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  1. /*
  2. ** $Id: liolib.c,v 2.73.1.4 2010/05/14 15:33:51 roberto Exp $
  3. ** Standard I/O (and system) library
  4. ** See Copyright Notice in lua.h
  5. */
  6.  
  7.  
  8. #include <errno.h>
  9. #include <stdio.h>
  10. #include <stdlib.h>
  11. #include <string.h>
  12.  
  13. #define liolib_c
  14. #define LUA_LIB
  15.  
  16. #include "lua.h"
  17.  
  18. #include "lauxlib.h"
  19. #include "lualib.h"
  20.  
  21.  
  22.  
  23. #define IO_INPUT        1
  24. #define IO_OUTPUT       2
  25.  
  26.  
  27. static const char *const fnames[] = {"input", "output"};
  28.  
  29.  
  30. static int pushresult (lua_State *L, int i, const char *filename) {
  31.   int en = errno;  /* calls to Lua API may change this value */
  32.   if (i) {
  33.     lua_pushboolean(L, 1);
  34.     return 1;
  35.   }
  36.   else {
  37.     lua_pushnil(L);
  38.     if (filename)
  39.       lua_pushfstring(L, "%s: %s", filename, strerror(en));
  40.     else
  41.       lua_pushfstring(L, "%s", strerror(en));
  42.     lua_pushinteger(L, en);
  43.     return 3;
  44.   }
  45. }
  46.  
  47.  
  48. static void fileerror (lua_State *L, int arg, const char *filename) {
  49.   lua_pushfstring(L, "%s: %s", filename, strerror(errno));
  50.   luaL_argerror(L, arg, lua_tostring(L, -1));
  51. }
  52.  
  53.  
  54. #define tofilep(L)      ((FILE **)luaL_checkudata(L, 1, LUA_FILEHANDLE))
  55.  
  56.  
  57. static int io_type (lua_State *L) {
  58.   void *ud;
  59.   luaL_checkany(L, 1);
  60.   ud = lua_touserdata(L, 1);
  61.   lua_getfield(L, LUA_REGISTRYINDEX, LUA_FILEHANDLE);
  62.   if (ud == NULL || !lua_getmetatable(L, 1) || !lua_rawequal(L, -2, -1))
  63.     lua_pushnil(L);  /* not a file */
  64.   else if (*((FILE **)ud) == NULL)
  65.     lua_pushliteral(L, "closed file");
  66.   else
  67.     lua_pushliteral(L, "file");
  68.   return 1;
  69. }
  70.  
  71.  
  72. static FILE *tofile (lua_State *L) {
  73.   FILE **f = tofilep(L);
  74.   if (*f == NULL)
  75.     luaL_error(L, "attempt to use a closed file");
  76.   return *f;
  77. }
  78.  
  79.  
  80.  
  81. /*
  82. ** When creating file handles, always creates a `closed' file handle
  83. ** before opening the actual file; so, if there is a memory error, the
  84. ** file is not left opened.
  85. */
  86. static FILE **newfile (lua_State *L) {
  87.   FILE **pf = (FILE **)lua_newuserdata(L, sizeof(FILE *));
  88.   *pf = NULL;  /* file handle is currently `closed' */
  89.   luaL_getmetatable(L, LUA_FILEHANDLE);
  90.   lua_setmetatable(L, -2);
  91.   return pf;
  92. }
  93.  
  94.  
  95. /*
  96. ** function to (not) close the standard files stdin, stdout, and stderr
  97. */
  98. static int io_noclose (lua_State *L) {
  99.   lua_pushnil(L);
  100.   lua_pushliteral(L, "cannot close standard file");
  101.   return 2;
  102. }
  103.  
  104.  
  105. /*
  106. ** function to close 'popen' files
  107. */
  108. static int io_pclose (lua_State *L) {
  109.   FILE **p = tofilep(L);
  110.   int ok = lua_pclose(L, *p);
  111.   *p = NULL;
  112.   return pushresult(L, ok, NULL);
  113. }
  114.  
  115.  
