| 1 | |
| 2 | * Helpers for formatting and printing strings
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| 3 | *
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| 4 | * Copyright 31 August 2008 James Bottomley
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| 5 | * Copyright (C) 2013, Intel Corporation
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| 6 |
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| 7 | #include <linux/kernel.h>
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| 8 | #include <linux/math64.h>
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| 9 | #include <linux/export.h>
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| 10 | #include <linux/ctype.h>
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| 11 | #include <linux/string_helpers.h>
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| 12 |
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| 13 | |
| 14 | * string_get_size - get the size in the specified units
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| 15 | * @size: The size to be converted
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| 16 | * @units: units to use (powers of 1000 or 1024)
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| 17 | * @buf: buffer to format to
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| 18 | * @len: length of buffer
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| 19 | *
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| 20 | * This function returns a string formatted to 3 significant figures
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| 21 | * giving the size in the required units. Returns 0 on success or
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| 22 | * error on failure. @buf is always zero terminated.
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| 23 | *
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| 24 |
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| 25 | int string_get_size(u64 size, const enum string_size_units units,
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| 26 | char *buf, int len)
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| 27 | {
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| 28 | static const char *const units_10[] = {
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| 29 | "B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB", NULL
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| 30 | };
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| 31 | static const char *const units_2[] = {
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| 32 | "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB",
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| 33 | NULL
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| 34 | };
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| 35 | static const char *const *const units_str[] = {
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| 36 | [STRING_UNITS_10] = units_10,
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| 37 | [STRING_UNITS_2] = units_2,
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| 38 | };
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| 39 | static const unsigned int divisor[] = {
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| 40 | [STRING_UNITS_10] = 1000,
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| 41 | [STRING_UNITS_2] = 1024,
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| 42 | };
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| 43 | int i, j;
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| 44 | u64 remainder = 0, sf_cap;
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| 45 | char tmp[8];
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| 46 |
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| 47 | tmp[0] = '\0';
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| 48 | i = 0;
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| 49 | if (size >= divisor[units]) {
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| 50 | while (size >= divisor[units] && units_str[units][i]) {
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| 51 | remainder = do_div(size, divisor[units]);
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| 52 | i++;
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| 53 | }
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| 54 |
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| 55 | sf_cap = size;
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| 56 | for (j = 0; sf_cap*10 < 1000; j++)
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| 57 | sf_cap *= 10;
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| 58 |
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| 59 | if (j) {
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| 60 | remainder *= 1000;
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| 61 | do_div(remainder, divisor[units]);
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| 62 | snprintf(tmp, sizeof(tmp), ".%03lld",
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| 63 | (unsigned long long)remainder);
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| 64 | tmp[j+1] = '\0';
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| 65 | }
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| 66 | }
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| 67 |
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| 68 | snprintf(buf, len, "%lld%s %s", (unsigned long long)size,
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| 69 | tmp, units_str[units][i]);
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| 70 |
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| 71 | return 0;
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| 72 | }
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| 73 | EXPORT_SYMBOL(string_get_size);
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| 74 |
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| 75 | static bool unescape_space(char **src, char **dst)
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| 76 | {
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| 77 | char *p = *dst, *q = *src;
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| 78 |
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| 79 | switch (*q) {
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| 80 | case 'n':
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| 81 | *p = '\n';
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| 82 | break;
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| 83 | case 'r':
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| 84 | *p = '\r';
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| 85 | break;
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| 86 | case 't':
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| 87 | *p = '\t';
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| 88 | break;
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| 89 | case 'v':
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| 90 | *p = '\v';
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| 91 | break;
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| 92 | case 'f':
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| 93 | *p = '\f';
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| 94 | break;
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| 95 | default:
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| 96 | return false;
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| 97 | }
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| 98 | *dst += 1;
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| 99 | *src += 1;
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| 100 | return true;
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| 101 | }
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| 102 |
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| 103 | static bool unescape_octal(char **src, char **dst)
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| 104 | {
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| 105 | char *p = *dst, *q = *src;
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| 106 | u8 num;
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| 107 |
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| 108 | if (isodigit(*q) == 0)
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| 109 | return false;
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| 110 |
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| 111 | num = (*q++) & 7;
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| 112 | while (num < 32 && isodigit(*q) && (q - *src < 3)) {
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| 113 | num <<= 3;
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| 114 | num += (*q++) & 7;
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| 115 | }
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| 116 | *p = num;
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| 117 | *dst += 1;
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| 118 | *src = q;
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| 119 | return true;
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| 120 | }
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| 121 |
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| 122 | static bool unescape_hex(char **src, char **dst)
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| 123 | {
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| 124 | char *p = *dst, *q = *src;
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| 125 | int digit;
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| 126 | u8 num;
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| 127 |
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| 128 | if (*q++ != 'x')
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| 129 | return false;
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| 130 |
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| 131 | num = digit = hex_to_bin(*q++);
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| 132 | if (digit < 0)
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| 133 | return false;
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| 134 |
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| 135 | digit = hex_to_bin(*q);
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| 136 | if (digit >= 0) {
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| 137 | q++;
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| 138 | num = (num << 4) | digit;
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| 139 | }
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| 140 | *p = num;
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| 141 | *dst += 1;
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| 142 | *src = q;
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| 143 | return true;
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| 144 | }
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| 145 |
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| 146 | static bool unescape_special(char **src, char **dst)
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| 147 | {
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| 148 | char *p = *dst, *q = *src;
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| 149 |
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| 150 | switch (*q) {
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| 151 | case '\"':
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| 152 | *p = '\"';
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| 153 | break;
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| 154 | case '\\':
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| 155 | *p = '\\';
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| 156 | break;
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| 157 | case 'a':
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| 158 | *p = '\a';
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| 159 | break;
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| 160 | case 'e':
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| 161 | *p = '\e';
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| 162 | break;
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| 163 | default:
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| 164 | return false;
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| 165 | }
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| 166 | *dst += 1;
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| 167 | *src += 1;
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| 168 | return true;
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| 169 | }
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| 170 |
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| 171 | int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
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| 172 | {
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| 173 | char *out = dst;
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| 174 |
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| 175 | while (*src && --size) {
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| 176 | if (src[0] == '\\' && src[1] != '\0' && size > 1) {
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| 177 | src++;
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| 178 | size--;
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| 179 |
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| 180 | if (flags & UNESCAPE_SPACE &&
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| 181 | unescape_space(&src, &out))
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| 182 | continue;
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| 183 |
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| 184 | if (flags & UNESCAPE_OCTAL &&
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| 185 | unescape_octal(&src, &out))
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| 186 | continue;
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| 187 |
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| 188 | if (flags & UNESCAPE_HEX &&
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| 189 | unescape_hex(&src, &out))
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| 190 | continue;
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| 191 |
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| 192 | if (flags & UNESCAPE_SPECIAL &&
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| 193 | unescape_special(&src, &out))
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| 194 | continue;
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| 195 |
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| 196 | *out++ = '\\';
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| 197 | }
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| 198 | *out++ = *src++;
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| 199 | }
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| 200 | *out = '\0';
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| 201 |
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| 202 | return out - dst;
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| 203 | }
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| 204 | EXPORT_SYMBOL(string_unescape);
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