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** $Id: liolib.c,v 2.111 2013/03/21 13:57:27 roberto Exp $
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** Standard I/O (and system) library
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** See Copyright Notice in lua.h
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** This definition must come before the inclusion of 'stdio.h'; it
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** should not affect non-POSIX systems
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#if !defined(_FILE_OFFSET_BITS)
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#define _FILE_OFFSET_BITS 64
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#if !defined(lua_checkmode)
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** Check whether 'mode' matches '[rwa]%+?b?'.
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** Change this macro to accept other modes for 'fopen' besides
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#define lua_checkmode(mode) \
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(*mode != '\0' && strchr("rwa", *(mode++)) != NULL && \
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(*mode != '+' || ++mode) && /* skip if char is '+' */ \
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(*mode != 'b' || ++mode) && /* skip if char is 'b' */ \
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** {======================================================
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** lua_popen spawns a new process connected to the current
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** one through the file streams.
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** =======================================================
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#if !defined(lua_popen) /* { */
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#if defined(LUA_USE_POPEN) /* { */
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#define lua_popen(L,c,m) ((void)L, fflush(NULL), popen(c,m))
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#define lua_pclose(L,file) ((void)L, pclose(file))
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#elif defined(LUA_WIN) /* }{ */
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#define lua_popen(L,c,m) ((void)L, _popen(c,m))
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#define lua_pclose(L,file) ((void)L, _pclose(file))
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#define lua_popen(L,c,m) ((void)((void)c, m), \
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luaL_error(L, LUA_QL("popen") " not supported"), (FILE*)0)
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#define lua_pclose(L,file) ((void)((void)L, file), -1)
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/* }====================================================== */
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** {======================================================
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** lua_fseek/lua_ftell: configuration for longer offsets
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** =======================================================
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#if !defined(lua_fseek) /* { */
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#if defined(LUA_USE_POSIX)
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#define l_fseek(f,o,w) fseeko(f,o,w)
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#define l_ftell(f) ftello(f)
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#define l_seeknum off_t
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#elif defined(LUA_WIN) && !defined(_CRTIMP_TYPEINFO) \
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&& defined(_MSC_VER) && (_MSC_VER >= 1400)
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/* Windows (but not DDK) and Visual C++ 2005 or higher */
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#define l_fseek(f,o,w) _fseeki64(f,o,w)
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#define l_ftell(f) _ftelli64(f)
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#define l_seeknum __int64
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#define l_fseek(f,o,w) fseek(f,o,w)
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#define l_ftell(f) ftell(f)
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#define l_seeknum long
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/* }====================================================== */
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#define IO_PREFIX "_IO_"
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#define IO_INPUT (IO_PREFIX "input")
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#define IO_OUTPUT (IO_PREFIX "output")
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typedef luaL_Stream LStream;
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#define tolstream(L) ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))
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#define isclosed(p) ((p)->closef == NULL)
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static int io_type (lua_State *L) {
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p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE);
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lua_pushnil(L); /* not a file */
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else if (isclosed(p))
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lua_pushliteral(L, "closed file");
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lua_pushliteral(L, "file");
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static int f_tostring (lua_State *L) {
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LStream *p = tolstream(L);
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lua_pushliteral(L, "file (closed)");
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lua_pushfstring(L, "file (%p)", p->f);
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static FILE *tofile (lua_State *L) {
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LStream *p = tolstream(L);
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luaL_error(L, "attempt to use a closed file");
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** When creating file handles, always creates a `closed' file handle
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** before opening the actual file; so, if there is a memory error, the
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** file is not left opened.
