Implement expand_number(3), which is the opposite of humanize_number(3), ie.

a number in human-readable form is converted to int64_t, for example:
123b -> 123
10k -> 10240
16G -> 17179869184

First version submitted by:	Eric Anderson <anderson@freebsd.org>
Approved by:	re (bmah)

1 files changed, 89 insertions, 0 deletions

diff --git a/lib/libutil/expand_number.c b/lib/libutil/expand_number.c
new file mode 100644
index 000000000000..b9ae5d230f2b
--- /dev/null
+++ b/lib/libutil/expand_number.c
@@ -0,0 +1,89 @@
+/*-
+ * Copyright (c) 2007 Eric Anderson <anderson@FreeBSD.org>
+ * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
+ * 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 AUTHORS 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 AUTHORS 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 <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <ctype.h>
+#include <errno.h>
+#include <libutil.h>
+#include <stdint.h>
+
+/*
+ * Convert an expression of the following forms to a int64_t.
+ * 	1) A positive decimal number.
+ *	2) A positive decimal number followed by a 'b' or 'B' (mult by 1).
+ *	3) A positive decimal number followed by a 'k' or 'K' (mult by 1 << 10).
+ *	4) A positive decimal number followed by a 'm' or 'M' (mult by 1 << 20).
+ *	5) A positive decimal number followed by a 'g' or 'G' (mult by 1 << 30).
+ *	6) A positive decimal number followed by a 't' or 'T' (mult by 1 << 40).
+ *	7) A positive decimal number followed by a 'p' or 'P' (mult by 1 << 50).
+ *	8) A positive decimal number followed by a 'e' or 'E' (mult by 1 << 60).
+ */
+int
+expand_number(char *buf, int64_t *num)
+{
+	static const char unit[] = "bkmgtpe";
+	char *endptr, s;
+	int64_t number;
+	int i;
+
+	number = strtoimax(buf, &endptr, 0);
+
+	if (endptr == buf) {
+		/* No valid digits. */
+		errno = EINVAL;
+		return (-1);
+	}
+
+	if (*endptr == '\0') {
+		/* No unit. */
+		*num = number;
+		return (0);
+	}
+
+	s = tolower(*endptr);
+	for (i = 0; i < unit[i] != '\0'; i++) {
+		if (s == unit[i])
+			break;
+		if ((number < 0 && (number << 10) > number) ||
+		    (number >= 0 && (number << 10) < number)) {
+			errno = ERANGE;
+			return (-1);
+		}
+		number <<= 10;
+	}
+	if (unit[i] == '\0') {
+		/* Unrecognized unit. */
+		errno = EINVAL;
+		return (-1);
+	}
+
+	*num = number;
+	return (0);
+}