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.

1 files changed, 425 insertions, 0 deletions

diff --git a/lib/libc/stdio/xprintf_float.c b/lib/libc/stdio/xprintf_float.c
new file mode 100644
index 0000000..b719aac
--- /dev/null
+++ b/lib/libc/stdio/xprintf_float.c
@@ -0,0 +1,425 @@
+/*-
+ * Copyright (c) 2005 Poul-Henning Kamp
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * 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.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ *
+ * $FreeBSD$
+ */
+
+#include <namespace.h>
+#include <stdio.h>
+#include <wchar.h>
+#include <assert.h>
+#include <locale.h>
+#include <limits.h>
+
+#define	dtoa		__dtoa
+#define	freedtoa	__freedtoa
+
+#include <float.h>
+#include <math.h>
+#include "gdtoa.h"
+#include "floatio.h"
+#include "printf.h"
+#include <un-namespace.h>
+
+/*
+ * The size of the buffer we use as scratch space for integer
+ * conversions, among other things.  Technically, we would need the
+ * most space for base 10 conversions with thousands' grouping
+ * characters between each pair of digits.  100 bytes is a
+ * conservative overestimate even for a 128-bit uintmax_t.
+ */
+#define	BUF	100
+
+#define	DEFPREC		6	/* Default FP precision */
+
+
+/* various globals ---------------------------------------------------*/
+
+
+/* padding function---------------------------------------------------*/
+
+#define	PRINTANDPAD(p, ep, len, with) do {		\
+	n2 = (ep) - (p);       				\
+	if (n2 > (len))					\
+		n2 = (len);				\
+	if (n2 > 0)					\
+		ret += __printf_puts(io, (p), n2);		\
+	ret += __printf_pad(io, (len) - (n2 > 0 ? n2 : 0), (with));	\
+} while(0)
+
+/* misc --------------------------------------------------------------*/
+
+#define	to_char(n)	((n) + '0')
+
+static int
+exponent(char *p0, int expo, int fmtch)
+{
+	char *p, *t;
+	char expbuf[MAXEXPDIG];
+
+	p = p0;
+	*p++ = fmtch;
+	if (expo < 0) {
+		expo = -expo;
+		*p++ = '-';
+	}
+	else
+		*p++ = '+';
+	t = expbuf + MAXEXPDIG;
+	if (expo > 9) {
+		do {
+			*--t = to_char(expo % 10);
+		} while ((expo /= 10) > 9);
+		*--t = to_char(expo);
+		for (; t < expbuf + MAXEXPDIG; *p++ = *t++)
+			;
+	}
+	else {
+		/*
+		 * Exponents for decimal floating point conversions
+		 * (%[eEgG]) must be at least two characters long,
+		 * whereas exponents for hexadecimal conversions can
+		 * be only one character long.
+		 */
+		if (fmtch == 'e' || fmtch == 'E')
+			*p++ = '0';
+		*p++ = to_char(expo);
+	}
+	return (p - p0);
+}
+
+/* 'f' ---------------------------------------------------------------*/
+
+int
+__printf_arginfo_float(const struct printf_info *pi, size_t n, int *argt)
+{
+	assert (n > 0);
+	argt[0] = PA_DOUBLE;
+	if (pi->is_long_double)
+		argt[0] |= PA_FLAG_LONG_DOUBLE;
+	return (1);
+}
+
+/*
+ * We can decompose the printed representation of floating
+ * point numbers into several parts, some of which may be empty:
+ *
+ * [+|-| ] [0x|0X] MMM . NNN [e|E|p|P] [+|-] ZZ
+ *    A       B     ---C---      D       E   F
+ *
+ * A:	'sign' holds this value if present; '\0' otherwise
+ * B:	ox[1] holds the 'x' or 'X'; '\0' if not hexadecimal
+ * C:	cp points to the string MMMNNN.  Leading and trailing
+ *	zeros are not in the string and must be added.
