refactor for efficiency

php/ext/google/protobuf/names.c

@@ -261,3 +261,32 @@ char *GetPhpClassname(const upb_FileDef *file, const char *fullname, bool previo
   free(prefix);
   return ret;
 }
+
+bool IsPreviouslyUnreservedClassName(const char* fullname) {
+  const char *classname = strrchr(fullname, '\\');
+  if (classname) {
+    classname += 1;
+  } else {
+    classname = fullname;
+  }
+  if (strncmp(classname, "PB", 2) != 0) {
+    return false;
+  }
+  classname += 2;
+  int length = strlen(classname);
+  char* lower = calloc(1, length + 1);
+  memcpy(lower, classname, length);
+  int i = 0;
+  while(lower[i]) {
+    lower[i] = nolocale_tolower(lower[i]);
+    i++;
+  }
+  lower[length] = 0;
+  int j;
+  for (j = 0; kPreviouslyUnreservedNames[j]; j++) {
+    if (strcmp(kPreviouslyUnreservedNames[j], lower) == 0) {
+      return true;
+    }
+  }
+  return false;
+}

php/ext/google/protobuf/names.h

@@ -36,5 +36,6 @@
 // Translates a protobuf symbol name (eg. foo.bar.Baz) into a PHP class name
 // (eg. \Foo\Bar\Baz).
 char *GetPhpClassname(const upb_FileDef *file, const char *fullname, bool previous);
+bool IsPreviouslyUnreservedClassName(const char* fullname);
 
 #endif  // PHP_PROTOBUF_NAMES_H_

php/ext/google/protobuf/protobuf.c

@@ -244,12 +244,12 @@ bool ObjCache_Get(const void *upb_obj, zval *val) {
 void NameMap_AddMessage(const upb_MessageDef *m) {
   char *k = GetPhpClassname(upb_MessageDef_File(m), upb_MessageDef_FullName(m), false);
   zend_hash_str_add_ptr(&PROTOBUF_G(name_msg_cache), k, strlen(k), (void*)m);
-  char *k2 = GetPhpClassname(upb_MessageDef_File(m), upb_MessageDef_FullName(m), true);
-  if (strcmp(k, k2) != 0) {
+  if (IsPreviouslyUnreservedClassName(k)) {
+    char *k2 = GetPhpClassname(upb_MessageDef_File(m), upb_MessageDef_FullName(m), true);
     zend_hash_str_add_ptr(&PROTOBUF_G(name_msg_cache), k2, strlen(k2), (void*)m);
+    free(k2);
   }
   free(k);
-  free(k2);
 }
 
 void NameMap_AddEnum(const upb_EnumDef *e) {