {NULL, NULL}
  715. };
  716.  
  717.  
  718. /*
  719. ** methods for file handles
  720. */
  721. static const luaL_Reg flib[] = {
  722.   {"close", f_close},
  723.   {"flush", f_flush},
  724.   {"lines", f_lines},
  725.   {"read", f_read},
  726.   {"seek", f_seek},
  727.   {"setvbuf", f_setvbuf},
  728.   {"write", f_write},
  729.   {"__gc", f_gc},
  730.   {"__tostring", f_tostring},
  731.   {NULL, NULL}
  732. };
  733.  
  734.  
  735. static void createmeta (lua_State *L) {
  736.   luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */
  737.   lua_pushvalue(L, -1);  /* push metatable */
  738.   lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
  739.   luaL_setfuncs(L, flib, 0);  /* add file methods to new metatable */
  740.   lua_pop(L, 1);  /* pop new metatable */
  741. }
  742.  
  743.  
  744. /*
  745. ** function to (not) close the standard files stdin, stdout, and stderr
  746. */
  747. static int io_noclose (lua_State *L) {
  748.   LStream *p = tolstream(L);
  749.   p->closef = &io_noclose;  /* keep file opened */
  750.   lua_pushnil(L);
  751.   lua_pushliteral(L, "cannot close standard file");
  752.   return 2;
  753. }
  754.  
  755.  
  756. static void createstdfile (lua_State *L, FILE *f, const char *k,
  757.                            const char *fname) {
  758.   LStream *p = newprefile(L);
  759.   p->f = f;
  760.   p->closef = &io_noclose;
  761.   if (k != NULL) {
  762.     lua_pushvalue(L, -1);
  763.     lua_setfield(L, LUA_REGISTRYINDEX, k);  /* add file to registry */
  764.   }
  765.   lua_setfield(L, -2, fname);  /* add file to module */
  766. }
  767.  
  768.  
  769. LUAMOD_API int luaopen_io (lua_State *L) {
  770.   luaL_newlib(L, iolib);  /* new module */
  771.   createmeta(L);
  772.   /* create (and set) default files */
  773.   createstdfile(L, stdin, IO_INPUT, "stdin");
  774.   createstdfile(L, stdout, IO_OUTPUT, "stdout");
  775.   createstdfile(L, stderr, NULL, "stderr");
  776.   return 1;
  777. }
  778.  
  779.