diff src/libsys/sprintf/integer.c @ 86:425ab6d987f3

src/libsys: pieced together from Citrine
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 20 Jul 2018 20:36:19 +0000
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/libsys/sprintf/integer.c	Fri Jul 20 20:36:19 2018 +0000
@@ -0,0 +1,54 @@
+/*
+ * Embedded [v]sprintf() implementation by Mychaela Falconia,
+ * loosely based on the 4.3BSD-Tahoe version.
+ *
+ * This module contains the integer conversion functions.
+ */
+
+#include <sys/types.h>
+#include <ctype.h>
+#include "defs.h"
+
+extern u_char * _sprintf_field(u_char *op, int width, int flags, int sign,
+			u_char *body, int size, int dprec, int fpprec);
+
+static const char lcdigits[] = "0123456789abcdef";
+static const char ucdigits[] = "0123456789ABCDEF";
+
+u_char *
+_sprintf_integer(u_char *op, int width, int flags, int sign,
+		unsigned number, int base, int prec)
+{
+	const char *digits;
+	char buf[12];
+	char *t, *endp;
+
+	/*
+	 * ``... diouXx conversions ... if a precision is
+	 * specified, the 0 flag will be ignored.''
+	 *	-- ANSI X3J11
+	 */
+	if (prec >= 0)
+		flags &= ~ZEROPAD;
+
+	if (flags & UPPERCASE)
+		digits = ucdigits;
+	else
+		digits = lcdigits;
+
+	/*
+	 * ``The result of converting a zero value with an
+	 * explicit precision of zero is no characters.''
+	 *	-- ANSI X3J11
+	 */
+	t = endp = buf + sizeof(buf);
+	if (number != 0 || prec != 0) {
+		do {
+			*--t = digits[number % base];
+			number /= base;
+		} while (number);
+		if (flags & ALT && base == 8 && *t != '0')
+			*--t = '0'; /* octal leading 0 */
+	}
+	return _sprintf_field(op, width, flags, sign, t, endp - t, prec, 0);
+}