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new functions "seek" and "flush".

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This commit is contained in:
Roberto Ierusalimschy 1998-08-24 17:14:56 -03:00
parent cc117253c8
commit ee22af5ced
2 changed files with 107 additions and 44 deletions
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49
liolib.c
View File

@ -1,5 +1,5 @@
/* /*
** $Id: liolib.c,v 1.21 1998/06/18 17:04:28 roberto Exp roberto $ ** $Id: liolib.c,v 1.22 1998/08/21 17:43:44 roberto Exp roberto $
** Standard I/O (and system) library ** Standard I/O (and system) library
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -76,7 +76,7 @@ static int ishandler (lua_Object f)
else return 0; else return 0;
} }
static FILE *getfile (char *name) static FILE *getfilebyname (char *name)
{ {
lua_Object f = lua_getglobal(name); lua_Object f = lua_getglobal(name);
if (!ishandler(f)) if (!ishandler(f))
@ -85,21 +85,26 @@ static FILE *getfile (char *name)
} }
static FILE *getfileparam (char *name, int *arg) static FILE *getfile (int arg) {
{ lua_Object f = lua_getparam(arg);
lua_Object f = lua_getparam(*arg); return (ishandler(f)) ? lua_getuserdata(f) : NULL;
if (ishandler(f)) { }
static FILE *getfileparam (char *name, int *arg) {
FILE *f = getfile(*arg);
if (f) {
(*arg)++; (*arg)++;
return lua_getuserdata(f); return f;
} }
else else
return getfile(name); return getfilebyname(name);
} }
static void closefile (char *name) static void closefile (char *name)
{ {
FILE *f = getfile(name); FILE *f = getfilebyname(name);
if (f == stdin || f == stdout) return; if (f == stdin || f == stdout) return;
if (pclose(f) == -1) if (pclose(f) == -1)
fclose(f); fclose(f);
@ -271,6 +276,30 @@ static void io_write (void)
} }
static void io_seek (void) {
static int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
static char *modenames[] = {"set", "cur", "end", NULL};
FILE *f = getfile(FIRSTARG-1+1);
int op = luaL_findstring(luaL_opt_string(FIRSTARG-1+2, "cur"), modenames);
long offset = luaL_opt_number(FIRSTARG-1+3, 0);
luaL_arg_check(f, 1, "invalid file handler");
luaL_arg_check(op != -1, 2, "invalid mode");
op = fseek(f, offset, mode[op]);
if (op)
pushresult(0); /* error */
else
lua_pushnumber(ftell(f));
}
static void io_flush (void) {
FILE *f = getfile(FIRSTARG);
luaL_arg_check(f || lua_getparam(FIRSTARG) == LUA_NOOBJECT, 1,
"invalid file handler");
pushresult(fflush(f) == 0);
}
static void io_execute (void) static void io_execute (void)
{ {
lua_pushnumber(system(luaL_check_string(1))); lua_pushnumber(system(luaL_check_string(1)));
@ -420,7 +449,9 @@ static struct luaL_reg iolibtag[] = {
{"readfrom", io_readfrom}, {"readfrom", io_readfrom},
{"writeto", io_writeto}, {"writeto", io_writeto},
{"appendto", io_appendto}, {"appendto", io_appendto},
{"flush", io_flush},
{"read", io_read}, {"read", io_read},
{"seek", io_seek},
{"write", io_write} {"write", io_write}
}; };

102
manual.tex
View File

@ -1,4 +1,4 @@
% $Id: manual.tex,v 1.17 1998/06/29 18:09:28 roberto Exp roberto $ % $Id: manual.tex,v 1.18 1998/08/21 17:43:44 roberto Exp roberto $
\documentclass[11pt]{article} \documentclass[11pt]{article}
\usepackage{fullpage,bnf} \usepackage{fullpage,bnf}
@ -41,7 +41,7 @@ Waldemar Celes
\tecgraf\ --- Computer Science Department --- PUC-Rio \tecgraf\ --- Computer Science Department --- PUC-Rio
} }
%\date{\small \verb$Date: 1998/06/29 18:09:28 $} %\date{\small \verb$Date: 1998/08/21 17:43:44 $}
\maketitle \maketitle
@ -1879,7 +1879,7 @@ and \verb|lua_iolibopen|, declared in \verb|lualib.h|.
