1/*
2 * Copyright (C) 2012 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/StringPrintStream.h>
28
29#include <stdarg.h>
30#include <stdio.h>
31#include <wtf/FastMalloc.h>
32
33namespace WTF {
34
35StringPrintStream::StringPrintStream()
36 : m_buffer(m_inlineBuffer)
37 , m_next(0)
38 , m_size(sizeof(m_inlineBuffer))
39{
40 m_buffer[0] = 0; // Make sure that we always have a null terminator.
41}
42
43StringPrintStream::~StringPrintStream()
44{
45 if (m_buffer == m_inlineBuffer)
46 return;
47 fastFree(m_buffer);
48}
49
50void StringPrintStream::vprintf(const char* format, va_list argList)
51{
52 ASSERT_WITH_SECURITY_IMPLICATION(m_next < m_size);
53 ASSERT(!m_buffer[m_next]);
54
55 va_list firstPassArgList;
56 va_copy(firstPassArgList, argList);
57
58 int numberOfBytesNotIncludingTerminatorThatWouldHaveBeenWritten =
59 vsnprintf(m_buffer + m_next, m_size - m_next, format, firstPassArgList);
60
61 va_end(firstPassArgList);
62
63 int numberOfBytesThatWouldHaveBeenWritten =
64 numberOfBytesNotIncludingTerminatorThatWouldHaveBeenWritten + 1;
65
66 if (m_next + numberOfBytesThatWouldHaveBeenWritten <= m_size) {
67 m_next += numberOfBytesNotIncludingTerminatorThatWouldHaveBeenWritten;
68 return; // This means that vsnprintf() succeeded.
69 }
70
71 increaseSize(m_next + numberOfBytesThatWouldHaveBeenWritten);
72
73 int numberOfBytesNotIncludingTerminatorThatWereWritten =
74 vsnprintf(m_buffer + m_next, m_size - m_next, format, argList);
75
76 int numberOfBytesThatWereWritten = numberOfBytesNotIncludingTerminatorThatWereWritten + 1;
77
78 ASSERT_UNUSED(numberOfBytesThatWereWritten, m_next + numberOfBytesThatWereWritten <= m_size);
79
80 m_next += numberOfBytesNotIncludingTerminatorThatWereWritten;
81
82 ASSERT_WITH_SECURITY_IMPLICATION(m_next < m_size);
83 ASSERT(!m_buffer[m_next]);
84}
85
86CString StringPrintStream::toCString()
87{
88 ASSERT(m_next == strlen(m_buffer));
89 return CString(m_buffer, m_next);
90}
91
92void StringPrintStream::reset()
93{
94 m_next = 0;
95 m_buffer[0] = 0;
96}
97
98String StringPrintStream::toString()
99{
100 ASSERT(m_next == strlen(m_buffer));
101 return String::fromUTF8(m_buffer, m_next);
102}
103
104String StringPrintStream::toStringWithLatin1Fallback()
105{
106 ASSERT(m_next == strlen(m_buffer));
107 return String::fromUTF8WithLatin1Fallback(m_buffer, m_next);
108}
109
110void StringPrintStream::increaseSize(size_t newSize)
111{
112 ASSERT_WITH_SECURITY_IMPLICATION(newSize > m_size);
113 ASSERT(newSize > sizeof(m_inlineBuffer));
114
115 // Use exponential resizing to reduce thrashing.
116 m_size = newSize << 1;
117
118 // Use fastMalloc instead of fastRealloc because we know that for the sizes we're using,
119 // fastRealloc will just do malloc+free anyway. Also, this simplifies the code since
120 // we can't realloc the inline buffer.
121 char* newBuffer = static_cast<char*>(fastMalloc(m_size));
122 memcpy(newBuffer, m_buffer, m_next + 1);
123 if (m_buffer != m_inlineBuffer)
124 fastFree(m_buffer);
125 m_buffer = newBuffer;
126}
127
128} // namespace WTF
129
130