1 files changed, 97 insertions, 0 deletions
diff --git a/libbb/human_readable.c b/libbb/human_readable.c
new file mode 100644
index 0000000..61c8567
--- /dev/null
+++ b/libbb/human_readable.c
@@ -0,0 +1,97 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * June 30, 2001                 Manuel Novoa III
+ *
+ * All-integer version (hey, not everyone has floating point) of
+ * make_human_readable_str, modified from similar code I had written
+ * for busybox several months ago.
+ *
+ * Notes:
+ *   1) I'm using an unsigned long long to hold the product size * block_size,
+ *      as df (which calls this routine) could request a representation of a
+ *      partition size in bytes > max of unsigned long.  If long longs aren't
+ *      available, it would be possible to do what's needed using polynomial
+ *      representations (say, powers of 1024) and manipulating coefficients.
+ *      The base ten "bytes" output could be handled similarly.
+ *
+ *   2) This routine always outputs a decimal point and a tenths digit when
+ *      display_unit != 0.  Hence, it isn't uncommon for the returned string
+ *      to have a length of 5 or 6.
+ *
+ *      It might be nice to add a flag to indicate no decimal digits in
+ *      that case.  This could be either an additional parameter, or a
+ *      special value of display_unit.  Such a flag would also be nice for du.
+ *
+ *      Some code to omit the decimal point and tenths digit is sketched out
+ *      and "#if 0"'d below.
+ */
+
+#include "libbb.h"
+
+const char* FAST_FUNC make_human_readable_str(unsigned long long size,
+	unsigned long block_size, unsigned long display_unit)
+{
+	/* The code will adjust for additional (appended) units */
+	static const char unit_chars[] ALIGN1 = {
+		'\0', 'K', 'M', 'G', 'T', 'P', 'E'
+	};
+	static const char fmt[] ALIGN1 = "%llu";
+	static const char fmt_tenths[] ALIGN1 = "%llu.%d%c";
+
+	static char str[21] ALIGN1;  /* Sufficient for 64 bit unsigned integers */
+
+	unsigned long long val;
+	int frac;
+	const char *u;
+	const char *f;
+	smallint no_tenths;
+
+	if (size == 0)
+		return "0";
+
+	/* If block_size is 0 then do not print tenths */
+	no_tenths = 0;
+	if (block_size == 0) {
+		no_tenths = 1;
+		block_size = 1;
+	}
+
+	u = unit_chars;
+	val = size * block_size;
+	f = fmt;
+	frac = 0;
+
+	if (display_unit) {
+		val += display_unit/2;	/* Deal with rounding */
+		val /= display_unit;	/* Don't combine with the line above!!! */
+		/* will just print it as ulonglong (below) */
+	} else {
+		while ((val >= 1024)
+		 && (u < unit_chars + sizeof(unit_chars) - 1)
+		) {
+			f = fmt_tenths;
+			u++;
+			frac = (((int)(val % 1024)) * 10 + 1024/2) / 1024;
+			val /= 1024;
+		}
+		if (frac >= 10) {		/* We need to round up here. */
+			++val;
+			frac = 0;
+		}
+#if 1
+		/* Sample code to omit decimal point and tenths digit. */
+		if (no_tenths) {
+			if (frac >= 5) {
+				++val;
+			}
+			f = "%llu%*c" /* fmt_no_tenths */;
+			frac = 1;
+		}
+#endif
+	}
+
+	/* If f==fmt then 'frac' and 'u' are ignored. */
+	snprintf(str, sizeof(str), f, val, frac, *u);
+
+	return str;
+}