127 lines
3.5 KiB
C
127 lines
3.5 KiB
C
/*
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* Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
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* Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __PJ_FIFOBUF_H__
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#define __PJ_FIFOBUF_H__
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/**
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* @file fifobuf.h
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* @brief Circular buffer
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*/
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/**
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* @defgroup PJ_FIFOBUF Circular buffer
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* @ingroup PJ_DS
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* @{
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*/
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#include <pj/types.h>
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PJ_BEGIN_DECL
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/**
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* A FIFO buffer provides chunks of memory to the application with first in
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* first out policy (or more correctly, first out first in). The fifobuf is
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* created by providing it with a fixed buffer. After that, application may
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* request chunks of memory from this buffer. When the app is done with a
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* chunk of memory, it must return that chunk back to the fifobuf, with the
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* requirement that the oldest allocated chunk must be returned first.
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*/
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typedef struct pj_fifobuf_t
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{
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/** The start of the buffer */
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char *first;
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/** The end of the buffer */
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char *last;
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/** The start of used area in the buffer */
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char *ubegin;
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/** The end of used area in the buffer */
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char *uend;
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/** Full flag when ubegin==uend */
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int full;
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} pj_fifobuf_t;
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/**
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* Initialize the fifobuf by giving it a buffer and size.
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*
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* @param fb The fifobuf
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* @param buffer Buffer to be used to allocate/free chunks of memory from by
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* the fifo buffer.
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* @param size The size of the buffer.
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*/
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PJ_DECL(void) pj_fifobuf_init(pj_fifobuf_t *fb, void *buffer, unsigned size);
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/**
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* Returns the capacity (initial size) of the buffer.
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*
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* @param fb The fifobuf
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*
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* @return Capacity in bytes.
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*/
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PJ_DECL(unsigned) pj_fifobuf_capacity(pj_fifobuf_t *fb);
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/**
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* Returns maximum size of memory chunk that can be allocated from the buffer.
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*
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* @param fb The fifobuf
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*
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* @return Size in bytes
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*/
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PJ_DECL(unsigned) pj_fifobuf_available_size(pj_fifobuf_t *fb);
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/**
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* Allocate a chunk of memory from the fifobuf.
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*
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* @param fb The fifobuf
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* @param size Size to allocate
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*
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* @return Allocated buffer or NULL if the buffer cannot be allocated
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*/
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PJ_DECL(void*) pj_fifobuf_alloc(pj_fifobuf_t *fb, unsigned size);
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/**
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* Return the space used by the earliest allocated memory chunk back to the
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* fifobuf. For example, if app previously allocated ptr0, ptr1, and ptr2
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* (in that order), then pj_fifobuf_free() can only be called with ptr0 as
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* parameter. Subsequent pj_fifobuf_free() must be called with ptr1, and
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* the next one with ptr2, and so on.
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*
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* @param fb The fifobuf
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* @param buf Pointer to memory chunk previously returned by
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* pj_fifobuf_alloc()
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*
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* @return PJ_SUCCESS or the appropriate error.
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*/
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PJ_DECL(pj_status_t) pj_fifobuf_free(pj_fifobuf_t *fb, void *buf);
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PJ_END_DECL
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/**
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* @} // PJ_FIFOBUF group
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*/
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#endif /* __PJ_FIFOBUF_H__ */
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