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-rw-r--r--src/serialport/qt4support/include/private/qringbuffer_p.h318
1 files changed, 93 insertions, 225 deletions
diff --git a/src/serialport/qt4support/include/private/qringbuffer_p.h b/src/serialport/qt4support/include/private/qringbuffer_p.h
index ddd10e5..5aa1f16 100644
--- a/src/serialport/qt4support/include/private/qringbuffer_p.h
+++ b/src/serialport/qt4support/include/private/qringbuffer_p.h
@@ -61,9 +61,9 @@ QT_BEGIN_NAMESPACE
class QRingBuffer
{
public:
- explicit inline QRingBuffer(int growth = 4096) : basicBlockSize(growth) {
- buffers << QByteArray();
- clear();
+ explicit inline QRingBuffer(int growth = 4096) :
+ head(0), tail(0), tailBuffer(0), basicBlockSize(growth), bufferSize(0) {
+ buffers.append(QByteArray());
}
inline int nextDataBlockSize() const {
@@ -78,115 +78,65 @@ public:
// the out-variable length will contain the amount of bytes readable
// from there, e.g. the amount still the same QByteArray
inline const char *readPointerAtPosition(qint64 pos, qint64 &length) const {
- if (buffers.isEmpty()) {
- length = 0;
- return 0;
- }
-
- if (pos >= bufferSize) {
- length = 0;
- return 0;
- }
-
- // special case: it is in the first buffer
- int nextDataBlockSizeValue = nextDataBlockSize();
- if (pos - head < nextDataBlockSizeValue) {
- length = nextDataBlockSizeValue - pos;
- return buffers.at(0).constData() + head + pos;
- }
-
- // special case: we only had one buffer and tried to read over it
- if (buffers.length() == 1) {
- length = 0;
- return 0;
- }
-
- // skip the first
- pos -= nextDataBlockSizeValue;
-
- // normal case: it is somewhere in the second to the-one-before-the-tailBuffer
- for (int i = 1; i < tailBuffer; i++) {
- if (pos >= buffers[i].size()) {
- pos -= buffers[i].size();
- continue;
+ if (pos >= 0) {
+ pos += head;
+ for (int i = 0; i < buffers.size(); ++i) {
+ length = (i == tailBuffer ? tail : buffers[i].size());
+ if (length > pos) {
+ length -= pos;
+ return buffers[i].constData() + pos;
+ }
+ pos -= length;
}
-
- length = buffers[i].length() - pos;
- return buffers[i].constData() + pos;
}
- // it is in the tail buffer
- length = tail - pos;
- return buffers[tailBuffer].constData() + pos;
+ length = 0;
+ return 0;
}
inline void free(int bytes) {
- bufferSize -= bytes;
- if (bufferSize < 0)
- bufferSize = 0;
-
- for (;;) {
- int nextBlockSize = nextDataBlockSize();
- if (bytes < nextBlockSize) {
- head += bytes;
- if (head == tail && tailBuffer == 0)
- head = tail = 0;
- break;
- }
-
- bytes -= nextBlockSize;
- if (buffers.count() == 1) {
- if (buffers.at(0).size() != basicBlockSize)
- buffers[0].resize(basicBlockSize);
- head = tail = 0;
- tailBuffer = 0;
- break;
+ while (bytes > 0) {
+ int blockSize = buffers.first().size() - head;
+
+ if (tailBuffer == 0 || blockSize > bytes) {
+ bufferSize -= bytes;
+ if (bufferSize <= 0)
+ clear(); // try to minify/squeeze us
+ else
+ head += bytes;
+ return;
}
- buffers.removeAt(0);
+ bufferSize -= blockSize;
+ bytes -= blockSize;
+ buffers.removeFirst();
--tailBuffer;
head = 0;
}
-
- if (isEmpty())
- clear(); // try to minify/squeeze us
}
inline char *reserve(int bytes) {
- // if this is a fresh empty QRingBuffer
- if (bufferSize == 0) {
- buffers[0].resize(qMax(basicBlockSize, bytes));
- bufferSize += bytes;
- tail = bytes;
- return buffers[tailBuffer].data();
- }
-
- bufferSize += bytes;
+ if (bytes <= 0)
+ return 0;
- // if there is already enough space, simply return.
- if (tail + bytes <= buffers.at(tailBuffer).size()) {
- char *writePtr = buffers[tailBuffer].data() + tail;
- tail += bytes;
- return writePtr;
- }
+ // if need buffer reallocation
+ if (tail + bytes > buffers.last().size()) {
+ if (tail >= basicBlockSize) {
+ // shrink this buffer to its current size
+ buffers.last().resize(tail);
- // if our buffer isn't half full yet, simply resize it.