  116. /*
  117. ** function to close regular files
  118. */
  119. static int io_fclose (lua_State *L) {
  120.   FILE **p = tofilep(L);
  121.   int ok = (fclose(*p) == 0);
  122.   *p = NULL;
  123.   return pushresult(L, ok, NULL);
  124. }
  125.  
  126.  
  127. static int aux_close (lua_State *L) {
  128.   lua_getfenv(L, 1);
  129.   lua_getfield(L, -1, "__close");
  130.   return (lua_tocfunction(L, -1))(L);
  131. }
  132.  
  133.  
  134. static int io_close (lua_State *L) {
  135.   if (lua_isnone(L, 1))
  136.     lua_rawgeti(L, LUA_ENVIRONINDEX, IO_OUTPUT);
  137.   tofile(L);  /* make sure argument is a file */
  138.   return aux_close(L);
  139. }
  140.  
  141.  
  142. static int io_gc (lua_State *L) {
  143.   FILE *f = *tofilep(L);
  144.   /* ignore closed files */
  145.   if (f != NULL)
  146.     aux_close(L);
  147.   return 0;
  148. }
  149.  
  150.  
  151. static int io_tostring (lua_State *L) {
  152.   FILE *f = *tofilep(L);
  153.   if (f == NULL)
  154.     lua_pushliteral(L, "file (closed)");
  155.   else
  156.     lua_pushfstring(L, "file (%p)", f);
  157.   return 1;
  158. }
  159.  
  160.  
  161. static int io_open (lua_State *L) {
  162.   const char *filename = luaL_checkstring(L, 1);
  163.   const char *mode = luaL_optstring(L, 2, "r");
  164.   FILE **pf = newfile(L);
  165.   *pf = fopen(filename, mode);
  166.   return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
  167. }
  168.  
  169.  
  170. /*
  171. ** this function has a separated environment, which defines the
  172. ** correct __close for 'popen' files
  173. */
  174. static int io_popen (lua_State *L) {
  175.   const char *filename = luaL_checkstring(L, 1);
  176.   const char *mode = luaL_optstring(L, 2, "r");
  177.   FILE **pf = newfile(L);
  178.   *pf = lua_popen(L, filename, mode);
  179.   return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
  180. }
  181.  
  182.  
  183. static int io_tmpfile (lua_State *L) {
  184.   FILE **pf = newfile(L);
  185.   *pf = tmpfile();
  186.   return (*pf == NULL) ? pushresult(L, 0, NULL) : 1;
  187. }
  188.  
  189.  
  190. static FILE *getiofile (lua_State *L, int findex) {
  191.   FILE *f;
  192.   lua_rawgeti(L, LUA_ENVIRONINDEX, findex);
  193.   f = *(FILE **)lua_touserdata(L, -1);
  194.   if (f == NULL)
  195.     luaL_error(L, "standard %s file is closed", fnames[findex - 1]);
  196.   return f;
  197. }
  198.  
  199.  
  200. static int g_iofile (lua_State *L, int f, const char *mode) {
  201.   if (!lua_isnoneornil(L, 1)) {
  202.     const char *filename = lua_tostring(L, 1);
  203.     if (filename) {
  204.       FILE **pf = newfile(L);
  205.       *pf = fopen(filename, mode);
  206.       if (*pf == NULL)
  207.         fileerror(L, 1, filename);
  208.     }
  209.     else {
  210.       tofile(L);  /* check that it's a valid file handle */
  211.       lua_pushvalue(L, 1);
  212.     }
  213.     lua_rawseti(L, LUA_ENVIRONINDEX, f);
  214.   }
  215.   /* return current value */
  216.   lua_rawgeti(L, LUA_ENVIRONINDEX, f);
  217.   return 1;
  218. }
  219.  
  220.  
  221. static int io_input (lua_State *L) {
  222.   return g_iofile(L, IO_INPUT, "r");
  223. }
  224.  
  225.  
  226. static int io_output (lua_State *L) {
  227.   return g_iofile(L, IO_OUTPUT, "w");
  228. }
  229.  
  230.  
  231. static int io_readline (lua_State *L);
  232.  
  233.  
