1/*
2 * Copyright (C) 2011 Google 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 are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include "config.h"
32#include "platform/text/QuotedPrintable.h"
33
34#include "wtf/ASCIICType.h"
35
36namespace blink {
37
38static const size_t maximumLineLength = 76;
39
40static const char crlfLineEnding[] = "\r\n";
41
42static size_t lengthOfLineEndingAtIndex(const char* input, size_t inputLength, size_t index)
43{
44    ASSERT_WITH_SECURITY_IMPLICATION(index < inputLength);
45    if (input[index] == '\n')
46        return 1; // Single LF.
47
48    if (input[index] == '\r') {
49        if ((index + 1) == inputLength || input[index + 1] != '\n')
50            return 1; // Single CR (Classic Mac OS).
51        return 2; // CR-LF.
52    }
53
54    return 0;
55}
56
57void quotedPrintableEncode(const Vector<char>& in, Vector<char>& out)
58{
59    quotedPrintableEncode(in.data(), in.size(), out);
60}
61
62void quotedPrintableEncode(const char* input, size_t inputLength, Vector<char>& out)
63{
64    out.clear();
65    out.reserveCapacity(inputLength);
66    size_t currentLineLength = 0;
67    for (size_t i = 0; i < inputLength; ++i) {
68        bool isLastCharacter = (i == inputLength - 1);
69        char currentCharacter = input[i];
70        bool requiresEncoding = false;
71        // All non-printable ASCII characters and = require encoding.
72        if ((currentCharacter < ' ' || currentCharacter > '~' || currentCharacter == '=') && currentCharacter != '\t')
73            requiresEncoding = true;
74
75        // Space and tab characters have to be encoded if they appear at the end of a line.
76        if (!requiresEncoding && (currentCharacter == '\t' || currentCharacter == ' ') && (isLastCharacter || lengthOfLineEndingAtIndex(input, inputLength, i + 1)))
77            requiresEncoding = true;
78
79        // End of line should be converted to CR-LF sequences.
80        if (!isLastCharacter) {
81            size_t lengthOfLineEnding = lengthOfLineEndingAtIndex(input, inputLength, i);
82            if (lengthOfLineEnding) {
83                out.append(crlfLineEnding, strlen(crlfLineEnding));
84                currentLineLength = 0;
85                i += (lengthOfLineEnding - 1); // -1 because we'll ++ in the for() above.
86                continue;
87            }
88        }
89
90        size_t lengthOfEncodedCharacter = 1;
91        if (requiresEncoding)
92            lengthOfEncodedCharacter += 2;
93        if (!isLastCharacter)
94            lengthOfEncodedCharacter += 1; // + 1 for the = (soft line break).
95
96        // Insert a soft line break if necessary.
97        if (currentLineLength + lengthOfEncodedCharacter > maximumLineLength) {
98            out.append('=');
99            out.append(crlfLineEnding, strlen(crlfLineEnding));
100            currentLineLength = 0;
101        }
102
103        // Finally, insert the actual character(s).
104        if (requiresEncoding) {
105            out.append('=');
106            out.append(upperNibbleToASCIIHexDigit(currentCharacter));
107            out.append(lowerNibbleToASCIIHexDigit(currentCharacter));
108            currentLineLength += 3;
109        } else {
110            out.append(currentCharacter);
111            currentLineLength++;
112        }
113    }
114}
115
116void quotedPrintableDecode(const Vector<char>& in, Vector<char>& out)
117{
118    quotedPrintableDecode(in.data(), in.size(), out);
119}
120
121void quotedPrintableDecode(const char* data, size_t dataLength, Vector<char>& out)
122{
123    out.clear();
124    if (!dataLength)
125        return;
126
127    for (size_t i = 0; i < dataLength; ++i) {
128        char currentCharacter = data[i];
129        if (currentCharacter != '=') {
130            out.append(currentCharacter);
131            continue;
132        }
133        // We are dealing with a '=xx' sequence.
134        if (dataLength - i < 3) {
135            // Unfinished = sequence, append as is.
136            out.append(currentCharacter);
137            continue;
138        }
139        char upperCharacter = data[++i];
140        char lowerCharacter = data[++i];
141        if (upperCharacter == '\r' && lowerCharacter == '\n')
142            continue;
143
144        if (!isASCIIHexDigit(upperCharacter) || !isASCIIHexDigit(lowerCharacter)) {
145            // Invalid sequence, = followed by non hex digits, just insert the characters as is.
146            out.append('=');
147            out.append(upperCharacter);
148            out.append(lowerCharacter);
149            continue;
150        }
151        out.append(static_cast<char>(toASCIIHexValue(upperCharacter, lowerCharacter)));
152    }
153}
154
155}
156