2 * Helpers for formatting and printing strings
4 * Copyright 31 August 2008 James Bottomley
5 * Copyright (C) 2013, Intel Corporation
7 #include <linux/kernel.h>
8 #include <linux/math64.h>
9 #include <linux/export.h>
10 #include <linux/ctype.h>
11 #include <linux/string_helpers.h>
14 * string_get_size - get the size in the specified units
15 * @size: The size to be converted
16 * @units: units to use (powers of 1000 or 1024)
17 * @buf: buffer to format to
18 * @len: length of buffer
20 * This function returns a string formatted to 3 significant figures
21 * giving the size in the required units. Returns 0 on success or
22 * error on failure. @buf is always zero terminated.
25 int string_get_size(u64 size, const enum string_size_units units,
28 static const char *const units_10[] = {
29 "B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB", NULL
31 static const char *const units_2[] = {
32 "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB",
35 static const char *const *const units_str[] = {
36 [STRING_UNITS_10] = units_10,
37 [STRING_UNITS_2] = units_2,
39 static const unsigned int divisor[] = {
40 [STRING_UNITS_10] = 1000,
41 [STRING_UNITS_2] = 1024,
44 u64 remainder = 0, sf_cap;
49 if (size >= divisor[units]) {
50 while (size >= divisor[units] && units_str[units][i]) {
51 remainder = do_div(size, divisor[units]);
56 for (j = 0; sf_cap*10 < 1000; j++)
61 do_div(remainder, divisor[units]);
62 snprintf(tmp, sizeof(tmp), ".%03lld",
63 (unsigned long long)remainder);
68 snprintf(buf, len, "%lld%s %s", (unsigned long long)size,
69 tmp, units_str[units][i]);
73 EXPORT_SYMBOL(string_get_size);
75 static bool unescape_space(char **src, char **dst)
77 char *p = *dst, *q = *src;
103 static bool unescape_octal(char **src, char **dst)
105 char *p = *dst, *q = *src;
108 if (isodigit(*q) == 0)
112 while (num < 32 && isodigit(*q) && (q - *src < 3)) {
122 static bool unescape_hex(char **src, char **dst)
124 char *p = *dst, *q = *src;
131 num = digit = hex_to_bin(*q++);
135 digit = hex_to_bin(*q);
138 num = (num << 4) | digit;
146 static bool unescape_special(char **src, char **dst)
148 char *p = *dst, *q = *src;
171 int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
175 while (*src && --size) {
176 if (src[0] == '\\' && src[1] != '\0' && size > 1) {
180 if (flags & UNESCAPE_SPACE &&
181 unescape_space(&src, &out))
184 if (flags & UNESCAPE_OCTAL &&
185 unescape_octal(&src, &out))
188 if (flags & UNESCAPE_HEX &&
189 unescape_hex(&src, &out))
192 if (flags & UNESCAPE_SPECIAL &&
193 unescape_special(&src, &out))
204 EXPORT_SYMBOL(string_unescape);