Fix sscanf/wcstod parsing of NaNs.

The parsefloat routines -- which let us pass NaNs and infinities on to
strto(f|d|ld) -- come from NetBSD.

Also fix LP64's strtold to return a NaN, and fix all the architectures
to return quiet NaNs.

Also fix wcstof/wcstod/wcstold to use parsefloat so they support hex
floats.

Lots of new tests.

Bug: http://b/31101647
Change-Id: Id7d46ac2d8acb8770b5e8c445e87cfabfde6f111

1 files changed, 336 insertions, 0 deletions

diff --git a/libc/stdio/parsefloat.c b/libc/stdio/parsefloat.c
new file mode 100644
index 000000000..e911da412
--- /dev/null
+++ b/libc/stdio/parsefloat.c
@@ -0,0 +1,336 @@
+/*-
+ * 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.
+ */
+
+#include <ctype.h>
+#include <stdlib.h>
+
+#include "local.h"
+#include "floatio.h"
+
+#define	BUF		513	/* Maximum length of numeric string. */
+
+size_t parsefloat(FILE *fp, char *buf, char *end) {
+	char *commit, *p;
+	int infnanpos = 0;
+	enum {
+		S_START, S_GOTSIGN, S_INF, S_NAN, S_MAYBEHEX,
+		S_DIGITS, S_FRAC, S_EXP, S_EXPDIGITS
+	} state = S_START;
+	unsigned char c;
+	int gotmantdig = 0, ishex = 0;
+
+	/*
+	 * We set commit = p whenever the string we have read so far
+	 * constitutes a valid representation of a floating point
+	 * number by itself.  At some point, the parse will complete
+	 * or fail, and we will ungetc() back to the last commit point.
+	 * To ensure that the file offset gets updated properly, it is
+	 * always necessary to read at least one character that doesn't
+	 * match; thus, we can't short-circuit "infinity" or "nan(...)".
+	 */
+	commit = buf - 1;
+	for (p = buf; p < end; ) {
+		c = *fp->_p;
+reswitch:
+		switch (state) {
+		case S_START:
+			state = S_GOTSIGN;
+			if (c == '-' || c == '+')
+				break;
+			else
+				goto reswitch;
+		case S_GOTSIGN:
+			switch (c) {
+			case '0':
+				state = S_MAYBEHEX;
+				commit = p;
+				break;
+			case 'I':
+			case 'i':
+				state = S_INF;
+				break;
+			case 'N':
+			case 'n':
+				state = S_NAN;
+				break;
+			default:
+				state = S_DIGITS;
+				goto reswitch;
+			}
+			break;
+		case S_INF:
+			if (infnanpos > 6 ||
+			    (c != "nfinity"[infnanpos] &&
+			     c != "NFINITY"[infnanpos]))
+				goto parsedone;
+			if (infnanpos == 1 || infnanpos == 6)
+				commit = p;	/* inf or infinity */
+			infnanpos++;
+			break;
+		case S_NAN:
+			switch (infnanpos) {
+			case -1:	/* XXX kludge to deal with nan(...) */
+				goto parsedone;
+			case 0:
+				if (c != 'A' && c != 'a')
+					goto parsedone;
+				break;
+			case 1:
+				if (c != 'N' && c != 'n')
+					goto parsedone;
+				else
+					commit = p;
+				break;
+			case 2:
+				if (c != '(')
+					goto parsedone;
+				break;
+			default:
+				if (c == ')') {
+					commit = p;
+					infnanpos = -2;
+				} else if (!isalnum(c) && c != '_')
+					goto parsedone;
+				break;
+			}
+			infnanpos++;
+			break;
+		case S_MAYBEHEX:
+			state = S_DIGITS;
+			if (c == 'X' || c == 'x') {
+				ishex = 1;
+				break;
+			} else {	/* we saw a '0', but no 'x' */
+				gotmantdig = 1;
+				goto reswitch;
+			}
+		case S_DIGITS:
+			if ((ishex && isxdigit(c)) || isdigit(c))
+				gotmantdig = 1;
+			else {
+				state = S_FRAC;
+				if (c != '.')
+					goto reswitch;
+			}
+			if (gotmantdig)
+				commit = p;
+			break;
+		case S_FRAC:
+			if (((c == 'E' || c == 'e') && !ishex) ||
+			    ((c == 'P' || c == 'p') && ishex)) {
+				if (!gotmantdig)
+					goto parsedone;
+				else
+					state = S_EXP;
+			} else if ((ishex && isxdigit(c)) || isdigit(c)) {
+				commit = p;
+				gotmantdig = 1;
+			} else
+				goto parsedone;
+			break;
+		case S_EXP:
+			state = S_EXPDIGITS;
