Implement fmemopen and open_memstream.

* libc/stdio/fmemopen.c (_fmemopen_r, fmemopen): New file.
* libc/stdio/open_memstream.c (_open_memstream_r, open_memstream):
New file.
* libc/stdio/fopencookie.c (fcwriter): Minor optimization.
* libc/include/stdio.h (dprintf, vdprintf): Group all POSIX 200x
functions together.
(fmemopen, open_memstream): Declare new functions.
* libc/stdio/stdio.tex: Document them.
* libc/stdio/Makefile.am (ELIX_4_SOURCES, CHEWOUT_FILES): Add
fmemopen and open_memstream.
* libc/stdio/Makefile.in: Regenerate.
This commit is contained in:
Eric Blake 2007-08-02 20:23:06 +00:00
parent 191814588a
commit 6ddcdb9da5
8 changed files with 780 additions and 10 deletions

View File

@ -1,3 +1,18 @@
2007-08-02 Eric Blake <ebb9@byu.net>
Implement fmemopen and open_memstream.
* libc/stdio/fmemopen.c (_fmemopen_r, fmemopen): New file.
* libc/stdio/open_memstream.c (_open_memstream_r, open_memstream):
New file.
* libc/stdio/fopencookie.c (fcwriter): Minor optimization.
* libc/include/stdio.h (dprintf, vdprintf): Group all POSIX 200x
functions together.
(fmemopen, open_memstream): Declare new functions.
* libc/stdio/stdio.tex: Document them.
* libc/stdio/Makefile.am (ELIX_4_SOURCES, CHEWOUT_FILES): Add
fmemopen and open_memstream.
* libc/stdio/Makefile.in: Regenerate.
2007-07-31 Eric Blake <ebb9@byu.net>
More POSIX stream corner cases.

View File

@ -244,11 +244,9 @@ char * _EXFUN(asnprintf, (char *, size_t *, const char *, ...)
_ATTRIBUTE ((__format__ (__printf__, 3, 4))));
int _EXFUN(asprintf, (char **, const char *, ...)
_ATTRIBUTE ((__format__ (__printf__, 2, 3))));
#ifndef dprintf
#ifndef diprintf
int _EXFUN(diprintf, (int, const char *, ...)
_ATTRIBUTE ((__format__ (__printf__, 2, 3))));
int _EXFUN(dprintf, (int, const char *, ...)
_ATTRIBUTE ((__format__ (__printf__, 2, 3))));
#endif
int _EXFUN(fcloseall, (_VOID));
int _EXFUN(fiprintf, (FILE *, const char *, ...)
@ -278,8 +276,6 @@ int _EXFUN(vasprintf, (char **, const char *, __VALIST)
_ATTRIBUTE ((__format__ (__printf__, 2, 0))));
int _EXFUN(vdiprintf, (int, const char *, __VALIST)
_ATTRIBUTE ((__format__ (__printf__, 2, 0))));
int _EXFUN(vdprintf, (int, const char *, __VALIST)
_ATTRIBUTE ((__format__ (__printf__, 2, 0))));
int _EXFUN(vfiprintf, (FILE *, const char *, __VALIST)
_ATTRIBUTE ((__format__ (__printf__, 2, 0))));
int _EXFUN(vfiscanf, (FILE *, const char *, __VALIST)
@ -306,7 +302,7 @@ int _EXFUN(vsscanf, (const char *, const char *, __VALIST)
#endif /* !__STRICT_ANSI__ */
/*
* Routines in POSIX 1003.1.
* Routines in POSIX 1003.1:2001.
*/
#ifndef __STRICT_ANSI__
@ -329,6 +325,26 @@ int _EXFUN(putc_unlocked, (int, FILE *));
int _EXFUN(putchar_unlocked, (int));
#endif /* ! __STRICT_ANSI__ */
/*
* Routines in POSIX 1003.1:200x.
*/
#ifndef __STRICT_ANSI__
# ifndef _REENT_ONLY
# ifndef dprintf
int _EXFUN(dprintf, (int, const char *, ...)
_ATTRIBUTE ((__format__ (__printf__, 2, 3))));
# endif
FILE * _EXFUN(fmemopen, (void *, size_t, const char *));
/* getdelim - see __getdelim for now */
/* getline - see __getline for now */
FILE * _EXFUN(open_memstream, (char **, size_t *));
/* renameat - unimplemented for now */
int _EXFUN(vdprintf, (int, const char *, __VALIST)
_ATTRIBUTE ((__format__ (__printf__, 2, 0))));
# endif
#endif
/*
* Recursive versions of the above.
*/
@ -354,6 +370,7 @@ int _EXFUN(_fiprintf_r, (struct _reent *, FILE *, const char *, ...)
_ATTRIBUTE ((__format__ (__printf__, 3, 4))));
int _EXFUN(_fiscanf_r, (struct _reent *, FILE *, const char *, ...)
_ATTRIBUTE ((__format__ (__scanf__, 3, 4))));
FILE * _EXFUN(_fmemopen_r, (struct _reent *, void *, size_t, const char *));
FILE * _EXFUN(_fopen_r, (struct _reent *, const char *, const char *));
int _EXFUN(_fprintf_r, (struct _reent *, FILE *, const char *, ...)
_ATTRIBUTE ((__format__ (__printf__, 3, 4))));
@ -376,6 +393,7 @@ int _EXFUN(_iscanf_r, (struct _reent *, const char *, ...)
_ATTRIBUTE ((__format__ (__scanf__, 2, 3))));
int _EXFUN(_mkstemp_r, (struct _reent *, char *));
char * _EXFUN(_mktemp_r, (struct _reent *, char *));
FILE * _EXFUN(_open_memstream_r, (struct _reent *, char **, size_t *));
void _EXFUN(_perror_r, (struct _reent *, const char *));
int _EXFUN(_printf_r, (struct _reent *, const char *, ...)
_ATTRIBUTE ((__format__ (__printf__, 2, 3))));

