15d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)// Copyright 2014 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)#ifndef MEDIA_FORMATS_COMMON_OFFSET_BYTE_QUEUE_H_ 65d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)#define MEDIA_FORMATS_COMMON_OFFSET_BYTE_QUEUE_H_ 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/basictypes.h" 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "media/base/byte_queue.h" 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "media/base/media_export.h" 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace media { 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A wrapper around a ByteQueue which maintains a notion of a 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// monotonically-increasing offset. All buffer access is done by passing these 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// offsets into this class, going some way towards preventing the proliferation 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// of many different meanings of "offset", "head", etc. 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class MEDIA_EXPORT OffsetByteQueue { 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) OffsetByteQueue(); 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ~OffsetByteQueue(); 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // These work like their underlying ByteQueue counterparts. 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Reset(); 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Push(const uint8* buf, int size); 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Peek(const uint8** buf, int* size); 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Pop(int count); 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Sets |buf| to point at the first buffered byte corresponding to |offset|, 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // and |size| to the number of bytes available starting from that offset. 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // It is an error if the offset is before the current head. It's not an error 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // if the current offset is beyond tail(), but you will of course get back 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // a null |buf| and a |size| of zero. 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void PeekAt(int64 offset, const uint8** buf, int* size); 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Marks the bytes up to (but not including) |max_offset| as ready for 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // deletion. This is relatively inexpensive, but will not necessarily reduce 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // the resident buffer size right away (or ever). 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns true if the full range of bytes were successfully trimmed, 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // including the case where |max_offset| is less than the current head. 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns false if |max_offset| > tail() (although all bytes currently 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // buffered are still cleared). 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool Trim(int64 max_offset); 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The head and tail positions, in terms of the file's absolute offsets. 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // tail() is an exclusive bound. 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int64 head() { return head_; } 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int64 tail() { return head_ + size_; } 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Synchronize |buf_| and |size_| with |queue_|. 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Sync(); 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ByteQueue queue_; 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const uint8* buf_; 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int size_; 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int64 head_; 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(OffsetByteQueue); 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace media 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 665d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)#endif // MEDIA_FORMATS_COMMON_OFFSET_BYTE_QUEUE_H_ 67