diff --git a/ngx_http_zip_file.c b/ngx_http_zip_file.c
index 787a5ef..91f7cb4 100644
--- a/ngx_http_zip_file.c
+++ b/ngx_http_zip_file.c
@@ -353,20 +353,30 @@ ngx_http_zip_generate_pieces(ngx_http_request_t *r, ngx_http_zip_ctx_t *ctx)
         if(file->size >= (off_t) NGX_MAX_UINT32_VALUE)
             ctx->zip64_used = file->need_zip64 = 1;
 
-        ctx->cd_size += sizeof(ngx_zip_central_directory_file_header_t) + file->filename.len + sizeof(ngx_zip_extra_field_central_t)
-            + (file->need_zip64_offset ?
-                    (file->need_zip64 ? sizeof(ngx_zip_extra_field_zip64_sizes_offset_t) : sizeof(ngx_zip_extra_field_zip64_offset_only_t)) :
-                    (file->need_zip64 ? sizeof(ngx_zip_extra_field_zip64_sizes_only_t) : 0) +
-                    (ctx->unicode_path && file->filename_utf8.len ? (sizeof(ngx_zip_extra_field_unicode_path_t) + file->filename_utf8.len): 0)
-              );
+        ctx->cd_size += sizeof(ngx_zip_central_directory_file_header_t) + file->filename.len + sizeof(ngx_zip_extra_field_central_t);
+        if (file->need_zip64) {
+            if (file->need_zip64_offset) {
+                ctx->cd_size += sizeof(ngx_zip_extra_field_zip64_sizes_offset_t);
+            } else {
+                ctx->cd_size += sizeof(ngx_zip_extra_field_zip64_sizes_only_t);
+            }
+        } else if (file->need_zip64_offset) {
+            ctx->cd_size += sizeof(ngx_zip_extra_field_zip64_offset_only_t);
+        }
+        if (ctx->unicode_path && file->filename_utf8.len)
+            ctx->cd_size += sizeof(ngx_zip_extra_field_unicode_path_t) + file->filename_utf8.len;
 
         header_piece = &ctx->pieces[piece_i++];
         header_piece->type = zip_header_piece;
         header_piece->file = file;
         header_piece->range.start = offset;
-        header_piece->range.end = offset += sizeof(ngx_zip_local_file_header_t)
-            + file->filename.len + sizeof(ngx_zip_extra_field_local_t) + (file->need_zip64? sizeof(ngx_zip_extra_field_zip64_sizes_only_t):0)
-            + (ctx->unicode_path && file->filename_utf8.len ? (sizeof(ngx_zip_extra_field_unicode_path_t) + file->filename_utf8.len): 0);
+
+        offset += sizeof(ngx_zip_local_file_header_t) + file->filename.len + sizeof(ngx_zip_extra_field_local_t);
+        if (file->need_zip64)
+            offset += sizeof(ngx_zip_extra_field_zip64_sizes_only_t);
+        if (ctx->unicode_path && file->filename_utf8.len)
+            offset += sizeof(ngx_zip_extra_field_unicode_path_t) + file->filename_utf8.len;
+        header_piece->range.end = offset;
 
         file_piece = &ctx->pieces[piece_i++];
         file_piece->type = zip_file_piece;
@@ -417,6 +427,7 @@ ngx_http_zip_file_header_chain_link(ngx_http_request_t *r, ngx_http_zip_ctx_t *c
 {
     ngx_chain_t *link;
     ngx_buf_t   *b;
+    u_char      *p;
 
     ngx_http_zip_file_t *file = piece->file;
     ngx_zip_extra_field_local_t   extra_field_local;
@@ -424,9 +435,11 @@ ngx_http_zip_file_header_chain_link(ngx_http_request_t *r, ngx_http_zip_ctx_t *c
     ngx_zip_local_file_header_t   local_file_header;
     ngx_zip_extra_field_unicode_path_t extra_field_unicode_path;
 
-    size_t len = sizeof(ngx_zip_local_file_header_t) + file->filename.len
-        + sizeof(ngx_zip_extra_field_local_t) + (file->need_zip64? sizeof(ngx_zip_extra_field_zip64_sizes_only_t):0
-        + (ctx->unicode_path && file->filename_utf8.len ? (sizeof(ngx_zip_extra_field_unicode_path_t) + file->filename_utf8.len): 0));
+    size_t len = sizeof(ngx_zip_local_file_header_t) + file->filename.len + sizeof(ngx_zip_extra_field_local_t);
+    if (file->need_zip64)
+        len += sizeof(ngx_zip_extra_field_zip64_sizes_only_t);
+    if (ctx->unicode_path && file->filename_utf8.len)
+        len += sizeof(ngx_zip_extra_field_unicode_path_t) + file->filename_utf8.len;
 
     if ((link = ngx_alloc_chain_link(r->pool)) == NULL || (b = ngx_calloc_buf(r->pool)) == NULL
             || (b->pos = ngx_pcalloc(r->pool, len)) == NULL)
@@ -459,7 +472,8 @@ ngx_http_zip_file_header_chain_link(ngx_http_request_t *r, ngx_http_zip_ctx_t *c
 
     if (file->need_zip64) {
         local_file_header.version = htole16(zip_version_zip64);
-        local_file_header.extra_field_len = sizeof(ngx_zip_extra_field_zip64_sizes_only_t) + sizeof(ngx_zip_extra_field_local_t);
+        local_file_header.extra_field_len += sizeof(ngx_zip_extra_field_zip64_sizes_only_t);
+
         extra_field_zip64.uncompressed_size = extra_field_zip64.compressed_size = htole64(file->size);
     } else {
         local_file_header.compressed_size = htole32(file->size);
@@ -488,21 +502,28 @@ ngx_http_zip_file_header_chain_link(ngx_http_request_t *r, ngx_http_zip_ctx_t *c
     extra_field_local.mtime = htole32(file->unix_time);
     extra_field_local.atime = htole32(file->unix_time);
 
