Wraps another input stream, and reads from a specific part of it. More...
Inherits InputStream.
Public Member Functions | |
| SubregionStream (InputStream *sourceStream, int64 startPositionInSourceStream, int64 lengthOfSourceStream, bool deleteSourceWhenDestroyed) | |
| Creates a SubregionStream from an input source. | |
| ~SubregionStream () | |
| Destructor. | |
| int64 | getTotalLength () |
| Returns the total number of bytes available for reading in this stream. | |
| int64 | getPosition () |
| Returns the offset of the next byte that will be read from the stream. | |
| bool | setPosition (int64 newPosition) |
| Tries to move the current read position of the stream. | |
| int | read (void *destBuffer, int maxBytesToRead) |
| Reads a set of bytes from the stream into a memory buffer. | |
| bool | isExhausted () |
| Returns true if the stream has no more data to read. | |
Wraps another input stream, and reads from a specific part of it.
This lets you take a subsection of a stream and present it as an entire stream in its own right.
| SubregionStream::SubregionStream | ( | InputStream * | sourceStream, |
| int64 | startPositionInSourceStream, | ||
| int64 | lengthOfSourceStream, | ||
| bool | deleteSourceWhenDestroyed | ||
| ) |
Creates a SubregionStream from an input source.
| sourceStream | the source stream to read from |
| startPositionInSourceStream | this is the position in the source stream that corresponds to position 0 in this stream |
| lengthOfSourceStream | this specifies the maximum number of bytes from the source stream that will be passed through by this stream. When the position of this stream exceeds lengthOfSourceStream, it will cause an end-of-stream. If the length passed in here is greater than the length of the source stream (as returned by getTotalLength()), then the smaller value will be used. Passing a negative value for this parameter means it will keep reading until the source's end-of-stream. |
| deleteSourceWhenDestroyed | whether the sourceStream that is passed in should be deleted by this object when it is itself deleted. |
| SubregionStream::~SubregionStream | ( | ) |
Destructor.
This may also delete the source stream, if that option was chosen when the buffered stream was created.
| int64 SubregionStream::getTotalLength | ( | ) | [virtual] |
Returns the total number of bytes available for reading in this stream.
Note that this is the number of bytes available from the start of the stream, not from the current position.
If the size of the stream isn't actually known, this may return -1.
Implements InputStream.
| int64 SubregionStream::getPosition | ( | ) | [virtual] |
Returns the offset of the next byte that will be read from the stream.
Implements InputStream.
| bool SubregionStream::setPosition | ( | int64 | newPosition ) | [virtual] |
Tries to move the current read position of the stream.
The position is an absolute number of bytes from the stream's start.
Some streams might not be able to do this, in which case they should do nothing and return false. Others might be able to manage it by resetting themselves and skipping to the correct position, although this is obviously a bit slow.
Implements InputStream.
| int SubregionStream::read | ( | void * | destBuffer, |
| int | maxBytesToRead | ||
| ) | [virtual] |
Reads a set of bytes from the stream into a memory buffer.
This is the only read method that subclasses actually need to implement, as the InputStream base class implements the other read methods in terms of this one (although it's often more efficient for subclasses to implement them directly).
| destBuffer | the destination buffer for the data |
| maxBytesToRead | the maximum number of bytes to read - make sure the memory block passed in is big enough to contain this many bytes. |
Implements InputStream.
| bool SubregionStream::isExhausted | ( | ) | [virtual] |
Returns true if the stream has no more data to read.
Implements InputStream.
