On date Saturday 2011-07-16 17:00:59 +0200, Diego Biurrun encoded: > On Sat, Jul 16, 2011 at 10:25:58AM +0200, Stefano Sabatini wrote: > > > > --- a/libavutil/fifo.h > > +++ b/libavutil/fifo.h > > @@ -106,11 +107,34 @@ int av_fifo_realloc2(AVFifoBuffer *f, unsigned int > > size); > > > > +/** > > + * Return a pointer to the data stored in a FIFO buffer at a certain > > offset. > > + * The FIFO buffer is not modified. > > + * > > + * @param f pointer to the FIFO buffer to peek at, must be non-NULL > > So every caller must check for NULL?
Yes, this is consistent with the rest of the av_fifo_* API, and most part of libav*, so I don't know if it is a good idea to add a NULL check here. > > + * @param offs an offset in bytes, its absolute value must be less > > + * than the used buffer size or the returned pointer will point > > + * outside to the buffer data > > How would the caller know the used buffer size? Added a note about av_fifo_size(). > Vertical alignment would help make this more readable. Updated.
>From d5b9a012308a766de5ef27ec1c7f4a431bd50f13 Mon Sep 17 00:00:00 2001 From: Stefano Sabatini <[email protected]> Date: Wed, 29 Jun 2011 17:30:23 +0200 Subject: [PATCH] fifo: add av_fifo_peek2(), and deprecate av_fifo_peek() The new function provides a more generic interface than av_fifo_peek() for peeking at a FIFO buffer data. --- doc/APIchanges | 3 +++ libavformat/dvenc.c | 4 ++-- libavutil/avutil.h | 3 +++ libavutil/fifo.h | 31 ++++++++++++++++++++++++++++--- 4 files changed, 36 insertions(+), 5 deletions(-) diff --git a/doc/APIchanges b/doc/APIchanges index c533818..f7f604b 100644 --- a/doc/APIchanges +++ b/doc/APIchanges @@ -13,6 +13,9 @@ libavutil: 2011-04-18 API changes, most recent first: +2011-07-XX - xxxxxx - lavu 52.X.0 + Add av_fifo_peek2(), deprecate av_fifo_peek(). + 2011-07-10 - a67c061 - lavf 53.3.0 Add avformat_find_stream_info(), deprecate av_find_stream_info(). diff --git a/libavformat/dvenc.c b/libavformat/dvenc.c index 5aab683..d1cca9e 100644 --- a/libavformat/dvenc.c +++ b/libavformat/dvenc.c @@ -192,8 +192,8 @@ static void dv_inject_audio(DVMuxContext *c, int channel, uint8_t* frame_ptr) if (of*2 >= size) continue; - frame_ptr[d] = av_fifo_peek(c->audio_data[channel], of*2+1); // FIXME: maybe we have to admit - frame_ptr[d+1] = av_fifo_peek(c->audio_data[channel], of*2); // that DV is a big-endian PCM + frame_ptr[d] = *av_fifo_peek2(c->audio_data[channel], of*2+1); // FIXME: maybe we have to admit + frame_ptr[d+1] = *av_fifo_peek2(c->audio_data[channel], of*2); // that DV is a big-endian PCM } frame_ptr += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */ } diff --git a/libavutil/avutil.h b/libavutil/avutil.h index 01e4e2f..dd75b8d 100644 --- a/libavutil/avutil.h +++ b/libavutil/avutil.h @@ -63,6 +63,9 @@ #ifndef FF_API_FIND_OPT #define FF_API_FIND_OPT (LIBAVUTIL_VERSION_MAJOR < 52) #endif +#ifndef FF_API_AV_FIFO_PEEK +#define FF_API_AV_FIFO_PEEK (LIBAVUTIL_VERSION_MAJOR < 52) +#endif /** * Return the LIBAVUTIL_VERSION_INT constant. diff --git a/libavutil/fifo.h b/libavutil/fifo.h index cd361b0..771ce3e 100644 --- a/libavutil/fifo.h +++ b/libavutil/fifo.h @@ -25,6 +25,7 @@ #define AVUTIL_FIFO_H #include <stdint.h> +#include "avutil.h" typedef struct AVFifoBuffer { uint8_t *buffer; @@ -106,11 +107,35 @@ int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size); */ void av_fifo_drain(AVFifoBuffer *f, int size); -static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs) +/** + * Return a pointer to the data stored in a FIFO buffer at a certain offset. + * The FIFO buffer is not modified. + * + * @param *f AVFifoBuffer to peek at, f must be non-NULL + * @param offs an offset in bytes, its absolute value must be less + * than the used buffer size or the returned pointer will + * point outside to the buffer data. + * The used buffer size can be checked with av_fifo_size(). + */ +static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs) { uint8_t *ptr = f->rptr + offs; if (ptr >= f->end) - ptr -= f->end - f->buffer; - return *ptr; + ptr = f->buffer + (ptr - f->end); + else if (ptr < f->buffer) + ptr = f->end - (f->buffer - ptr); + return ptr; } + +#if FF_API_AV_FIFO_PEEK +/** + * @deprecated Use av_fifo_peek2() instead. + */ +attribute_deprecated +static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs) +{ + return *av_fifo_peek2(f, offs); +} +#endif + #endif /* AVUTIL_FIFO_H */ -- 1.7.2.5
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