+ * D:	expchar holds this character; '\0' if no exponent, e.g. %f
+ * F:	at least two digits for decimal, at least one digit for hex
+ */
+
+int
+__printf_render_float(struct __printf_io *io, const struct printf_info *pi, const void *const *arg)
+{
+	int prec;		/* precision from format; <0 for N/A */
+	char *dtoaresult;	/* buffer allocated by dtoa */
+	char expchar;		/* exponent character: [eEpP\0] */
+	char *cp;
+	int expt;		/* integer value of exponent */
+	int signflag;		/* true if float is negative */
+	char *dtoaend;		/* pointer to end of converted digits */
+	char sign;		/* sign prefix (' ', '+', '-', or \0) */
+	int size;		/* size of converted field or string */
+	int ndig;		/* actual number of digits returned by dtoa */
+	int expsize;		/* character count for expstr */
+	char expstr[MAXEXPDIG+2];	/* buffer for exponent string: e+ZZZ */
+	int nseps;		/* number of group separators with ' */
+	int nrepeats;		/* number of repeats of the last group */
+	const char *grouping;	/* locale specific numeric grouping rules */
+	int lead;		/* sig figs before decimal or group sep */
+	long double ld;
+	double d;
+	int realsz;		/* field size expanded by dprec, sign, etc */
+	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */
+	char ox[2];		/* space for 0x; ox[1] is either x, X, or \0 */
+	int prsize;             /* max size of printed field */
+	int ret;		/* return value accumulator */
+	char *decimal_point;	/* locale specific decimal point */
+	int n2;			/* XXX: for PRINTANDPAD */
+	char thousands_sep;	/* locale specific thousands separator */
+	char buf[BUF];		/* buffer with space for digits of uintmax_t */
+	const char *xdigs;
+	int flag;
+
+	prec = pi->prec;
+	ox[1] = '\0';
+	sign = pi->showsign;
+	flag = 0;
+	ret = 0;
+
+	thousands_sep = *(localeconv()->thousands_sep);
+	grouping = NULL;
+	if (pi->alt)
+		grouping = localeconv()->grouping;
+	decimal_point = localeconv()->decimal_point;
+	dprec = -1;
+
+	switch(pi->spec) {
+	case 'a':
+	case 'A':
+		if (pi->spec == 'a') {
+			ox[1] = 'x';
+			xdigs = __lowercase_hex;
+			expchar = 'p';
+		} else {
+			ox[1] = 'X';
+			xdigs = __uppercase_hex;
+			expchar = 'P';
+		}
+		if (prec >= 0)
+			prec++;
+		if (pi->is_long_double) {
+			ld = *((long double *)arg[0]);
+			dtoaresult = cp =
+			    __hldtoa(ld, xdigs, prec,
+			    &expt, &signflag, &dtoaend);
+		} else {
+			d = *((double *)arg[0]);
+			dtoaresult = cp =
+			    __hdtoa(d, xdigs, prec,
+			    &expt, &signflag, &dtoaend);
+		}
+		if (prec < 0)
+			prec = dtoaend - cp;
+		if (expt == INT_MAX)
+			ox[1] = '\0';
+		goto fp_common;
+	case 'e':
+	case 'E':
+		expchar = pi->spec;
+		if (prec < 0)	/* account for digit before decpt */
+			prec = DEFPREC + 1;
+		else
+			prec++;
+		break;
+	case 'f':
+	case 'F':
+		expchar = '\0';
+		break;
+	case 'g':
+	case 'G':
+		expchar = pi->spec - ('g' - 'e');
+		if (prec == 0)
+			prec = 1;
+		break;
+	default:
+		assert(pi->spec == 'f');
+	}
+
+	if (prec < 0)
+		prec = DEFPREC;
+	if (pi->is_long_double) {
+		ld = *((long double *)arg[0]);
+		dtoaresult = cp =
+		    __ldtoa(&ld, expchar ? 2 : 3, prec,
+		    &expt, &signflag, &dtoaend);
+	} else {
+		d = *((double *)arg[0]);
+		dtoaresult = cp =
+		    dtoa(d, expchar ? 2 : 3, prec,
+		    &expt, &signflag, &dtoaend);
+		if (expt == 9999)
+			expt = INT_MAX;
+	}
+fp_common:
+	if (signflag)
+		sign = '-';
+	if (expt == INT_MAX) {	/* inf or nan */
+		if (*cp == 'N') {
+			cp = (pi->spec >= 'a') ? "nan" : "NAN";
+			sign = '\0';
+		} else
+			cp = (pi->spec >= 'a') ? "inf" : "INF";
+		size = 3;
+		flag = 1;
+		goto here;
+	}
+	ndig = dtoaend - cp;
+	if (pi->spec == 'g' || pi->spec == 'G') {
+		if (expt > -4 && expt <= prec) {
+			/* Make %[gG] smell like %[fF] */
+			expchar = '\0';
+			if (pi->alt)
+				prec -= expt;
+			else
+				prec = ndig - expt;
+			if (prec < 0)
+				prec = 0;
+		} else {
+			/*
+			 * Make %[gG] smell like %[eE], but
+			 * trim trailing zeroes if no # flag.
