mirror of https://github.com/FFmpeg/FFmpeg.git
This can be useful in other places, e.g. it can replace objpool in fftools. The API is modified in the following nontrivial ways: * opaque pointers can be passed through to all user callbacks * read and write were previously separate callbacks in order to accomodate the caller wishing to write a new reference to the FIFO and keep the original one; the two callbacks are now merged into one, and a flags argument is added that allows to request such behaviour on a per-call basis * new peek and drain functionspull/391/head
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9 changed files with 215 additions and 145 deletions
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/*
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#ifndef AVCODEC_CONTAINER_FIFO_H |
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#define AVCODEC_CONTAINER_FIFO_H |
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#include <stddef.h> |
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/**
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* ContainerFifo is a FIFO for "containers" - dynamically allocated reusable |
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* structs (e.g. AVFrame or AVPacket). ContainerFifo uses an internal pool of |
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* such containers to avoid allocating and freeing them repeatedly. |
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*/ |
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typedef struct ContainerFifo ContainerFifo; |
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/**
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* Allocate a new ContainerFifo for the container type defined by provided |
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* callbacks. |
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* |
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* @param container_alloc allocate a new container instance and return a pointer |
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* to it, or NULL on failure |
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* @param container_reset reset the provided container instance to a clean state |
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* @param container_free free the provided container instance |
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* @param fifo_write transfer the contents of src to dst, where src is a |
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* container instance provided to ff_container_fifo_write() |
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* @param fifo_read transfer the contents of src to dst in other cases |
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* |
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* @note fifo_read() and fifo_write() are different parameters in order to allow |
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* fifo_write() implementations that make a new reference in dst, leaving |
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* src untouched (see e.g. ff_container_fifo_alloc_avframe()) |
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*/ |
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ContainerFifo* |
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ff_container_fifo_alloc(void* (*container_alloc)(void), |
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void (*container_reset)(void *obj), |
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void (*container_free) (void *obj), |
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int (*fifo_write) (void *dst, void *src), |
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int (*fifo_read) (void *dst, void *src)); |
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/**
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* Allocate a ContainerFifo instance for AVFrames. |
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* Note that ff_container_fifo_write() will call av_frame_ref() on src, making a |
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* new reference in dst and leaving src untouched. |
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* |
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* @param flags unused currently |
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*/ |
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ContainerFifo *ff_container_fifo_alloc_avframe(unsigned flags); |
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/**
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* Free a ContainerFifo and everything in it. |
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*/ |
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void ff_container_fifo_free(ContainerFifo **pf); |
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/**
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* Write the contents of obj to the FIFO. |
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* |
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* The fifo_write() callback previously provided to ff_container_fifo_alloc() |
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* will be called with obj as src in order to perform the actual transfer. |
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*/ |
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int ff_container_fifo_write(ContainerFifo *pf, void *obj); |
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/**
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* Read the next available object from the FIFO into obj. |
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* |
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* The fifo_read() callback previously provided to ff_container_fifo_alloc() |
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* will be called with obj as dst in order to perform the actual transfer. |
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*/ |
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int ff_container_fifo_read(ContainerFifo *pf, void *obj); |
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/**
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* @return number of objects available for reading |
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*/ |
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size_t ff_container_fifo_can_read(ContainerFifo *pf); |
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#endif // AVCODEC_CONTAINER_FIFO_H
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@ -0,0 +1,130 @@ |
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/*
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#ifndef AVUTIL_CONTAINER_FIFO_H |
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#define AVUTIL_CONTAINER_FIFO_H |
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#include <stddef.h> |
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/**
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* AVContainerFifo is a FIFO for "containers" - dynamically allocated reusable |
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* structs (e.g. AVFrame or AVPacket). AVContainerFifo uses an internal pool of |
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* such containers to avoid allocating and freeing them repeatedly. |
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*/ |
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typedef struct AVContainerFifo AVContainerFifo; |
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enum AVContainerFifoFlags { |
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/**
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* Signal to av_container_fifo_write() that it should make a new reference |
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* to data in src rather than consume its contents. |
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* |
