avutil/opt: add av_opt_copy()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 42 insertions, 0 deletions

diff --git a/libavutil/opt.c b/libavutil/opt.c
index b4dd0fd0c1..694295dc35 100644
--- a/libavutil/opt.c
+++ b/libavutil/opt.c
@@ -1539,6 +1539,48 @@ static int opt_size(enum AVOptionType type)
     return 0;
 }
 
+int av_opt_copy(void *dst, void *src)
+{
+    const AVOption *o = NULL;
+    const AVClass *c;
+    int ret = 0;
+
+    if (!src)
+        return 0;
+
+    c = *(AVClass**)src;
+    if (*(AVClass**)dst && c != *(AVClass**)dst)
+        return AVERROR(EINVAL);
+
+    while ((o = av_opt_next(src, o))) {
+        void *field_dst = ((uint8_t*)dst) + o->offset;
+        void *field_src = ((uint8_t*)src) + o->offset;
+        uint8_t **field_dst8 = (uint8_t**)field_dst;
+        uint8_t **field_src8 = (uint8_t**)field_src;
+
+        if (o->type == AV_OPT_TYPE_STRING) {
+            set_string(dst, o, *field_src8, field_dst8);
+            if (*field_src8 && !*field_dst8)
+                ret = AVERROR(ENOMEM);
+        } else if (o->type == AV_OPT_TYPE_BINARY) {
+            int len = *(int*)(field_src8 + 1);
+            if (*field_dst8 != *field_src8)
+                av_freep(field_dst8);
+            *field_dst8 = av_memdup(*field_src8, len);
+            if (len && !*field_dst8) {
+                ret = AVERROR(ENOMEM);
+                len = 0;
+            }
+            *(int*)(field_dst8 + 1) = len;
+        } else if (o->type == AV_OPT_TYPE_CONST) {
+            // do nothing
+        } else {
+            memcpy(field_dst, field_src, opt_size(o->type));
+        }
+    }
+    return ret;
+}
+
 int av_opt_query_ranges(AVOptionRanges **ranges_arg, void *obj, const char *key, int flags)
 {
     int ret;