Fix: pass private data to context callbacks

[lttng-ust.git] / snprintf / various.h

/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (C) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 */

#ifndef UST_SNPRINTF_VARIOUS_H
#define UST_SNPRINTF_VARIOUS_H

#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <wchar.h>

struct __lttng_ust_sbuf {
        unsigned char *_base;
        int     _size;
};

/*
 * stdio state variables.
 *
 * The following always hold:
 *
 *      if (_flags&(__SLBF|__SWR)) == (__SLBF|__SWR),
 *              _lbfsize is -_bf._size, else _lbfsize is 0
 *      if _flags&__SRD, _w is 0
 *      if _flags&__SWR, _r is 0
 *
 * This ensures that the getc and putc macros (or inline functions) never
 * try to write or read from a file that is in `read' or `write' mode.
 * (Moreover, they can, and do, automatically switch from read mode to
 * write mode, and back, on "r+" and "w+" files.)
 *
 * _lbfsize is used only to make the inline line-buffered output stream
 * code as compact as possible.
 *
 * _ub, _up, and _ur are used when ungetc() pushes back more characters
 * than fit in the current _bf, or when ungetc() pushes back a character
 * that does not match the previous one in _bf.  When this happens,
 * _ub._base becomes non-nil (i.e., a stream has ungetc() data iff
 * _ub._base!=NULL) and _up and _ur save the current values of _p and _r.
 */
typedef struct __lttng_ust_sFILE {
        unsigned char *_p;      /* current position in (some) buffer */
        int     _r;             /* read space left for getc() */
        int     _w;             /* write space left for putc() */
        short   _flags;         /* flags, below; this FILE is free if 0 */
        short   _file;          /* fileno, if Unix descriptor, else -1 */
        struct  __lttng_ust_sbuf _bf;     /* the buffer (at least 1 byte, if !NULL) */
        int     _lbfsize;       /* 0 or -_bf._size, for inline putc */

        /* operations */
        void    *_cookie;       /* cookie passed to io functions */
        int     (*_close)(void *);
        int     (*_read)(void *, char *, int);
        fpos_t  (*_seek)(void *, fpos_t, int);
        int     (*_write)(void *, const char *, int);

        /* extension data, to avoid further ABI breakage */
        struct  __lttng_ust_sbuf _ext;
        /* data for long sequences of ungetc() */
        unsigned char *_up;     /* saved _p when _p is doing ungetc data */
        int     _ur;            /* saved _r when _r is counting ungetc data */

        /* tricks to meet minimum requirements even when malloc() fails */
        unsigned char _ubuf[3]; /* guarantee an ungetc() buffer */
        unsigned char _nbuf[1]; /* guarantee a getc() buffer */

        /* separate buffer for fgetln() when line crosses buffer boundary */
        struct  __lttng_ust_sbuf _lb;     /* buffer for fgetln() */

        /* Unix stdio files get aligned to block boundaries on fseek() */
        int     _blksize;       /* stat.st_blksize (may be != _bf._size) */
        fpos_t  _offset;        /* current lseek offset */
} LTTNG_UST_LFILE;

#define __SLBF  0x0001          /* line buffered */
#define __SNBF  0x0002          /* unbuffered */
#define __SRD   0x0004          /* OK to read */
#define __SWR   0x0008          /* OK to write */
        /* RD and WR are never simultaneously asserted */
#define __SRW   0x0010          /* open for reading & writing */
#define __SEOF  0x0020          /* found EOF */
#define __SERR  0x0040          /* found error */
#define __SMBF  0x0080          /* _buf is from malloc */
#define __SAPP  0x0100          /* fdopen()ed in append mode */
#define __SSTR  0x0200          /* this is an sprintf/snprintf string */
#define __SOPT  0x0400          /* do fseek() optimisation */
#define __SNPT  0x0800          /* do not do fseek() optimisation */
#define __SOFF  0x1000          /* set iff _offset is in fact correct */
#define __SMOD  0x2000          /* true => fgetln modified _p text */
#define __SALC  0x4000          /* allocate string space dynamically */

#define __sferror(p)    (((p)->_flags & __SERR) != 0)

extern int ust_safe_fflush(LTTNG_UST_LFILE *fp)
	__attribute__((visibility("hidden")));

extern int ust_safe_vfprintf(LTTNG_UST_LFILE *fp, const char *fmt0, va_list ap)
	__attribute__((visibility("hidden")));

extern size_t ust_safe_mbrtowc(wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
	__attribute__((visibility("hidden")));

#endif /* UST_SNPRINTF_VARIOUS_H */