From abf093bce24374f1c3741e358566f534fb5f4d5f Mon Sep 17 00:00:00 2001
From: Robert Smallshire <robert@smallshire.org.uk>
Date: Wed, 6 May 2015 10:38:32 +0200
Subject: [PATCH] Achieves another 30% increase in trace header reading
 performance.

---
 segpy/packer.py | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/segpy/packer.py b/segpy/packer.py
index e0bbd93..b266470 100644
--- a/segpy/packer.py
+++ b/segpy/packer.py
@@ -123,6 +123,8 @@ class HeaderPacker:
             header_format_class.LENGTH_IN_BYTES,
             endian)
         self._struct = Struct(self._format)
+        self._one_to_one = all(len(fields) == 1 for fields in self._field_name_allocations)
+        pass
 
     @property
     def header_format_class(self):
@@ -151,11 +153,14 @@ class HeaderPacker:
         """
         values = self._struct.unpack(buffer)
 
-        kwargs = {name: value
-                  for names, value in zip(self._field_name_allocations, values)
-                  for name in names}
+        if self._one_to_one:
+            return self._header_format_class(*values)
+        else:
+            kwargs = {name: value
+                      for names, value in zip(self._field_name_allocations, values)
+                      for name in names}
 
-        return self._header_format_class(**kwargs)
+            return self._header_format_class(**kwargs)
 
     def __repr__(self):
         return "{}({})".format(