\subsubsection*{\ff \T{call (func, arg [, mode [, errhandler]])}}\Deffunc{call} \subsubsection*{\ff \T{call (func, arg [, mode [, errhandler]])}}\Deffunc{call}
\label{pdf-call} \label{pdf-call}
This function calls function \verb|func| with Calls function \verb|func| with
the arguments given by the table \verb|arg|. the arguments given by the table \verb|arg|.
The call is equivalent to The call is equivalent to
\begin{verbatim} \begin{verbatim}
@ -1932,7 +1932,7 @@ this limit.
the API function \verb|lua_collectgarbage|. the API function \verb|lua_collectgarbage|.
\subsubsection*{\ff \T{dofile (filename)}}\Deffunc{dofile} \subsubsection*{\ff \T{dofile (filename)}}\Deffunc{dofile}
This function receives a file name, Receives a file name,
opens the file, and executes the file contents as a Lua chunk, opens the file, and executes the file contents as a Lua chunk,
or as pre-compiled chunks. or as pre-compiled chunks.
When called without arguments, When called without arguments,
@ -1945,7 +1945,7 @@ It issues an error when called with a non string argument.
\verb|dofile| is equivalent to the API function \verb|lua_dofile|. \verb|dofile| is equivalent to the API function \verb|lua_dofile|.
\subsubsection*{\ff \T{dostring (string [, chunkname])}}\Deffunc{dostring} \subsubsection*{\ff \T{dostring (string [, chunkname])}}\Deffunc{dostring}
This function executes a given string as a Lua chunk. Executes a given string as a Lua chunk.
If there is any error executing the string, If there is any error executing the string,
\verb|dostring| returns \nil. \verb|dostring| returns \nil.
Otherwise, it returns the values returned by the chunk, Otherwise, it returns the values returned by the chunk,
@ -1960,7 +1960,7 @@ Returns a new tag.
\verb|newtag| is equivalent to the API function \verb|lua_newtag|. \verb|newtag| is equivalent to the API function \verb|lua_newtag|.
\subsubsection*{\ff \T{next (table, index)}}\Deffunc{next} \subsubsection*{\ff \T{next (table, index)}}\Deffunc{next}
This function allows a program to traverse all fields of a table. Allows a program to traverse all fields of a table.
Its first argument is a table and its second argument Its first argument is a table and its second argument
is an index in this table. is an index in this table.
It returns the next index of the table and the It returns the next index of the table and the
@ -2038,13 +2038,13 @@ end
\end{verbatim} \end{verbatim}
\subsubsection*{\ff \T{tostring (e)}}\Deffunc{tostring} \subsubsection*{\ff \T{tostring (e)}}\Deffunc{tostring}
This function receives an argument of any type and Receives an argument of any type and
converts it to a string in a reasonable format. converts it to a string in a reasonable format.
For complete control on how numbers are converted, For complete control on how numbers are converted,
use function \verb|format|. use function \verb|format|.
\subsubsection*{\ff \T{print (e1, e2, ...)}}\Deffunc{print} \subsubsection*{\ff \T{print (e1, e2, ...)}}\Deffunc{print}
This function receives any number of arguments, Receives any number of arguments,
and prints their values using the strings returned by \verb|tostring|. and prints their values using the strings returned by \verb|tostring|.
This function is not intended for formatted output, This function is not intended for formatted output,
but only as a quick way to show a value, but only as a quick way to show a value,
@ -2052,14 +2052,14 @@ for instance for debugging.
See \See{libio} for functions for formatted output. See \See{libio} for functions for formatted output.
\subsubsection*{\ff \T{_ALERT (message)}}\Deffunc{alert}\label{alert} \subsubsection*{\ff \T{_ALERT (message)}}\Deffunc{alert}\label{alert}
This function prints its only string argument to \IndexVerb{stderr}. Prints its only string argument to \IndexVerb{stderr}.
All error messages in Lua are printed through this function. All error messages in Lua are printed through this function.
Therefore, a program may redefine it Therefore, a program may redefine it
to change the way such messages are shown to change the way such messages are shown
(for instance, for systems without \verb|stderr|). (for instance, for systems without \verb|stderr|).
\subsubsection*{\ff \T{tonumber (e [, base])}}\Deffunc{tonumber} \subsubsection*{\ff \T{tonumber (e [, base])}}\Deffunc{tonumber}
This function receives one argument, Receives one argument,
and tries to convert it to a number. and tries to convert it to a number.
If the argument is already a number or a string convertible If the argument is already a number or a string convertible
to a number, then \verb|tonumber| returns that number; to a number, then \verb|tonumber| returns that number;
@ -2075,7 +2075,7 @@ as well as an optional exponent part \see{coercion}.
