[FFmpeg-cvslog] av_opt: add av_opt_ptr() to return a pointer to a field of a object based on
Michael Niedermayer
git at videolan.org
Mon Dec 5 05:04:38 CET 2011
ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sat Dec 3 21:16:46 2011 +0100| [dff97be8084594a0bd900782ca91612680c77bbc] | committer: Michael Niedermayer
av_opt: add av_opt_ptr() to return a pointer to a field of a object based on
an AVClass
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=dff97be8084594a0bd900782ca91612680c77bbc
---
libavutil/opt.c | 8 ++++++++
libavutil/opt.h | 11 +++++++++++
2 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/libavutil/opt.c b/libavutil/opt.c
index 1d7ef38..f0b5deb 100644
--- a/libavutil/opt.c
+++ b/libavutil/opt.c
@@ -806,6 +806,14 @@ const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *pre
return NULL;
}
+void *av_opt_ptr(const AVClass *class, void *obj, const char *name)
+{
+ AVOption *opt= av_opt_find2(&class, name, NULL, 0, AV_OPT_SEARCH_FAKE_OBJ, NULL);
+ if(!opt)
+ return NULL;
+ return (uint8_t*)obj + opt->offset;
+}
+
#ifdef TEST
#undef printf
diff --git a/libavutil/opt.h b/libavutil/opt.h
index 5fce09a..2d282b3 100644
--- a/libavutil/opt.h
+++ b/libavutil/opt.h
@@ -586,6 +586,17 @@ int av_opt_get_double(void *obj, const char *name, int search_flags, double
int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val);
/**
* @}
+ */
+/**
+ * Gets a pointer to the requested field in a struct.
+ * This function allows accessing a struct even when its fields are moved or
+ * renamed since the application making the access has been compiled,
+ *
+ * @returns a pointer to the field, it can be cast to the correct type and read
+ * or written to.
+ */
+void *av_opt_ptr(const AVClass *class, void *obj, const char *name);
+/**
* @}
*/
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