  234. static void aux_lines (lua_State *L, int idx, int toclose) {
  235.   lua_pushvalue(L, idx);
  236.   lua_pushboolean(L, toclose);  /* close/not close file when finished */
  237.   lua_pushcclosure(L, io_readline, 2);
  238. }
  239.  
  240.  
  241. static int f_lines (lua_State *L) {
  242.   tofile(L);  /* check that it's a valid file handle */
  243.   aux_lines(L, 1, 0);
  244.   return 1;
  245. }
  246.  
  247.  
  248. static int io_lines (lua_State *L) {
  249.   if (lua_isnoneornil(L, 1)) {  /* no arguments? */
  250.     /* will iterate over default input */
  251.     lua_rawgeti(L, LUA_ENVIRONINDEX, IO_INPUT);
  252.     return f_lines(L);
  253.   }
  254.   else {
  255.     const char *filename = luaL_checkstring(L, 1);
  256.     FILE **pf = newfile(L);
  257.     *pf = fopen(filename, "r");
  258.     if (*pf == NULL)
  259.       fileerror(L, 1, filename);
  260.     aux_lines(L, lua_gettop(L), 1);
  261.     return 1;
  262.   }
  263. }
  264.  
  265.  
  266. /*
  267. ** {======================================================
  268. ** READ
  269. ** =======================================================
  270. */
  271.  
  272.  
  273. static int read_number (lua_State *L, FILE *f) {
  274.   lua_Number d;
  275.   if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1) {
  276.     lua_pushnumber(L, d);
  277.     return 1;
  278.   }
  279.   else {
  280.     lua_pushnil(L);  /* "result" to be removed */
  281.     return 0;  /* read fails */
  282.   }
  283. }
  284.  
  285.  
  286. static int test_eof (lua_State *L, FILE *f) {
  287.   int c = getc(f);
  288.   ungetc(c, f);
  289.   lua_pushlstring(L, NULL, 0);
  290.   return (c != EOF);
  291. }
  292.  
  293.  
  294. static int read_line (lua_State *L, FILE *f) {
  295.   luaL_Buffer b;
  296.   luaL_buffinit(L, &b);
  297.   for (;;) {
  298.     size_t l;
  299.     char *p = luaL_prepbuffer(&b);
  300.     if (fgets(p, LUAL_BUFFERSIZE, f) == NULL) {  /* eof? */
  301.       luaL_pushresult(&b);  /* close buffer */
  302.       return (lua_objlen(L, -1) > 0);  /* check whether read something */
  303.     }
  304.     l = strlen(p);
  305.     if (l == 0 || p[l-1] != '\n')
  306.       luaL_addsize(&b, l);
  307.     else {
  308.       luaL_addsize(&b, l - 1);  /* do not include `eol' */
  309.       luaL_pushresult(&b);  /* close buffer */
  310.       return 1;  /* read at least an `eol' */
  311.     }
  312.   }
  313. }
  314.  
  315.  
  316. static int read_chars (lua_State *L, FILE *f, size_t n) {
  317.   size_t rlen;  /* how much to read */
  318.   size_t nr;  /* number of chars actually read */
  319.   luaL_Buffer b;
  320.   luaL_buffinit(L, &b);
  321.   rlen = LUAL_BUFFERSIZE;  /* try to read that much each time */
  322.   do {
  323.     char *p = luaL_prepbuffer(&b);
  324.     if (rlen > n) rlen = n;  /* cannot read more than asked */
  325.     nr = fread(p, sizeof(char), rlen, f);
  326.     luaL_addsize(&b, nr);
  327.     n -= nr;  /* still have to read `n' chars */
  328.   } while (n > 0 && nr == rlen);  /* until end of count or eof */
  329.   luaL_pushresult(&b);  /* close buffer */
  330.   return (n == 0 || lua_objlen(L, -1) > 0);
  331. }
  332.  
  333.  
