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/errno.h>
12 #include <linux/string.h>
13 #include <linux/string_helpers.h>
16 * string_get_size - get the size in the specified units
17 * @size: The size to be converted
18 * @units: units to use (powers of 1000 or 1024)
19 * @buf: buffer to format to
20 * @len: length of buffer
22 * This function returns a string formatted to 3 significant figures
23 * giving the size in the required units. @buf should have room for
24 * at least 9 bytes and will always be zero terminated.
27 void string_get_size(u64 size, const enum string_size_units units,
30 static const char *const units_10[] = {
31 "B", "kB", "MB", "GB", "TB", "PB", "EB"
33 static const char *const units_2[] = {
34 "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB"
36 static const char *const *const units_str[] = {
37 [STRING_UNITS_10] = units_10,
38 [STRING_UNITS_2] = units_2,
40 static const unsigned int divisor[] = {
41 [STRING_UNITS_10] = 1000,
42 [STRING_UNITS_2] = 1024,
45 u32 remainder = 0, sf_cap;
50 if (size >= divisor[units]) {
51 while (size >= divisor[units]) {
52 remainder = do_div(size, divisor[units]);
57 for (j = 0; sf_cap*10 < 1000; j++)
62 remainder /= divisor[units];
63 snprintf(tmp, sizeof(tmp), ".%03u", remainder);
68 snprintf(buf, len, "%u%s %s", (u32)size,
69 tmp, units_str[units][i]);
71 EXPORT_SYMBOL(string_get_size);
73 static bool unescape_space(char **src, char **dst)
75 char *p = *dst, *q = *src;
101 static bool unescape_octal(char **src, char **dst)
103 char *p = *dst, *q = *src;
106 if (isodigit(*q) == 0)
110 while (num < 32 && isodigit(*q) && (q - *src < 3)) {
120 static bool unescape_hex(char **src, char **dst)
122 char *p = *dst, *q = *src;
129 num = digit = hex_to_bin(*q++);
133 digit = hex_to_bin(*q);
136 num = (num << 4) | digit;
144 static bool unescape_special(char **src, char **dst)
146 char *p = *dst, *q = *src;
170 * string_unescape - unquote characters in the given string
171 * @src: source buffer (escaped)
172 * @dst: destination buffer (unescaped)
173 * @size: size of the destination buffer (0 to unlimit)
174 * @flags: combination of the flags (bitwise OR):
178 * '\r' - carriage return
179 * '\t' - horizontal tab
180 * '\v' - vertical tab
182 * '\NNN' - byte with octal value NNN (1 to 3 digits)
184 * '\xHH' - byte with hexadecimal value HH (1 to 2 digits)
186 * '\"' - double quote
191 * all previous together
194 * The function unquotes characters in the given string.
196 * Because the size of the output will be the same as or less than the size of
197 * the input, the transformation may be performed in place.
199 * Caller must provide valid source and destination pointers. Be aware that
200 * destination buffer will always be NULL-terminated. Source string must be
201 * NULL-terminated as well.
204 * The amount of the characters processed to the destination buffer excluding
205 * trailing '\0' is returned.
207 int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
211 while (*src && --size) {
212 if (src[0] == '\\' && src[1] != '\0' && size > 1) {
216 if (flags & UNESCAPE_SPACE &&
217 unescape_space(&src, &out))
220 if (flags & UNESCAPE_OCTAL &&
221 unescape_octal(&src, &out))
224 if (flags & UNESCAPE_HEX &&
225 unescape_hex(&src, &out))
228 if (flags & UNESCAPE_SPECIAL &&
229 unescape_special(&src, &out))
240 EXPORT_SYMBOL(string_unescape);
242 static bool escape_passthrough(unsigned char c, char **dst, char *end)
252 static bool escape_space(unsigned char c, char **dst, char *end)
288 static bool escape_special(unsigned char c, char **dst, char *end)
318 static bool escape_null(unsigned char c, char **dst, char *end)
336 static bool escape_octal(unsigned char c, char **dst, char *end)
344 *out = ((c >> 6) & 0x07) + '0';
347 *out = ((c >> 3) & 0x07) + '0';
350 *out = ((c >> 0) & 0x07) + '0';
357 static bool escape_hex(unsigned char c, char **dst, char *end)
368 *out = hex_asc_hi(c);
371 *out = hex_asc_lo(c);
379 * string_escape_mem - quote characters in the given memory buffer
380 * @src: source buffer (unescaped)
381 * @isz: source buffer size
382 * @dst: destination buffer (escaped)
383 * @osz: destination buffer size
384 * @flags: combination of the flags (bitwise OR):
388 * '\r' - carriage return
389 * '\t' - horizontal tab
390 * '\v' - vertical tab
398 * '\NNN' - byte with octal value NNN (3 digits)
400 * all previous together
402 * escape only non-printable characters (checked by isprint)
404 * all previous together
406 * '\xHH' - byte with hexadecimal value HH (2 digits)
407 * @esc: NULL-terminated string of characters any of which, if found in
408 * the source, has to be escaped
411 * The process of escaping byte buffer includes several parts. They are applied
412 * in the following sequence.
413 * 1. The character is matched to the printable class, if asked, and in
414 * case of match it passes through to the output.
415 * 2. The character is not matched to the one from @esc string and thus
416 * must go as is to the output.
417 * 3. The character is checked if it falls into the class given by @flags.
418 * %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
419 * character. Note that they actually can't go together, otherwise
420 * %ESCAPE_HEX will be ignored.
422 * Caller must provide valid source and destination pointers. Be aware that
423 * destination buffer will not be NULL-terminated, thus caller have to append
427 * The total size of the escaped output that would be generated for
428 * the given input and flags. To check whether the output was
429 * truncated, compare the return value to osz. There is room left in
430 * dst for a '\0' terminator if and only if ret < osz.
432 int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
433 unsigned int flags, const char *esc)
437 bool is_dict = esc && *esc;
440 unsigned char c = *src++;
443 * Apply rules in the following sequence:
444 * - the character is printable, when @flags has
446 * - the @esc string is supplied and does not contain a
447 * character under question
448 * - the character doesn't fall into a class of symbols
449 * defined by given @flags
450 * In these cases we just pass through a character to the
453 if ((flags & ESCAPE_NP && isprint(c)) ||
454 (is_dict && !strchr(esc, c))) {
457 if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
460 if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end))
463 if (flags & ESCAPE_NULL && escape_null(c, &p, end))
466 /* ESCAPE_OCTAL and ESCAPE_HEX always go last */
467 if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end))
470 if (flags & ESCAPE_HEX && escape_hex(c, &p, end))
474 escape_passthrough(c, &p, end);
479 EXPORT_SYMBOL(string_escape_mem);