View File

@ -117,8 +117,10 @@ ELIX_4_SOURCES = \
asnprintf.c \
diprintf.c \
dprintf.c \
fmemopen.c \
fopencookie.c \
funopen.c \
open_memstream.c \
vasniprintf.c \
vasnprintf.c
endif !ELIX_LEVEL_3
@ -179,6 +181,7 @@ CHEWOUT_FILES = \
fgetpos.def \
fgets.def \
fileno.def \
fmemopen.def \
fopen.def \
fopencookie.def \
fputc.def \
@ -199,6 +202,7 @@ CHEWOUT_FILES = \
gets.def \
getw.def \
mktemp.def \
open_memstream.def \
perror.def \
putc.def \
putc_u.def \
@ -244,6 +248,7 @@ $(lpfx)fclose.$(oext): local.h
$(lpfx)fdopen.$(oext): local.h
$(lpfx)fflush.$(oext): local.h
$(lpfx)findfp.$(oext): local.h
$(lpfx)fmemopen.$(oext): local.h
$(lpfx)fopen.$(oext): local.h
$(lpfx)fopencookie.$(oext): local.h
$(lpfx)fputs.$(oext): fvwrite.h
@ -257,6 +262,7 @@ $(lpfx)fwalk.$(oext): local.h
$(lpfx)fwrite.$(oext): local.h fvwrite.h
$(lpfx)iscanf.$(oext): local.h
$(lpfx)makebuf.$(oext): local.h
$(lpfx)open_memstream.$(oext): local.h
$(lpfx)puts.$(oext): fvwrite.h
$(lpfx)refill.$(oext): local.h
$(lpfx)scanf.$(oext): local.h

