1/*
2   Copyright (C) 2000-2001 Dawit Alemayehu <adawit@kde.org>
3   Copyright (C) 2006 Alexey Proskuryakov <ap@webkit.org>
4   Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
5   Copyright (C) 2010 Patrick Gansterer <paroga@paroga.com>
6
7   This program is free software; you can redistribute it and/or modify
8   it under the terms of the GNU Lesser General Public License (LGPL)
9   version 2 as published by the Free Software Foundation.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU Library General Public
17   License along with this program; if not, write to the Free Software
18   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
19
20   This code is based on the java implementation in HTTPClient
21   package by Ronald Tschalär Copyright (C) 1996-1999.
22*/
23
24#include "config.h"
25#include "Base64.h"
26
27#include <limits.h>
28#include <wtf/StringExtras.h>
29#include <wtf/text/WTFString.h>
30
31namespace WebCore {
32
33static const char base64EncMap[64] = {
34    0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
35    0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
36    0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
37    0x59, 0x5A, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
38    0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E,
39    0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76,
40    0x77, 0x78, 0x79, 0x7A, 0x30, 0x31, 0x32, 0x33,
41    0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x2B, 0x2F
42};
43
44static const char base64DecMap[128] = {
45    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
46    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
47    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
48    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
49    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
50    0x00, 0x00, 0x00, 0x3E, 0x00, 0x00, 0x00, 0x3F,
51    0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B,
52    0x3C, 0x3D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
53    0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
54    0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
55    0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
56    0x17, 0x18, 0x19, 0x00, 0x00, 0x00, 0x00, 0x00,
57    0x00, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20,
58    0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
59    0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,
60    0x31, 0x32, 0x33, 0x00, 0x00, 0x00, 0x00, 0x00
61};
62
63String base64Encode(const char* data, unsigned length, bool insertLFs)
64{
65    Vector<char> result;
66    base64Encode(data, length, result, insertLFs);
67    return String(result.data(), result.size());
68}
69
70void base64Encode(const char* data, unsigned len, Vector<char>& out, bool insertLFs)
71{
72    out.clear();
73    if (!len)
74        return;
75
76    // If the input string is pathologically large, just return nothing.
77    // Note: Keep this in sync with the "outLength" computation below.
78    // Rather than being perfectly precise, this is a bit conservative.
79    const unsigned maxInputBufferSize = UINT_MAX / 77 * 76 / 4 * 3 - 2;
80    if (len > maxInputBufferSize)
81        return;
82
83    unsigned sidx = 0;
84    unsigned didx = 0;
85
86    unsigned outLength = ((len + 2) / 3) * 4;
87
88    // Deal with the 76 character per line limit specified in RFC 2045.
89    insertLFs = (insertLFs && outLength > 76);
90    if (insertLFs)
91        outLength += ((outLength - 1) / 76);
92
93    int count = 0;
94    out.grow(outLength);
95
96    // 3-byte to 4-byte conversion + 0-63 to ascii printable conversion
97    if (len > 1) {
98        while (sidx < len - 2) {
99            if (insertLFs) {
100                if (count && !(count % 76))
101                    out[didx++] = '\n';
102                count += 4;
103            }
104            out[didx++] = base64EncMap[(data[sidx] >> 2) & 077];
105            out[didx++] = base64EncMap[((data[sidx + 1] >> 4) & 017) | ((data[sidx] << 4) & 077)];
106            out[didx++] = base64EncMap[((data[sidx + 2] >> 6) & 003) | ((data[sidx + 1] << 2) & 077)];
107            out[didx++] = base64EncMap[data[sidx + 2] & 077];
108            sidx += 3;
109        }
110    }
111
112    if (sidx < len) {
113        if (insertLFs && (count > 0) && !(count % 76))
114           out[didx++] = '\n';
115
116        out[didx++] = base64EncMap[(data[sidx] >> 2) & 077];
117        if (sidx < len - 1) {
118            out[didx++] = base64EncMap[((data[sidx + 1] >> 4) & 017) | ((data[sidx] << 4) & 077)];
119            out[didx++] = base64EncMap[(data[sidx + 1] << 2) & 077];
120        } else
121            out[didx++] = base64EncMap[(data[sidx] << 4) & 077];
122    }
123
124    // Add padding
125    while (didx < out.size()) {
126        out[didx] = '=';
127        didx++;
128    }
129}
130
131bool base64Decode(const Vector<char>& in, Vector<char>& out, Base64DecodePolicy policy)
132{
133    out.clear();
134
135    // If the input string is pathologically large, just return nothing.
136    if (in.size() > UINT_MAX)
137        return false;
138
139    return base64Decode(in.data(), in.size(), out, policy);
140}
141
142template<typename T>
143static inline bool base64DecodeInternal(const T* data, unsigned len, Vector<char>& out, Base64DecodePolicy policy)
144{
145    out.clear();
146    if (!len)
147        return true;
148
149    out.grow(len);
150
151    bool sawEqualsSign = false;
152    unsigned outLength = 0;
153    for (unsigned idx = 0; idx < len; idx++) {
154        unsigned ch = data[idx];
155        if (ch == '=')
156            sawEqualsSign = true;
157        else if (('0' <= ch && ch <= '9') || ('A' <= ch && ch <= 'Z') || ('a' <= ch && ch <= 'z') || ch == '+' || ch == '/') {
158            if (sawEqualsSign)
159                return false;
160            out[outLength] = base64DecMap[ch];
161            outLength++;
162        } else if (policy == FailOnInvalidCharacter || (policy == IgnoreWhitespace && !isSpaceOrNewline(ch)))
163            return false;
164    }
165
166    if (!outLength)
167        return !sawEqualsSign;
168
169    // Valid data is (n * 4 + [0,2,3]) characters long.
170    if ((outLength % 4) == 1)
171        return false;
172
173    // 4-byte to 3-byte conversion
174    outLength -= (outLength + 3) / 4;
175    if (!outLength)
176        return false;
177
178    unsigned sidx = 0;
179    unsigned didx = 0;
180    if (outLength > 1) {
181        while (didx < outLength - 2) {
182            out[didx] = (((out[sidx] << 2) & 255) | ((out[sidx + 1] >> 4) & 003));
183            out[didx + 1] = (((out[sidx + 1] << 4) & 255) | ((out[sidx + 2] >> 2) & 017));
184            out[didx + 2] = (((out[sidx + 2] << 6) & 255) | (out[sidx + 3] & 077));
185            sidx += 4;
186            didx += 3;
187        }
188    }
189
190    if (didx < outLength)
191        out[didx] = (((out[sidx] << 2) & 255) | ((out[sidx + 1] >> 4) & 003));
192
193    if (++didx < outLength)
194        out[didx] = (((out[sidx + 1] << 4) & 255) | ((out[sidx + 2] >> 2) & 017));
195
196    if (outLength < out.size())
197        out.shrink(outLength);
198
199    return true;
200}
201
202bool base64Decode(const char* data, unsigned len, Vector<char>& out, Base64DecodePolicy policy)
203{
204    return base64DecodeInternal<char>(data, len, out, policy);
205}
206
207bool base64Decode(const String& in, Vector<char>& out, Base64DecodePolicy policy)
208{
209    return base64DecodeInternal<UChar>(in.characters(), in.length(), out, policy);
210}
211
212} // namespace WebCore
213