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static LStream *newprefile (lua_State *L) {
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LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream));
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p->closef = NULL; /* mark file handle as 'closed' */
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luaL_setmetatable(L, LUA_FILEHANDLE);
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static int aux_close (lua_State *L) {
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LStream *p = tolstream(L);
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lua_CFunction cf = p->closef;
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p->closef = NULL; /* mark stream as closed */
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return (*cf)(L); /* close it */
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static int io_close (lua_State *L) {
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if (lua_isnone(L, 1)) /* no argument? */
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lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT); /* use standard output */
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tofile(L); /* make sure argument is an open stream */
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static int f_gc (lua_State *L) {
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LStream *p = tolstream(L);
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if (!isclosed(p) && p->f != NULL)
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aux_close(L); /* ignore closed and incompletely open files */
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** function to close regular files
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static int io_fclose (lua_State *L) {
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LStream *p = tolstream(L);
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int res = fclose(p->f);
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return luaL_fileresult(L, (res == 0), NULL);
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static LStream *newfile (lua_State *L) {
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LStream *p = newprefile(L);
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p->closef = &io_fclose;
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static void opencheck (lua_State *L, const char *fname, const char *mode) {
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LStream *p = newfile(L);
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p->f = fopen(fname, mode);
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luaL_error(L, "cannot open file " LUA_QS " (%s)", fname, strerror(errno));
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static int io_open (lua_State *L) {
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const char *filename = luaL_checkstring(L, 1);
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const char *mode = luaL_optstring(L, 2, "r");
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LStream *p = newfile(L);
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const char *md = mode; /* to traverse/check mode */
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luaL_argcheck(L, lua_checkmode(md), 2, "invalid mode");
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p->f = fopen(filename, mode);
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return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
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** function to close 'popen' files
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static int io_pclose (lua_State *L) {
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LStream *p = tolstream(L);
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return luaL_execresult(L, lua_pclose(L, p->f));
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static int io_popen (lua_State *L) {
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const char *filename = luaL_checkstring(L, 1);
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const char *mode = luaL_optstring(L, 2, "r");
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LStream *p = newprefile(L);
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p->f = lua_popen(L, filename, mode);
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p->closef = &io_pclose;
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return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
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static int io_tmpfile (lua_State *L) {
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LStream *p = newfile(L);
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return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1;
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static FILE *getiofile (lua_State *L, const char *findex) {
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lua_getfield(L, LUA_REGISTRYINDEX, findex);
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p = (LStream *)lua_touserdata(L, -1);
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luaL_error(L, "standard %s file is closed", findex + strlen(IO_PREFIX));
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static int g_iofile (lua_State *L, const char *f, const char *mode) {
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if (!lua_isnoneornil(L, 1)) {
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const char *filename = lua_tostring(L, 1);
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opencheck(L, filename, mode);
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tofile(L); /* check that it's a valid file handle */
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lua_setfield(L, LUA_REGISTRYINDEX, f);
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/* return current value */
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lua_getfield(L, LUA_REGISTRYINDEX, f);
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static int io_input (lua_State *L) {
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return g_iofile(L, IO_INPUT, "r");
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static int io_output (lua_State *L) {
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return g_iofile(L, IO_OUTPUT, "w");
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static int io_readline (lua_State *L);
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static void aux_lines (lua_State *L, int toclose) {
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int n = lua_gettop(L) - 1; /* number of arguments to read */
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/* ensure that arguments will fit here and into 'io_readline' stack */
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luaL_argcheck(L, n <= LUA_MINSTACK - 3, LUA_MINSTACK - 3, "too many options");
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lua_pushvalue(L, 1); /* file handle */
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lua_pushinteger(L, n); /* number of arguments to read */
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lua_pushboolean(L, toclose); /* close/not close file when finished */
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for (i = 1; i <= n; i++) lua_pushvalue(L, i + 1); /* copy arguments */
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lua_pushcclosure(L, io_readline, 3 + n);
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static int f_lines (lua_State *L) {
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tofile(L); /* check that it's a valid file handle */
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static int io_lines (lua_State *L) {
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if (lua_isnone(L, 1)) lua_pushnil(L); /* at least one argument */
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if (lua_isnil(L, 1)) { /* no file name? */
