epoc32/include/libc/sys/stdio_t.h
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:27:01 +0100
branchSymbian2
changeset 3 e1b950c65cb4
parent 0 061f57f2323e
child 4 837f303aceeb
permissions -rw-r--r--
Attempt to represent the S^2->S^3 header reorganisation as a series of "hg rename" operations
     1 /*
     2 * Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).
     3 * All rights reserved.
     4 * This component and the accompanying materials are made available
     5 * under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members
     6 * which accompanies this distribution, and is available
     7 * at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".
     8 *
     9 * Initial Contributors:
    10 * Nokia Corporation - initial contribution.
    11 *
    12 * Contributors:
    13 *
    14 * Description:
    15 *
    16 */
    17 
    18 
    19 
    20 
    21 
    22 #ifndef _SYS_STDIO_T_H_
    23 #define _SYS_STDIO_T_H_
    24 #ifdef __cplusplus
    25 extern "C" {
    26 #endif
    27 
    28 #include <_ansi.h>
    29 
    30 /**
    31 Stdio buffers.
    32 @publishedAll
    33 @released
    34 */
    35 struct __sbuf {
    36 	unsigned char *	_base;
    37 	int				_size;
    38 };
    39 
    40 /**
    41 We need fpos_t for the following, but it doesn't have a leading "_",
    42 so we use _fpos_t instead.
    43 @publishedAll
    44 @released
    45 */
    46 
    47 typedef long _fpos_t;		/* XXX must match off_t in <sys/types.h> */
    48 							/* (and must be `long' for now) */
    49 
    50 /**
    51 Stdio state variables.
    52 
    53 The following always hold:
    54 
    55 if (_flags&(__SLBF|__SWR)) == (__SLBF|__SWR),
    56 	_lbfsize is -_bf._size, else _lbfsize is 0
    57 if _flags&__SRD, _w is 0
    58 	if _flags&__SWR, _r is 0
    59 
    60 This ensures that the getc and putc macros (or inline functions) never
    61 try to write or read from a file that is in `read' or `write' mode.
    62 (Moreover, they can, and do, automatically switch from read mode to
    63 write mode, and back, on "r+" and "w+" files.)
    64 
    65 _lbfsize is used only to make the inline line-buffered output stream
    66 code as compact as possible.
    67 
    68 _ub, _up, and _ur are used when ungetc() pushes back more characters
    69 than fit in the current _bf, or when ungetc() pushes back a character
    70 that does not match the previous one in _bf.  When this happens,
    71 _ub._base becomes non-nil (i.e., a stream has ungetc() data iff
    72 _ub._base!=NULL) and _up and _ur save the current values of _p and _r.
    73 @publishedAll
    74 @released
    75 */
    76 struct __sFILE {
    77   unsigned char *_p;			/* current position in (some) buffer */
    78   int			 _r;			/* read space left for getc() */
    79   int			 _w;			/* write space left for putc() */
    80   short			 _flags;		/* flags, below; this FILE is free if 0 */
    81   short			 _file;			/* fileno, if Unix descriptor, else -1 */
    82   struct __sbuf	 _bf;			/* the buffer (at least 1 byte, if !NULL) */
    83   int			 _lbfsize;		/* 0 or -_bf._size, for inline putc */
    84 
    85   /* operations */
    86   void *		 _cookie;		/* cookie passed to io functions */
    87 
    88   int		(*_read) (void * _cookie, char *_buf, int _n);
    89   int		(*_write)(void * _cookie, const char *_buf, int _n);
    90   _fpos_t	(*_seek) (void * _cookie, _fpos_t _offset, int _whence);
    91   int		(*_close)(void * _cookie);
    92 
    93   /* separate buffer for long sequences of ungetc() */
    94   struct __sbuf		_ub;		/* ungetc buffer */
    95   unsigned char *	_up;		/* saved _p when _p is doing ungetc data */
    96   int				_ur;		/* saved _r when _r is counting ungetc data */
    97 
    98   /* tricks to meet minimum requirements even when malloc() fails */
    99   unsigned char		_ubuf[3];	/* guarantee an ungetc() buffer */
   100   unsigned char		_nbuf[1];	/* guarantee a getc() buffer */
   101 
   102   /* separate buffer for fgetline() when line crosses buffer boundary */
   103   struct __sbuf		_lb;		/* buffer for fgetline() */
   104 
   105   /* Unix stdio files get aligned to block boundaries on fseek() */
   106   int				_blksize;	/* stat.st_blksize (may be != _bf._size) */
   107   int				_offset;	/* current lseek offset */
   108 
   109   struct _reent *	_data;		/* pointer back to re-entrancy context block */
   110 };
   111 
   112 
   113 #ifdef __cplusplus
   114 }
   115 #endif
   116 #endif /* _SYS_STDIO_T_H_ */