In other bases, only integers are accepted. In other bases, only integers are accepted.
\subsubsection*{\ff \T{type (v)}}\Deffunc{type}\label{pdf-type} \subsubsection*{\ff \T{type (v)}}\Deffunc{type}\label{pdf-type}
This function allows Lua to test the type of a value. Allows Lua to test the type of a value.
It receives one argument, and returns its type, coded as a string. It receives one argument, and returns its type, coded as a string.
The possible results of this function are The possible results of this function are
\verb|"nil"| (a string, not the value \nil), \verb|"nil"| (a string, not the value \nil),
@ -2086,12 +2086,12 @@ The possible results of this function are
and \verb|"userdata"|. and \verb|"userdata"|.
\subsubsection*{\ff \T{tag (v)}}\Deffunc{tag} \subsubsection*{\ff \T{tag (v)}}\Deffunc{tag}
This function allows Lua to test the tag of a value \see{TypesSec}. Allows Lua to test the tag of a value \see{TypesSec}.
It receives one argument, and returns its tag (a number). It receives one argument, and returns its tag (a number).
\verb|tag| is equivalent to the API function \verb|lua_tag|. \verb|tag| is equivalent to the API function \verb|lua_tag|.
\subsubsection*{\ff \T{settag (t, tag)}}\Deffunc{settag} \subsubsection*{\ff \T{settag (t, tag)}}\Deffunc{settag}
This function sets the tag of a given table \see{TypesSec}. Sets the tag of a given table \see{TypesSec}.
\verb|tag| must be a value created with \verb|newtag| \verb|tag| must be a value created with \verb|newtag|
\see{pdf-newtag}. \see{pdf-newtag}.
It returns the value of its first argument (the table). It returns the value of its first argument (the table).
@ -2100,7 +2100,7 @@ it is impossible to change the tag of a userdata from Lua.
\subsubsection*{\ff \T{assert (v [, message])}}\Deffunc{assert} \subsubsection*{\ff \T{assert (v [, message])}}\Deffunc{assert}
This function issues an \emph{``assertion failed!''} error Issues an \emph{``assertion failed!''} error
when its argument is \nil. when its argument is \nil.
This function is equivalent to the following Lua function: This function is equivalent to the following Lua function:
\begin{verbatim} \begin{verbatim}
@ -2113,7 +2113,7 @@ end
\end{verbatim} \end{verbatim}
\subsubsection*{\ff \T{error (message)}}\Deffunc{error}\label{pdf-error} \subsubsection*{\ff \T{error (message)}}\Deffunc{error}\label{pdf-error}
This function calls the error handler and then terminates Calls the error handler and then terminates
the last protected function called the last protected function called
(in~C: \verb|lua_dofile|, \verb|lua_dostring|, (in~C: \verb|lua_dofile|, \verb|lua_dostring|,
\verb|lua_dobuffer|, or \verb|lua_callfunction|; \verb|lua_dobuffer|, or \verb|lua_callfunction|;
@ -2136,7 +2136,7 @@ without invoking any tag method.
and \verb|value| is any Lua value. and \verb|value| is any Lua value.
\subsubsection*{\ff \T{rawsetglobal (name, value)}}\Deffunc{rawsetglobal} \subsubsection*{\ff \T{rawsetglobal (name, value)}}\Deffunc{rawsetglobal}
This function assigns the given value to a global variable. Assigns the given value to a global variable.
The string \verb|name| does not need to be a The string \verb|name| does not need to be a
syntactically valid variable name. syntactically valid variable name.
Therefore, Therefore,
@ -2145,7 +2145,7 @@ this function can set global variables with strange names like
Function \verb|rawsetglobal| returns the value of its second argument. Function \verb|rawsetglobal| returns the value of its second argument.
\subsubsection*{\ff \T{setglobal (name, value)}}\Deffunc{setglobal} \subsubsection*{\ff \T{setglobal (name, value)}}\Deffunc{setglobal}
This function assigns the given value to a global variable, Assigns the given value to a global variable,
or calls a tag method. or calls a tag method.
Its full semantics is explained in \See{tag-method}. Its full semantics is explained in \See{tag-method}.
The string \verb|name| does not need to be a The string \verb|name| does not need to be a
@ -2153,12 +2153,12 @@ syntactically valid variable name.
Function \verb|setglobal| returns the value of its second argument. Function \verb|setglobal| returns the value of its second argument.
