FFmpeg
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  */
57 
58 /**
59  * Free an AVFifoBuffer and reset pointer to NULL.
60  * @param f AVFifoBuffer to free
61  */
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 at specific position 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 offset offset from current read position
91  * @param buf_size number of bytes to read
92  * @param func generic read function
93  * @param dest data destination
94  */
95 int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void (*func)(void*, void*, int));
96 
97 /**
98  * Feed data from an AVFifoBuffer to a user-supplied callback.
99  * Similar as av_fifo_gereric_read but without discarding data.
100  * @param f AVFifoBuffer to read from
101  * @param buf_size number of bytes to read
102  * @param func generic read function
103  * @param dest data destination
104  */
105 int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
106 
107 /**
108  * Feed data from an AVFifoBuffer to a user-supplied callback.
109  * @param f AVFifoBuffer to read from
110  * @param buf_size number of bytes to read
111  * @param func generic read function
112  * @param dest data destination
113  */
114 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
115 
116 /**
117  * Feed data from a user-supplied callback to an AVFifoBuffer.
118  * @param f AVFifoBuffer to write to
119  * @param src data source; non-const since it may be used as a
120  * modifiable context by the function defined in func
121  * @param size number of bytes to write
122  * @param func generic write function; the first parameter is src,
123  * the second is dest_buf, the third is dest_buf_size.
124  * func must return the number of bytes written to dest_buf, or <= 0 to
125  * indicate no more data available to write.
126  * If func is NULL, src is interpreted as a simple byte array for source data.
127  * @return the number of bytes written to the FIFO
128  */
129 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
130 
131 /**
132  * Resize an AVFifoBuffer.
133  * In case of reallocation failure, the old FIFO is kept unchanged.
134  *
135  * @param f AVFifoBuffer to resize
136  * @param size new AVFifoBuffer size in bytes
137  * @return <0 for failure, >=0 otherwise
138  */
139 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
140 
141 /**
142  * Enlarge an AVFifoBuffer.
143  * In case of reallocation failure, the old FIFO is kept unchanged.
144  * The new fifo size may be larger than the requested size.
145  *
146  * @param f AVFifoBuffer to resize
147  * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
148  * @return <0 for failure, >=0 otherwise
149  */
150 int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);
151 
152 /**
153  * Read and discard the specified amount of data from an AVFifoBuffer.
154  * @param f AVFifoBuffer to read from
155  * @param size amount of data to read in bytes
156  */
157 void av_fifo_drain(AVFifoBuffer *f, int size);
158 
159 /**
160  * Return a pointer to the data stored in a FIFO buffer at a certain offset.
161  * The FIFO buffer is not modified.
162  *
163  * @param f AVFifoBuffer to peek at, f must be non-NULL
164  * @param offs an offset in bytes, its absolute value must be less
165  * than the used buffer size or the returned pointer will
166  * point outside to the buffer data.
167  * The used buffer size can be checked with av_fifo_size().
168  */
169 static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
170 {
171  uint8_t *ptr = f->rptr + offs;
172  if (ptr >= f->end)
173  ptr = f->buffer + (ptr - f->end);
174  else if (ptr < f->buffer)
175  ptr = f->end - (f->buffer - ptr);
176  return ptr;
177 }
178 
179 #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:213
int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size)
Resize an AVFifoBuffer.
Definition: fifo.c:87
Convenience header that includes libavutil&#39;s core.
#define src
Definition: vp8dsp.c:254
uint32_t rndx
Definition: fifo.h:34
Macro definitions for various function/variable attributes.
int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void(*func)(void *, void *, int))
Feed data at specific position from an AVFifoBuffer to a user-supplied callback.
Definition: fifo.c:151
uint8_t
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
#define f(width, name)
Definition: cbs_vp9.c:255
AVFifoBuffer * av_fifo_alloc(unsigned int size)
Initialize an AVFifoBuffer.
Definition: fifo.c:43
ptrdiff_t size
Definition: opengl_enc.c:100
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:169
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:189
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
int(* func)(AVBPrint *dst, const char *in, const char *arg)
Definition: jacosubdec.c:67
uint8_t * buffer
Definition: fifo.h:32
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:233
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:101