1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/os/ossrv/genericopenlibs/cstdlib/LSTDIO/SETVBUF.C Fri Jun 15 03:10:57 2012 +0200
1.3 @@ -0,0 +1,199 @@
1.4 +/* SETVBUF.C
1.5 + *
1.6 + * Portions Copyright (c) 1990-2009 Nokia Corporation and/or its subsidiary(-ies).
1.7 + * All rights reserved.
1.8 + */
1.9 +
1.10 +/*
1.11 + * Copyright (c) 1990 The Regents of the University of California.
1.12 + * All rights reserved.
1.13 + *
1.14 + * Redistribution and use in source and binary forms are permitted
1.15 + * provided that the above copyright notice and this paragraph are
1.16 + * duplicated in all such forms and that any documentation,
1.17 + * advertising materials, and other materials related to such
1.18 + * distribution and use acknowledge that the software was developed
1.19 + * by the University of California, Berkeley. The name of the
1.20 + * University may not be used to endorse or promote products derived
1.21 + * from this software without specific prior written permission.
1.22 + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
1.23 + * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
1.24 + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
1.25 + */
1.26 +
1.27 +/*
1.28 +FUNCTION
1.29 +<<setvbuf>>---specify file or stream buffering
1.30 +
1.31 +INDEX
1.32 + setvbuf
1.33 +
1.34 +ANSI_SYNOPSIS
1.35 + #include <stdio.h>
1.36 + int setvbuf(FILE *<[fp]>, char *<[buf]>,
1.37 + int <[mode]>, size_t <[size]>);
1.38 +
1.39 +TRAD_SYNOPSIS
1.40 + #include <stdio.h>
1.41 + int setvbuf(<[fp]>, <[buf]>, <[mode]>, <[size]>)
1.42 + FILE *<[fp]>;
1.43 + char *<[buf]>;
1.44 + int <[mode]>;
1.45 + size_t <[size]>;
1.46 +
1.47 +DESCRIPTION
1.48 +Use <<setvbuf>> to specify what kind of buffering you want for the
1.49 +file or stream identified by <[fp]>, by using one of the following
1.50 +values (from <<stdio.h>>) as the <[mode]> argument:
1.51 +
1.52 +o+
1.53 +o _IONBF
1.54 +Do not use a buffer: send output directly to the host system for the
1.55 +file or stream identified by <[fp]>.
1.56 +
1.57 +o _IOFBF
1.58 +Use full output buffering: output will be passed on to the host system
1.59 +only when the buffer is full, or when an input operation intervenes.
1.60 +
1.61 +o _IOLBF
1.62 +Use line buffering: pass on output to the host system at every
1.63 +newline, as well as when the buffer is full, or when an input
1.64 +operation intervenes.
1.65 +o-
1.66 +
1.67 +Use the <[size]> argument to specify how large a buffer you wish. You
1.68 +can supply the buffer itself, if you wish, by passing a pointer to a
1.69 +suitable area of memory as <[buf]>. Otherwise, you may pass <<NULL>>
1.70 +as the <[buf]> argument, and <<setvbuf>> will allocate the buffer.
1.71 +
1.72 +WARNINGS
1.73 +You may only use <<setvbuf>> before performing any file operation other
1.74 +than opening the file.
1.75 +
1.76 +If you supply a non-null <[buf]>, you must ensure that the associated
1.77 +storage continues to be available until you close the stream
1.78 +identified by <[fp]>.
1.79 +
1.80 +RETURNS
1.81 +A <<0>> result indicates success, <<EOF>> failure (invalid <[mode]> or
1.82 +<[size]> can cause failure).
1.83 +
1.84 +PORTABILITY
1.85 +Both ANSI C and the System V Interface Definition (Issue 2) require
1.86 +<<setvbuf>>. However, they differ on the meaning of a <<NULL>> buffer
1.87 +pointer: the SVID issue 2 specification says that a <<NULL>> buffer
1.88 +pointer requests unbuffered output. For maximum portability, avoid
1.89 +<<NULL>> buffer pointers.
1.90 +
1.91 +Both specifications describe the result on failure only as a
1.92 +nonzero value.
1.93 +
1.94 +Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
1.95 +<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
1.96 +*/
1.97 +
1.98 +#include <stdio_r.h>
1.99 +#include <stdlib_r.h>
1.100 +#include "LOCAL.H"
1.101 +
1.102 +/**
1.103 +Change stream buffering.