View File

@ -110,8 +110,10 @@ am__objects_1 = lib_a-clearerr.$(OBJEXT) lib_a-fclose.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ lib_a-asnprintf.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ lib_a-diprintf.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ lib_a-dprintf.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ lib_a-fmemopen.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ lib_a-fopencookie.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ lib_a-funopen.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ lib_a-open_memstream.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ lib_a-vasniprintf.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ lib_a-vasnprintf.$(OBJEXT)
@USE_LIBTOOL_FALSE@am_lib_a_OBJECTS = $(am__objects_1) \
@ -141,8 +143,10 @@ am__objects_4 = clearerr.lo fclose.lo fdopen.lo feof.lo ferror.lo \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ asnprintf.lo \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ diprintf.lo \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ dprintf.lo \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ fmemopen.lo \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ fopencookie.lo \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ funopen.lo \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ open_memstream.lo \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ vasniprintf.lo \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ vasnprintf.lo
@USE_LIBTOOL_TRUE@am_libstdio_la_OBJECTS = $(am__objects_4) \
@ -423,8 +427,10 @@ GENERAL_SOURCES = \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ asnprintf.c \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ diprintf.c \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ dprintf.c \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ fmemopen.c \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ fopencookie.c \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ funopen.c \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ open_memstream.c \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ vasniprintf.c \
@ELIX_LEVEL_1_FALSE@@ELIX_LEVEL_2_FALSE@@ELIX_LEVEL_3_FALSE@ vasnprintf.c
@ -463,6 +469,7 @@ CHEWOUT_FILES = \
fgetpos.def \
fgets.def \
fileno.def \
fmemopen.def \
fopen.def \
fopencookie.def \
fputc.def \
@ -483,6 +490,7 @@ CHEWOUT_FILES = \
gets.def \
getw.def \
mktemp.def \
open_memstream.def \
perror.def \
putc.def \
putc_u.def \
@ -1138,6 +1146,12 @@ lib_a-dprintf.o: dprintf.c
lib_a-dprintf.obj: dprintf.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-dprintf.obj `if test -f 'dprintf.c'; then $(CYGPATH_W) 'dprintf.c'; else $(CYGPATH_W) '$(srcdir)/dprintf.c'; fi`
lib_a-fmemopen.o: fmemopen.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-fmemopen.o `test -f 'fmemopen.c' || echo '$(srcdir)/'`fmemopen.c
lib_a-fmemopen.obj: fmemopen.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-fmemopen.obj `if test -f 'fmemopen.c'; then $(CYGPATH_W) 'fmemopen.c'; else $(CYGPATH_W) '$(srcdir)/fmemopen.c'; fi`
lib_a-fopencookie.o: fopencookie.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-fopencookie.o `test -f 'fopencookie.c' || echo '$(srcdir)/'`fopencookie.c
@ -1150,6 +1164,12 @@ lib_a-funopen.o: funopen.c
lib_a-funopen.obj: funopen.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-funopen.obj `if test -f 'funopen.c'; then $(CYGPATH_W) 'funopen.c'; else $(CYGPATH_W) '$(srcdir)/funopen.c'; fi`
lib_a-open_memstream.o: open_memstream.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-open_memstream.o `test -f 'open_memstream.c' || echo '$(srcdir)/'`open_memstream.c
lib_a-open_memstream.obj: open_memstream.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-open_memstream.obj `if test -f 'open_memstream.c'; then $(CYGPATH_W) 'open_memstream.c'; else $(CYGPATH_W) '$(srcdir)/open_memstream.c'; fi`
lib_a-vasniprintf.o: vasniprintf.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-vasniprintf.o `test -f 'vasniprintf.c' || echo '$(srcdir)/'`vasniprintf.c
@ -1342,6 +1362,7 @@ $(lpfx)fclose.$(oext): local.h
$(lpfx)fdopen.$(oext): local.h
$(lpfx)fflush.$(oext): local.h
$(lpfx)findfp.$(oext): local.h
$(lpfx)fmemopen.$(oext): local.h
$(lpfx)fopen.$(oext): local.h
$(lpfx)fopencookie.$(oext): local.h
$(lpfx)fputs.$(oext): fvwrite.h
@ -1355,6 +1376,7 @@ $(lpfx)fwalk.$(oext): local.h
$(lpfx)fwrite.$(oext): local.h fvwrite.h
$(lpfx)iscanf.$(oext): local.h
$(lpfx)makebuf.$(oext): local.h
$(lpfx)open_memstream.$(oext): local.h
$(lpfx)puts.$(oext): fvwrite.h
$(lpfx)refill.$(oext): local.h
$(lpfx)scanf.$(oext): local.h

