liolib.c

Lua 语言解释器源码

/*
** $Id: liolib.c,v 2.39a 2003/03/19 21:16:12 roberto Exp $
** Standard I/O (and system) library
** See Copyright Notice in lua.h
*/


#include <errno.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define liolib_c

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"



/*
** by default, gcc does not get `tmpname'
*/
#ifndef USE_TMPNAME
#ifdef __GNUC__
#define USE_TMPNAME	0
#else
#define USE_TMPNAME	1
#endif
#endif


/*
** by default, posix systems get `popen'
*/
#ifndef USE_POPEN
#ifdef _POSIX_C_SOURCE
#if _POSIX_C_SOURCE >= 2
#define USE_POPEN	1
#endif
#endif
#endif

#ifndef USE_POPEN
#define USE_POPEN	0
#endif




/*
** {======================================================
** FILE Operations
** =======================================================
*/


#if !USE_POPEN
#define pclose(f)    (-1)
#endif


#define FILEHANDLE		"FILE*"

#define IO_INPUT		"_input"
#define IO_OUTPUT		"_output"


static int pushresult (lua_State *L, int i, const char *filename) {
  if (i) {
    lua_pushboolean(L, 1);
    return 1;
  }
  else {
    lua_pushnil(L);
    if (filename)
      lua_pushfstring(L, "%s: %s", filename, strerror(errno));
    else
      lua_pushfstring(L, "%s", strerror(errno));
    lua_pushnumber(L, errno);
    return 3;
  }
}


static FILE **topfile (lua_State *L, int findex) {
  FILE **f = (FILE **)luaL_checkudata(L, findex, FILEHANDLE);
  if (f == NULL) luaL_argerror(L, findex, "bad file");
  return f;
}


static int io_type (lua_State *L) {
  FILE **f = (FILE **)luaL_checkudata(L, 1, FILEHANDLE);
  if (f == NULL) lua_pushnil(L);
  else if (*f == NULL)
    lua_pushliteral(L, "closed file");
  else
    lua_pushliteral(L, "file");
  return 1;
}


static FILE *tofile (lua_State *L, int findex) {
  FILE **f = topfile(L, findex);
  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, FILEHANDLE);
  lua_setmetatable(L, -2);
  return pf;
}


/*
** assumes that top of the stack is the `io' library, and next is
** the `io' metatable
*/
static void registerfile (lua_State *L, FILE *f, const char *name,
                                                 const char *impname) {
  lua_pushstring(L, name);
  *newfile(L) = f;
  if (impname) {
    lua_pushstring(L, impname);
    lua_pushvalue(L, -2);
    lua_settable(L, -6);  /* metatable[impname] = file */
  }
  lua_settable(L, -3);  /* io[name] = file */
}


static int aux_close (lua_State *L) {
  FILE *f = tofile(L, 1);
  if (f == stdin || f == stdout || f == stderr)
    return 0;  /* file cannot be closed */
  else {
    int ok = (pclose(f) != -1) || (fclose(f) == 0);
    if (ok)
      *(FILE **)lua_touserdata(L, 1) = NULL;  /* mark file as closed */
    return ok;
  }
}


static int io_close (lua_State *L) {
  if (lua_isnone(L, 1) && lua_type(L, lua_upvalueindex(1)) == LUA_TTABLE) {
    lua_pushstring(L, IO_OUTPUT);
    lua_rawget(L, lua_upvalueindex(1));
  }
  return pushresult(L, aux_close(L), NULL);
}


static int io_gc (lua_State *L) {
  FILE **f = topfile(L, 1);
  if (*f != NULL)  /* ignore closed files */
    aux_close(L);
  return 0;
}


static int io_tostring (lua_State *L) {
  char buff[128];
  FILE **f = topfile(L, 1);
  if (*f == NULL)
    strcpy(buff, "closed");
  else
    sprintf(buff, "%p", lua_touserdata(L, 1));
  lua_pushfstring(L, "file (%s)", buff);
  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) {
#if !USE_POPEN
  luaL_error(L, "`popen' not supported");
  return 0;
#else
  const char *filename = luaL_checkstring(L, 1);
  const char *mode = luaL_optstring(L, 2, "r");
  FILE **pf = newfile(L);
  *pf = popen(filename, mode);
  return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
#endif
}


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, const char *name) {
  lua_pushstring(L, name);
  lua_rawget(L, lua_upvalueindex(1));
  return tofile(L, -1);
}


static int g_iofile (lua_State *L, const char *name, const char *mode) {
  if (!lua_isnoneornil(L, 1)) {
    const char *filename = lua_tostring(L, 1);
    lua_pushstring(L, name);
    if (filename) {
      FILE **pf = newfile(L);
      *pf = fopen(filename, mode);
      if (*pf == NULL) {
        lua_pushfstring(L, "%s: %s", filename, strerror(errno));
        luaL_argerror(L, 1, lua_tostring(L, -1));
      }
    }
    else {
      tofile(L, 1);  /* check that it's a valid file handle */
      lua_pushvalue(L, 1);
    }
    lua_rawset(L, lua_upvalueindex(1));
  }
  /* return current value */
  lua_pushstring(L, name);
  lua_rawget(L, lua_upvalueindex(1));
  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 close) {
  lua_pushliteral(L, FILEHANDLE);
  lua_rawget(L, LUA_REGISTRYINDEX);
  lua_pushvalue(L, idx);
  lua_pushboolean(L, close);  /* close/not close file when finished */
  lua_pushcclosure(L, io_readline, 3);
}


static int f_lines (lua_State *L) {
  tofile(L, 1);  /* 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? */
    lua_pushstring(L, IO_INPUT);
    lua_rawget(L, lua_upvalueindex(1));  /* will iterate over default input */
    return f_lines(L);
  }
  else {
    const char *filename = luaL_checkstring(L, 1);
    FILE **pf = newfile(L);
    *pf = fopen(filename, "r");
    luaL_argcheck(L, *pf, 1,  strerror(errno));
    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 (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;
  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_tonumber(L, n);
        success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);