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/*

** $Id: liolib.c,v 2.73 2006/05/08 20:14:16 roberto Exp $

** Standard I/O (and system) library

** See Copyright Notice in lua.h

*/

#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#define liolib_c

#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"

#include "lualib.h"

#define IO_INPUT	1

#define IO_OUTPUT	2

static const char *const fnames[] = {"input", "output"};

static int pushresult (lua_State *L, int i, const char *filename) {

  int en = errno;  /* calls to Lua API may change this value */

  if (i) {

    lua_pushboolean(L, 1);

    return 1;

  }

  else {

    lua_pushnil(L);

    if (filename)

      lua_pushfstring(L, "%s: %s", filename, strerror(en));

    else

      lua_pushfstring(L, "%s", strerror(en));

    lua_pushinteger(L, en);

    return 3;

  }

}

static void fileerror (lua_State *L, int arg, const char *filename) {

  lua_pushfstring(L, "%s: %s", filename, strerror(errno));

  luaL_argerror(L, arg, lua_tostring(L, -1));

}

#define topfile(L)	((FILE **)luaL_checkudata(L, 1, LUA_FILEHANDLE))

static int io_type (lua_State *L) {

  void *ud;

  luaL_checkany(L, 1);

  ud = lua_touserdata(L, 1);

  lua_getfield(L, LUA_REGISTRYINDEX, LUA_FILEHANDLE);

  if (ud == NULL || !lua_getmetatable(L, 1) || !lua_rawequal(L, -2, -1))

    lua_pushnil(L);  /* not a file */

  else if (*((FILE **)ud) == NULL)

    lua_pushliteral(L, "closed file");

  else

    lua_pushliteral(L, "file");

  return 1;

}

static FILE *tofile (lua_State *L) {

  FILE **f = topfile(L);

  if (*f == NULL)

    luaL_error(L, "attempt to use a closed file");

  return *f;

}

/*

** When creating file handles, always creates a `closed' file handle

** before opening the actual file; so, if there is a memory error, the

** file is not left opened.

*/

static FILE **newfile (lua_State *L) {

  FILE **pf = (FILE **)lua_newuserdata(L, sizeof(FILE *));

  *pf = NULL;  /* file handle is currently `closed' */

  luaL_getmetatable(L, LUA_FILEHANDLE);

  lua_setmetatable(L, -2);

  return pf;

}

/*

** this function has a separated environment, which defines the

** correct __close for 'popen' files

*/

static int io_pclose (lua_State *L) {

  FILE **p = topfile(L);

  int ok = lua_pclose(L, *p);

  *p = NULL;

  return pushresult(L, ok, NULL);

}

static int io_fclose (lua_State *L) {

  FILE **p = topfile(L);

  int ok = (fclose(*p) == 0);

  *p = NULL;

  return pushresult(L, ok, NULL);

}

static int aux_close (lua_State *L) {

  lua_getfenv(L, 1);

  lua_getfield(L, -1, "__close");

  return (lua_tocfunction(L, -1))(L);

}

static int io_close (lua_State *L) {

  if (lua_isnone(L, 1))

    lua_rawgeti(L, LUA_ENVIRONINDEX, IO_OUTPUT);

  tofile(L);  /* make sure argument is a file */

  return aux_close(L);

}

static int io_gc (lua_State *L) {

  FILE *f = *topfile(L);

  /* ignore closed files and standard files */

  if (f != NULL && f != stdin && f != stdout && f != stderr)

    aux_close(L);

  return 0;

}

static int io_tostring (lua_State *L) {

  FILE *f = *topfile(L);

  if (f == NULL)

    lua_pushstring(L, "file (closed)");

  else

    lua_pushfstring(L, "file (%p)", f);

  return 1;

}

static int io_open (lua_State *L) {

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

  const char *mode = luaL_optstring(L, 2, "r");

  FILE **pf = newfile(L);

  *pf = fopen(filename, mode);

  return (*pf == NULL) ? pushresult(L, 0, filename) : 1;

}

static int io_popen (lua_State *L) {

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

  const char *mode = luaL_optstring(L, 2, "r");

  FILE **pf = newfile(L);

  *pf = lua_popen(L, filename, mode);

  return (*pf == NULL) ? pushresult(L, 0, filename) : 1;

}

static int io_tmpfile (lua_State *L) {

  FILE **pf = newfile(L);

  *pf = tmpfile();

  return (*pf == NULL) ? pushresult(L, 0, NULL) : 1;

}

static FILE *getiofile (lua_State *L, int findex) {

  FILE *f;

  lua_rawgeti(L, LUA_ENVIRONINDEX, findex);

  f = *(FILE **)lua_touserdata(L, -1);

  if (f == NULL)

    luaL_error(L, "standard %s file is closed", fnames[findex - 1]);

  return f;

}

static int g_iofile (lua_State *L, int f, const char *mode) {

  if (!lua_isnoneornil(L, 1)) {

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

    if (filename) {

      FILE **pf = newfile(L);

