summaryrefslogtreecommitdiff
path: root/libbb/human_readable.c
blob: 50cbe41bbf78f8d340a6596d88422c5edb1fec98 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
/* 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.
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

#include "libbb.h"

const char* FAST_FUNC make_human_readable_str(unsigned long long val,
	unsigned long block_size, unsigned long display_unit)
{
	static const char unit_chars[] ALIGN1 = {
		'\0', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'
	};

	static char *str;

	unsigned frac; /* 0..9 - the fractional digit */
	const char *u;
	const char *fmt;

	if (val == 0)
		return "0";

	fmt = "%llu";
	if (block_size > 1)
		val *= block_size;
	frac = 0;
	u = unit_chars;

	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) - always true */
		) {
			fmt = "%llu.%u%c";
			u++;
			frac = (((unsigned)val % 1024) * 10 + 1024/2) / 1024;
			val /= 1024;
		}
		if (frac >= 10) { /* we need to round up here */
			++val;
			frac = 0;
		}
#if 1
		/* If block_size is 0, dont print fractional part */
		if (block_size == 0) {
			if (frac >= 5) {
				++val;
			}
			fmt = "%llu%*c";
			frac = 1;
		}
#endif
	}

	if (!str) {
		/* sufficient for any width of val */
		str = xmalloc(sizeof(val)*3 + 2 + 3);
	}
	sprintf(str, fmt, val, frac, *u);
	return str;
}


/* vda's implementations of the similar idea */

/* Convert unsigned long long value into compact 5-char representation.
 * String is not terminated (buf[5] is untouched) */
void FAST_FUNC smart_ulltoa5(unsigned long long ul, char buf[5], const char *scale)
{
	const char *fmt;
	char c;
	unsigned v, u, idx = 0;

	if (ul > 99999) { // do not scale if 99999 or less
		ul *= 10;
		do {
			ul /= 1024;
			idx++;
		} while (ul >= 100000);
	}
	v = ul; // ullong divisions are expensive, avoid them

	fmt = " 123456789";
	u = v / 10;
	v = v % 10;
	if (!idx) {
		// 99999 or less: use "12345" format
		// u is value/10, v is last digit
		c = buf[0] = " 123456789"[u/1000];
		if (c != ' ') fmt = "0123456789";
		c = buf[1] = fmt[u/100%10];
		if (c != ' ') fmt = "0123456789";
		c = buf[2] = fmt[u/10%10];
		if (c != ' ') fmt = "0123456789";
		buf[3] = fmt[u%10];
		buf[4] = "0123456789"[v];
	} else {
		// value has been scaled into 0..9999.9 range
		// u is value, v is 1/10ths (allows for 92.1M format)
		if (u >= 100) {
			// value is >= 100: use "1234M', " 123M" formats
			c = buf[0] = " 123456789"[u/1000];
			if (c != ' ') fmt = "0123456789";
			c = buf[1] = fmt[u/100%10];
			if (c != ' ') fmt = "0123456789";
			v = u % 10;
			u = u / 10;
			buf[2] = fmt[u%10];
		} else {
			// value is < 100: use "92.1M" format
			c = buf[0] = " 123456789"[u/10];
			if (c != ' ') fmt = "0123456789";
			buf[1] = fmt[u%10];
			buf[2] = '.';
		}
		buf[3] = "0123456789"[v];
		buf[4] = scale[idx]; /* typically scale = " kmgt..." */
	}
}

/* Convert unsigned long long value into compact 4-char
 * representation. Examples: "1234", "1.2k", " 27M", "123T"
 * String is not terminated (buf[4] is untouched) */
void FAST_FUNC smart_ulltoa4(unsigned long long ul, char buf[4], const char *scale)
{
	const char *fmt;
	char c;
	unsigned v, u, idx = 0;

	if (ul > 9999) { // do not scale if 9999 or less
		ul *= 10;
		do {
			ul /= 1024;
			idx++;
		} while (ul >= 10000);
	}
	v = ul; // ullong divisions are expensive, avoid them

	fmt = " 123456789";
	u = v / 10;
	v = v % 10;
	if (!idx) {
		// 9999 or less: use "1234" format
		// u is value/10, v is last digit
		c = buf[0] = " 123456789"[u/100];
		if (c != ' ') fmt = "0123456789";
		c = buf[1] = fmt[u/10%10];
		if (c != ' ') fmt = "0123456789";
		buf[2] = fmt[u%10];
		buf[3] = "0123456789"[v];
	} else {
		// u is value, v is 1/10ths (allows for 9.2M format)
		if (u >= 10) {
			// value is >= 10: use "123M', " 12M" formats
			c = buf[0] = " 123456789"[u/100];
			if (c != ' ') fmt = "0123456789";
			v = u % 10;
			u = u / 10;
			buf[1] = fmt[u%10];
		} else {
			// value is < 10: use "9.2M" format
			buf[0] = "0123456789"[u];
			buf[1] = '.';
		}
		buf[2] = "0123456789"[v];
		buf[3] = scale[idx]; /* typically scale = " kmgt..." */
	}
}