1.104 +Changes the buffer to be used for I/O operations with the specified stream.
1.105 +Size and mode for the buffer can be specified.
1.106 +This function should be called once the file associated with the stream
1.107 +has been opened but before any input or output operation has been done.
1.108 +The size of the buffer is specified by the size parameter,
1.109 +and can be any value between 2 and 32767 in bytes,
1.110 +this value may be rounded down by some system due to specific alignment.
1.111 +buffer can be NULL.
1.112 +@return If the buffer is correctly assigned to the file a 0 value is returned.
1.113 +On error, a non-zero value is returned. This can be because an invalid type or size has been specified or because an error allocating memory (if NULL buffer was specified).
1.114 +@param fp pointer to an open file.
1.115 +@param buf User allocated buffer. Must have at least a size of size bytes.
1.116 +@param mode Specifies a mode for file buffering
1.117 +@param Buffer size in bytes, must be more than 0 and less than 32768, this value may be rounded down by some systems due to specific alignment, in which case the minimum value should be 2.
1.118 +*/
1.119 +EXPORT_C int
1.120 +setvbuf (FILE * fp, char *buf, int mode, size_t size)
1.121 +{
1.122 + int ret = 0;
1.123 + CHECK_INIT (fp);
1.124 +
1.125 + /*
1.126 + * Verify arguments. The `int' limit on `size' is due to this
1.127 + * particular implementation.
1.128 + */
1.129 +
1.130 + if ((mode != _IOFBF && mode != _IOLBF && mode != _IONBF) || (int) size < 0)
1.131 + return (EOF);
1.132 +
1.133 + /*
1.134 + * Write current buffer, if any; drop read count, if any.
1.135 + * Make sure putc() will not think fp is line buffered.
1.136 + * Free old buffer if it was from malloc(). Clear line and
1.137 + * non buffer flags, and clear malloc flag.
1.138 + */
1.139 +
1.140 + (void) fflush (fp);
1.141 + fp->_r = 0;
1.142 + fp->_lbfsize = 0;
1.143 + if (fp->_flags & __SMBF)
1.144 + _free_r (fp->_data, (void *) fp->_bf._base);
1.145 + fp->_flags &= ~(__SLBF | __SNBF | __SMBF);
1.146 +
1.147 + if (mode == _IONBF)
1.148 + goto nbf;
1.149 +
1.150 + /*
1.151 + * Allocate buffer if needed. */
1.152 + if (buf == NULL)
1.153 + {
1.154 + if ((buf = (char *)malloc (size)) == NULL)
1.155 + {
1.156 + ret = EOF;
1.157 + /* Try another size... */
1.158 + buf = (char *)malloc (BUFSIZ);
1.159 + }
1.160 + if (buf == NULL)
1.161 + {
1.162 + /* Can't allocate it, let's try another approach */
1.163 +nbf:
1.164 + fp->_flags |= __SNBF;
1.165 + fp->_w = 0;
1.166 + fp->_bf._base = fp->_p = fp->_nbuf;
1.167 + fp->_bf._size = 1;
1.168 + return (ret);
1.169 + }
1.170 + fp->_flags |= __SMBF;
1.171 + }
1.172 + /*
1.173 + * Now put back whichever flag is needed, and fix _lbfsize
1.174 + * if line buffered. Ensure output flush on exit if the
1.175 + * stream will be buffered at all.
1.176 + * Force the buffer to be flushed and hence malloced on first use
1.177 + */
1.178 +
1.179 + switch (mode)
1.180 + {
1.181 + case _IOLBF:
1.182 + fp->_flags |= __SLBF;
1.183 + fp->_lbfsize = -(int)size;
1.184 + /* FALLTHROUGH */
1.185 +
1.186 + case _IOFBF:
1.187 + /* no flag */
1.188 + fp->_data->__cleanup = _cleanup_r;
1.189 + fp->_bf._base = fp->_p = (unsigned char *) buf;
1.190 + fp->_bf._size = size;
1.191 + break;
1.192 + }
1.193 +
1.194 + /*
1.195 + * Patch up write count if necessary.
1.196 + */
1.197 +
1.198 + if (fp->_flags & __SWR)
1.199 + fp->_w = fp->_flags & (__SLBF | __SNBF) ? 0 : size;
1.200 +
1.201 + return 0;
1.202 +}