  334. static int g_read (lua_State *L, FILE *f, int first) {
  335.   int nargs = lua_gettop(L) - 1;
  336.   int success;
  337.   int n;
  338.   clearerr(f);
  339.   if (nargs == 0) {  /* no arguments? */
  340.     success = read_line(L, f);
  341.     n = first+1;  /* to return 1 result */
  342.   }
  343.   else {  /* ensure stack space for all results and for auxlib's buffer */
  344.     luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");
  345.     success = 1;
  346.     for (n = first; nargs-- && success; n++) {
  347.       if (lua_type(L, n) == LUA_TNUMBER) {
  348.         size_t l = (size_t)lua_tointeger(L, n);
  349.         success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
  350.       }
  351.       else {
  352.         const char *p = lua_tostring(L, n);
  353.         luaL_argcheck(L, p && p[0] == '*', n, "invalid option");
  354.         switch (p[1]) {
  355.           case 'n':  /* number */
  356.             success = read_number(L, f);
  357.             break;
  358.           case 'l':  /* line */
  359.             success = read_line(L, f);
  360.             break;
  361.           case 'a':  /* file */
  362.             read_chars(L, f, ~((size_t)0));  /* read MAX_SIZE_T chars */
  363.             success = 1; /* always success */
  364.             break;
  365.           default:
  366.             return luaL_argerror(L, n, "invalid format");
  367.         }
  368.       }
  369.     }
  370.   }
  371.   if (ferror(f))
  372.     return pushresult(L, 0, NULL);
  373.   if (!success) {
  374.     lua_pop(L, 1);  /* remove last result */
  375.     lua_pushnil(L);  /* push nil instead */
  376.   }
  377.   return n - first;
  378. }
  379.  
  380.  
  381. static int io_read (lua_State *L) {
  382.   return g_read(L, getiofile(L, IO_INPUT), 1);
  383. }
  384.  
  385.  
  386. static int f_read (lua_State *L) {
  387.   return g_read(L, tofile(L), 2);
  388. }
  389.  
  390.  
  391. static int io_readline (lua_State *L) {
  392.   FILE *f = *(FILE **)lua_touserdata(L, lua_upvalueindex(1));
  393.   int sucess;
  394.   if (f == NULL)  /* file is already closed? */
  395.     luaL_error(L, "file is already closed");
  396.   sucess = read_line(L, f);
  397.   if (ferror(f))
  398.     return luaL_error(L, "%s", strerror(errno));
  399.   if (sucess) return 1;
  400.   else {  /* EOF */
  401.     if (lua_toboolean(L, lua_upvalueindex(2))) {  /* generator created file? */
  402.       lua_settop(L, 0);
  403.       lua_pushvalue(L, lua_upvalueindex(1));
  404.       aux_close(L);  /* close it */
  405.     }
  406.     return 0;
  407.   }
  408. }
  409.  
  410. /* }====================================================== */
  411.  
  412.  
  413. static int g_write (lua_State *L, FILE *f, int arg) {
  414.   int nargs = lua_gettop(L) - 1;
  415.   int status = 1;
  416.   for (; nargs--; arg++) {
  417.     if (lua_type(L, arg) == LUA_TNUMBER) {
  418.       /* optimization: could be done exactly as for strings */
  419.       status = status &&
  420.           fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
  421.     }
  422.     else {
  423.       size_t l;
  424.       const char *s = luaL_checklstring(L, arg, &l);
  425.       status = status && (fwrite(s, sizeof(char), l, f) == l);
  426.     }
  427.   }
  428.   return pushresult(L, status, NULL);
  429. }
  430.  
  431.  
  432. static int io_write (lua_State *L) {
  433.   return g_write(L, getiofile(L, IO_OUTPUT), 1);
  434. }
  435.  
  436.  
  437. static int f_write (lua_State *L) {
  438.   return g_write(L, tofile(L), 2);
  439. }
  440.  
  441.  
  442. static int f_seek (lua_State *L) {
  443.   static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
  444.   static const char *const modenames[] = {"set", "cur", "end", NULL};
  445.   FILE *f = tofile(L);
  446.   int op = luaL_checkoption(L, 2, "cur", modenames);
  447.   long offset = luaL_optlong(L, 3, 0);
  448.   op = fseek(f, offset, mode[op]);
  449.   if (op)
  450.     return pushresult(L, 0, NULL);  /* error */
  451.   else {
  452.     lua_pushinteger(L, ftell(f));
  453.     return 1;
  454.   }
  455. }
  456.  
