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. Returns 0 on success or
24 * error on failure. @buf is always zero terminated.
27 int 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]);
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;
172 * string_unescape - unquote characters in the given string
173 * @src: source buffer (escaped)
174 * @dst: destination buffer (unescaped)
175 * @size: size of the destination buffer (0 to unlimit)
176 * @flags: combination of the flags (bitwise OR):
180 * '\r' - carriage return
181 * '\t' - horizontal tab
182 * '\v' - vertical tab
184 * '\NNN' - byte with octal value NNN (1 to 3 digits)
186 * '\xHH' - byte with hexadecimal value HH (1 to 2 digits)
188 * '\"' - double quote
193 * all previous together
196 * The function unquotes characters in the given string.
198 * Because the size of the output will be the same as or less than the size of
199 * the input, the transformation may be performed in place.
201 * Caller must provide valid source and destination pointers. Be aware that
202 * destination buffer will always be NULL-terminated. Source string must be
203 * NULL-terminated as well.
206 * The amount of the characters processed to the destination buffer excluding
207 * trailing '\0' is returned.
209 int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
213 while (*src && --size) {
214 if (src[0] == '\\' && src[1] != '\0' && size > 1) {
218 if (flags & UNESCAPE_SPACE &&
219 unescape_space(&src, &out))
222 if (flags & UNESCAPE_OCTAL &&
223 unescape_octal(&src, &out))
226 if (flags & UNESCAPE_HEX &&
227 unescape_hex(&src, &out))
230 if (flags & UNESCAPE_SPECIAL &&
231 unescape_special(&src, &out))
242 EXPORT_SYMBOL(string_unescape);
244 static int escape_passthrough(unsigned char c, char **dst, size_t *osz)
259 static int escape_space(unsigned char c, char **dst, size_t *osz)
296 static int escape_special(unsigned char c, char **dst, size_t *osz)
327 static int escape_null(unsigned char c, char **dst, size_t *osz)
346 static int escape_octal(unsigned char c, char **dst, size_t *osz)
354 *out++ = ((c >> 6) & 0x07) + '0';
355 *out++ = ((c >> 3) & 0x07) + '0';
356 *out++ = ((c >> 0) & 0x07) + '0';
364 static int escape_hex(unsigned char c, char **dst, size_t *osz)
373 *out++ = hex_asc_hi(c);
374 *out++ = hex_asc_lo(c);
383 * string_escape_mem - quote characters in the given memory buffer
384 * @src: source buffer (unescaped)
385 * @isz: source buffer size
386 * @dst: destination buffer (escaped)
387 * @osz: destination buffer size
388 * @flags: combination of the flags (bitwise OR):
392 * '\r' - carriage return
393 * '\t' - horizontal tab
394 * '\v' - vertical tab
402 * '\NNN' - byte with octal value NNN (3 digits)
404 * all previous together
406 * escape only non-printable characters (checked by isprint)
408 * all previous together
410 * '\xHH' - byte with hexadecimal value HH (2 digits)
411 * @esc: NULL-terminated string of characters any of which, if found in
412 * the source, has to be escaped
415 * The process of escaping byte buffer includes several parts. They are applied
416 * in the following sequence.
417 * 1. The character is matched to the printable class, if asked, and in
418 * case of match it passes through to the output.
419 * 2. The character is not matched to the one from @esc string and thus
420 * must go as is to the output.
421 * 3. The character is checked if it falls into the class given by @flags.
422 * %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
423 * character. Note that they actually can't go together, otherwise
424 * %ESCAPE_HEX will be ignored.
426 * Caller must provide valid source and destination pointers. Be aware that
427 * destination buffer will not be NULL-terminated, thus caller have to append
431 * The amount of the characters processed to the destination buffer, or
432 * %-ENOMEM if the size of buffer is not enough to put an escaped character is
435 * Even in the case of error @dst pointer will be updated to point to the byte
436 * after the last processed character.
438 int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
439 unsigned int flags, const char *esc)
441 char *out = *dst, *p = out;
442 bool is_dict = esc && *esc;
446 unsigned char c = *src++;
449 * Apply rules in the following sequence:
450 * - the character is printable, when @flags has
452 * - the @esc string is supplied and does not contain a
453 * character under question
454 * - the character doesn't fall into a class of symbols
455 * defined by given @flags
456 * In these cases we just pass through a character to the
459 if ((flags & ESCAPE_NP && isprint(c)) ||
460 (is_dict && !strchr(esc, c))) {
463 if (flags & ESCAPE_SPACE) {
464 ret = escape_space(c, &p, &osz);
471 if (flags & ESCAPE_SPECIAL) {
472 ret = escape_special(c, &p, &osz);
479 if (flags & ESCAPE_NULL) {
480 ret = escape_null(c, &p, &osz);
487 /* ESCAPE_OCTAL and ESCAPE_HEX always go last */
488 if (flags & ESCAPE_OCTAL) {
489 ret = escape_octal(c, &p, &osz);
494 if (flags & ESCAPE_HEX) {
495 ret = escape_hex(c, &p, &osz);
502 ret = escape_passthrough(c, &p, &osz);
514 EXPORT_SYMBOL(string_escape_mem);