diff options
Diffstat (limited to 'stdio/fmemopen.c')
-rw-r--r-- | stdio/fmemopen.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/stdio/fmemopen.c b/stdio/fmemopen.c new file mode 100644 index 0000000..42a137a --- /dev/null +++ b/stdio/fmemopen.c @@ -0,0 +1,108 @@ +/* Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include <ansidecl.h> +#include <errno.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + + +/* Defined in fopen.c. */ +extern int EXFUN(__getmode, (CONST char *mode, __io_mode *mptr)); + +/* Open a new stream that will read and/or write from the buffer in + S, which is of LEN bytes. If the mode indicates appending, the + buffer pointer is set to point to the first '\0' in the buffer. + If S is NULL, the buffer is allocated by malloc and will be freed + when the stream is closed. The only purpose of this is to write + things and then read what's been written. If LEN is zero, writes will + always return errors and reads will always return end-of-file. + + The stream is set up such that seeks and tells will always fail and + once the buffer is full of written characters or empty of characters + to read, attempted writes always return an output error and attempted + reads always return end-of-file. */ +FILE * +DEFUN(fmemopen, (s, len, mode), + PTR s AND size_t len AND CONST char *mode) +{ + __io_mode m; + register FILE *stream; + + if (!__getmode (mode, &m)) + return NULL; + + stream = __newstream (); + if (stream == NULL) + return NULL; + + stream->__mode = m; + + /* Input gets EOF. */ + stream->__room_funcs.__input = NULL; + /* Output gets error. */ + stream->__room_funcs.__output = NULL; + + /* Do nothing for close. */ + stream->__io_funcs.__close = NULL; + /* Can't seek outside the buffer. */ + stream->__io_funcs.__seek = NULL; + /* There is no associated file descriptor to fetch. */ + stream->__io_funcs.__fileno = NULL; + + stream->__seen = 1; + + stream->__userbuf = s != NULL && len > 0; + if (s == NULL) + { + s = malloc (len); + if (s == NULL) + { + int save = errno; + (void) fclose (stream); + errno = save; + return NULL; + } + } + + stream->__buffer = (char *) s; + stream->__bufsize = len; + + stream->__bufp = stream->__buffer; + stream->__get_limit = (stream->__buffer + + (stream->__mode.__read ? stream->__bufsize : 0)); + stream->__put_limit = (stream->__buffer + + (stream->__mode.__write ? stream->__bufsize : 0)); + stream->__cookie = NULL; + + if (stream->__mode.__append) + { + char *p = memchr (stream->__bufp, '\0', + stream->__get_limit - stream->__bufp); + if (p == NULL) + stream->__bufp = stream->__get_limit; + else + stream->__bufp = p; + } + else if (stream->__mode.__truncate) + memset ((PTR) stream->__buffer, 0, len); + + return stream; +} |