Cross-Platform C++

ot::io
class ByteArrayInputStream

#include "ot/io/ByteArrayInputStream.h"

ot::io::InputStream ot::ManagedObject An input stream which uses a byte array as its input source.

See also:
ByteArrayOutputStream



Constructor/Destructor Summary
ByteArrayInputStream(const Byte* pData, size_t dataLen)
         Constructs a ByteArrayInputStream with a copy of the byte array starting at pData for a length of dataLen.

Method Summary
 virtual size_t available()
         Returns the number of bytes that can be read without blocking.
 virtual void close()
         Closes the InputStream.
 virtual void mark(size_t readLimit)
         Marks the current position in the byte stream.
 virtual bool markSupported() const
         Tests whether the ByteArrayInputStream supports the mark() operation, which it does.
 virtual long read(Byte* pBuffer, size_t bufLen)
         Reads up to bufLen bytes into the supplied buffer.
 virtual void reset()
         Resets the position in the byte stream to a previously marked position.

Methods inherited from class ot::io::InputStream
read, skip

Methods inherited from class ot::ManagedObject
addRef, getRefCount, onFinalRelease, operator=, release

Constructor/Destructor Detail

ByteArrayInputStream

 ByteArrayInputStream(const Byte* pData,
                      size_t dataLen)
Constructs a ByteArrayInputStream with a copy of the byte array starting at pData for a length of dataLen.

Exceptions:
NullPointerException - if pData is null.

Method Detail

available

virtual size_t available()
Returns the number of bytes that can be read without blocking. Some data sources (notably network socket and pipe streams) may make bytes available at a rate that is slower than the application can read them. In this case calls to read() may block until at least one byte becomes available. This method may be used to avoid making blocking calls.

Note, however, that the utility of this function is severely limited. Some sub-classes (e.g. FileInputStream) always return zero from available() and zero is also returned when the stream is at the end. For these reasons, it is rarely appropriate for an application to loop waiting for a positive return value from available().

Returns:
the number of bytes that can be read without blocking
Exceptions:
IOException - if an I/O error occurs

close

virtual void close()
Closes the InputStream. Once an InputStream is closed, all system resources associated with the stream are released, preventing any further read(), mark(), reset() or skip() operations. Further calls to close() have no effect.

Exceptions:
IOException - if an I/O error occurs.

mark

virtual void mark(size_t readLimit)
Marks the current position in the byte stream. Subsequent reset() operations will attempt to re-establish the stream's position to the marked position.

Supporting mark() implies that the InputStream must maintain an internal buffer containing all the bytes read from the point at which mark() was called. The size of this buffer is implementation dependent, but is guaranteed to hold at least readLimit bytes before it becomes full. When the buffer limit is exceeded, the marked position is automatically invalidated, with the result that subsequent reset() operations will fail.

Only one mark position is maintained by the InputStream. Further calls to mark() will establish a new mark position; reset() can only reset the position to the most recently established mark position.

Parameters:
readLimit - specifies the minimum number of bytes that the InputStream must return before making the marked position invalid.
Exceptions:
IOException - if the InputStream does not support the mark() operation.
IOException - if the InputStream is closed.
See also:
markSupported() , reset()

markSupported

virtual bool markSupported() const
Tests whether the ByteArrayInputStream supports the mark() operation, which it does.

Returns:
true for ByteArrayInputStream.
See also:
mark() , reset()

read

virtual long read(Byte* pBuffer,
                  size_t bufLen)
Reads up to bufLen bytes into the supplied buffer.

Parameters:
pBuffer - A pointer to the buffer into which the bytes will be copied. This must be capable of holding at least bufLen bytes.
bufLen - The maximum number of bytes to read into the passed buffer. If this exceeds the maximum value that can be represented by a long integer, it is reduced to a value that can be so represented.
Returns:
The number of bytes read or InputStream::EndOfFile if the end of the stream has been reached.
Exceptions:
IllegalArgumentException - if bufLen is zero
NullPointerException - if pBuffer is null
IOException - if an error occurs while reading from the byte stream

reset

virtual void reset()
Resets the position in the byte stream to a previously marked position. It is permitted to call reset() multiple times. Each time it is called, the position will be reset to the position established by the most recent mark() operation.

Exceptions:
IOException - if mark() is not supported
IOException - if the InputStream is closed.
IOException - if mark() was not successfully called or the internal buffer has been exhausted (i.e. the readLimit specified in the mark() call has been exceeded)
See also:
mark()


Cross-Platform C++

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