/****************************************************************************
**
**
** Implementation of QBuffer class
**
** Created : 930812
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** LICENSE.QPL included in the packaging of this file.
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** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
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#include "qbuffer.h"
#include <stdlib.h>
// REVISED: paul
/*!
\class QBuffer qbuffer.h
\brief The QBuffer class is an I/O device that operates on a QByteArray
\ingroup io
QBuffer allows reading and writing a memory buffer. It is normally
used together with a QTextStream or a QDataStream. QBuffer has an
associated QByteArray which holds the buffer data. The size() of the
buffer is automatically adjusted as data is written.
The constructor \c QBuffer(QByteArray) creates a QBuffer with an
existing byte array. The byte array can also be set with setBuffer().
Writing to the QBuffer will modify the original byte array, since
QByteArray is \link shclass.html explicitly shared.\endlink
Use open() to open the buffer before use, and to set the mode
(read-only,write-only, etc.). close() closes the buffer. The buffer
must be closed before reopening or calling setBuffer().
The common way to use QBuffer is through \l QDataStream or \l QTextStream
which have constructors that take a QBuffer parameter. For
convenience, there are also QDataStream and QTextStream constructors
that take a QByteArray parameter. These constructors create and open
an internal QBuffer.
Note that QTextStream can also operate on a QString (a Unicode
string); a QBuffer cannot.
You can also use QBuffer directly through the standard QIODevice
functions readBlock(), writeBlock() readLine(), at(), getch(), putch() and
ungetch().
\sa QFile, QDataStream, QTextStream, QByteArray, \link shclass.html Shared Classes\endlink
*/
/*!
Constructs an empty buffer.
*/
QBuffer::QBuffer()
{
setFlags( IO_Direct );
a_inc = 16; // initial increment
a_len = 0;
ioIndex = 0;
}
/*!
Constructs a buffer that operates on \a buf.
If you open the buffer in write mode (\c IO_WriteOnly or
\c IO_ReadWrite) and write something into the buffer, \a buf
will be modified.
Example:
\code
QCString str = "abc";
QBuffer b( str );
b.open( IO_WriteOnly );
b.at( 3 ); // position at \0
b.writeBlock( "def", 4 ); // write including \0
b.close();
// Now, str == "abcdef"
\endcode
\sa setBuffer()
*/
QBuffer::QBuffer( QByteArray buf ) : a(buf)
{
setFlags( IO_Direct );
a_len = a.size();
a_inc = (a_len > 512) ? 512 : a_len; // initial increment
if ( a_inc < 16 )
a_inc = 16;
ioIndex = 0;
}
/*!
Destructs the buffer.
*/
QBuffer::~QBuffer()
{
}
/*!
Replaces the buffer's contents with \a buf.
This may not be done when isOpen() is TRUE.
Note that if you open the buffer in write mode (\c IO_WriteOnly or
IO_ReadWrite) and write something into the buffer, \a buf is also
modified because QByteArray is an explicitly shared class.
\sa buffer(), open(), close()
*/
bool QBuffer::setBuffer( QByteArray buf )
{
if ( isOpen() ) {
#if defined(CHECK_STATE)
qWarning( "QBuffer::setBuffer: Buffer is open");
#endif
return FALSE;
}
a = buf;
a_len = a.size();
a_inc = (a_len > 512) ? 512 : a_len; // initial increment
if ( a_inc < 16 )
a_inc = 16;
ioIndex = 0;
return TRUE;
}
/*!
\fn QByteArray QBuffer::buffer() const
Returns this buffer's byte array.
\sa setBuffer()
*/
/*!
\reimp
Opens the buffer in the mode \a m. Returns TRUE if successful,
otherwise FALSE. The buffer must be opened before use.
The mode parameter \a m must be a combination of the following flags.
<ul>
<li>\c IO_ReadOnly opens a buffer in read-only mode.
<li>\c IO_WriteOnly opens a buffer in write-only mode.
<li>\c IO_ReadWrite opens a buffer in read/write mode.
<li>\c IO_Append sets the buffer index to the end of the buffer.
<li>\c IO_Truncate truncates the buffer.
</ul>
\sa close(), isOpen()
*/
bool QBuffer::open( int m )
{
if ( isOpen() ) { // buffer already open
#if defined(CHECK_STATE)
qWarning( "QBuffer::open: Buffer already open" );
#endif
return FALSE;
}
setMode( m );
if ( m & IO_Truncate ) { // truncate buffer
a.resize( 0 );
a_len = 0;
}
if ( m & IO_Append ) { // append to end of buffer
ioIndex = a.size();
} else {
ioIndex = 0;
}
a_inc = 16;
setState( IO_Open );
setStatus( 0 );
return TRUE;
}
/*!
\reimp
Closes an open buffer.
\sa open()
*/
void QBuffer::close()
{
if ( isOpen() ) {
setFlags( IO_Direct );
ioIndex = 0;
a_inc = 16;
}
}
/*!
\reimp
The flush function does nothing for a QBuffer.
*/
void QBuffer::flush()
{
return;
}
/*!
\fn int QBuffer::at() const
\reimp
*/
/*!
\fn uint QBuffer::size() const
\reimp
*/
/*!