View File

@ -0,0 +1,371 @@
/* Copyright (C) 2007 Eric Blake
* Permission to use, copy, modify, and distribute this software
* is freely granted, provided that this notice is preserved.
*/
/*
FUNCTION
<<fmemopen>>---open a stream around a fixed-length string
INDEX
fmemopen
ANSI_SYNOPSIS
#include <stdio.h>
FILE *fmemopen(void *restrict <[buf]>, size_t <[size]>,
const char *restrict <[mode]>);
DESCRIPTION
<<fmemopen>> creates a seekable <<FILE>> stream that wraps a
fixed-length buffer of <[size]> bytes starting at <[buf]>. The stream
is opened with <[mode]> treated as in <<fopen>>, where append mode
starts writing at the first NUL byte. If <[buf]> is NULL, then
<[size]> bytes are automatically provided as if by <<malloc>>, with
the initial size of 0, and <[mode]> must contain <<+>> so that data
can be read after it is written.
The stream maintains a current position, which moves according to
bytes read or written, and which can be one past the end of the array.
The stream also maintains a current file size, which is never greater
than <[size]>. If <[mode]> starts with <<r>>, the position starts at
<<0>>, and file size starts at <[size]> if <[buf]> was provided. If
<[mode]> starts with <<w>>, the position and file size start at <<0>>,
and if <[buf]> was provided, the first byte is set to NUL. If
<[mode]> starts with <<a>>, the position and file size start at the
location of the first NUL byte, or else <[size]> if <[buf]> was
provided.
When reading, NUL bytes have no significance, and reads cannot exceed
the current file size. When writing, the file size can increase up to
<[size]> as needed, and NUL bytes may be embedded in the stream (see
<<open_memstream>> for an alternative that automatically enlarges the
buffer). When the stream is flushed or closed after a write that
changed the file size, a NUL byte is written at the current position
if there is still room; if the stream is not also open for reading, a
NUL byte is additionally written at the last byte of <[buf]> when the
stream has exceeded <[size]>, so that a write-only <[buf]> is always
NUL-terminated when the stream is flushed or closed (and the initial
<[size]> should take this into account). It is not possible to seek
outside the bounds of <[size]>. A NUL byte written during a flush is
restored to its previous value when seeking elsewhere in the string.
RETURNS
The return value is an open FILE pointer on success. On error,
<<NULL>> is returned, and <<errno>> will be set to EINVAL if <[size]>
is zero or <[mode]> is invalid, ENOMEM if <[buf]> was NULL and memory
could not be allocated, or EMFILE if too many streams are already
open.
PORTABILITY
This function is being added to POSIX 200x, but is not in POSIX 2001.
Supporting OS subroutines required: <<sbrk>>.
*/
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/lock.h>
#include "local.h"
/* Describe details of an open memstream. */
typedef struct fmemcookie {
void *storage; /* storage to free on close */
char *buf; /* buffer start */
size_t pos; /* current position */
size_t eof; /* current file size */
size_t max; /* maximum file size */
char append; /* nonzero if appending */
char writeonly; /* 1 if write-only */
char saved; /* saved character that lived at pos before write-only NUL */
} fmemcookie;
/* Read up to non-zero N bytes into BUF from stream described by
COOKIE; return number of bytes read (0 on EOF). */
static _READ_WRITE_RETURN_TYPE
_DEFUN(fmemreader, (ptr, cookie, buf, n),
struct _reent *ptr _AND
void *cookie _AND
char *buf _AND
int n)
{
fmemcookie *c = (fmemcookie *) cookie;
/* Can't read beyond current size, but EOF condition is not an error. */
if (c->pos > c->eof)
return 0;
if (n >= c->eof - c->pos)
n = c->eof - c->pos;
memcpy (buf, c->buf + c->pos, n);
c->pos += n;
return n;
}
/* Write up to non-zero N bytes of BUF into the stream described by COOKIE,
returning the number of bytes written or EOF on failure. */
static _READ_WRITE_RETURN_TYPE
_DEFUN(fmemwriter, (ptr, cookie, buf, n),
struct _reent *ptr _AND
void *cookie _AND
const char *buf _AND
int n)
{
fmemcookie *c = (fmemcookie *) cookie;
int adjust = 0; /* true if at EOF, but still need to write NUL. */
/* Append always seeks to eof; otherwise, if we have previously done
a seek beyond eof, ensure all intermediate bytes are NUL. */
if (c->append)
c->pos = c->eof;
else if (c->pos > c->eof)
memset (c->buf + c->eof, '\0', c->pos - c->eof);
/* Do not write beyond EOF; saving room for NUL on write-only stream. */
if (c->pos + n > c->max - c->writeonly)
{
adjust = c->writeonly;
n = c->max - c->pos;
}
/* Now n is the number of bytes being modified, and adjust is 1 if
the last byte is NUL instead of from buf. Write a NUL if
write-only; or if read-write, eof changed, and there is still
