Anoter try to make +- behave sanely.

Originally committed as revision 13281 to svn://svn.ffmpeg.org/ffmpeg/trunk
17 years ago · 9d2e6e84ce
parent ebea1d7668
commit 9d2e6e84ce
1 changed files with 4 additions and 2 deletions
--- a/libavcodec/opt.c
+++ b/libavcodec/opt.c
@ -146,6 +146,7 @@ const AVOption *av_set_string(void *obj, const char *name, const char *val){
        return o;
    }
    if(o->type != FF_OPT_TYPE_STRING){
+        int notfirst=0;
        for(;;){
            int i;
            char buf[256];
@ -180,8 +181,8 @@ const AVOption *av_set_string(void *obj, const char *name, const char *val){
                if     (cmd=='+') d= av_get_int(obj, name, NULL) | (int64_t)d;
                else if(cmd=='-') d= av_get_int(obj, name, NULL) &~(int64_t)d;
            }else{
-                if     (cmd=='+') d= av_get_double(obj, name, NULL) + d;
-                else if(cmd=='-') d= av_get_double(obj, name, NULL) - d;
+                if     (cmd=='+') d= notfirst*av_get_double(obj, name, NULL) + d;
+                else if(cmd=='-') d= notfirst*av_get_double(obj, name, NULL) - d;
            }

            if (!av_set_number(obj, name, d, 1, 1))
@ -189,6 +190,7 @@ const AVOption *av_set_string(void *obj, const char *name, const char *val){
            val+= i;
            if(!*val)
                return o;
+            notfirst=1;
        }
        return NULL;
    }