constrain sub-image list

ImageMagick · Apr 9, 2021 · c4392ae · c4392ae
1 parent 75c05e1
commit c4392ae
Showing 1 changed file with 2 additions and 14 deletions.
diff --git a/magick/list.c b/magick/list.c
@@ -248,24 +248,12 @@ MagickExport Image *CloneImages(const Image *images,const char *scenes,
 
     while ((isspace((int) ((unsigned char) *p)) != 0) || (*p == ','))
       p++;
-    first=(ssize_t) strtol(p,&p,10);
-    if (first < 0)
-      first+=(ssize_t) length;
-    else
-      if (first > (ssize_t) length)
-        first=(ssize_t) length;
+    first=(ssize_t) strtol(p,&p,10) % (length << 1);
     last=first;
     while (isspace((int) ((unsigned char) *p)) != 0)
       p++;
     if (*p == '-')
-      {
-        last=(ssize_t) strtol(p+1,&p,10);
-        if (last < 0)
-          last+=(ssize_t) length;
-        else
-          if (last > (ssize_t) length)
-            last=(ssize_t) length;
-      }
+      last=(ssize_t) strtol(p+1,&p,10) % (length << 1);
     match=MagickFalse;
     step=1;
     if (artifact != (const char *) NULL)