From 8440d69222385f3300892485bc6b4d2a33cef067 Mon Sep 17 00:00:00 2001
From: John Evans <john.g.evans.ne@gmail.com>
Date: Wed, 31 Dec 2014 23:29:39 -0500
Subject: [PATCH] codestream now a property of Jp2k object, closes #275

repeated calls to get_codestream removed
---
 docs/source/how_do_i.rst |  4 ++--
 glymur/jp2k.py           | 40 ++++++++++++++++++++++++----------------
 2 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/docs/source/how_do_i.rst b/docs/source/how_do_i.rst
index 8a62b32..33366b5 100644
--- a/docs/source/how_do_i.rst
+++ b/docs/source/how_do_i.rst
@@ -214,9 +214,9 @@ making use of the :py:meth:`set_printoptions` function::
         UUID:  be7acfcb-97a9-42e8-9c71-999491e3afac (XMP)
     Contiguous Codestream Box (jp2c) @ (3223, 1132296)
 
-It is possible to print all the gory codestream details as well, i.e. ::
+It is possible to easily print the codestream header details as well, i.e. ::
 
-    >>> print(j.get_codestream())   # details not shown
+    >>> print(j.codestream)   # details not show
 
 ... add XML metadata?
 =====================
diff --git a/glymur/jp2k.py b/glymur/jp2k.py
index b5d61a2..de386dc 100644
--- a/glymur/jp2k.py
+++ b/glymur/jp2k.py
@@ -60,6 +60,8 @@ class Jp2k(Jp2kBox):
     verbose : bool
         whether or not to print informational messages produced by the
         OpenJPEG library, defaults to false
+    codestream : object
+        JP2 or J2K codestream object
 
     Examples
     --------
@@ -145,6 +147,7 @@ class Jp2k(Jp2kBox):
         self._codec_format = None
         self._colorspace = None
         self._layer = 0
+        self._codestream = None
         if data is not None:
             self._shape = data.shape
         else:
@@ -179,6 +182,16 @@ class Jp2k(Jp2kBox):
             raise RuntimeError(msg)
         self._layer = layer
 
+    @property
+    def codestream(self):
+        if self._codestream is None:
+            self._codestream = self.get_codestream(header_only=True)
+        return self._codestream
+
+    @codestream.setter
+    def codestream(self, the_codestream):
+        self._codestream = the_codestream
+
     @property
     def verbose(self):
         return self._verbose
@@ -192,7 +205,7 @@ class Jp2k(Jp2kBox):
         if self._shape is not None:
             return self._shape
 
-        cstr = self.get_codestream(header_only=True)
+        cstr = self.codestream
         height = cstr.segment[1].ysiz
         width = cstr.segment[1].xsiz
         num_components = len(cstr.segment[1].xrsiz)
@@ -233,8 +246,7 @@ class Jp2k(Jp2kBox):
             for box in self.box:
                 metadata.append(str(box))
         else:
-            codestream = self.get_codestream()
-            metadata.append(str(codestream))
+            metadata.append(str(self.codestream))
         return '\n'.join(metadata)
 
     def parse(self):
@@ -865,10 +877,9 @@ class Jp2k(Jp2kBox):
                  FileTypeBox(),
                  JP2HeaderBox(),
                  ContiguousCodestreamBox()]
-        codestream = self.get_codestream()
-        height = codestream.segment[1].ysiz
-        width = codestream.segment[1].xsiz
-        num_components = len(codestream.segment[1].xrsiz)
+        height = self.codestream.segment[1].ysiz
+        width = self.codestream.segment[1].xsiz
+        num_components = len(self.codestream.segment[1].xrsiz)
         if num_components < 3:
             colorspace = core.GREYSCALE
         else:
@@ -907,10 +918,9 @@ class Jp2k(Jp2kBox):
         """
         Slicing protocol.
         """
-        codestream = self.get_codestream(header_only=True)
-        numrows = codestream.segment[1].ysiz
-        numcols = codestream.segment[1].xsiz
-        numbands = codestream.segment[1].Csiz
+        numrows = self.codestream.segment[1].ysiz
+        numcols = self.codestream.segment[1].xsiz
+        numbands = self.codestream.segment[1].Csiz
 
         if isinstance(pargs, int):
             # Not a very good use of this protocol, but technically legal.
@@ -1072,9 +1082,8 @@ class Jp2k(Jp2kBox):
     def _subsampling_sanity_check(self):
         """Check for differing subsample factors.
         """
-        codestream = self.get_codestream(header_only=True)
-        dxs = np.array(codestream.segment[1].xrsiz)
-        dys = np.array(codestream.segment[1].yrsiz)
+        dxs = np.array(self.codestream.segment[1].xrsiz)
+        dys = np.array(self.codestream.segment[1].yrsiz)
         if np.any(dxs - dxs[0]) or np.any(dys - dys[0]):
             msg = "Components must all have the same subsampling factors "
             msg += "to use this method.  Please consider using OPENJP2 and "
@@ -1277,8 +1286,7 @@ class Jp2k(Jp2kBox):
         # Must check the specified rlevel against the maximum.
         if rlevel != 0:
             # Must check the specified rlevel against the maximum.
-            codestream = self.get_codestream()
-            max_rlevel = codestream.segment[2].spcod[4]
+            max_rlevel = self.codestream.segment[2].spcod[4]
             if rlevel == -1:
                 # -1 is shorthand for the largest rlevel
                 rlevel = max_rlevel