  457.  
  458. static int f_setvbuf (lua_State *L) {
  459.   static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
  460.   static const char *const modenames[] = {"no", "full", "line", NULL};
  461.   FILE *f = tofile(L);
  462.   int op = luaL_checkoption(L, 2, NULL, modenames);
  463.   lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
  464.   int res = setvbuf(f, NULL, mode[op], sz);
  465.   return pushresult(L, res == 0, NULL);
  466. }
  467.  
  468.  
  469.  
  470. static int io_flush (lua_State *L) {
  471.   return pushresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
  472. }
  473.  
  474.  
  475. static int f_flush (lua_State *L) {
  476.   return pushresult(L, fflush(tofile(L)) == 0, NULL);
  477. }
  478.  
  479.  
  480. static const luaL_Reg iolib[] = {
  481.   {"close", io_close},
  482.   {"flush", io_flush},
  483.   {"input", io_input},
  484.   {"lines", io_lines},
  485.   {"open", io_open},
  486.   {"output", io_output},
  487.   {"popen", io_popen},
  488.   {"read", io_read},
  489.   {"tmpfile", io_tmpfile},
  490.   {"type", io_type},
  491.   {"write", io_write},
  492.   {NULL, NULL}
  493. };
  494.  
  495.  
  496. static const luaL_Reg flib[] = {
  497.   {"close", io_close},
  498.   {"flush", f_flush},
  499.   {"lines", f_lines},
  500.   {"read", f_read},
  501.   {"seek", f_seek},
  502.   {"setvbuf", f_setvbuf},
  503.   {"write", f_write},
  504.   {"__gc", io_gc},
  505.   {"__tostring", io_tostring},
  506.   {NULL, NULL}
  507. };
  508.  
  509.  
  510. static void createmeta (lua_State *L) {
  511.   luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */
  512.   lua_pushvalue(L, -1);  /* push metatable */
  513.   lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
  514.   luaL_register(L, NULL, flib);  /* file methods */
  515. }
  516.  
  517.  
  518. static void createstdfile (lua_State *L, FILE *f, int k, const char *fname) {
  519.   *newfile(L) = f;
  520.   if (k > 0) {
  521.     lua_pushvalue(L, -1);
  522.     lua_rawseti(L, LUA_ENVIRONINDEX, k);
  523.   }
  524.   lua_pushvalue(L, -2);  /* copy environment */
  525.   lua_setfenv(L, -2);  /* set it */
  526.   lua_setfield(L, -3, fname);
  527. }
  528.  
  529.  
  530. static void newfenv (lua_State *L, lua_CFunction cls) {
  531.   lua_createtable(L, 0, 1);
  532.   lua_pushcfunction(L, cls);
  533.   lua_setfield(L, -2, "__close");
  534. }
  535.  
  536.  
  537. LUALIB_API int luaopen_io (lua_State *L) {
  538.   createmeta(L);
  539.   /* create (private) environment (with fields IO_INPUT, IO_OUTPUT, __close) */
  540.   newfenv(L, io_fclose);
  541.   lua_replace(L, LUA_ENVIRONINDEX);
  542.   /* open library */
  543.   luaL_register(L, LUA_IOLIBNAME, iolib);
  544.   /* create (and set) default files */
  545.   newfenv(L, io_noclose);  /* close function for default files */
  546.   createstdfile(L, stdin, IO_INPUT, "stdin");
  547.   createstdfile(L, stdout, IO_OUTPUT, "stdout");
  548.   createstdfile(L, stderr, 0, "stderr");
  549.   lua_pop(L, 1);  /* pop environment for default files */
  550.   lua_getfield(L, -1, "popen");
  551.   newfenv(L, io_pclose);  /* create environment for 'popen' */
  552.   lua_setfenv(L, -2);  /* set fenv for 'popen' */
  553.   lua_pop(L, 1);  /* pop 'popen' */
  554.   return 1;
  555. }
  556.  
  557.