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fifo.h
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 /**
20  * @file
21  * a very simple circular buffer FIFO implementation
22  */
23 
24 #ifndef AVUTIL_FIFO_H
25 #define AVUTIL_FIFO_H
26 
27 #include <stdint.h>
28 #include "avutil.h"
29 #include "attributes.h"
30 
31 typedef struct AVFifoBuffer {
34  uint32_t rndx, wndx;
35 } AVFifoBuffer;
36 
37 /**
38  * Initialize an AVFifoBuffer.
39  * @param size of FIFO
40  * @return AVFifoBuffer or NULL in case of memory allocation failure
41  */
42 AVFifoBuffer *av_fifo_alloc(unsigned int size);
43 
44 /**
45  * Initialize an AVFifoBuffer.
46  * @param nmemb number of elements
47  * @param size size of the single element
48  * @return AVFifoBuffer or NULL in case of memory allocation failure
49  */
50 AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size);
51 
52 /**
53  * Free an AVFifoBuffer.
54  * @param f AVFifoBuffer to free
55  */
56 void av_fifo_free(AVFifoBuffer *f);
57 
58 /**
59  * Free an AVFifoBuffer and reset pointer to NULL.
60  * @param f AVFifoBuffer to free
61  */
62 void av_fifo_freep(AVFifoBuffer **f);
63 
64 /**
65  * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
66  * @param f AVFifoBuffer to reset
67  */
69 
70 /**
71  * Return the amount of data in bytes in the AVFifoBuffer, that is the
72  * amount of data you can read from it.
73  * @param f AVFifoBuffer to read from
74  * @return size
75  */
76 int av_fifo_size(const AVFifoBuffer *f);
77 
78 /**
79  * Return the amount of space in bytes in the AVFifoBuffer, that is the
80  * amount of data you can write into it.
81  * @param f AVFifoBuffer to write into
82  * @return size
83  */
84 int av_fifo_space(const AVFifoBuffer *f);
85 
86 /**
87  * Feed data from an AVFifoBuffer to a user-supplied callback.
88  * Similar as av_fifo_gereric_read but without discarding data.
89  * @param f AVFifoBuffer to read from
90  * @param buf_size number of bytes to read
91  * @param func generic read function
92  * @param dest data destination
93  */
94 int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
95 
96 /**
97  * Feed data from an AVFifoBuffer to a user-supplied callback.
98  * @param f AVFifoBuffer to read from
99  * @param buf_size number of bytes to read
100  * @param func generic read function
101  * @param dest data destination
102  */
103 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
104 
105 /**
106  * Feed data from a user-supplied callback to an AVFifoBuffer.
107  * @param f AVFifoBuffer to write to
108  * @param src data source; non-const since it may be used as a
109  * modifiable context by the function defined in func
110  * @param size number of bytes to write
111  * @param func generic write function; the first parameter is src,
112  * the second is dest_buf, the third is dest_buf_size.
113  * func must return the number of bytes written to dest_buf, or <= 0 to
114  * indicate no more data available to write.
115  * If func is NULL, src is interpreted as a simple byte array for source data.
116  * @return the number of bytes written to the FIFO
117  */
118 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
119 
120 /**
121  * Resize an AVFifoBuffer.
122  * In case of reallocation failure, the old FIFO is kept unchanged.
123  *
124  * @param f AVFifoBuffer to resize
125  * @param size new AVFifoBuffer size in bytes
126  * @return <0 for failure, >=0 otherwise
127  */
128 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
129 
130 /**
131  * Enlarge an AVFifoBuffer.
132  * In case of reallocation failure, the old FIFO is kept unchanged.
133  * The new fifo size may be larger than the requested size.
134  *
135  * @param f AVFifoBuffer to resize
136  * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
137  * @return <0 for failure, >=0 otherwise
138  */
139 int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);
140 
141 /**
142  * Read and discard the specified amount of data from an AVFifoBuffer.
143  * @param f AVFifoBuffer to read from
144  * @param size amount of data to read in bytes
145  */
146 void av_fifo_drain(AVFifoBuffer *f, int size);
147 
148 /**
149  * Return a pointer to the data stored in a FIFO buffer at a certain offset.
150  * The FIFO buffer is not modified.
151  *
152  * @param f AVFifoBuffer to peek at, f must be non-NULL
153  * @param offs an offset in bytes, its absolute value must be less
154  * than the used buffer size or the returned pointer will
155  * point outside to the buffer data.
156  * The used buffer size can be checked with av_fifo_size().
157  */
158 static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
159 {
160  uint8_t *ptr = f->rptr + offs;
161  if (ptr >= f->end)
162  ptr = f->buffer + (ptr - f->end);
163  else if (ptr < f->buffer)
164  ptr = f->end - (f->buffer - ptr);
165  return ptr;
166 }
167 
168 #endif /* AVUTIL_FIFO_H */
uint8_t * wptr
Definition: fifo.h:33
int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void(*func)(void *, void *, int))
Feed data from an AVFifoBuffer to a user-supplied callback.
Definition: fifo.c:177
int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size)
Resize an AVFifoBuffer.
Definition: fifo.c:87
external API header
uint32_t rndx
Definition: fifo.h:34
Macro definitions for various function/variable attributes.
uint8_t
AVFifoBuffer * av_fifo_alloc(unsigned int size)
Initialize an AVFifoBuffer.
Definition: fifo.c:43
ptrdiff_t size
Definition: opengl_enc.c:101
int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int(*func)(void *, void *, int))
Feed data from a user-supplied callback to an AVFifoBuffer.
Definition: fifo.c:122
int av_fifo_size(const AVFifoBuffer *f)
Return the amount of data in bytes in the AVFifoBuffer, that is the amount of data you can read from ...
Definition: fifo.c:77
static uint8_t * av_fifo_peek2(const AVFifoBuffer *f, int offs)
Return a pointer to the data stored in a FIFO buffer at a certain offset.
Definition: fifo.h:158
void av_fifo_freep(AVFifoBuffer **f)
Free an AVFifoBuffer and reset pointer to NULL.
Definition: fifo.c:63
uint8_t * end
Definition: fifo.h:33
AVFifoBuffer * av_fifo_alloc_array(size_t nmemb, size_t size)
Initialize an AVFifoBuffer.
Definition: fifo.c:49
uint8_t * rptr
Definition: fifo.h:33
int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void(*func)(void *, void *, int))
Feed data from an AVFifoBuffer to a user-supplied callback.
Definition: fifo.c:151
AVS_Value src
Definition: avisynth_c.h:482
int av_fifo_space(const AVFifoBuffer *f)
Return the amount of space in bytes in the AVFifoBuffer, that is the amount of data you can write int...
Definition: fifo.c:82
uint8_t * buffer
Definition: fifo.h:32
int(* func)(AVBPrint *dst, const char *in, const char *arg)
Definition: jacosubdec.c:67
void av_fifo_free(AVFifoBuffer *f)
Free an AVFifoBuffer.
Definition: fifo.c:55
int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space)
Enlarge an AVFifoBuffer.
Definition: fifo.c:107
uint32_t wndx
Definition: fifo.h:34
void av_fifo_drain(AVFifoBuffer *f, int size)
Read and discard the specified amount of data from an AVFifoBuffer.
Definition: fifo.c:197
void av_fifo_reset(AVFifoBuffer *f)
Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied...
Definition: fifo.c:71
GLuint buffer
Definition: opengl_enc.c:102