\subsubsection*{\ff \T{rawgetglobal (name)}}\Deffunc{rawgetglobal} \subsubsection*{\ff \T{rawgetglobal (name)}}\Deffunc{rawgetglobal}
This function retrieves the value of a global variable. Retrieves the value of a global variable.
The string \verb|name| does not need to be a The string \verb|name| does not need to be a
syntactically valid variable name. syntactically valid variable name.
\subsubsection*{\ff \T{getglobal (name)}}\Deffunc{getglobal} \subsubsection*{\ff \T{getglobal (name)}}\Deffunc{getglobal}
This function retrieves the value of a global variable, Retrieves the value of a global variable,
or calls a tag method. or calls a tag method.
Its full semantics is explained in \See{tag-method}. Its full semantics is explained in \See{tag-method}.
The string \verb|name| does not need to be a The string \verb|name| does not need to be a
@ -2166,19 +2166,19 @@ syntactically valid variable name.
\subsubsection*{\ff \T{settagmethod (tag, event, newmethod)}} \subsubsection*{\ff \T{settagmethod (tag, event, newmethod)}}
\Deffunc{settagmethod} \Deffunc{settagmethod}
This function sets a new tag method to the given pair \M{(tag, event)}. Sets a new tag method to the given pair \M{(tag, event)}.
It returns the old method. It returns the old method.
If \verb|newmethod| is \nil, If \verb|newmethod| is \nil,
\verb|settagmethod| restores the default behavior for the given event. \verb|settagmethod| restores the default behavior for the given event.
\subsubsection*{\ff \T{gettagmethod (tag, event)}} \subsubsection*{\ff \T{gettagmethod (tag, event)}}
\Deffunc{gettagmethod} \Deffunc{gettagmethod}
This function returns the current tag method Returns the current tag method
for a given pair \M{(tag, event)}. for a given pair \M{(tag, event)}.
\subsubsection*{\ff \T{copytagmethods (tagto, tagfrom)}} \subsubsection*{\ff \T{copytagmethods (tagto, tagfrom)}}
\Deffunc{copytagmethods} \Deffunc{copytagmethods}
This function copies all tag methods from one tag to another; Copies all tag methods from one tag to another;
it returns \verb|tagto|. it returns \verb|tagto|.
@ -2190,7 +2190,7 @@ When indexing a string, the first character is at position~1
\subsubsection*{\ff \T{strfind (str, pattern [, init [, plain]])}} \subsubsection*{\ff \T{strfind (str, pattern [, init [, plain]])}}
\Deffunc{strfind} \Deffunc{strfind}
This function looks for the first \emph{match} of Looks for the first \emph{match} of
\verb|pattern| in \verb|str|. \verb|pattern| in \verb|str|.
If it finds one, then it returns the indices on \verb|str| If it finds one, then it returns the indices on \verb|str|
where this occurrence starts and ends; where this occurrence starts and ends;
@ -2265,7 +2265,7 @@ Note that numerical codes are not necessarily portable across platforms.
\subsubsection*{\ff \T{format (formatstring, e1, e2, \ldots)}}\Deffunc{format} \subsubsection*{\ff \T{format (formatstring, e1, e2, \ldots)}}\Deffunc{format}
\label{format} \label{format}
This function returns a formatted version of its variable number of arguments Returns a formatted version of its variable number of arguments
following the description given in its first argument (which must be a string). following the description given in its first argument (which must be a string).
The format string follows the same rules as the \verb|printf| family of The format string follows the same rules as the \verb|printf| family of
standard C functions. standard C functions.
@ -2579,7 +2579,7 @@ usually limited and depends on the system.
\subsubsection*{\ff \T{appendto (filename)}}\Deffunc{appendto} \subsubsection*{\ff \T{appendto (filename)}}\Deffunc{appendto}
This function opens a file named \verb|filename| and sets it as the Opens a file named \verb|filename| and sets it as the
value of \verb|_OUTPUT|. value of \verb|_OUTPUT|.
Unlike the \verb|writeto| operation, Unlike the \verb|writeto| operation,
this function does not erase any previous content of the file. this function does not erase any previous content of the file.
@ -2591,26 +2591,58 @@ available to close an output file opened by \verb|appendto|.
\subsubsection*{\ff \T{remove (filename)}}\Deffunc{remove} \subsubsection*{\ff \T{remove (filename)}}\Deffunc{remove}
This function deletes the file with the given name. Deletes the file with the given name.
If this function fails, it returns \nil, If this function fails, it returns \nil,
plus a string describing the error. plus a string describing the error.