- if (tail < buffers.at(tailBuffer).size() / 2) {
- buffers[tailBuffer].resize(tail + bytes);
- char *writePtr = buffers[tailBuffer].data() + tail;
- tail += bytes;
- return writePtr;
+ // create a new QByteArray
+ buffers.append(QByteArray());
+ ++tailBuffer;
+ tail = 0;
+ }
+ buffers.last().resize(qMax(basicBlockSize, tail + bytes));
}
- // shrink this buffer to its current size
- buffers[tailBuffer].resize(tail);
-
- // create a new QByteArray with the right size
- buffers << QByteArray();
- ++tailBuffer;
- buffers[tailBuffer].resize(qMax(basicBlockSize, bytes));
- tail = bytes;
- return buffers[tailBuffer].data();
+ char *writePtr = buffers.last().data() + tail;
+ bufferSize += bytes;
+ tail += bytes;
+ return writePtr;
}
inline void truncate(int pos) {
@@ -195,33 +145,22 @@ public:
}
inline void chop(int bytes) {
- bufferSize -= bytes;
- if (bufferSize < 0)
- bufferSize = 0;
-
- for (;;) {
- // special case: head and tail are in the same buffer
- if (tailBuffer == 0) {
- tail -= bytes;
- if (tail <= head)
- tail = head = 0;
- return;
- }
-
- if (bytes <= tail) {
- tail -= bytes;
+ while (bytes > 0) {
+ if (tailBuffer == 0 || tail > bytes) {
+ bufferSize -= bytes;
+ if (bufferSize <= 0)
+ clear(); // try to minify/squeeze us
+ else
+ tail -= bytes;
return;
}
+ bufferSize -= tail;
bytes -= tail;
- buffers.removeAt(tailBuffer);
-
+ buffers.removeLast();
--tailBuffer;
- tail = buffers.at(tailBuffer).size();
+ tail = buffers.last().size();
}
-
- if (isEmpty())
- clear(); // try to minify/squeeze us
}
inline bool isEmpty() const {
@@ -245,11 +184,11 @@ public:
--head;
if (head < 0) {
buffers.prepend(QByteArray());
- buffers[0].resize(basicBlockSize);
+ buffers.first().resize(basicBlockSize);
head = basicBlockSize - 1;
++tailBuffer;
}
- buffers[0][head] = c;
+ buffers.first()[head] = c;
++bufferSize;
}
@@ -259,8 +198,7 @@ public:
inline void clear() {
buffers.erase(buffers.begin() + 1, buffers.end());
- buffers[0].resize(0);
- buffers[0].squeeze();
+ buffers.first().clear();
head = tail = 0;
tailBuffer = 0;
@@ -269,47 +207,34 @@ public:
inline int indexOf(char c) const {
int index = 0;
+ int j = head;
for (int i = 0; i < buffers.size(); ++i) {
- int start = 0;
- int end = buffers.at(i).size();
-
- if (i == 0)
- start = head;
- if (i == tailBuffer)
- end = tail;
- const char *ptr = buffers.at(i).data() + start;
- for (int j = start; j < end; ++j) {
+ const char *ptr = buffers[i].constData() + j;
+ j = index + (i == tailBuffer ? tail : buffers[i].size()) - j;
+
+ while (index < j) {
if (*ptr++ == c)
return index;
++index;
}
+ j = 0;
}
return -1;
}
inline int indexOf(char c, int maxLength) const {
int index = 0;
- int remain = qMin(size(), maxLength);
- for (int i = 0; remain && i < buffers.size(); ++i) {
- int start = 0;
- int end = buffers.at(i).size();
-
- if (i == 0)
- start = head;
- if (i == tailBuffer)
- end = tail;
- if (remain < end - start) {
- end = start + remain;
- remain = 0;
- } else {
- remain -= end - start;
- }
- const char *ptr = buffers.at(i).data() + start;
- for (int j = start; j < end; ++j) {
+ int j = head;
+ for (int i = 0; index < maxLength && i < buffers.size(); ++i) {
+ const char *ptr = buffers[i].constData() + j;
+ j = qMin(index + (i == tailBuffer ? tail : buffers[i].size()) - j, maxLength);
+
+ while (index < j) {
if (*ptr++ == c)
return index;
++index;
}
+ j = 0;
}
return -1;
}
@@ -318,95 +243,47 @@ public:
int bytesToRead = qMin(size(), maxLength);
int readSoFar = 0;
while (readSoFar < bytesToRead) {
- const char *ptr = readPointer();
int bytesToReadFromThisBlock = qMin(bytesToRead - readSoFar, nextDataBlockSize());
if (data)
- memcpy(data + readSoFar, ptr, bytesToReadFromThisBlock);
+ memcpy(data + readSoFar, readPointer(), bytesToReadFromThisBlock);
readSoFar += bytesToReadFromThisBlock;
free(bytesToReadFromThisBlock);
}
return readSoFar;
}
- inline QByteArray read(int maxLength) {
- QByteArray tmp;
- tmp.resize(qMin(maxLength, size()));
- read(tmp.data(), tmp.size());
- return tmp;
- }
-
- inline QByteArray readAll() {
- return read(size());
- }
-
// read an unspecified amount (will read the first buffer)
inline QByteArray read() {
if (bufferSize == 0)
return QByteArray();
- // multiple buffers, just take the first one
- if (head == 0 && tailBuffer != 0) {
- QByteArray qba = buffers.takeFirst();
- --tailBuffer;
- bufferSize -= qba.length();
- return qba;
- }
+ QByteArray qba(buffers.takeFirst());
- // one buffer with good value for head. Just take it.