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* @note you must handle this flag manually in your own fifo_transfer() |
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* callback |
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*/ |
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AV_CONTAINER_FIFO_FLAG_REF = (1 << 0), |
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/**
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* This and all higher bits in flags may be set to any value by the caller |
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* and are guaranteed to be passed through to the fifo_transfer() callback |
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* and not be interpreted by AVContainerFifo code. |
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*/ |
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AV_CONTAINER_FIFO_FLAG_USER = (1 << 16), |
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}; |
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/**
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* Allocate a new AVContainerFifo for the container type defined by provided |
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* callbacks. |
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* |
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* @param opaque user data that will be passed to the callbacks provided to this |
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* function |
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* @param container_alloc allocate a new container instance and return a pointer |
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* to it, or NULL on failure |
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* @param container_reset reset the provided container instance to a clean state |
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* @param container_free free the provided container instance |
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* @param fifo_transfer Transfer the contents of container src to dst. |
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* @param flags currently unused |
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* |
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* @return newly allocated AVContainerFifo, or NULL on failure |
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*/ |
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AVContainerFifo* |
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av_container_fifo_alloc(void *opaque, |
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void* (*container_alloc)(void *opaque), |
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void (*container_reset)(void *opaque, void *obj), |
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void (*container_free) (void *opaque, void *obj), |
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int (*fifo_transfer) (void *opaque, void *dst, void *src, unsigned flags), |
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unsigned flags); |
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/**
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* Allocate an AVContainerFifo instance for AVFrames. |
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* |
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* @param flags currently unused |
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*/ |
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AVContainerFifo *av_container_fifo_alloc_avframe(unsigned flags); |
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/**
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* Free a AVContainerFifo and everything in it. |
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*/ |
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void av_container_fifo_free(AVContainerFifo **cf); |
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/**
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* Write the contents of obj to the FIFO. |
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* |
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* The fifo_transfer() callback previously provided to av_container_fifo_alloc() |
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* will be called with obj as src in order to perform the actual transfer. |
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*/ |
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int av_container_fifo_write(AVContainerFifo *cf, void *obj, unsigned flags); |
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/**
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* Read the next available object from the FIFO into obj. |
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* |
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* The fifo_read() callback previously provided to av_container_fifo_alloc() |
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* will be called with obj as dst in order to perform the actual transfer. |
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*/ |
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int av_container_fifo_read(AVContainerFifo *cf, void *obj, unsigned flags); |
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/**
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* Access objects stored in the FIFO without retrieving them. The |
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* fifo_transfer() callback will NOT be invoked and the FIFO state will not be |
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* modified. |
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* |
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* @param pobj Pointer to the object stored in the FIFO will be written here on |
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* success. The object remains owned by the FIFO and the caller may |
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* only access it as long as the FIFO is not modified. |
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* @param offset Position of the object to retrieve - 0 is the next item that |
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* would be read, 1 the one after, etc. Must be smaller than |
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* av_container_fifo_can_read(). |
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* |
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* @retval 0 success, a pointer was written into pobj |
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* @retval AVERROR(EINVAL) invalid offset value |
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*/ |
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int av_container_fifo_peek(AVContainerFifo *cf, void **pobj, size_t offset); |
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/**
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* Discard the specified number of elements from the FIFO. |
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* |
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* @param nb_elems number of elements to discard, MUST NOT be larger than |
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* av_fifo_can_read(f) |
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*/ |
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void av_container_fifo_drain(AVContainerFifo *cf, size_t nb_elems); |
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/**
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* @return number of objects available for reading |
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*/ |
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size_t av_container_fifo_can_read(const AVContainerFifo *cf); |
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#endif // AVCODEC_CONTAINER_FIFO_H
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