      *pf = fopen(filename, mode);

      if (*pf == NULL)

        fileerror(L, 1, filename);

    }

    else {

      tofile(L);  /* check that it's a valid file handle */

      lua_pushvalue(L, 1);

    }

    lua_rawseti(L, LUA_ENVIRONINDEX, f);

  }

  /* return current value */

  lua_rawgeti(L, LUA_ENVIRONINDEX, f);

  return 1;

}

static int io_input (lua_State *L) {

  return g_iofile(L, IO_INPUT, "r");

}

static int io_output (lua_State *L) {

  return g_iofile(L, IO_OUTPUT, "w");

}

static int io_readline (lua_State *L);

static void aux_lines (lua_State *L, int idx, int toclose) {

  lua_pushvalue(L, idx);

  lua_pushboolean(L, toclose);  /* close/not close file when finished */

  lua_pushcclosure(L, io_readline, 2);

}

static int f_lines (lua_State *L) {

  tofile(L);  /* check that it's a valid file handle */

  aux_lines(L, 1, 0);

  return 1;

}

static int io_lines (lua_State *L) {

  if (lua_isnoneornil(L, 1)) {  /* no arguments? */

    /* will iterate over default input */

    lua_rawgeti(L, LUA_ENVIRONINDEX, IO_INPUT);

    return f_lines(L);

  }

  else {

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

    FILE **pf = newfile(L);

    *pf = fopen(filename, "r");

    if (*pf == NULL)

      fileerror(L, 1, filename);

    aux_lines(L, lua_gettop(L), 1);

    return 1;

  }

}

/*

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

** READ

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

*/

static int read_number (lua_State *L, FILE *f) {

  lua_Number d;

  if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1) {

    lua_pushnumber(L, d);

    return 1;

  }

  else return 0;  /* read fails */

}

static int test_eof (lua_State *L, FILE *f) {

  int c = getc(f);

  ungetc(c, f);

  lua_pushlstring(L, NULL, 0);

  return (c != EOF);

}

static int read_line (lua_State *L, FILE *f) {

  luaL_Buffer b;

  luaL_buffinit(L, &b);

  for (;;) {

    size_t l;

    char *p = luaL_prepbuffer(&b);

    if (fgets(p, LUAL_BUFFERSIZE, f) == NULL) {  /* eof? */

      luaL_pushresult(&b);  /* close buffer */

      return (lua_strlen(L, -1) > 0);  /* check whether read something */

    }

    l = strlen(p);

    if (l == 0 || p[l-1] != '\n')

      luaL_addsize(&b, l);

    else {

      luaL_addsize(&b, l - 1);  /* do not include `eol' */

      luaL_pushresult(&b);  /* close buffer */

      return 1;  /* read at least an `eol' */

    }

  }

}

static int read_chars (lua_State *L, FILE *f, size_t n) {

  size_t rlen;  /* how much to read */

  size_t nr;  /* number of chars actually read */

  luaL_Buffer b;

  luaL_buffinit(L, &b);

  rlen = LUAL_BUFFERSIZE;  /* try to read that much each time */

  do {

    char *p = luaL_prepbuffer(&b);

    if (rlen > n) rlen = n;  /* cannot read more than asked */

    nr = fread(p, sizeof(char), rlen, f);

    luaL_addsize(&b, nr);

    n -= nr;  /* still have to read `n' chars */

  } while (n > 0 && nr == rlen);  /* until end of count or eof */

  luaL_pushresult(&b);  /* close buffer */

  return (n == 0 || lua_strlen(L, -1) > 0);

}

static int g_read (lua_State *L, FILE *f, int first) {

  int nargs = lua_gettop(L) - 1;

  int success;

  int n;

  clearerr(f);

  if (nargs == 0) {  /* no arguments? */

    success = read_line(L, f);

    n = first+1;  /* to return 1 result */

  }

  else {  /* ensure stack space for all results and for auxlib's buffer */

    luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");

    success = 1;

    for (n = first; nargs-- && success; n++) {

      if (lua_type(L, n) == LUA_TNUMBER) {

        size_t l = (size_t)lua_tointeger(L, n);

        success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);

      }

      else {

        const char *p = lua_tostring(L, n);

        luaL_argcheck(L, p && p[0] == '*', n, "invalid option");

        switch (p[1]) {

          case 'n':  /* number */

            success = read_number(L, f);

            break;

          case 'l':  /* line */

            success = read_line(L, f);

            break;

          case 'a':  /* file */

            read_chars(L, f, ~((size_t)0));  /* read MAX_SIZE_T chars */

            success = 1; /* always success */

            break;

          default:

            return luaL_argerror(L, n, "invalid format");

        }

      }

    }

  }

  if (ferror(f))

    return pushresult(L, 0, NULL);

  if (!success) {

    lua_pop(L, 1);  /* remove last result */

    lua_pushnil(L);  /* push nil instead */

  }

  return n - first;

}

static int io_read (lua_State *L) {

  return g_read(L, getiofile(L, IO_INPUT), 1);