-    ngx_memcpy(b->pos, &local_file_header, sizeof(ngx_zip_local_file_header_t));
-    ngx_memcpy(b->pos + sizeof(ngx_zip_local_file_header_t), file->filename.data, file->filename.len);
-    ngx_memcpy(b->pos + sizeof(ngx_zip_local_file_header_t) + file->filename.len,
-            &extra_field_local, sizeof(ngx_zip_extra_field_local_t));
+    p = b->pos;
+
+    ngx_memcpy(p, &local_file_header, sizeof(ngx_zip_local_file_header_t));
+    p += sizeof(ngx_zip_local_file_header_t);
+
+    ngx_memcpy(p, file->filename.data, file->filename.len);
+    p += file->filename.len;
+
+    ngx_memcpy(p, &extra_field_local, sizeof(ngx_zip_extra_field_local_t));
+    p += sizeof(ngx_zip_extra_field_local_t);
+
     if (file->need_zip64) {
-        ngx_memcpy(b->pos + sizeof(ngx_zip_local_file_header_t) + file->filename.len + sizeof(ngx_zip_extra_field_local_t),
-                &extra_field_zip64, sizeof(ngx_zip_extra_field_zip64_sizes_only_t));
+        ngx_memcpy(p, &extra_field_zip64, sizeof(ngx_zip_extra_field_zip64_sizes_only_t));
+        p += sizeof(ngx_zip_extra_field_zip64_sizes_only_t);
+    }
 
-        if (ctx->unicode_path && file->filename_utf8.len) {
-            ngx_memcpy(b->pos + sizeof(ngx_zip_local_file_header_t) + file->filename.len + sizeof(ngx_zip_extra_field_local_t) + sizeof(ngx_zip_extra_field_zip64_sizes_only_t), &extra_field_unicode_path, sizeof(ngx_zip_extra_field_unicode_path_t));
-            ngx_memcpy(b->pos + sizeof(ngx_zip_local_file_header_t) + file->filename.len + sizeof(ngx_zip_extra_field_local_t) + sizeof(ngx_zip_extra_field_zip64_sizes_only_t) + sizeof(ngx_zip_extra_field_unicode_path_t), file->filename_utf8.data, file->filename_utf8.len);
-        }
-    } else if (ctx->unicode_path && file->filename_utf8.len) {
-        ngx_memcpy(b->pos + sizeof(ngx_zip_local_file_header_t) + file->filename.len + sizeof(ngx_zip_extra_field_local_t), &extra_field_unicode_path, sizeof(ngx_zip_extra_field_unicode_path_t));
-        ngx_memcpy(b->pos + sizeof(ngx_zip_local_file_header_t) + file->filename.len + sizeof(ngx_zip_extra_field_local_t) + sizeof(ngx_zip_extra_field_unicode_path_t), file->filename_utf8.data, file->filename_utf8.len);
+    if (ctx->unicode_path && file->filename_utf8.len) {
+        ngx_memcpy(p, &extra_field_unicode_path, sizeof(ngx_zip_extra_field_unicode_path_t));
+        p += sizeof(ngx_zip_extra_field_unicode_path_t);
+
+        ngx_memcpy(p, file->filename_utf8.data, file->filename_utf8.len);
+        p += file->filename_utf8.len;
     }
 
     ngx_http_zip_truncate_buffer(b, &piece->range, range);
@@ -687,15 +708,13 @@ ngx_http_zip_write_central_directory_entry(u_char *p, ngx_http_zip_file_t *file,
             extra_zip64_ptr = &extra_zip64_size;
             extra_zip64_ptr_size = sizeof(extra_zip64_size);
         }
-    } else {
-        if (file->need_zip64_offset){
-            extra_zip64_offset = ngx_zip_extra_field_zip64_offset_only_template;
-            extra_zip64_offset.tag = htole16(extra_zip64_offset.tag);
-            extra_zip64_offset.size = htole16(extra_zip64_offset.size);
-            extra_zip64_offset.relative_header_offset = htole64(file->offset);
-            extra_zip64_ptr = &extra_zip64_offset;
-            extra_zip64_ptr_size = sizeof(extra_zip64_offset);
-        }
+    } else if (file->need_zip64_offset) {
+        extra_zip64_offset = ngx_zip_extra_field_zip64_offset_only_template;
+        extra_zip64_offset.tag = htole16(extra_zip64_offset.tag);
+        extra_zip64_offset.size = htole16(extra_zip64_offset.size);
+        extra_zip64_offset.relative_header_offset = htole64(file->offset);
+        extra_zip64_ptr = &extra_zip64_offset;
+        extra_zip64_ptr_size = sizeof(extra_zip64_offset);
     }
     central_directory_file_header.extra_field_len=sizeof(ngx_zip_extra_field_central_t)+extra_zip64_ptr_size;
     extra_field_central = ngx_zip_extra_field_central_template;