Apply modified version of Andrew Dalke's patch in #874 to create a quicker-loading numpy.

5 files changed, 57 insertions, 19 deletions

diff --git a/numpy/_import_tools.py b/numpy/_import_tools.py
index b06fbff7e..4bda26d87 100644
--- a/numpy/_import_tools.py
+++ b/numpy/_import_tools.py
@@ -2,7 +2,6 @@
 import os
 import sys
 import imp
-from glob import glob
 
 __all__ = ['PackageLoader']
 
diff --git a/numpy/core/memmap.py b/numpy/core/memmap.py
index 05aaefef0..dd09b8e28 100644
--- a/numpy/core/memmap.py
+++ b/numpy/core/memmap.py
@@ -1,6 +1,5 @@
 __all__ = ['memmap']
 
-import mmap
 import warnings
 from numeric import uint8, ndarray, dtype
 
@@ -173,6 +172,8 @@ class memmap(ndarray):
     __array_priority__ = -100.0
     def __new__(subtype, filename, dtype=uint8, mode='r+', offset=0,
                 shape=None, order='C'):
+        # Import here to minimize 'import numpy' overhead
+        import mmap
         try:
             mode = mode_equivalents[mode]
         except KeyError:
diff --git a/numpy/core/numerictypes.py b/numpy/core/numerictypes.py
index a368a2bec..8a89f40c6 100644
--- a/numpy/core/numerictypes.py
+++ b/numpy/core/numerictypes.py
@@ -88,9 +88,22 @@ from __builtin__ import bool, int, long, float, complex, object, unicode, str
 
 # String-handling utilities to avoid locale-dependence.
 
-import string
-LOWER_TABLE = string.maketrans(string.ascii_uppercase, string.ascii_lowercase)
-UPPER_TABLE = string.maketrans(string.ascii_lowercase, string.ascii_uppercase)
+# "import string" is costly to import!
+# Construct the translation tables directly
+#   "A" = chr(65), "a" = chr(97)
+_all_chars = map(chr, range(256))
+_ascii_upper = _all_chars[65:65+26]
+_ascii_lower = _all_chars[97:97+26]
+LOWER_TABLE="".join(_all_chars[:65] + _ascii_lower + _all_chars[65+26:])
+UPPER_TABLE="".join(_all_chars[:97] + _ascii_upper + _all_chars[97+26:])
+
+#import string
+# assert (string.maketrans(string.ascii_uppercase, string.ascii_lowercase) == \
+#          LOWER_TABLE)
+# assert (string.maketrnas(string_ascii_lowercase, string.ascii_uppercase) == \
+#          UPPER_TABLE)
+#LOWER_TABLE = string.maketrans(string.ascii_uppercase, string.ascii_lowercase)
+#UPPER_TABLE = string.maketrans(string.ascii_lowercase, string.ascii_uppercase)
 
 def english_lower(s):
     """ Apply English case rules to convert ASCII strings to all lower case.
diff --git a/numpy/lib/_datasource.py b/numpy/lib/_datasource.py
index 1201f3d7e..3055bf47a 100644
--- a/numpy/lib/_datasource.py
+++ b/numpy/lib/_datasource.py
@@ -36,21 +36,39 @@ __docformat__ = "restructuredtext en"
 
 import os
 from shutil import rmtree
-from urlparse import urlparse
 
-# TODO: .zip support, .tar support?
-_file_openers = {None: open}
-try:
-    import bz2
-    _file_openers[".bz2"] = bz2.BZ2File
-except ImportError:
-    pass
-try:
-    import gzip
-    _file_openers[".gz"] = gzip.open
-except ImportError:
-    pass
+# Using a class instead of a module-level dictionary
+# to reduce the inital 'import numpy' overhead by 
+# deferring the import of bz2 and gzip until needed
 
+# TODO: .zip support, .tar support?
+class _FileOpeners(object):
+    def __init__(self):
+        self._loaded = False
+        self._file_openers = {None: open}
+    def _load(self):
+        if self._loaded:
+            return
+        try:
+            import bz2
+            self._file_openers[".bz2"] = bz2.BZ2File
+        except ImportError:
+            pass
+        try:
+            import gzip
+            self._file_openers[".gz"] = gzip.open
+        except ImportError:
+            pass
+        self._loaded = True
+
+    def keys(self):
+        self._load()
+        return self._file_openers.keys()
+    def __getitem__(self, key):
+        self._load()
+        return self._file_openers[key]
+
+_file_openers = _FileOpeners()
 
 def open(path, mode='r', destpath=os.curdir):
     """Open ``path`` with ``mode`` and return the file object.
@@ -179,6 +197,9 @@ class DataSource (object):
 
     def _isurl(self, path):
         """Test if path is a net location.  Tests the scheme and netloc."""
+        
+        # We do this here to reduce the 'import numpy' initial import time.
+        from urlparse import urlparse
 
         # BUG : URLs require a scheme string ('http://') to be used.
         #       www.google.com will fail.
@@ -276,6 +297,9 @@ class DataSource (object):
             `open` : Method that downloads and opens files.
 
         """
+        # We do this here to reduce the 'import numpy' initial import time.
+        from urlparse import urlparse
+
 
         # TODO:  This should be more robust.  Handles case where path includes
         #        the destpath, but not other sub-paths. Failing case:
diff --git a/numpy/lib/format.py b/numpy/lib/format.py
index 4192e1225..32a23ae18 100644
--- a/numpy/lib/format.py
+++ b/numpy/lib/format.py
@@ -57,7 +57,6 @@ means there is 1 element) by dtype.itemsize.
 """
 
 import cPickle
-import struct
 
 import numpy
 from numpy.lib.utils import safe_eval
@@ -180,6 +179,7 @@ def write_array_header_1_0(fp, d):
         This has the appropriate entries for writing its string representation
         to the header of the file.
     """
+    import struct
     header = ["{"]
     for key, value in sorted(d.items()):
         # Need to use repr here, since we eval these when reading
@@ -230,6 +230,7 @@ def read_array_header_1_0(fp):
     """
     # Read an unsigned, little-endian short int which has the length of the
     # header.
+    import struct
     hlength_str = fp.read(2)
     if len(hlength_str) != 2:
         msg = "EOF at %s before reading array header length"