room. When we are within the file contents, remember what we
overwrite so we can restore it if we seek elsewhere later. */
if (c->pos + n > c->eof)
{
c->eof = c->pos + n;
if (c->eof - adjust < c->max)
c->saved = c->buf[c->eof - adjust] = '\0';
}
else if (c->writeonly)
{
if (n)
{
c->saved = c->buf[c->pos + n - adjust];
c->buf[c->pos + n - adjust] = '\0';
}
else
adjust = 0;
}
c->pos += n;
if (n - adjust)
memcpy (c->buf + c->pos - n, buf, n - adjust);
else
{
ptr->_errno = ENOSPC;
return EOF;
}
return n;
}
/* Seek to position POS relative to WHENCE within stream described by
COOKIE; return resulting position or fail with EOF. */
static _fpos_t
_DEFUN(fmemseeker, (ptr, cookie, pos, whence),
struct _reent *ptr _AND
void *cookie _AND
_fpos_t pos _AND
int whence)
{
fmemcookie *c = (fmemcookie *) cookie;
#ifndef __LARGE64_FILES
off_t offset = (off_t) pos;
#else /* __LARGE64_FILES */
_off64_t offset = (_off64_t) pos;
#endif /* __LARGE64_FILES */
if (whence == SEEK_CUR)
offset += c->pos;
else if (whence == SEEK_END)
offset += c->eof;
if (offset < 0)
{
ptr->_errno = EINVAL;
offset = -1;
}
else if (offset > c->max)
{
ptr->_errno = ENOSPC;
offset = -1;
}
#ifdef __LARGE64_FILES
else if ((_fpos_t) offset != offset)
{
ptr->_errno = EOVERFLOW;
offset = -1;
}
#endif /* __LARGE64_FILES */
else
{
if (c->writeonly && c->pos < c->eof)
{
c->buf[c->pos] = c->saved;
c->saved = '\0';
}
c->pos = offset;
if (c->writeonly && c->pos < c->eof)
{
c->saved = c->buf[c->pos];
c->buf[c->pos] = '\0';
}
}
return (_fpos_t) offset;
}
/* Seek to position POS relative to WHENCE within stream described by
COOKIE; return resulting position or fail with EOF. */
#ifdef __LARGE64_FILES
static _fpos64_t
_DEFUN(fmemseeker64, (ptr, cookie, pos, whence),
struct _reent *ptr _AND
void *cookie _AND
_fpos64_t pos _AND
int whence)
{
_off64_t offset = (_off64_t) pos;
fmemcookie *c = (fmemcookie *) cookie;
if (whence == SEEK_CUR)
offset += c->pos;
else if (whence == SEEK_END)
offset += c->eof;
if (offset < 0)
{
ptr->_errno = EINVAL;
offset = -1;
}
else if (offset > c->max)
{
ptr->_errno = ENOSPC;
offset = -1;
}
else
{
if (c->writeonly && c->pos < c->eof)
{
c->buf[c->pos] = c->saved;
c->saved = '\0';
}
c->pos = offset;
if (c->writeonly && c->pos < c->eof)
{
c->saved = c->buf[c->pos];
c->buf[c->pos] = '\0';
}
}
return (_fpos64_t) offset;
}
#endif /* __LARGE64_FILES */
/* Reclaim resources used by stream described by COOKIE. */
static int
_DEFUN(fmemcloser, (ptr, cookie),
struct _reent *ptr _AND
void *cookie)
{
fmemcookie *c = (fmemcookie *) cookie;
_free_r (ptr, c->storage);
return 0;
}
/* Open a memstream around buffer BUF of SIZE bytes, using MODE.
Return the new stream, or fail with NULL. */
FILE *
_DEFUN(_fmemopen_r, (ptr, buf, size, mode),
struct _reent *ptr _AND
void *buf _AND
size_t size _AND
const char *mode)
{
FILE *fp;
fmemcookie *c;
int flags;
int dummy;
if ((flags = __sflags (ptr, mode, &dummy)) == 0)
return NULL;
if (!size || !(buf || flags & __SAPP))
{
ptr->_errno = EINVAL;
return NULL;
}
if ((fp = __sfp (ptr)) == NULL)
return NULL;
if ((c = (fmemcookie *) _malloc_r (ptr, sizeof *c + (buf ? 0 : size)))
== NULL)
{
__sfp_lock_acquire ();
fp->_flags = 0; /* release */
#ifndef __SINGLE_THREAD__
__lock_close_recursive (fp->_lock);
#endif
__sfp_lock_release ();
return NULL;
}
c->storage = c;
c->max = size;
/* 9 modes to worry about. */
/* w/a, buf or no buf: Guarantee a NUL after any file writes. */
c->writeonly = (flags & __SWR) != 0;
c->saved = '\0';
if (!buf)
{
/* r+/w+/a+, and no buf: file starts empty. */
c->buf = (char *) (c + 1);
*(char *) buf = '\0';
c->pos = c->eof = 0;
c->append = (flags & __SAPP) != 0;
}
else
{
c->buf = (char *) buf;
switch (*mode)
{
case 'a':
/* a/a+ and buf: position and size at first NUL. */
buf = memchr (c->buf, '\0', size);
c->eof = c->pos = buf ? (char *) buf - c->buf : size;
if (!buf && c->writeonly)
/* a: guarantee a NUL within size even if no writes. */
c->buf[size - 1] = '\0';
c->append = 1;
break;
case 'r':
/* r/r+ and buf: read at beginning, full size available. */
c->pos = c->append = 0;
c->eof = size;
break;
case 'w':
/* w/w+ and buf: write at beginning, truncate to empty. */
c->pos = c->append = c->eof = 0;
*c->buf = '\0';
break;
default:
abort ();
}
}
_flockfile (fp);
fp->_file = -1;
fp->_flags = flags;
fp->_cookie = c;
fp->_read = flags & (__SRD | __SRW) ? fmemreader : NULL;
fp->_write = flags & (__SWR | __SRW) ? fmemwriter : NULL;
fp->_seek = fmemseeker;
#ifdef __LARGE64_FILES
fp->_seek64 = fmemseeker64;
fp->_flags |= __SL64;
#endif
fp->_close = fmemcloser;
_funlockfile (fp);
return fp;
}
#ifndef _REENT_ONLY
FILE *
_DEFUN(fmemopen, (buf, size, mode),
void *buf _AND
size_t size _AND
const char *mode)
{
return _fmemopen_r (_REENT, buf, size, mode);
}
#endif /* !_REENT_ONLY */