\reimp
*/
bool QBuffer::at( int pos )
{
#if defined(CHECK_STATE)
if ( !isOpen() ) {
qWarning( "QBuffer::at: Buffer is not open" );
return FALSE;
}
#endif
if ( (uint)pos > a_len ) {
#if defined(CHECK_RANGE)
qWarning( "QBuffer::at: Index %d out of range", pos );
#endif
return FALSE;
}
ioIndex = pos;
return TRUE;
}
/*!
\reimp
*/
int QBuffer::readBlock( char *p, uint len )
{
#if defined(CHECK_STATE)
CHECK_PTR( p );
if ( !isOpen() ) { // buffer not open
qWarning( "QBuffer::readBlock: Buffer not open" );
return -1;
}
if ( !isReadable() ) { // reading not permitted
qWarning( "QBuffer::readBlock: Read operation not permitted" );
return -1;
}
#endif
if ( (uint)ioIndex + len > a.size() ) { // overflow
if ( (uint)ioIndex >= a.size() ) {
setStatus( IO_ReadError );
return -1;
} else {
len = a.size() - (uint)ioIndex;
}
}
memcpy( p, a.data()+ioIndex, len );
ioIndex += len;
return len;
}
/*!
\reimp
Writes \a len bytes from \a p into the buffer at the current index,
overwriting any characters there and extending the buffer if necessary.
Returns the number of bytes actually written.
Returns -1 if a serious error occurred.
\sa readBlock()
*/
int QBuffer::writeBlock( const char *p, uint len )
{
#if defined(CHECK_NULL)
if ( p == 0 && len != 0 )
qWarning( "QBuffer::writeBlock: Null pointer error" );
#endif
#if defined(CHECK_STATE)
if ( !isOpen() ) { // buffer not open
qWarning( "QBuffer::writeBlock: Buffer not open" );
return -1;
}
if ( !isWritable() ) { // writing not permitted
qWarning( "QBuffer::writeBlock: Write operation not permitted" );
return -1;
}
#endif
if ( (uint)ioIndex + len >= a_len ) { // overflow
uint new_len = a_len + a_inc*(((uint)ioIndex+len-a_len)/a_inc+1);
if ( !a.resize( new_len ) ) { // could not resize
#if defined(CHECK_NULL)
qWarning( "QBuffer::writeBlock: Memory allocation error" );
#endif
setStatus( IO_ResourceError );
return -1;
}
a_inc *= 2; // double increment
a_len = new_len;
a.shd->len = (uint)ioIndex + len;
}
memcpy( a.data()+ioIndex, p, len );
ioIndex += len;
if ( a.shd->len < (uint)ioIndex )
a.shd->len = (uint)ioIndex; // fake (not alloc'd) length
return len;
}
/*!
\reimp
*/
int QBuffer::readLine( char *p, uint maxlen )
{
#if defined(CHECK_STATE)
CHECK_PTR( p );
if ( !isOpen() ) { // buffer not open
qWarning( "QBuffer::readLine: Buffer not open" );
return -1;
}
if ( !isReadable() ) { // reading not permitted
qWarning( "QBuffer::readLine: Read operation not permitted" );
return -1;
}
#endif
if ( maxlen == 0 )
return 0;
uint start = (uint)ioIndex;
char *d = a.data() + ioIndex;
maxlen--; // make room for 0-terminator
if ( a.size() - (uint)ioIndex < maxlen )
maxlen = a.size() - (uint)ioIndex;
while ( maxlen-- ) {
if ( (*p++ = *d++) == '\n' )
break;
}
*p = '\0';
ioIndex = (int)(d - a.data());
return (uint)ioIndex - start;
}
/*!
\reimp
*/
int QBuffer::getch()
{
#if defined(CHECK_STATE)
if ( !isOpen() ) { // buffer not open
qWarning( "QBuffer::getch: Buffer not open" );
return -1;
}
if ( !isReadable() ) { // reading not permitted
qWarning( "QBuffer::getch: Read operation not permitted" );
return -1;
}
#endif
if ( (uint)ioIndex+1 > a.size() ) { // overflow
setStatus( IO_ReadError );
return -1;
}
return uchar(*(a.data()+ioIndex++));
}
/*!
\reimp
Writes the character \a ch into the buffer, overwriting
the character at the current index, extending the buffer
if necessary.
Returns \a ch, or -1 if some error occurred.
\sa getch(), ungetch()
*/
int QBuffer::putch( int ch )
{
#if defined(CHECK_STATE)
if ( !isOpen() ) { // buffer not open
qWarning( "QBuffer::putch: Buffer not open" );
return -1;
}
if ( !isWritable() ) { // writing not permitted
qWarning( "QBuffer::putch: Write operation not permitted" );
return -1;
}
#endif
if ( (uint)ioIndex + 1 >= a_len ) { // overflow
char buf[1];
buf[0] = (char)ch;
if ( writeBlock(buf,1) != 1 )
return -1; // write error
} else {
*(a.data() + ioIndex++) = (char)ch;
if ( a.shd->len < (uint)ioIndex )
a.shd->len = (uint)ioIndex;
}
return ch;
}
/*!
\reimp
*/
int QBuffer::ungetch( int ch )
{
#if defined(CHECK_STATE)
if ( !isOpen() ) { // buffer not open
qWarning( "QBuffer::ungetch: Buffer not open" );
return -1;
}
if ( !isReadable() ) { // reading not permitted
qWarning( "QBuffer::ungetch: Read operation not permitted" );
return -1;
}
#endif
if ( ch != -1 ) {
if ( ioIndex )
ioIndex--;
else
ch = -1;
}
return ch;
}