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lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT); /* get default input */
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lua_replace(L, 1); /* put it at index 1 */
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tofile(L); /* check that it's a valid file handle */
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toclose = 0; /* do not close it after iteration */
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else { /* open a new file */
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const char *filename = luaL_checkstring(L, 1);
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opencheck(L, filename, "r");
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lua_replace(L, 1); /* put file at index 1 */
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toclose = 1; /* close it after iteration */
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aux_lines(L, toclose);
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** {======================================================
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** =======================================================
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static int read_number (lua_State *L, FILE *f) {
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if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1) {
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lua_pushnumber(L, d);
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lua_pushnil(L); /* "result" to be removed */
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return 0; /* read fails */
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static int test_eof (lua_State *L, FILE *f) {
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lua_pushlstring(L, NULL, 0);
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static int read_line (lua_State *L, FILE *f, int chop) {
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luaL_buffinit(L, &b);
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char *p = luaL_prepbuffer(&b);
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if (fgets(p, LUAL_BUFFERSIZE, f) == NULL) { /* eof? */
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luaL_pushresult(&b); /* close buffer */
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return (lua_rawlen(L, -1) > 0); /* check whether read something */
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if (l == 0 || p[l-1] != '\n')
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luaL_addsize(&b, l - chop); /* chop 'eol' if needed */
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luaL_pushresult(&b); /* close buffer */
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return 1; /* read at least an `eol' */
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#define MAX_SIZE_T (~(size_t)0)
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static void read_all (lua_State *L, FILE *f) {
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size_t rlen = LUAL_BUFFERSIZE; /* how much to read in each cycle */
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luaL_buffinit(L, &b);
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char *p = luaL_prepbuffsize(&b, rlen);
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size_t nr = fread(p, sizeof(char), rlen, f);
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luaL_addsize(&b, nr);
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if (nr < rlen) break; /* eof? */
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else if (rlen <= (MAX_SIZE_T / 4)) /* avoid buffers too large */
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rlen *= 2; /* double buffer size at each iteration */
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luaL_pushresult(&b); /* close buffer */
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static int read_chars (lua_State *L, FILE *f, size_t n) {
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size_t nr; /* number of chars actually read */
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luaL_buffinit(L, &b);
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p = luaL_prepbuffsize(&b, n); /* prepare buffer to read whole block */
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nr = fread(p, sizeof(char), n, f); /* try to read 'n' chars */
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luaL_addsize(&b, nr);
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luaL_pushresult(&b); /* close buffer */
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return (nr > 0); /* true iff read something */
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static int g_read (lua_State *L, FILE *f, int first) {
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int nargs = lua_gettop(L) - 1;
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if (nargs == 0) { /* no arguments? */
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success = read_line(L, f, 1);
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n = first+1; /* to return 1 result */
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else { /* ensure stack space for all results and for auxlib's buffer */
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luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");
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for (n = first; nargs-- && success; n++) {
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if (lua_type(L, n) == LUA_TNUMBER) {
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size_t l = (size_t)lua_tointeger(L, n);
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success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
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const char *p = lua_tostring(L, n);
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luaL_argcheck(L, p && p[0] == '*', n, "invalid option");
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case 'n': /* number */
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success = read_number(L, f);
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success = read_line(L, f, 1);
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case 'L': /* line with end-of-line */
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success = read_line(L, f, 0);
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read_all(L, f); /* read entire file */
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success = 1; /* always success */
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return luaL_argerror(L, n, "invalid format");
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return luaL_fileresult(L, 0, NULL);
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lua_pop(L, 1); /* remove last result */
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lua_pushnil(L); /* push nil instead */
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static int io_read (lua_State *L) {
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return g_read(L, getiofile(L, IO_INPUT), 1);
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static int f_read (lua_State *L) {
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return g_read(L, tofile(L), 2);
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static int io_readline (lua_State *L) {
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LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1));
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int n = (int)lua_tointeger(L, lua_upvalueindex(2));
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if (isclosed(p)) /* file is already closed? */
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return luaL_error(L, "file is already closed");
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for (i = 1; i <= n; i++) /* push arguments to 'g_read' */
