Next round of stdio changes: Remove all inlining of stdio operations and

move the definition of the type backing FILE (struct __sFILE) into an
internal header.
- Remove macros to inline certain operations from stdio.h.  Applications
  will now always call the functions instead.
- Move the various foo_unlocked() functions from unlocked.c into foo.c.
  This lets some of the inlining macros (e.g. __sfeof()) move into
  foo.c.
- Update a few comments.
- struct __sFILE can now go back to using mbstate_t, pthread_t, and
  pthread_mutex_t instead of knowing about their private, backing types.

MFC after:	1 month
Reviewed by:	kan

1 files changed, 132 insertions, 2 deletions

diff --git a/lib/libc/stdio/local.h b/lib/libc/stdio/local.h
index 09b3a18..d5bf737 100644
--- a/lib/libc/stdio/local.h
+++ b/lib/libc/stdio/local.h
@@ -39,9 +39,105 @@
 #include <wchar.h>
 
 /*
- * Information local to this implementation of stdio,
- * in particular, macros and private variables.
+ * Information local to this implementation of stdio, in particular,
+ * macros, private functions, private variables, and the definition of
+ * FILE.
+ *
+ * NB: to fit things in six character monocase externals, the stdio
+ * code uses the prefix `__s' for stdio objects, typically followed
+ * by a three-character attempt at a mnemonic.
+ */
+
+/* stdio buffers */
+struct __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.
+ *
+ * Certain members of __sFILE are accessed directly via macros or
+ * inline functions.  To preserve ABI compat, these members must not
+ * be disturbed.  These members are marked below with (*).
  */
+struct __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	__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);
+
+	/* separate buffer for long sequences of ungetc() */
+	struct	__sbuf _ub;	/* ungetc buffer */
+	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	__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 */
+
+	pthread_mutex_t _fl_mutex;	/* used for MT-safety */
+	pthread_t _fl_owner;	/* current owner */
+	int	_fl_count;	/* recursive lock count */
+	int	_orientation;	/* orientation for fwide() */
+	mbstate_t _mbstate;	/* multibyte conversion state */
+};
+
+#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() optimization */
+#define	__SNPT	0x0800		/* do not do fseek() optimization */
+#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	__SIGN	0x8000		/* ignore this file in _fwalk */
 
 extern int	_sread(FILE *, char *, int);
 extern int	_swrite(FILE *, char const *, int);
@@ -57,6 +153,8 @@ extern FILE	*__sfp(void);
 extern int	__slbexpand(FILE *, size_t);
 extern int	__srefill(FILE *);
 extern int	__sread(void *, char *, int);
+extern int	__srget(FILE *);
+extern int	__swbuf(int, FILE *);
 extern int	__swrite(void *, char const *, int);
 extern fpos_t	__sseek(void *, fpos_t, int);
 extern int	__sclose(void *);
@@ -81,6 +179,38 @@ extern int	__sdidinit;
 
 
 /*
+ * Get and store individual characters from a file stream.
+ */
+#define	__sgetc(p) (--(p)->_r < 0 ? __srget(p) : (int)(*(p)->_p++))
+#if defined(__GNUC__) && defined(__STDC__)
+static __inline int
+__sputc(int _c, FILE *_p)
+{
+	if (--_p->_w >= 0 || (_p->_w >= _p->_lbfsize && (char)_c != '\n'))
+		return (*_p->_p++ = _c);
+	else
+		return (__swbuf(_c, _p));
+}
+#else
+/*
+ * This has been tuned to generate reasonable code on the vax using pcc.
+ */
+#define	__sputc(c, p) \
+	(--(p)->_w < 0 ? \
+		(p)->_w >= (p)->_lbfsize ? \
+			(*(p)->_p = (c)), *(p)->_p != '\n' ? \
+				(int)*(p)->_p++ : \
+				__swbuf('\n', p) : \
+			__swbuf((int)(c), p) : \
+		(*(p)->_p = (c), (int)*(p)->_p++))
+#endif
+
+/*
+ * Return true if the file stream has encountered an error.
+ */
+#define	__sferror(p)	(((p)->_flags & __SERR) != 0)
+
+/*
  * Prepare the given FILE for writing, and return 0 iff it
  * can be written now.  Otherwise, return EOF and set errno.
  */