View File

@ -122,9 +122,9 @@ _DEFUN(fcwriter, (ptr, cookie, buf, n),
if (c->fp->_flags & __SAPP && c->fp->_seek)
{
#ifdef __LARGE64_FILES
c->fp->_seek64 (ptr, c->fp->_cookie, 0, SEEK_END);
c->fp->_seek64 (ptr, cookie, 0, SEEK_END);
#else
c->fp->_seek (ptr, c->fp->_cookie, 0, SEEK_END);
c->fp->_seek (ptr, cookie, 0, SEEK_END);
#endif
}
errno = 0;
@ -134,7 +134,7 @@ _DEFUN(fcwriter, (ptr, cookie, buf, n),
}
static _fpos_t
_DEFUN(fcseeker, (ptr, cookie, off, whence),
_DEFUN(fcseeker, (ptr, cookie, pos, whence),
struct _reent *ptr _AND
void *cookie _AND
_fpos_t pos _AND
@ -162,7 +162,7 @@ _DEFUN(fcseeker, (ptr, cookie, off, whence),
#ifdef __LARGE64_FILES
static _fpos64_t
_DEFUN(fcseeker64, (ptr, cookie, off, whence),
_DEFUN(fcseeker64, (ptr, cookie, pos, whence),
struct _reent *ptr _AND
void *cookie _AND
_fpos64_t pos _AND