+			 */
+			if (!pi->alt)
+				prec = ndig;
+		}
+	}
+	if (expchar) {
+		expsize = exponent(expstr, expt - 1, expchar);
+		size = expsize + prec;
+		if (prec > 1 || pi->alt)
+			++size;
+	} else {
+		/* space for digits before decimal point */
+		if (expt > 0)
+			size = expt;
+		else	/* "0" */
+			size = 1;
+		/* space for decimal pt and following digits */
+		if (prec || pi->alt)
+			size += prec + 1;
+		if (grouping && expt > 0) {
+			/* space for thousands' grouping */
+			nseps = nrepeats = 0;
+			lead = expt;
+			while (*grouping != CHAR_MAX) {
+				if (lead <= *grouping)
+					break;
+				lead -= *grouping;
+				if (*(grouping+1)) {
+					nseps++;
+					grouping++;
+				} else
+					nrepeats++;
+			}
+			size += nseps + nrepeats;
+		} else
+			lead = expt;
+	}
+
+here:
+	/*
+	 * All reasonable formats wind up here.  At this point, `cp'
+	 * points to a string which (if not flags&LADJUST) should be
+	 * padded out to `width' places.  If flags&ZEROPAD, it should
+	 * first be prefixed by any sign or other prefix; otherwise,
+	 * it should be blank padded before the prefix is emitted.
+	 * After any left-hand padding and prefixing, emit zeroes
+	 * required by a decimal [diouxX] precision, then print the
+	 * string proper, then emit zeroes required by any leftover
+	 * floating precision; finally, if LADJUST, pad with blanks.
+	 *
+	 * Compute actual size, so we know how much to pad.
+	 * size excludes decimal prec; realsz includes it.
+	 */
+	realsz = dprec > size ? dprec : size;
+	if (sign)
+		realsz++;
+	if (ox[1])
+		realsz += 2;
+
+	prsize = pi->width > realsz ? pi->width : realsz;
+
+	/* right-adjusting blank padding */
+	if (pi->pad != '0' && pi->left == 0)
+		ret += __printf_pad(io, pi->width - realsz, 0);
+
+	/* prefix */
+	if (sign)
+		ret += __printf_puts(io, &sign, 1);
+
+	if (ox[1]) {	/* ox[1] is either x, X, or \0 */
+		ox[0] = '0';
+		ret += __printf_puts(io, ox, 2);
+	}
+
+	/* right-adjusting zero padding */
+	if (pi->pad == '0' && pi->left == 0)
+		ret += __printf_pad(io, pi->width - realsz, 1);
+
+	/* leading zeroes from decimal precision */
+	ret += __printf_pad(io, dprec - size, 1);
+
+	if (flag)
+		ret += __printf_puts(io, cp, size);
+	else {
+		/* glue together f_p fragments */
+		if (!expchar) {	/* %[fF] or sufficiently short %[gG] */
+			if (expt <= 0) {
+				ret += __printf_puts(io, "0", 1);
+				if (prec || pi->alt)
+					ret += __printf_puts(io, decimal_point, 1);
+				ret += __printf_pad(io, -expt, 1);
+				/* already handled initial 0's */
+				prec += expt;
+			} else {
+				PRINTANDPAD(cp, dtoaend, lead, 1);
+				cp += lead;
+				if (grouping) {
+					while (nseps>0 || nrepeats>0) {
+						if (nrepeats > 0)
+							nrepeats--;
+						else {
+							grouping--;
+							nseps--;
+						}
+						ret += __printf_puts(io, &thousands_sep, 1);
+						PRINTANDPAD(cp,dtoaend,
+						    *grouping, 1);
+						cp += *grouping;
+					}
+					if (cp > dtoaend)
+						cp = dtoaend;
+				}
+				if (prec || pi->alt)
+					ret += __printf_puts(io, decimal_point,1);
+			}
+			PRINTANDPAD(cp, dtoaend, prec, 1);
+		} else {	/* %[eE] or sufficiently long %[gG] */
+			if (prec > 1 || pi->alt) {
+				buf[0] = *cp++;
+				buf[1] = *decimal_point;
+				ret += __printf_puts(io, buf, 2);
+				ret += __printf_puts(io, cp, ndig-1);
+				ret += __printf_pad(io, prec - ndig, 1);
+			} else	/* XeYYY */
+				ret += __printf_puts(io, cp, 1);
+			ret += __printf_puts(io, expstr, expsize);
+		}
+	}
+	/* left-adjusting padding (always blank) */
+	if (pi->left)
+		ret += __printf_pad(io, pi->width - realsz, 0);
+
+	__printf_flush(io);
+	if (dtoaresult != NULL)
+		freedtoa(dtoaresult);
+
+	return (ret);
+}