Add rpmtdDup() method for deep copying of tag containers

lib/rpmtd.c

@@ -205,3 +205,29 @@ int rpmtdFromArgi(rpmtd td, rpmTag tag, ARGI_t argi)
     td->data = argiData(argi);
     return 1;
 }
+
+rpmtd rpmtdDup(rpmtd td)
+{
+    rpmtd newtd = NULL;
+    char **data = NULL;
+    int i;
+    
+    assert(td != NULL);
+    /* TODO: permit other types too */
+    if (td->type != RPM_STRING_ARRAY_TYPE && td->type != RPM_I18NSTRING_TYPE) {
+	return NULL;
+    }
+
+    /* deep-copy container and data, drop immutable flag */
+    newtd = rpmtdNew();
+    memcpy(newtd, td, sizeof(*td));
+    newtd->flags &= ~(RPMTD_IMMUTABLE);
+
+    newtd->flags |= (RPMTD_ALLOCED | RPMTD_PTR_ALLOCED);
+    newtd->data = data = xmalloc(td->count * sizeof(*data));
+    while ((i = rpmtdNext(td)) >= 0) {
+	data[i] = xstrdup(rpmtdGetString(td));
+    }
+
+    return newtd;
+}

lib/rpmtd.h

@@ -179,4 +179,14 @@ int rpmtdFromArgv(rpmtd td, rpmTag tag, ARGV_t argv);
  */
 int rpmtdFromArgi(rpmtd td, rpmTag tag, ARGI_t argi);
 
+/* \ingroup rpmtd
+ * Perform deep copy of container.
+ * Create a modifiable copy of tag data container (on string arrays each
+ * string is separately allocated)
+ * @todo		Only string arrays types are supported currently
+ * @param td		Container to copy
+ * @return		New container or NULL on error
+ */
+rpmtd rpmtdDup(rpmtd td);
+
 #endif /* _RPMTD_H */