diff --git a/http_common.cc b/http_common.cc
new file mode 100644
index 0000000..647faba
--- /dev/null
+++ b/http_common.cc
@@ -0,0 +1,53 @@
+// Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Implementation of common HTTP related functions.
+
+#include "base/basictypes.h"
+
+#include "update_engine/http_common.h"
+
+
+const char *GetHttpResponseDescription(HttpResponseCode code) {
+  static const struct {
+    HttpResponseCode code;
+    const char* description;
+  } http_response_table[] = {
+    { kHttpResponseOk,                  "OK" },
+    { kHttpResponseCreated,             "Created" },
+    { kHttpResponseAccepted,            "Accepted" },
+    { kHttpResponseNonAuthInfo,         "Non-Authoritative Information" },
+    { kHttpResponseNoContent,           "No Content" },
+    { kHttpResponseResetContent,        "Reset Content" },
+    { kHttpResponsePartialContent,      "Partial Content" },
+    { kHttpResponseMultipleChoices,     "Multiple Choices" },
+    { kHttpResponseMovedPermanently,    "Moved Permanently" },
+    { kHttpResponseFound,               "Found" },
+    { kHttpResponseSeeOther,            "See Other" },
+    { kHttpResponseNotModified,         "Not Modified" },
+    { kHttpResponseUseProxy,            "Use Proxy" },
+    { kHttpResponseTempRedirect,        "Temporary Redirect" },
+    { kHttpResponseBadRequest,          "Bad Request" },
+    { kHttpResponseUnauth,              "Unauthorized" },
+    { kHttpResponseForbidden,           "Forbidden" },
+    { kHttpResponseNotFound,            "Not Found" },
+    { kHttpResponseRequestTimeout,      "Request Timeout" },
+    { kHttpResponseInternalServerError, "Internal Server Error" },
+    { kHttpResponseNotImplemented,      "Not Implemented" },
+    { kHttpResponseServiceUnavailable,  "Service Unavailable" },
+    { kHttpResponseVersionNotSupported, "HTTP Version Not Supported" },
+  };
+
+  bool is_found = false;
+  size_t i;
+  for (i = 0; i < ARRAYSIZE_UNSAFE(http_response_table); i++)
+    if ((is_found = (http_response_table[i].code == code)))
+      break;
+
+  return (is_found ? http_response_table[i].description : "(unsupported)");
+}
+
+HttpResponseCode StringToHttpResponseCode(const char *s) {
+  return static_cast<HttpResponseCode>(strtoul(s, NULL, 10));
+}