+			if (c == '-' || c == '+')
+				break;
+			else
+				goto reswitch;
+		case S_EXPDIGITS:
+			if (isdigit(c))
+				commit = p;
+			else
+				goto parsedone;
+			break;
+		default:
+			abort();
+		}
+		*p++ = c;
+		if (--fp->_r > 0)
+			fp->_p++;
+		else if (__srefill(fp))
+			break;	/* EOF */
+	}
+
+parsedone:
+	while (commit < --p)
+		(void)ungetc(*(unsigned char *)p, fp);
+	*++commit = '\0';
+	return commit - buf;
+}
+
+size_t wparsefloat(FILE *fp, wchar_t *buf, wchar_t *end) {
+	wchar_t *commit, *p;
+	int infnanpos = 0;
+	enum {
+		S_START, S_GOTSIGN, S_INF, S_NAN, S_MAYBEHEX,
+		S_DIGITS, S_FRAC, S_EXP, S_EXPDIGITS
+	} state = S_START;
+	wint_t c;
+	int gotmantdig = 0, ishex = 0;
+
+	/*
+	 * We set commit = p whenever the string we have read so far
+	 * constitutes a valid representation of a floating point
+	 * number by itself.  At some point, the parse will complete
+	 * or fail, and we will ungetc() back to the last commit point.
+	 * To ensure that the file offset gets updated properly, it is
+	 * always necessary to read at least one character that doesn't
+	 * match; thus, we can't short-circuit "infinity" or "nan(...)".
+	 */
+	commit = buf - 1;
+	c = WEOF;
+	for (p = buf; p < end; ) {
+		if ((c = __fgetwc_unlock(fp)) == WEOF)
+			break;
+reswitch:
+		switch (state) {
+		case S_START:
+			state = S_GOTSIGN;
+			if (c == '-' || c == '+')
+				break;
+			else
+				goto reswitch;
+		case S_GOTSIGN:
+			switch (c) {
+			case '0':
+				state = S_MAYBEHEX;
+				commit = p;
+				break;
+			case 'I':
+			case 'i':
+				state = S_INF;
+				break;
+			case 'N':
+			case 'n':
+				state = S_NAN;
+				break;
+			default:
+				state = S_DIGITS;
+				goto reswitch;
+			}
+			break;
+		case S_INF:
+			if (infnanpos > 6 ||
+			    (c != (wint_t)"nfinity"[infnanpos] &&
+			     c != (wint_t)"NFINITY"[infnanpos]))
+				goto parsedone;
+			if (infnanpos == 1 || infnanpos == 6)
+				commit = p;	/* inf or infinity */
+			infnanpos++;
+			break;
+		case S_NAN:
+			switch (infnanpos) {
+			case -1:	/* XXX kludge to deal with nan(...) */
+				goto parsedone;
+			case 0:
+				if (c != 'A' && c != 'a')
+					goto parsedone;
+				break;
+			case 1:
+				if (c != 'N' && c != 'n')
+					goto parsedone;
+				else
+					commit = p;
+				break;
+			case 2:
+				if (c != '(')
+					goto parsedone;
+				break;
+			default:
+				if (c == ')') {
+					commit = p;
+					infnanpos = -2;
+				} else if (!iswalnum(c) && c != '_')
+					goto parsedone;
+				break;
+			}
+			infnanpos++;
+			break;
+		case S_MAYBEHEX:
+			state = S_DIGITS;
+			if (c == 'X' || c == 'x') {
+				ishex = 1;
+				break;
+			} else {	/* we saw a '0', but no 'x' */
+				gotmantdig = 1;
+				goto reswitch;
+			}
+		case S_DIGITS:
+			if ((ishex && iswxdigit(c)) || iswdigit(c))
+				gotmantdig = 1;
+			else {
+				state = S_FRAC;
+				if (c != L'.')
+					goto reswitch;
+			}
+			if (gotmantdig)
+				commit = p;
+			break;
+		case S_FRAC:
+			if (((c == 'E' || c == 'e') && !ishex) ||
+			    ((c == 'P' || c == 'p') && ishex)) {
+				if (!gotmantdig)
+					goto parsedone;
+				else
+					state = S_EXP;
+			} else if ((ishex && iswxdigit(c)) || iswdigit(c)) {
+				commit = p;
+				gotmantdig = 1;
+			} else
+				goto parsedone;
+			break;
+		case S_EXP:
+			state = S_EXPDIGITS;
+			if (c == '-' || c == '+')
+				break;
+			else
+				goto reswitch;
+		case S_EXPDIGITS:
+			if (iswdigit(c))
+				commit = p;
+			else
+				goto parsedone;
+			break;
+		default:
+			abort();
+		}
+		*p++ = c;
+		c = WEOF;
+	}
+
+parsedone:
+	if (c != WEOF)
+		ungetwc(c, fp);
+	while (commit < --p)
+		ungetwc(*p, fp);
+	*++commit = '\0';
+	return (int)(commit - buf);
+}