\subsubsection*{\ff \T{rename (name1, name2)}}\Deffunc{rename} \subsubsection*{\ff \T{rename (name1, name2)}}\Deffunc{rename}
This function renames file named \verb|name1| to \verb|name2|. Renames file named \verb|name1| to \verb|name2|.
If this function fails, it returns \nil, If this function fails, it returns \nil,
plus a string describing the error. plus a string describing the error.
\subsubsection*{\ff \T{flush ([filehandle])}}\Deffunc{flush}
Saves any written data to the given file.
If \verb|filehandle| is not specified,
flushes all open files.
If this function fails, it returns \nil,
plus a string describing the error.
\subsubsection*{\ff \T{seek (filehandle [, whence] [, offset])}}\Deffunc{seek}
Sets the file position, measured in bytes from the beginning of the file,
to the position given by \verb|offset| plus a base
specified by the string \verb|whence|, as follows:
\begin{description}
\item[\tt "set"] base is position 0 (beginning of the file);
\item[\tt "cur"] base is current position;
\item[\tt "end"] base is end of file;
\end{description}
In case of success, function \verb|seek| returns the final file position,
measured in bytes from the beginning of the file.
If the call fails, it returns \nil,
plus a string describing the error.
The default value for \verb|whence| is \verb|"cur"|,
and for \verb|offset| is 0.
Therefore, the call \verb|seek(file)| returns the current
file position, without changing it;
the call \verb|seek(file, "set")| sets the position to the
beginning of the file (and returns 0);
and the call \verb|seek(file, "end")| sets the position to the
end of the file, and returns its size.
\subsubsection*{\ff \T{tmpname ()}}\Deffunc{tmpname} \subsubsection*{\ff \T{tmpname ()}}\Deffunc{tmpname}
This function returns a string with a file name that can safely Returns a string with a file name that can safely
be used for a temporary file. be used for a temporary file.
The file must be explicitly removed when no longer needed. The file must be explicitly removed when no longer needed.
\subsubsection*{\ff \T{read ([filehandle] [readpattern])}}\Deffunc{read} \subsubsection*{\ff \T{read ([filehandle] [readpattern])}}\Deffunc{read}
This function reads the file \verb|_INPUT|, Reads file \verb|_INPUT|,
or from \verb|filehandle| if this argument is given, or \verb|filehandle| if this argument is given,
according to a read pattern, which specifies how much to read; according to a read pattern, which specifies how much to read;
characters are read from the input file until characters are read from the input file until
the read pattern fails or ends. the read pattern fails or ends.
@ -2662,9 +2694,9 @@ or \nil\ if the next characters do not conform to an integer format.
\subsubsection*{\ff \T{write ([filehandle, ] value1, ...)}}\Deffunc{write} \subsubsection*{\ff \T{write ([filehandle, ] value1, ...)}}\Deffunc{write}
This function writes the value of each of its arguments to the Writes the value of each of its arguments to
file \verb|_OUTPUT|, file \verb|_OUTPUT|,
or to \verb|filehandle| if this argument is given, or to \verb|filehandle| if this argument is given.
The arguments must be strings or numbers. The arguments must be strings or numbers.
To write other values, To write other values,
use \verb|tostring| or \verb|format| before \verb|write|. use \verb|tostring| or \verb|format| before \verb|write|.
@ -2673,7 +2705,7 @@ plus a string describing the error.
\subsubsection*{\ff \T{date ([format])}}\Deffunc{date} \subsubsection*{\ff \T{date ([format])}}\Deffunc{date}
This function returns a string containing date and time Returns a string containing date and time
formatted according to the given string \verb|format|, formatted according to the given string \verb|format|,
following the same rules of the ANSI C function \verb|strftime|. following the same rules of the ANSI C function \verb|strftime|.
When called without arguments, When called without arguments,
@ -2682,12 +2714,12 @@ the host system and the locale.
\subsubsection*{\ff \T{clock ()}}\Deffunc{clock} \subsubsection*{\ff \T{clock ()}}\Deffunc{clock}
This function returns an approximation of the amount of CPU time Returns an approximation of the amount of CPU time
used by the program, in seconds. used by the program, in seconds.
\subsubsection*{\ff \T{exit ([code])}}\Deffunc{exit} \subsubsection*{\ff \T{exit ([code])}}\Deffunc{exit}
This function calls the C function \verb|exit|, Calls the C function \verb|exit|,
with an optional \verb|code|, with an optional \verb|code|,
to terminate the program. to terminate the program.
The default value for \verb|code| is 1. The default value for \verb|code| is 1.