fix error when response parsed by sub filter, then by SSI filter
and some response parts are output as file buffers
diff --git a/src/http/modules/ngx_http_ssi_filter_module.c b/src/http/modules/ngx_http_ssi_filter_module.c
index a855868..d8fc8f3 100644
--- a/src/http/modules/ngx_http_ssi_filter_module.c
+++ b/src/http/modules/ngx_http_ssi_filter_module.c
@@ -558,8 +558,9 @@
                     if (b->in_file) {
                         if (slcf->min_file_chunk < (size_t) (b->last - b->pos))
                         {
-                            b->file_last = b->file_pos + (b->last - b->start);
-                            b->file_pos += b->pos - b->start;
+                            b->file_last = b->file_pos
+                                                   + (b->last - ctx->buf->pos);
+                            b->file_pos += b->pos - ctx->buf->pos;
 
                         } else {
                             b->in_file = 0;
diff --git a/src/http/modules/ngx_http_sub_filter_module.c b/src/http/modules/ngx_http_sub_filter_module.c
index 6a9bb1c..e45ca6e 100644
--- a/src/http/modules/ngx_http_sub_filter_module.c
+++ b/src/http/modules/ngx_http_sub_filter_module.c
@@ -322,8 +322,8 @@
                 b->recycled = 0;
 
                 if (b->in_file) {
-                    b->file_last = b->file_pos + (b->last - b->start);
-                    b->file_pos += b->pos - b->start;
+                    b->file_last = b->file_pos + (b->last - ctx->buf->pos);
+                    b->file_pos += b->pos - ctx->buf->pos;
                 }
 
                 cl->next = NULL;