View File

@ -0,0 +1,330 @@
/* Copyright (C) 2007 Eric Blake
* Permission to use, copy, modify, and distribute this software
* is freely granted, provided that this notice is preserved.
*/
/*
FUNCTION
<<open_memstream>>---open a write stream around an arbitrary-length string
INDEX
open_memstream
ANSI_SYNOPSIS
#include <stdio.h>
FILE *open_memstream(char **restrict <[buf]>,
size_t *restrict <[size]>);
DESCRIPTION
<<open_memstream>> creates a seekable <<FILE>> stream that wraps an
arbitrary-length buffer, created as if by <<malloc>>. The current
contents of *<[buf]> are ignored; this implementation uses *<[size]>
as a hint of the maximum size expected, but does not fail if the hint
was wrong. The parameters <[buf]> and <[size]> are later stored
through following any call to <<fflush>> or <<fclose>>, set to the
current address and usable size of the allocated string; although
after fflush, the pointer is only valid until another stream operation
that results in a write. Behavior is undefined if the user alters
either *<[buf]> or *<[size]> prior to <<fclose>>.
The stream is write-only, since the user can directly read *<[buf]>
after a flush; see <<fmemopen>> for a way to wrap a string with a
readable stream. The user is responsible for calling <<free>> on
the final *<[buf]> after <<fclose>>.
Any time the stream is flushed, a NUL byte is written at the current
position (but is not counted in the buffer length), so that the string
is always NUL-terminated after at most *<[size]> bytes. However, data
previously written beyond the current stream offset is not lost, and
the NUL byte written during a flush is restored to its previous value
when seeking elsewhere in the string.
RETURNS
The return value is an open FILE pointer on success. On error,
<<NULL>> is returned, and <<errno>> will be set to EINVAL if <[buf]>
or <[size]> is NULL, ENOMEM if memory could not be allocated, or
EMFILE if too many streams are already open.
PORTABILITY
This function is being added to POSIX 200x, but is not in POSIX 2001.
Supporting OS subroutines required: <<sbrk>>.
*/
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/lock.h>
#include "local.h"
#ifndef __LARGE64_FILES
# define OFF_T off_t
#else
# define OFF_T _off64_t
#endif
/* Describe details of an open memstream. */
typedef struct memstream {
void *storage; /* storage to free on close */
char **pbuf; /* pointer to the current buffer */
size_t *psize; /* pointer to the current size, smaller of pos or eof */
size_t pos; /* current position */
size_t eof; /* current file size */
size_t max; /* current malloc buffer size, always > eof */
char saved; /* saved character that lived at *psize before NUL */
} memstream;
/* Write up to non-zero N bytes of BUF into the stream described by COOKIE,
returning the number of bytes written or EOF on failure. */
static _READ_WRITE_RETURN_TYPE
_DEFUN(memwriter, (ptr, cookie, buf, n),
struct _reent *ptr _AND
void *cookie _AND
const char *buf _AND
int n)
{
memstream *c = (memstream *) cookie;
char *cbuf = *c->pbuf;
/* size_t is unsigned, but off_t is signed. Don't let stream get so
big that user cannot do ftello. */
if (sizeof (OFF_T) == sizeof (size_t) && (ssize_t) (c->pos + n) < 0)
{
ptr->_errno = EFBIG;
return EOF;
}
/* Grow the buffer, if necessary. Choose a geometric growth factor
to avoid quadratic realloc behavior, but use a rate less than
(1+sqrt(5))/2 to accomodate malloc overhead. Overallocate, so
that we can add a trailing \0 without reallocating. The new
allocation should thus be max(prev_size*1.5, c->pos+n+1). */
if (c->pos + n >= c->max)
{
size_t newsize = c->max * 3 / 2;
if (newsize < c->pos + n + 1)
newsize = c->pos + n + 1;
cbuf = _realloc_r (ptr, cbuf, newsize);
if (! cbuf)
return EOF; /* errno already set to ENOMEM */
*c->pbuf = cbuf;
c->max = newsize;
}
/* If we have previously done a seek beyond eof, ensure all
intermediate bytes are NUL. */
if (c->pos > c->eof)
memset (cbuf + c->eof, '\0', c->pos - c->eof);
memcpy (cbuf + c->pos, buf, n);
c->pos += n;
/* If the user has previously written further, remember what the
trailing NUL is overwriting. Otherwise, extend the stream. */
if (c->pos > c->eof)
c->eof = c->pos;
else
c->saved = cbuf[c->pos];
cbuf[c->pos] = '\0';
*c->psize = c->pos;
return n;
}
/* Seek to position POS relative to WHENCE within stream described by
COOKIE; return resulting position or fail with EOF. */
static _fpos_t
_DEFUN(memseeker, (ptr, cookie, pos, whence),
struct _reent *ptr _AND
void *cookie _AND
_fpos_t pos _AND
int whence)
{
memstream *c = (memstream *) cookie;