}

static int f_read (lua_State *L) {

  return g_read(L, tofile(L), 2);

}

static int io_readline (lua_State *L) {

  FILE *f = *(FILE **)lua_touserdata(L, lua_upvalueindex(1));

  int sucess;

  if (f == NULL)  /* file is already closed? */

    luaL_error(L, "file is already closed");

  sucess = read_line(L, f);

  if (ferror(f))

    return luaL_error(L, "%s", strerror(errno));

  if (sucess) return 1;

  else {  /* EOF */

    if (lua_toboolean(L, lua_upvalueindex(2))) {  /* generator created file? */

      lua_settop(L, 0);

      lua_pushvalue(L, lua_upvalueindex(1));

      aux_close(L);  /* close it */

    }

    return 0;

  }

}

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

static int g_write (lua_State *L, FILE *f, int arg) {

  int nargs = lua_gettop(L) - 1;

  int status = 1;

  for (; nargs--; arg++) {

    if (lua_type(L, arg) == LUA_TNUMBER) {

      /* optimization: could be done exactly as for strings */

      status = status &&

          fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;

    }

    else {

      size_t l;

      const char *s = luaL_checklstring(L, arg, &l);

      status = status && (fwrite(s, sizeof(char), l, f) == l);

    }

  }

  return pushresult(L, status, NULL);

}

static int io_write (lua_State *L) {

  return g_write(L, getiofile(L, IO_OUTPUT), 1);

}

static int f_write (lua_State *L) {

  return g_write(L, tofile(L), 2);

}

static int f_seek (lua_State *L) {

  static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};

  static const char *const modenames[] = {"set", "cur", "end", NULL};

  FILE *f = tofile(L);

  int op = luaL_checkoption(L, 2, "cur", modenames);

  long offset = luaL_optlong(L, 3, 0);

  op = fseek(f, offset, mode[op]);

  if (op)

    return pushresult(L, 0, NULL);  /* error */

  else {

    lua_pushinteger(L, ftell(f));

    return 1;

  }

}

static int f_setvbuf (lua_State *L) {

  static const int mode[] = {_IONBF, _IOFBF, _IOLBF};

  static const char *const modenames[] = {"no", "full", "line", NULL};

  FILE *f = tofile(L);

  int op = luaL_checkoption(L, 2, NULL, modenames);

  lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);

  int res = setvbuf(f, NULL, mode[op], sz);

  return pushresult(L, res == 0, NULL);

}

static int io_flush (lua_State *L) {

  return pushresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);

}

static int f_flush (lua_State *L) {

  return pushresult(L, fflush(tofile(L)) == 0, NULL);

}

static const luaL_Reg iolib[] = {

  {"close", io_close},

  {"flush", io_flush},

  {"input", io_input},

  {"lines", io_lines},

  {"open", io_open},

  {"output", io_output},

  {"popen", io_popen},

  {"read", io_read},

  {"tmpfile", io_tmpfile},

  {"type", io_type},

  {"write", io_write},

  {NULL, NULL}

};

static const luaL_Reg flib[] = {

  {"close", io_close},

  {"flush", f_flush},

  {"lines", f_lines},

  {"read", f_read},

  {"seek", f_seek},

  {"setvbuf", f_setvbuf},

  {"write", f_write},

  {"__gc", io_gc},

  {"__tostring", io_tostring},

  {NULL, NULL}

};

static void createmeta (lua_State *L) {

  luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */

  lua_pushvalue(L, -1);  /* push metatable */

  lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */

  luaL_register(L, NULL, flib);  /* file methods */

}

static void createstdfile (lua_State *L, FILE *f, int k, const char *fname) {

  *newfile(L) = f;

  if (k > 0) {

    lua_pushvalue(L, -1);

    lua_rawseti(L, LUA_ENVIRONINDEX, k);

  }

  lua_setfield(L, -2, fname);

}

LUALIB_API int luaopen_io (lua_State *L) {

  createmeta(L);

  /* create (private) environment (with fields IO_INPUT, IO_OUTPUT, __close) */

  lua_createtable(L, 2, 1);

  lua_replace(L, LUA_ENVIRONINDEX);

  /* open library */

  luaL_register(L, LUA_IOLIBNAME, iolib);

  /* create (and set) default files */

  createstdfile(L, stdin, IO_INPUT, "stdin");

  createstdfile(L, stdout, IO_OUTPUT, "stdout");

  createstdfile(L, stderr, 0, "stderr");

  /* create environment for 'popen' */

  lua_getfield(L, -1, "popen");

  lua_createtable(L, 0, 1);

  lua_pushcfunction(L, io_pclose);

  lua_setfield(L, -2, "__close");

  lua_setfenv(L, -2);

  lua_pop(L, 1);  /* pop 'popen' */

  /* set default close function */

  lua_pushcfunction(L, io_fclose);

  lua_setfield(L, LUA_ENVIRONINDEX, "__close");

  return 1;

}