Lua liolib.c (5.1.5)

/*
** $Id: liolib.c,v 2.73.1.4 2010年05月14日 15:33:51 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 tofilep(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 = tofilep(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;
}
/*
** function to (not) close the standard files stdin, stdout, and stderr
*/
static int io_noclose (lua_State *L) {
 lua_pushnil(L);
 lua_pushliteral(L, "cannot close standard file");
 return 2;
}
/*
** function to close 'popen' files
*/
static int io_pclose (lua_State *L) {
 FILE **p = tofilep(L);
 int ok = lua_pclose(L, *p);
 *p = NULL;
 return pushresult(L, ok, NULL);
}
/*
** function to close regular files
*/
static int io_fclose (lua_State *L) {
 FILE **p = tofilep(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 = *tofilep(L);
 /* ignore closed files */
 if (f != NULL)
 aux_close(L);
 return 0;
}
static int io_tostring (lua_State *L) {
 FILE *f = *tofilep(L);
 if (f == NULL)
 lua_pushliteral(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;
}
/*
** this function has a separated environment, which defines the
** correct __close for 'popen' files
*/
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 {
 lua_pushnil(L); /* "result" to be removed */
 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_objlen(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_objlen(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_pushvalue(L, -2); /* copy environment */
 lua_setfenv(L, -2); /* set it */
 lua_setfield(L, -3, fname);
}
static void newfenv (lua_State *L, lua_CFunction cls) {
 lua_createtable(L, 0, 1);
 lua_pushcfunction(L, cls);
 lua_setfield(L, -2, "__close");
}
LUALIB_API int luaopen_io (lua_State *L) {
 createmeta(L);
 /* create (private) environment (with fields IO_INPUT, IO_OUTPUT, __close) */
 newfenv(L, io_fclose);
 lua_replace(L, LUA_ENVIRONINDEX);
 /* open library */
 luaL_register(L, LUA_IOLIBNAME, iolib);
 /* create (and set) default files */
 newfenv(L, io_noclose); /* close function for default files */
 createstdfile(L, stdin, IO_INPUT, "stdin");
 createstdfile(L, stdout, IO_OUTPUT, "stdout");
 createstdfile(L, stderr, 0, "stderr");
 lua_pop(L, 1); /* pop environment for default files */
 lua_getfield(L, -1, "popen");
 newfenv(L, io_pclose); /* create environment for 'popen' */
 lua_setfenv(L, -2); /* set fenv for 'popen' */
 lua_pop(L, 1); /* pop 'popen' */
 return 1;
}

Last update: Sat Mar 5 09:19:55 2016