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39
40#ifndef QBYTEDATA_P_H
41#define QBYTEDATA_P_H
42
43//
44// W A R N I N G
45// -------------
46//
47// This file is not part of the Qt API. It exists purely as an
48// implementation detail. This header file may change from version to
49// version without notice, or even be removed.
50//
51// We mean it.
52//
53
54#include <QtCore/private/qglobal_p.h>
55#include <qbytearray.h>
56
57QT_BEGIN_NAMESPACE
58
59// this class handles a list of QByteArrays. It is a variant of QRingBuffer
60// that avoid malloc/realloc/memcpy.
61class QByteDataBuffer
62{
63private:
64 QList<QByteArray> buffers;
65 qint64 bufferCompleteSize;
66 qint64 firstPos;
67public:
68 QByteDataBuffer() : bufferCompleteSize(0), firstPos(0)
69 {
70 }
71
72 ~QByteDataBuffer()
73 {
74 clear();
75 }
76
77 static inline void popFront(QByteArray &ba, qint64 n)
78 {
79 ba = QByteArray(ba.constData() + n, ba.size() - n);
80 }
81
82 inline void squeezeFirst()
83 {
84 if (!buffers.isEmpty() && firstPos > 0) {
85 popFront(buffers.first(), firstPos);
86 firstPos = 0;
87 }
88 }
89
90 inline void append(const QByteDataBuffer& other)
91 {
92 if (other.isEmpty())
93 return;
94
95 buffers.append(other.buffers);
96 bufferCompleteSize += other.byteAmount();
97
98 if (other.firstPos > 0)
99 popFront(buffers[bufferCount() - other.bufferCount()], other.firstPos);
100 }
101
102
103 inline void append(const QByteArray& bd)
104 {
105 if (bd.isEmpty())
106 return;
107
108 buffers.append(bd);
109 bufferCompleteSize += bd.size();
110 }
111
112 inline void prepend(const QByteArray& bd)
113 {
114 if (bd.isEmpty())
115 return;
116
117 squeezeFirst();
118
119 buffers.prepend(bd);
120 bufferCompleteSize += bd.size();
121 }
122
123 // return the first QByteData. User of this function has to free() its .data!
124 // preferably use this function to read data.
125 inline QByteArray read()
126 {
127 squeezeFirst();
128 bufferCompleteSize -= buffers.first().size();
129 return buffers.takeFirst();
130 }
131
132 // return everything. User of this function has to free() its .data!
133 // avoid to use this, it might malloc and memcpy.
134 inline QByteArray readAll()
135 {
136 return read(byteAmount());
137 }
138
139 // return amount. User of this function has to free() its .data!
140 // avoid to use this, it might malloc and memcpy.
141 inline QByteArray read(qint64 amount)
142 {
143 amount = qMin(byteAmount(), amount);
144 QByteArray byteData;
145 byteData.resize(amount);
146 read(byteData.data(), byteData.size());
147 return byteData;
148 }
149
150 // return amount bytes. User of this function has to free() its .data!
151 // avoid to use this, it will memcpy.
152 qint64 read(char* dst, qint64 amount)
153 {
154 amount = qMin(amount, byteAmount());
155 qint64 originalAmount = amount;
156 char *writeDst = dst;
157
158 while (amount > 0) {
159 const QByteArray &first = buffers.first();
160 qint64 firstSize = first.size() - firstPos;
161 if (amount >= firstSize) {
162 // take it completely
163 bufferCompleteSize -= firstSize;
164 amount -= firstSize;
165 memcpy(writeDst, first.constData() + firstPos, firstSize);
166 writeDst += firstSize;
167 firstPos = 0;
168 buffers.takeFirst();
169 } else {
170 // take a part of it & it is the last one to take
171 bufferCompleteSize -= amount;
172 memcpy(writeDst, first.constData() + firstPos, amount);
173 firstPos += amount;
174 amount = 0;
175 }
176 }
177
178 return originalAmount;
179 }
180
181 inline char getChar()
182 {
183 char c;
184 read(&c, 1);
185 return c;
186 }
187
188 inline void clear()
189 {
190 buffers.clear();
191 bufferCompleteSize = 0;
192 firstPos = 0;
193 }
194
195 // The byte count of all QByteArrays
196 inline qint64 byteAmount() const
197 {
198 return bufferCompleteSize;
199 }
200
201 // the number of QByteArrays
202 inline int bufferCount() const
203 {
204 return buffers.length();
205 }
206
207 inline bool isEmpty() const
208 {
209 return byteAmount() == 0;
210 }
211
212 inline qint64 sizeNextBlock() const
213 {
214 if(buffers.isEmpty())
215 return 0;
216 else
217 return buffers.first().size() - firstPos;
218 }
219
220 inline QByteArray& operator[](int i)
221 {
222 if (i == 0)
223 squeezeFirst();
224
225 return buffers[i];
226 }
227
228 inline bool canReadLine() const {
229 int i = 0;
230 if (i < buffers.length()) {
231 if (buffers.at(i).indexOf('\n', firstPos) != -1)
232 return true;
233 ++i;
234
235 for (; i < buffers.length(); i++)
236 if (buffers.at(i).contains('\n'))
237 return true;
238 }
239 return false;
240 }
241};
242
243QT_END_NAMESPACE
244
245#endif // QBYTEDATA_P_H
246