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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_TOOLS_BALSA_BUFFER_INTERFACE_H__
#define NET_TOOLS_BALSA_BUFFER_INTERFACE_H__
namespace net {
class BufferInterface {
public:
// Returns the bytes which can be read from the buffer. There is no
// guarantee that the bytes are contiguous.
virtual int ReadableBytes() const = 0;
// Summary:
// returns the size of this buffer
// Returns:
// size of this buffer.
virtual int BufferSize() const = 0;
// Summary:
// returns the number of bytes free in this buffer.
// Returns:
// number of bytes free.
virtual int BytesFree() const = 0;
// Summary:
// Returns true if empty.
// Returns:
// true - if empty
// false - otherwise
virtual bool Empty() const = 0;
// Summary:
// Returns true if the buffer is full.
virtual bool Full() const = 0;
// Summary:
// returns the number of characters written.
// appends up-to-'size' bytes to the buffer.
// Args:
// bytes - bytes which are read, and copied into the buffer.
// size - number of bytes which are read and copied.
// this number shall be >= 0.
virtual int Write(const char* bytes, int size) = 0;
// Summary:
// Gets a pointer which can be written to (assigned to).
// this pointer (and size) can be used in functions like
// recv() or read(), etc.
// If *size is zero upon returning from this function, that it
// is unsafe to dereference *ptr.
// Args:
// ptr - assigned a pointer to which we can write
// size - the amount of data (in bytes) that it is safe to write to ptr.
virtual void GetWritablePtr(char **ptr, int* size) const = 0;
// Summary:
// Gets a pointer which can be read from
// this pointer (and size) can be used in functions like
// send() or write(), etc.
// If *size is zero upon returning from this function, that it
// is unsafe to dereference *ptr.
// Args:
// ptr - assigned a pointer from which we may read
// size - the amount of data (in bytes) that it is safe to read
virtual void GetReadablePtr(char **ptr, int* size) const = 0;
// Summary:
// Reads bytes out of the buffer, and writes them into 'bytes'.
// Returns the number of bytes read.
// Consumes bytes from the buffer (possibly, but not necessarily
// rendering them free)
// Args:
// bytes - the pointer into which bytes are read from this buffer
// and written into
// size - number of bytes which are read and copied.
// this number shall be >= 0.
// Returns:
// the number of bytes read from 'bytes'
virtual int Read(char* bytes, int size) = 0;
// Summary:
// removes all data from the buffer
virtual void Clear() = 0;
// Summary:
// reserves contiguous writable empty space in the buffer of size bytes.
// Returns true if the reservation is successful.
// If a derive class chooses not to implement reservation, its
// implementation should return false.
virtual bool Reserve(int size) = 0;
// Summary:
// removes the oldest 'amount_to_consume' characters from this buffer,
// Args:
// amount_to_advance - .. this should be self-explanatory =)
// this number shall be >= 0.
virtual void AdvanceReadablePtr(int amount_to_advance) = 0;
// Summary:
// Moves the internal pointers around such that the
// amount of data specified here is expected to
// already be resident (as if it was Written)
// Args:
// amount_to_advance - self explanatory.
// this number shall be >= 0.
virtual void AdvanceWritablePtr(int amount_to_advance) = 0;
virtual ~BufferInterface() {}
protected:
BufferInterface() {}
};
} // namespace net
#endif // NET_TOOLS_BALSA_BUFFER_INTERFACE__H__
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