Add an extensible version of our *printf(3) implementation to libc

on probationary terms:  it may go away again if it transpires it is
a bad idea.

This extensible printf version will only be used if either
    environment variable USE_XPRINTF is defined
or
    one of the extension functions are called.
or
    the global variable __use_xprintf is set greater than zero.

In all other cases our traditional printf implementation will
be used.

The extensible version is slower than the default printf, mostly
because less opportunity for combining I/O operation exists when
faced with extensions.  The default printf on the other hand
is a bad case of spaghetti code.

The extension API has a GLIBC compatible part and a FreeBSD version
of same.  The FreeBSD version exists because the GLIBC version may
run afoul of our FILE * locking in multithreaded programs and it
even further eliminate the opportunities for combining I/O operations.

Include three demo extensions which can be enabled if desired: time
(%T), hexdump (%H) and strvis (%V).

%T can format time_t (%T), struct timeval (%lT) and struct timespec (%llT)
   in one of two human readable duration formats:
	"%.3llT" -> "20349.245"
	"%#.3llT" -> "5h39m9.245"

%H will hexdump a sequence of bytes and takes a pointer and a length
   argument.  The width specifies number of bytes per line.
	"%4H" -> "65 72 20 65"
	"%+4H" -> "0000 65 72 20 65"
	"%#4H" -> "65 72 20 65  |er e|"
	"%+#4H" -> "0000 65 72 20 65  |er e|"

%V will dump a string in strvis format.
	"%V" -> "Hello\tWor\377ld"	(C-style)
	"%0V" -> "Hello\011Wor\377ld"	(octal)
	"%+V" -> "Hello%09Wor%FFld"	(http-style)

Tests, comments, bugreports etc are most welcome.

2 files changed, 156 insertions, 1 deletions

diff --git a/include/Makefile b/include/Makefile
index 89554f0..e488788 100644
--- a/include/Makefile
+++ b/include/Makefile
@@ -14,7 +14,7 @@ INCS=	a.out.h ar.h assert.h bitstring.h complex.h cpio.h _ctype.h ctype.h \
 	locale.h malloc.h memory.h monetary.h mpool.h mqueue.h \
 	ndbm.h netconfig.h \
 	netdb.h nl_types.h nlist.h nss.h nsswitch.h objformat.h paths.h \
-	proc_service.h pthread.h \
+	printf.h proc_service.h pthread.h \
 	pthread_np.h pwd.h ranlib.h readpassphrase.h regex.h regexp.h \
 	resolv.h runetype.h search.h setjmp.h sgtty.h \
 	signal.h stab.h \
diff --git a/include/printf.h b/include/printf.h
new file mode 100644
index 0000000..d16ad6e
--- /dev/null
+++ b/include/printf.h
@@ -0,0 +1,155 @@
+/*-
+ * Copyright (c) 2005 Poul-Henning Kamp
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _PRINTF_H_
+#define _PRINTF_H_
+
+union arg;
+
+/*
+ * The API defined by glibc allows a renderer to take multiple arguments
+ * This is obviously usable for things like (ptr+len) pairs etc.
+ * But the do not actually provide support for it at the end of the day,
+ * they offer only one argument to the arginfo function, but do accept
+ * >1 returns, although the do not check the types of those arguments
+ * argument
+ * Be compatible for now.
+ */
+#define __PRINTFMAXARG		2
+
+struct printf_info {
+	/* GLIBC compatible */
+	int		prec;
+	int		width;
+	wchar_t		spec;
+	unsigned 	is_long_double;
+	unsigned 	is_char;
+	unsigned	is_short;
+	unsigned	is_long;
+	unsigned	alt;
+	unsigned	space;
+	unsigned	left;
+	unsigned	showsign;
+	unsigned	group;
+	unsigned	extra;
+	unsigned	wide;
+	wchar_t		pad;
+
+	/* FreeBSD extensions */
+
+	unsigned	is_quad;
+	unsigned	is_intmax;
+	unsigned	is_ptrdiff;
+	unsigned	is_size;
+
+	/* private */
+	int		sofar;
+	unsigned	get_width;
+	unsigned	get_prec;
+	const char	*begin;
+	const char	*end;
+	void 		*arg[__PRINTFMAXARG];
+};
+
+enum {
+	PA_INT		= (1 << 0),	/* int */
+	PA_CHAR		= (1 << 1),	/* int, cast to char */
+	PA_WCHAR	= (1 << 2),	/* wide char */
+	PA_STRING	= (1 << 3),	/* const char * (with '\0') */
+	PA_WSTRING	= (1 << 4),	/* const wchar_t * */
+	PA_POINTER	= (1 << 5),	/* void * */
+	PA_FLOAT	= (1 << 6),	/* float */
+	PA_DOUBLE	= (1 << 7) 	/* double */
+};
+
+#define	PA_FLAG_MASK		0xff0000
+#define	PA_FLAG_LONG_LONG	(1 << 16)
+#define	PA_FLAG_LONG		(1 << 17)
+#define	PA_FLAG_SHORT		(1 << 18)
+#define	PA_FLAG_PTR		(1 << 19)
+#define	PA_FLAG_QUAD		(1 << 20)
+#define	PA_FLAG_INTMAX		(1 << 21)
+#define	PA_FLAG_SIZE		(1 << 22)
+#define	PA_FLAG_PTRDIFF		(1 << 23)
+#define	PA_FLAG_LONG_DOUBLE	PA_FLAG_LONG_LONG
+
+typedef int printf_arginfo_function(const struct printf_info *, size_t, int *);
+typedef int printf_function(FILE *, const struct printf_info *, const void *const *);
+
+/* FreeBSD extension */
+struct __printf_io;
+typedef int printf_render(struct __printf_io *, const struct printf_info *, const void *const *);
+
+/* vprintf.c */
+extern const char __lowercase_hex[17];
+extern const char __uppercase_hex[17];
+
+void __printf_flush(struct __printf_io *io);
+int __printf_puts(struct __printf_io *io, const void *ptr, int len);
+int __printf_pad(struct __printf_io *io, int n, int zero);
+int __printf_out(struct __printf_io *io, const struct printf_info *pi, const void *ptr, int len);
+
+int __xvprintf(FILE *fp, const char *fmt0, va_list ap);
+extern int __use_xprintf;
+
+/* GLIBC compat */
+int register_printf_function(int spec, printf_function *render, printf_arginfo_function *arginfo);
+
+/* FreeBSD */
+int register_printf_render(int spec, printf_render *render, printf_arginfo_function *arginfo);
+int register_printf_render_std(const unsigned char *specs);
+
+/* vprintf_float.c */
+printf_arginfo_function		__printf_arginfo_float;
+printf_render			__printf_render_float;
+
+/* vprintf_int.c */
+printf_arginfo_function		__printf_arginfo_ptr;
+printf_arginfo_function		__printf_arginfo_int;
+printf_render			__printf_render_ptr;
+printf_render			__printf_render_int;
+
+/* vprintf_str.c */
+printf_arginfo_function		__printf_arginfo_chr;
+printf_render			__printf_render_chr;
+printf_arginfo_function		__printf_arginfo_str;
+printf_render			__printf_render_str;
+
+/* vprintf_time.c */
+printf_arginfo_function		__printf_arginfo_time;
+printf_render			__printf_render_time;
+
+/* vprintf_hexdump.c */
+printf_arginfo_function		__printf_arginfo_hexdump;
+printf_render 			__printf_render_hexdump;
+
+/* vprintf_vis.c */
+printf_arginfo_function		__printf_arginfo_vis;
+printf_render 			__printf_render_vis;
+
+#endif /* !_PRINTF_H */