- if (head == 0 && tailBuffer == 0) {
- QByteArray qba = buffers.takeFirst();
- qba.resize(tail);
- buffers << QByteArray();
- bufferSize = 0;
- tail = 0;
- return qba;
- }
-
- // Bad case: We have to memcpy.
- // We can avoid by initializing the QRingBuffer with basicBlockSize of 0
- // and only using this read() function.
- QByteArray qba(readPointer(), nextDataBlockSize());
- buffers.removeFirst();
- head = 0;
+ qba.reserve(0); // avoid that resizing needlessly reallocates
if (tailBuffer == 0) {
- buffers << QByteArray();
+ qba.resize(tail);
tail = 0;
+ buffers.append(QByteArray());
} else {
--tailBuffer;
}
- bufferSize -= qba.length();
+ qba.remove(0, head); // does nothing if head is 0
+ head = 0;
+ bufferSize -= qba.size();
return qba;
}
// append a new buffer to the end
inline void append(const QByteArray &qba) {
- buffers[tailBuffer].resize(tail);
- buffers << qba;
- ++tailBuffer;
- tail = qba.length();
- bufferSize += qba.length();
- }
-
- inline QByteArray peek(int maxLength) const {
- int bytesToRead = qMin(size(), maxLength);
- if (maxLength <= 0)
- return QByteArray();
- QByteArray ret;
- ret.resize(bytesToRead);
- int readSoFar = 0;
- for (int i = 0; readSoFar < bytesToRead && i < buffers.size(); ++i) {
- int start = 0;
- int end = buffers.at(i).size();
- if (i == 0)
- start = head;
- if (i == tailBuffer)
- end = tail;
- const int len = qMin(ret.size()-readSoFar, end-start);
- memcpy(ret.data()+readSoFar, buffers.at(i).constData()+start, len);
- readSoFar += len;
+ if (tail == 0) {
+ buffers.last() = qba;
+ } else {
+ buffers.last().resize(tail);
+ buffers.append(qba);
+ ++tailBuffer;
}
- Q_ASSERT(readSoFar == ret.size());
- return ret;
+ tail = qba.size();
+ bufferSize += tail;
}
inline int skip(int length) {
@@ -414,35 +291,26 @@ public:
}
inline int readLine(char *data, int maxLength) {
- int index = indexOf('\n');
- if (index == -1)
- return read(data, maxLength);
- if (maxLength <= 0)
+ if (!data || --maxLength <= 0)
return -1;
- int readSoFar = 0;
- while (readSoFar < index + 1 && readSoFar < maxLength - 1) {
- int bytesToRead = qMin((index + 1) - readSoFar, nextDataBlockSize());
- bytesToRead = qMin(bytesToRead, (maxLength - 1) - readSoFar);
- memcpy(data + readSoFar, readPointer(), bytesToRead);
- readSoFar += bytesToRead;
- free(bytesToRead);
- }
+ int i = indexOf('\n', maxLength);
+ i = read(data, i >= 0 ? (i + 1) : maxLength);
// Terminate it.
- data[readSoFar] = '\0';
- return readSoFar;
+ data[i] = '\0';
+ return i;
}
inline bool canReadLine() const {
- return indexOf('\n') != -1;
+ return indexOf('\n') >= 0;
}
private:
QList<QByteArray> buffers;
int head, tail;
int tailBuffer; // always buffers.size() - 1
- int basicBlockSize;
+ const int basicBlockSize;
int bufferSize;
};
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