OFF_T offset = (OFF_T) pos;
if (whence == SEEK_CUR)
offset += c->pos;
else if (whence == SEEK_END)
offset += c->eof;
if (offset < 0)
{
ptr->_errno = EINVAL;
offset = -1;
}
else if ((size_t) offset != offset)
{
ptr->_errno = ENOSPC;
offset = -1;
}
#ifdef __LARGE64_FILES
else if ((_fpos_t) offset != offset)
{
ptr->_errno = EOVERFLOW;
offset = -1;
}
#endif /* __LARGE64_FILES */
else
{
if (c->pos < c->eof)
{
(*c->pbuf)[c->pos] = c->saved;
c->saved = '\0';
}
c->pos = offset;
if (c->pos < c->eof)
{
c->saved = (*c->pbuf)[c->pos];
(*c->pbuf)[c->pos] = '\0';
*c->psize = c->pos;
}
else
*c->psize = c->eof;
}
return (_fpos_t) offset;
}
/* Seek to position POS relative to WHENCE within stream described by
COOKIE; return resulting position or fail with EOF. */
#ifdef __LARGE64_FILES
static _fpos64_t
_DEFUN(memseeker64, (ptr, cookie, pos, whence),
struct _reent *ptr _AND
void *cookie _AND
_fpos64_t pos _AND
int whence)
{
_off64_t offset = (_off64_t) pos;
memstream *c = (memstream *) cookie;
if (whence == SEEK_CUR)
offset += c->pos;
else if (whence == SEEK_END)
offset += c->eof;
if (offset < 0)
{
ptr->_errno = EINVAL;
offset = -1;
}
else if ((size_t) offset != offset)
{
ptr->_errno = ENOSPC;
offset = -1;
}
else
{
if (c->pos < c->eof)
{
(*c->pbuf)[c->pos] = c->saved;
c->saved = '\0';
}
c->pos = offset;
if (c->pos < c->eof)
{
c->saved = (*c->pbuf)[c->pos];
(*c->pbuf)[c->pos] = '\0';
*c->psize = c->pos;
}
else
*c->psize = c->eof;
}
return (_fpos64_t) offset;
}
#endif /* __LARGE64_FILES */
/* Reclaim resources used by stream described by COOKIE. */
static int
_DEFUN(memcloser, (ptr, cookie),
struct _reent *ptr _AND
void *cookie)
{
memstream *c = (memstream *) cookie;
char *buf;
/* Be nice and try to reduce any unused memory. */
buf = _realloc_r (ptr, *c->pbuf, *c->psize + 1);
if (buf)
*c->pbuf = buf;
_free_r (ptr, c->storage);
return 0;
}
/* Open a memstream that tracks a dynamic buffer in BUF and SIZE.
Return the new stream, or fail with NULL. */
FILE *
_DEFUN(_open_memstream_r, (ptr, buf, size),
struct _reent *ptr _AND
char **buf _AND
size_t *size)
{
FILE *fp;
memstream *c;
int flags;
if (!buf || !size)
{
ptr->_errno = EINVAL;
return NULL;
}
if ((fp = __sfp (ptr)) == NULL)
return NULL;
if ((c = (memstream *) _malloc_r (ptr, sizeof *c)) == NULL)
{
__sfp_lock_acquire ();
fp->_flags = 0; /* release */
#ifndef __SINGLE_THREAD__
__lock_close_recursive (fp->_lock);
#endif
__sfp_lock_release ();
return NULL;
}
/* Use *size as a hint for initial sizing, but bound the initial
malloc between 64 bytes (same as asprintf, to avoid frequent
mallocs on small strings) and 64k bytes (to avoid overusing the
heap if *size was garbage). */
c->max = *size;
if (c->max < 64)
c->max = 64;
else if (c->max > 64 * 1024)
c->max = 64 * 1024;
*size = 0;
*buf = _malloc_r (ptr, c->max);
if (!*buf)
{
__sfp_lock_acquire ();
fp->_flags = 0; /* release */
#ifndef __SINGLE_THREAD__
__lock_close_recursive (fp->_lock);
#endif
__sfp_lock_release ();
_free_r (ptr, c);
return NULL;
}
**buf = '\0';
c->storage = c;
c->pbuf = buf;
c->psize = size;
c->eof = 0;
c->saved = '\0';
_flockfile (fp);
fp->_file = -1;
fp->_flags = __SWR;
fp->_cookie = c;
fp->_read = NULL;
fp->_write = memwriter;
fp->_seek = memseeker;
#ifdef __LARGE64_FILES
fp->_seek64 = memseeker64;
fp->_flags |= __SL64;
#endif
fp->_close = memcloser;
_funlockfile (fp);
return fp;
}
#ifndef _REENT_ONLY
FILE *
_DEFUN(open_memstream, (buf, size),
char **buf _AND
size_t *size)
{
return _open_memstream_r (_REENT, buf, size);
}
#endif /* !_REENT_ONLY */

View File

@ -37,6 +37,7 @@ structure.
* fgetpos:: Record position in a stream or file
* fgets:: Get character string from a file or stream
* fileno:: Get file descriptor associated with stream
* fmemopen:: Open a stream around a fixed-length buffer
* fopen:: Open a file
* fopencookie:: Open a stream with custom callbacks
* fputc:: Write a character on a stream or file
@ -57,6 +58,7 @@ structure.
* gets:: Get character string from standard input (obsolete)
* getw:: Get a word (int) from a file or stream
* mktemp:: Generate unused file name
* open_memstream:: Open a write stream around an arbitrary-length buffer
* perror:: Print an error message on standard error
* putc:: Write a character on a stream or file (macro)
* putc_unlocked:: Write a character on a stream or file (macro)
@ -123,6 +125,9 @@ structure.
@page
@include stdio/fileno.def
@page
@include stdio/fmemopen.def
@page
@include stdio/fopen.def
@ -183,6 +188,9 @@ structure.
@page
@include stdio/mktemp.def
@page
@include stdio/open_memstream.def
@page
@include stdio/perror.def