From dff97be8084594a0bd900782ca91612680c77bbc Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 3 Dec 2011 21:16:46 +0100 Subject: [PATCH] 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 --- libavutil/opt.c | 8 ++++++++ libavutil/opt.h | 11 +++++++++++ 2 files changed, 19 insertions(+) diff --git a/libavutil/opt.c b/libavutil/opt.c index 1d7ef38f1a..f0b5deb4f0 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 5fce09a5c8..2d282b3899 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); +/** * @} */