The type core.io.Buffer is used to store and transfer binary data in the IO library. In particular, it plays a central role when reading from and writing to streams. In addition to this, it can also be used in other contexts where it is necessary to store binary data without attaching a particular meaning to any of the bytes.

A core.io.Buffer is a value and is therefore handled by value. To avoid repeatedly copying large amounts of data, the Buffer implements by-reference semantics internally. This means that making a copy of a Buffer object creates two instances that refer to the same data, just as a class type would behave. Data is, however, copied whenever a buffer is passed between threads in order to avoid shared data. Because of these properties, it is typically a good idea to design interfaces that operate on Buffers to accept a buffer, and return a modified copy of the buffer. If the interface internally operates on and returns the same buffer, no copies will be made. The interface will, however, still function correctly if the system needs to copy data at any point. The IStream and OStream classes are designed according to this idea.

Each Buffer instance stores three things: a buffer large enough for a pre-determined number of bytes, the size of said buffer, and how many bytes are considered used. The number of bytes is ignored by the Buffer itself in most cases, and is rather designed as a convenient ways for other parts of the system to communicate how much of the buffer was actually filled.

The Buffer type has the following members. Note that some of them are implemented as free functions due to technicalities in the interface between Storm and C++. In languages like Basic Storm it is, however, possible to treat them as if they were members anyway.

Member Functions

Free Functions

The following functions are implemented outside of Buffer for technical reasons. Most of them can be considered proper member functions of the Buffer type.