From 732bd6893a9e65d33927b9083fe5e30c0864e409 Mon Sep 17 00:00:00 2001 From: Andreas Kling Date: Wed, 28 Oct 2009 14:06:39 +0100 Subject: Simplify byte swapping in QDataStream's stream operators. This makes the code a lot more readable and allows for some centralized platform-specific optimizations. Reviewed-by: Leonardo Sobral Cunha --- src/corelib/io/qdatastream.cpp | 231 ++++++++++------------------------------- src/corelib/tools/qstring.cpp | 3 +- 2 files changed, 59 insertions(+), 175 deletions(-) diff --git a/src/corelib/io/qdatastream.cpp b/src/corelib/io/qdatastream.cpp index 19e86a6..308e847 100644 --- a/src/corelib/io/qdatastream.cpp +++ b/src/corelib/io/qdatastream.cpp @@ -48,6 +48,7 @@ #include #include #include +#include "qendian.h" QT_BEGIN_NAMESPACE @@ -670,24 +671,12 @@ QDataStream &QDataStream::operator>>(qint16 &i) { i = 0; CHECK_STREAM_PRECOND(*this) - if (noswap) { - if (dev->read((char *)&i, 2) != 2) { - i = 0; - setStatus(ReadPastEnd); - } + if (dev->read((char *)&i, 2) != 2) { + i = 0; + setStatus(ReadPastEnd); } else { - union { - qint16 val1; - char val2[2]; - } x; - char *p = x.val2; - char b[2]; - if (dev->read(b, 2) == 2) { - *p++ = b[1]; - *p = b[0]; - i = x.val1; - } else { - setStatus(ReadPastEnd); + if (!noswap) { + i = qbswap(i); } } return *this; @@ -713,26 +702,12 @@ QDataStream &QDataStream::operator>>(qint32 &i) { i = 0; CHECK_STREAM_PRECOND(*this) - if (noswap) { - if (dev->read((char *)&i, 4) != 4) { - i = 0; - setStatus(ReadPastEnd); - } - } else { // swap bytes - union { - qint32 val1; - char val2[4]; - } x; - char *p = x.val2; - char b[4]; - if (dev->read(b, 4) == 4) { - *p++ = b[3]; - *p++ = b[2]; - *p++ = b[1]; - *p = b[0]; - i = x.val1; - } else { - setStatus(ReadPastEnd); + if (dev->read((char *)&i, 4) != 4) { + i = 0; + setStatus(ReadPastEnd); + } else { + if (!noswap) { + i = qbswap(i); } } return *this; @@ -761,31 +736,14 @@ QDataStream &QDataStream::operator>>(qint64 &i) quint32 i1, i2; *this >> i2 >> i1; i = ((quint64)i1 << 32) + i2; - } else if (noswap) { // no conversion needed + } else { if (dev->read((char *)&i, 8) != 8) { i = qint64(0); setStatus(ReadPastEnd); - } - } else { // swap bytes - union { - qint64 val1; - char val2[8]; - } x; - - char *p = x.val2; - char b[8]; - if (dev->read(b, 8) == 8) { - *p++ = b[7]; - *p++ = b[6]; - *p++ = b[5]; - *p++ = b[4]; - *p++ = b[3]; - *p++ = b[2]; - *p++ = b[1]; - *p = b[0]; - i = x.val1; } else { - setStatus(ReadPastEnd); + if (!noswap) { + i = qbswap(i); + } } } return *this; @@ -825,27 +783,17 @@ QDataStream &QDataStream::operator>>(float &f) f = 0.0f; CHECK_STREAM_PRECOND(*this) - if (noswap) { - if (dev->read((char *)&f, 4) != 4) { - f = 0.0f; - setStatus(ReadPastEnd); - } - } else { // swap bytes - union { - float val1; - char val2[4]; - } x; - - char *p = x.val2; - char b[4]; - if (dev->read(b, 4) == 4) { - *p++ = b[3]; - *p++ = b[2]; - *p++ = b[1]; - *p = b[0]; + if (dev->read((char *)&f, 4) != 4) { + f = 0.0f; + setStatus(ReadPastEnd); + } else { + if (!noswap) { + union { + float val1; + quint32 val2; + } x; + x.val2 = qbswap(*reinterpret_cast(&f)); f = x.val1; - } else { - setStatus(ReadPastEnd); } } return *this; @@ -878,30 +826,17 @@ QDataStream &QDataStream::operator>>(double &f) f = 0.0; CHECK_STREAM_PRECOND(*this) #ifndef Q_DOUBLE_FORMAT - if (noswap) { - if (dev->read((char *)&f, 8) != 8) { - f = 0.0; - setStatus(ReadPastEnd); - } - } else { // swap bytes - union { - double val1; - char val2[8]; - } x; - char *p = x.val2; - char b[8]; - if (dev->read(b, 8) == 8) { - *p++ = b[7]; - *p++ = b[6]; - *p++ = b[5]; - *p++ = b[4]; - *p++ = b[3]; - *p++ = b[2]; - *p++ = b[1]; - *p = b[0]; + if (dev->read((char *)&f, 8) != 8) { + f = 0.0; + setStatus(ReadPastEnd); + } else { + if (!noswap) { + union { + double val1; + quint64 val2; + } x; + x.val2 = qbswap(*reinterpret_cast(&f)); f = x.val1; - } else { - setStatus(ReadPastEnd); } } #else @@ -1073,20 +1008,10 @@ QDataStream &QDataStream::operator<<(qint8 i) QDataStream &QDataStream::operator<<(qint16 i) { CHECK_STREAM_PRECOND(*this) - if (noswap) { - dev->write((char *)&i, sizeof(qint16)); - } else { // swap bytes - union { - qint16 val1; - char val2[2]; - } x; - x.val1 = i; - char *p = x.val2; - char b[2]; - b[1] = *p++; - b[0] = *p; - dev->write(b, 2); + if (!noswap) { + i = qbswap(i); } + dev->write((char *)&i, sizeof(qint16)); return *this; } @@ -1100,22 +1025,10 @@ QDataStream &QDataStream::operator<<(qint16 i) QDataStream &QDataStream::operator<<(qint32 i) { CHECK_STREAM_PRECOND(*this) - if (noswap) { - dev->write((char *)&i, sizeof(qint32)); - } else { // swap bytes - union { - qint32 val1; - char val2[4]; - } x; - x.val1 = i; - char *p = x.val2; - char b[4]; - b[3] = *p++; - b[2] = *p++; - b[1] = *p++; - b[0] = *p; - dev->write(b, 4); + if (!noswap) { + i = qbswap(i); } + dev->write((char *)&i, sizeof(qint32)); return *this; } @@ -1141,25 +1054,11 @@ QDataStream &QDataStream::operator<<(qint64 i) quint32 i1 = i & 0xffffffff; quint32 i2 = i >> 32; *this << i2 << i1; - } else if (noswap) { // no conversion needed + } else { + if (!noswap) { + i = qbswap(i); + } dev->write((char *)&i, sizeof(qint64)); - } else { // swap bytes - union { - qint64 val1; - char val2[8]; - } x; - x.val1 = i; - char *p = x.val2; - char b[8]; - b[7] = *p++; - b[6] = *p++; - b[5] = *p++; - b[4] = *p++; - b[3] = *p++; - b[2] = *p++; - b[1] = *p++; - b[0] = *p; - dev->write(b, 8); } return *this; } @@ -1203,22 +1102,16 @@ QDataStream &QDataStream::operator<<(float f) CHECK_STREAM_PRECOND(*this) float g = f; // fixes float-on-stack problem - if (noswap) { // no conversion needed - dev->write((char *)&g, sizeof(float)); - } else { // swap bytes + if (!noswap) { union { float val1; - char val2[4]; + quint32 val2; } x; - x.val1 = f; - char *p = x.val2; - char b[4]; - b[3] = *p++; - b[2] = *p++; - b[1] = *p++; - b[0] = *p; - dev->write(b, 4); + x.val1 = g; + x.val2 = qbswap(x.val2); + g = x.val1; } + dev->write((char *)&g, sizeof(float)); return *this; } @@ -1242,26 +1135,16 @@ QDataStream &QDataStream::operator<<(double f) CHECK_STREAM_PRECOND(*this) #ifndef Q_DOUBLE_FORMAT - if (noswap) { - dev->write((char *)&f, sizeof(double)); - } else { + if (!noswap) { union { double val1; - char val2[8]; + quint64 val2; } x; x.val1 = f; - char *p = x.val2; - char b[8]; - b[7] = *p++; - b[6] = *p++; - b[5] = *p++; - b[4] = *p++; - b[3] = *p++; - b[2] = *p++; - b[1] = *p++; - b[0] = *p; - dev->write(b, 8); + x.val2 = qbswap(x.val2); + f = x.val1; } + dev->write((char *)&f, sizeof(double)); #else union { double val1; diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp index a996f30..3af53f5 100644 --- a/src/corelib/tools/qstring.cpp +++ b/src/corelib/tools/qstring.cpp @@ -55,6 +55,7 @@ #include "qtools_p.h" #include "qhash.h" #include "qdebug.h" +#include "qendian.h" #ifdef Q_OS_MAC #include @@ -7306,7 +7307,7 @@ QDataStream &operator>>(QDataStream &in, QString &str) != (QSysInfo::ByteOrder == QSysInfo::BigEndian)) { ushort *data = reinterpret_cast(str.data()); while (len--) { - *data = (*data >> 8) | (*data << 8); + *data = qbswap(*data); ++data; } } -- cgit v0.12