src/SDL_dataqueue.h
author Sam Lantinga <slouken@libsdl.org>
Wed, 03 Jan 2018 10:03:25 -0800
changeset 11811 5d94cb6b24d3
parent 11582 cc0b1273a381
child 12503 806492103856
permissions -rw-r--r--
Updated copyright for 2018
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/*
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  Simple DirectMedia Layer
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  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
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  This software is provided 'as-is', without any express or implied
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  warranty.  In no event will the authors be held liable for any damages
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  arising from the use of this software.
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  Permission is granted to anyone to use this software for any purpose,
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  including commercial applications, and to alter it and redistribute it
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  freely, subject to the following restrictions:
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  1. The origin of this software must not be misrepresented; you must not
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     claim that you wrote the original software. If you use this software
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     in a product, an acknowledgment in the product documentation would be
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     appreciated but is not required.
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  2. Altered source versions must be plainly marked as such, and must not be
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     misrepresented as being the original software.
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  3. This notice may not be removed or altered from any source distribution.
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*/
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#ifndef SDL_dataqueue_h_
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#define SDL_dataqueue_h_
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/* this is not (currently) a public API. But maybe it should be! */
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struct SDL_DataQueue;
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typedef struct SDL_DataQueue SDL_DataQueue;
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SDL_DataQueue *SDL_NewDataQueue(const size_t packetlen, const size_t initialslack);
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void SDL_FreeDataQueue(SDL_DataQueue *queue);
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void SDL_ClearDataQueue(SDL_DataQueue *queue, const size_t slack);
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int SDL_WriteToDataQueue(SDL_DataQueue *queue, const void *data, const size_t len);
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size_t SDL_ReadFromDataQueue(SDL_DataQueue *queue, void *buf, const size_t len);
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size_t SDL_PeekIntoDataQueue(SDL_DataQueue *queue, void *buf, const size_t len);
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size_t SDL_CountDataQueue(SDL_DataQueue *queue);
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/* this sets a section of the data queue aside (possibly allocating memory for it)
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   as if it's been written to, but returns a pointer to that space. You may write
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   to this space until a read would consume it. Writes (and other calls to this
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   function) will safely append their data after this reserved space and can
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   be in flight at the same time. There is no thread safety.
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   If there isn't an existing block of memory that can contain the reserved
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   space, one will be allocated for it. You can not (currently) allocate
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   a space larger than the packetlen requested in SDL_NewDataQueue.
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   Returned buffer is uninitialized.
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   This lets you avoid an extra copy in some cases, but it's safer to use
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   SDL_WriteToDataQueue() unless you know what you're doing.
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   Returns pointer to buffer of at least (len) bytes, NULL on error.
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*/
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void *SDL_ReserveSpaceInDataQueue(SDL_DataQueue *queue, const size_t len);
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#endif /* SDL_dataqueue_h_ */
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/* vi: set ts=4 sw=4 expandtab: */
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