IPWorksS3Stream Type

Syntax

IPWorksS3Stream (declared in ipworkss3.h)

Remarks

The S3Client class includes one or more API members that take a stream object as a parameter. To use such API members, create a concrete class that implements the IPWorksS3Stream interface and pass the S3Client class an instance of that concrete class.

When implementing the IPWorksS3Stream interface's properties and methods, they must behave as described below. If the concrete class's implementation does not behave as expected, undefined behavior may occur.

Properties

CanRead Whether the stream supports reading.

bool CanRead() { return true; }
CanSeek Whether the stream supports seeking.

bool CanSeek() { return true; }
CanWrite Whether the stream supports writing.

bool CanWrite() { return true; }
Length Gets the length of the stream, in bytes.

int64 GetLength() = 0;

Methods

Close Closes the stream, releasing all resources currently allocated for it.

void Close() {}

This method is called automatically when an IPWorksS3Stream object is deleted.

Flush Forces all data held by the stream's buffers to be written out to storage.

int Flush() { return 0; }

Must return 0 if flushing is successful; or -1 if an error occurs or the stream is closed. If the stream does not support writing, this method must do nothing and return 0.

Read Reads a sequence of bytes from the stream and advances the current position within the stream by the number of bytes read.

int Read(void* buffer, int count) = 0;

Buffer specifies the buffer to populate with data from the stream. Count specifies the number of bytes that should be read from the stream.

Must return the total number of bytes read into Buffer; this may be less than Count if that many bytes are not currently available, or 0 if the end of the stream has been reached. Must return -1 if an error occurs, if reading is not supported, or if the stream is closed.

Seek Sets the current position within the stream based on a particular point of origin.

int64 Seek(int64 offset, int seekOrigin) = 0;

Offset specifies the offset in the stream to seek to, relative to SeekOrigin. Valid values for SeekOrigin are:

  • 0: Seek from beginning.
  • 1: Seek from current position.
  • 2: Seek from end.

Must return the new position within the stream; or -1 if an error occurs, if seeking is not supported, or if the stream is closed (however, see note below). If -1 is returned, the current position within the stream must remain unchanged.

Note: If the stream is not closed, it must always be possible to call this method with an Offset of 0 and a SeekOrigin of 1 to obtain the current position within the stream, even if seeking is not otherwise supported.

Write Writes a sequence of bytes to the stream and advances the current position within the stream by the number of bytes written.

int Write(const void* buffer, int count) = 0;

Buffer specifies the buffer with data to write to the stream. Count specifies the number of bytes that should be written to the stream.

Must return the total number of bytes written to the stream; this may be less than Count if that many bytes could not be written. Must return -1 if an error occurs, if writing is not supported, or if the stream is closed.

Copyright (c) 2022 /n software inc. - All rights reserved.
IPWorks S3 2020 C++ Edition - Version 20.0 [Build 8164]