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lua_pushvalue(L, lua_upvalueindex(3 + i));
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n = g_read(L, p->f, 2); /* 'n' is number of results */
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lua_assert(n > 0); /* should return at least a nil */
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if (!lua_isnil(L, -n)) /* read at least one value? */
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return n; /* return them */
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else { /* first result is nil: EOF or error */
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if (n > 1) { /* is there error information? */
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/* 2nd result is error message */
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return luaL_error(L, "%s", lua_tostring(L, -n + 1));
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if (lua_toboolean(L, lua_upvalueindex(3))) { /* generator created file? */
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lua_pushvalue(L, lua_upvalueindex(1));
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aux_close(L); /* close it */
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/* }====================================================== */
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static int g_write (lua_State *L, FILE *f, int arg) {
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int nargs = lua_gettop(L) - arg;
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for (; nargs--; arg++) {
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if (lua_type(L, arg) == LUA_TNUMBER) {
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/* optimization: could be done exactly as for strings */
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fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
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const char *s = luaL_checklstring(L, arg, &l);
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status = status && (fwrite(s, sizeof(char), l, f) == l);
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if (status) return 1; /* file handle already on stack top */
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else return luaL_fileresult(L, status, NULL);
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static int io_write (lua_State *L) {
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return g_write(L, getiofile(L, IO_OUTPUT), 1);
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static int f_write (lua_State *L) {
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lua_pushvalue(L, 1); /* push file at the stack top (to be returned) */
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return g_write(L, f, 2);
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static int f_seek (lua_State *L) {
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static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
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static const char *const modenames[] = {"set", "cur", "end", NULL};
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int op = luaL_checkoption(L, 2, "cur", modenames);
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lua_Number p3 = luaL_optnumber(L, 3, 0);
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l_seeknum offset = (l_seeknum)p3;
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luaL_argcheck(L, (lua_Number)offset == p3, 3,
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"not an integer in proper range");
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op = l_fseek(f, offset, mode[op]);
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return luaL_fileresult(L, 0, NULL); /* error */
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lua_pushnumber(L, (lua_Number)l_ftell(f));
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static int f_setvbuf (lua_State *L) {
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static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
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static const char *const modenames[] = {"no", "full", "line", NULL};
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int op = luaL_checkoption(L, 2, NULL, modenames);
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lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
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int res = setvbuf(f, NULL, mode[op], sz);
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return luaL_fileresult(L, res == 0, NULL);
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static int io_flush (lua_State *L) {
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return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
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static int f_flush (lua_State *L) {
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return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL);
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** functions for 'io' library
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static const luaL_Reg iolib[] = {
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{"output", io_output},
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{"tmpfile", io_tmpfile},
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** methods for file handles
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static const luaL_Reg flib[] = {
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{"setvbuf", f_setvbuf},
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{"__tostring", f_tostring},
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static void createmeta (lua_State *L) {
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luaL_newmetatable(L, LUA_FILEHANDLE); /* create metatable for file handles */
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lua_pushvalue(L, -1); /* push metatable */
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lua_setfield(L, -2, "__index"); /* metatable.__index = metatable */
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luaL_setfuncs(L, flib, 0); /* add file methods to new metatable */
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lua_pop(L, 1); /* pop new metatable */
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** function to (not) close the standard files stdin, stdout, and stderr
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static int io_noclose (lua_State *L) {
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LStream *p = tolstream(L);
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p->closef = &io_noclose; /* keep file opened */
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lua_pushliteral(L, "cannot close standard file");
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static void createstdfile (lua_State *L, FILE *f, const char *k,
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LStream *p = newprefile(L);
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p->closef = &io_noclose;
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lua_pushvalue(L, -1);
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lua_setfield(L, LUA_REGISTRYINDEX, k); /* add file to registry */
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lua_setfield(L, -2, fname); /* add file to module */
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LUAMOD_API int luaopen_io (lua_State *L) {
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luaL_newlib(L, iolib); /* new module */
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/* create (and set) default files */
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createstdfile(L, stdin, IO_INPUT, "stdin");
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createstdfile(L, stdout, IO_OUTPUT, "stdout");
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createstdfile(L, stderr, NULL, "stderr");