| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Utility routines.
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| 4 | *
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| 5 | * Copyright (C) Manuel Novoa III <mjn3@codepoet.org>
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| 6 | * and Vladimir Oleynik <dzo@simtreas.ru>
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| 7 | *
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| 8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 9 | */
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| 10 |
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| 11 | #include "libbb.h"
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| 12 |
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| 13 | #define WANT_HEX_ESCAPES 1
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| 14 |
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| 15 | /* Usual "this only works for ascii compatible encodings" disclaimer. */
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| 16 | #undef _tolower
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| 17 | #define _tolower(X) ((X)|((char) 0x20))
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| 18 |
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| 19 | char FAST_FUNC bb_process_escape_sequence(const char **ptr)
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| 20 | {
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| 21 | const char *q;
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| 22 | unsigned num_digits;
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| 23 | unsigned n;
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| 24 | unsigned base;
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| 25 |
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| 26 | num_digits = n = 0;
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| 27 | base = 8;
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| 28 | q = *ptr;
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| 29 |
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| 30 | if (WANT_HEX_ESCAPES && *q == 'x') {
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| 31 | ++q;
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| 32 | base = 16;
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| 33 | ++num_digits;
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| 34 | }
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| 35 |
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| 36 | /* bash requires leading 0 in octal escapes:
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| 37 | * \02 works, \2 does not (prints \ and 2).
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| 38 | * We treat \2 as a valid octal escape sequence. */
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| 39 | do {
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| 40 | unsigned r;
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| 41 | #if !WANT_HEX_ESCAPES
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| 42 | unsigned d = (unsigned char)(*q) - '0';
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| 43 | #else
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| 44 | unsigned d = (unsigned char)_tolower(*q) - '0';
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| 45 | if (d >= 10)
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| 46 | d += ('0' - 'a' + 10);
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| 47 | #endif
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| 48 | if (d >= base) {
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| 49 | if (WANT_HEX_ESCAPES && base == 16) {
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| 50 | --num_digits;
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| 51 | if (num_digits == 0) {
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| 52 | /* \x<bad_char>: return '\',
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| 53 | * leave ptr pointing to x */
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| 54 | return '\\';
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| 55 | }
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| 56 | }
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| 57 | break;
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| 58 | }
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| 59 |
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| 60 | r = n * base + d;
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| 61 | if (r > UCHAR_MAX) {
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| 62 | break;
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| 63 | }
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| 64 |
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| 65 | n = r;
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| 66 | ++q;
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| 67 | } while (++num_digits < 3);
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| 68 |
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| 69 | if (num_digits == 0) {
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| 70 | /* Not octal or hex escape sequence.
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| 71 | * Is it one-letter one? */
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| 72 |
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| 73 | /* bash builtin "echo -e '\ec'" interprets \e as ESC,
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| 74 | * but coreutils "/bin/echo -e '\ec'" does not.
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| 75 | * Manpages tend to support coreutils way.
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| 76 | * Update: coreutils added support for \e on 28 Oct 2009. */
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| 77 | static const char charmap[] ALIGN1 = {
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| 78 | 'a', 'b', 'e', 'f', 'n', 'r', 't', 'v', '\\', '\0',
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| 79 | '\a', '\b', 27, '\f', '\n', '\r', '\t', '\v', '\\', '\\',
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| 80 | };
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| 81 | const char *p = charmap;
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| 82 | do {
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| 83 | if (*p == *q) {
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| 84 | q++;
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| 85 | break;
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| 86 | }
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| 87 | } while (*++p != '\0');
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| 88 | /* p points to found escape char or NUL,
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| 89 | * advance it and find what it translates to.
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| 90 | * Note that \NUL and unrecognized sequence \z return '\'
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| 91 | * and leave ptr pointing to NUL or z. */
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| 92 | n = p[sizeof(charmap) / 2];
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| 93 | }
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| 94 |
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| 95 | *ptr = q;
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| 96 |
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| 97 | return (char) n;
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| 98 | }
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| 99 |
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| 100 | char* FAST_FUNC strcpy_and_process_escape_sequences(char *dst, const char *src)
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| 101 | {
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| 102 | while (1) {
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| 103 | char c, c1;
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| 104 | c = c1 = *src++;
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| 105 | if (c1 == '\\')
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| 106 | c1 = bb_process_escape_sequence(&src);
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| 107 | *dst = c1;
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| 108 | if (c == '\0')
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| 109 | return dst;
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| 110 | dst++;
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| 111 | }
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| 112 | }
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