1/*
2 * Copyright (C) 2013 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include <wtf/SixCharacterHash.h>
28
29#include <wtf/ASCIICType.h>
30
31namespace WTF {
32
33unsigned sixCharacterHashStringToInteger(const char* string)
34{
35 unsigned hash = 0;
36
37 for (unsigned i = 0; i < 6; ++i) {
38 hash *= 62;
39 unsigned c = string[i];
40 RELEASE_ASSERT(c); // FIXME: Why does this need to be a RELEASE_ASSERT?
41 if (isASCIIUpper(c)) {
42 hash += c - 'A';
43 continue;
44 }
45 if (isASCIILower(c)) {
46 hash += c - 'a' + 26;
47 continue;
48 }
49 ASSERT(isASCIIDigit(c));
50 hash += c - '0' + 26 * 2;
51 }
52
53 RELEASE_ASSERT(!string[6]); // FIXME: Why does this need to be a RELEASE_ASSERT?
54
55 return hash;
56}
57
58std::array<char, 7> integerToSixCharacterHashString(unsigned hash)
59{
60 static const char table[63] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
61 std::array<char, 7> buffer;
62 unsigned accumulator = hash;
63 for (unsigned i = 6; i--;) {
64 buffer[i] = table[accumulator % 62];
65 accumulator /= 62;
66 }
67 buffer[6] = 0;
68 return buffer;
69}
70
71} // namespace WTF
72
73