---
libavutil/fifo.c | 37 +++++++++++++++++++++++++++++++++++++
libavutil/fifo.h | 11 +++++++++++
tests/ref/fate/fifo | 14 ++++++++++++++
3 files changed, 62 insertions(+)
diff --git a/libavutil/fifo.c b/libavutil/fifo.c
index 07fb4ec..cabb009 100644
--- a/libavutil/fifo.c
+++ b/libavutil/fifo.c
@@ -148,6 +148,35 @@ int av_fifo_generic_write(AVFifoBuffer *f, void *src, int
size,
return total - size;
}
+int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int
buf_size, void (*func)(void*, void*, int))
+{
+ uint8_t *rptr = f->rptr + offset;
+ uint32_t rndx = f->rndx + offset;
+
+ av_assert2(offset >= 0);
+ while (buf_size > 0) {
+ int len;
+
+ if (rptr >= f->end)
+ rptr -= f->end - f->buffer;
+
+ av_assert2(rndx < f->wndx);
+ len = FFMIN(f->end - rptr, buf_size);
+ if (func)
+ func(dest, rptr, len);
+ else {
+ memcpy(dest, rptr, len);
+ dest = (uint8_t *)dest + len;
+ }
+
+ buf_size -= len;
+ rptr += len;
+ rndx += len;
+ }
+
+ return 0;
+}
+
int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size,
void (*func)(void *, void *, int))
{
@@ -223,6 +252,14 @@ int main(void)
}
printf("\n");
+ /* peek_at at FIFO */
+ n = av_fifo_size(fifo) / sizeof(int);
+ for (i = 0; i < n; i++) {
+ av_fifo_generic_peek_at(fifo, &j, i * sizeof(int), sizeof(j), NULL);
+ printf("%d: %d\n", i, j);
+ }
+ printf("\n");
+
/* read data */
for (i = 0; av_fifo_size(fifo) >= sizeof(int); i++) {
av_fifo_generic_read(fifo, &j, sizeof(int), NULL);
diff --git a/libavutil/fifo.h b/libavutil/fifo.h
index 0e4070b..dc7bc6f 100644
--- a/libavutil/fifo.h
+++ b/libavutil/fifo.h
@@ -84,6 +84,17 @@ int av_fifo_size(const AVFifoBuffer *f);
int av_fifo_space(const AVFifoBuffer *f);
/**
+ * Feed data at specific position from an AVFifoBuffer to a user-supplied
callback.
+ * Similar as av_fifo_gereric_read but without discarding data.
+ * @param f AVFifoBuffer to read from
+ * @param offset offset from current read position
+ * @param buf_size number of bytes to read
+ * @param func generic read function
+ * @param dest data destination
+ */
+int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int
buf_size, void (*func)(void*, void*, int));
+
+/**
* Feed data from an AVFifoBuffer to a user-supplied callback.
* Similar as av_fifo_gereric_read but without discarding data.
* @param f AVFifoBuffer to read from
diff --git a/tests/ref/fate/fifo b/tests/ref/fate/fifo
index 18a5691..5a59c5a 100644
--- a/tests/ref/fate/fifo
+++ b/tests/ref/fate/fifo
@@ -24,4 +24,18 @@
11: 11
12: 12
+0: 0
+1: 1
+2: 2
+3: 3
+4: 4
+5: 5
+6: 6
+7: 7
+8: 8
+9: 9
+10: 10
+11: 11
+12: 12
+
0 1 2 3 4 5 6 7 8 9 10 11 12
--
2.5.3
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