From 645465c65cf33d6202aa43b71bef2d007f81ef9c Mon Sep 17 00:00:00 2001
From: sidhant007 <sidhbansal@gmail.com>
Date: Wed, 24 Jun 2020 12:37:10 +0800
Subject: [PATCH 1/5] ENH: Add file like support to np.core.records.fromfile
 (#2504)

---
 numpy/compat/py3k.py              |  5 ++++-
 numpy/compat/tests/test_compat.py | 18 +++++++++++++++++-
 numpy/core/records.py             | 18 ++++++++----------
 numpy/core/tests/test_records.py  |  7 +++++++
 4 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/numpy/compat/py3k.py b/numpy/compat/py3k.py
index fd9f8bd4217e..0ea40107575f 100644
--- a/numpy/compat/py3k.py
+++ b/numpy/compat/py3k.py
@@ -10,7 +10,7 @@
 compatibility with numpy while they transition their code to newer versions of
 Python.
 """
-__all__ = ['bytes', 'asbytes', 'isfileobj', 'getexception', 'strchar',
+__all__ = ['bytes', 'asbytes', 'isfileobj', 'isfilelikeobj', 'getexception', 'strchar',
            'unicode', 'asunicode', 'asbytes_nested', 'asunicode_nested',
            'asstr', 'open_latin1', 'long', 'basestring', 'sixu',
            'integer_types', 'is_pathlib_path', 'npy_load_module', 'Path',
@@ -53,6 +53,9 @@ def asstr(s):
 def isfileobj(f):
     return isinstance(f, (io.FileIO, io.BufferedReader, io.BufferedWriter))
 
+def isfilelikeobj(f):
+    return hasattr(f, 'readinto')
+
 def open_latin1(filename, mode='r'):
     return open(filename, mode=mode, encoding='iso-8859-1')
 
diff --git a/numpy/compat/tests/test_compat.py b/numpy/compat/tests/test_compat.py
index 2b8acbaa0662..a6f7a8f49db0 100644
--- a/numpy/compat/tests/test_compat.py
+++ b/numpy/compat/tests/test_compat.py
@@ -1,9 +1,11 @@
 from os.path import join
 
-from numpy.compat import isfileobj
+from numpy.compat import isfileobj, isfilelikeobj
 from numpy.testing import assert_
 from numpy.testing import tempdir
 
+import io
+import gzip
 
 def test_isfileobj():
     with tempdir(prefix="numpy_test_compat_") as folder:
@@ -17,3 +19,17 @@ def test_isfileobj():
 
         with open(filename, 'rb') as f:
             assert_(isfileobj(f))
+
+def test_isfilelikeobj():
+    with tempdir(prefix="numpy_test_compat_") as folder:
+        filename = join(folder, 'a.bin')
+
+        with open(filename, 'wb') as f:
+            assert_(isfilelikeobj(f))
+
+        with gzip.open(filename, 'rb') as f:
+            assert_(isfilelikeobj(f))
+
+        assert_(isfilelikeobj(io.BytesIO()))
+
+        assert_(not isfilelikeobj(io.StringIO()))
diff --git a/numpy/core/records.py b/numpy/core/records.py
index 0d3fd9118396..df91091b74ff 100644
--- a/numpy/core/records.py
+++ b/numpy/core/records.py
@@ -40,7 +40,7 @@
 from . import numeric as sb
 from . import numerictypes as nt
 from numpy.compat import (
-    isfileobj, os_fspath, contextlib_nullcontext
+    isfilelikeobj, os_fspath, contextlib_nullcontext
 )
 from numpy.core.overrides import set_module
 from .arrayprint import get_printoptions
@@ -847,12 +847,10 @@ def fromstring(datastring, dtype=None, shape=None, offset=0, formats=None,
     return _array
 
 def get_remaining_size(fd):
-    try:
-        fn = fd.fileno()
-    except AttributeError:
-        return os.path.getsize(fd.name) - fd.tell()
-    st = os.fstat(fn)
-    size = st.st_size - fd.tell()
+    pos = fd.tell()
+    fd.seek(0, 2)
+    size = fd.tell() - pos
+    fd.seek(pos, 0)
     return size
 
 def fromfile(fd, dtype=None, shape=None, offset=0, formats=None,
@@ -911,7 +909,7 @@ def fromfile(fd, dtype=None, shape=None, offset=0, formats=None,
     elif isinstance(shape, int):
         shape = (shape,)
 
-    if isfileobj(fd):
+    if isfilelikeobj(fd):
         # file already opened
         ctx = contextlib_nullcontext(fd)
     else:
@@ -1036,7 +1034,7 @@ def array(obj, dtype=None, shape=None, offset=0, strides=None, formats=None,
     array('def', dtype='<U3')
     """
 
-    if ((isinstance(obj, (type(None), str)) or isfileobj(obj)) and
+    if ((isinstance(obj, (type(None), str)) or isfilelikeobj(obj)) and
            formats is None and dtype is None):
         raise ValueError("Must define formats (or dtype) if object is "
                          "None, string, or an open file")
@@ -1078,7 +1076,7 @@ def array(obj, dtype=None, shape=None, offset=0, strides=None, formats=None,
             new = new.copy()
         return new
 
-    elif isfileobj(obj):
+    elif isfilelikeobj(obj):
         return fromfile(obj, dtype=dtype, shape=shape, offset=offset)
 
     elif isinstance(obj, ndarray):
diff --git a/numpy/core/tests/test_records.py b/numpy/core/tests/test_records.py
index 4350a3407c79..f28ad5ac9098 100644
--- a/numpy/core/tests/test_records.py
+++ b/numpy/core/tests/test_records.py
@@ -1,5 +1,6 @@
 import collections.abc
 import textwrap
+from io import BytesIO
 from os import path
 from pathlib import Path
 import pytest
@@ -79,8 +80,14 @@ def test_recarray_fromfile(self):
         r1 = np.rec.fromfile(fd, formats='f8,i4,a5', shape=3, byteorder='big')
         fd.seek(2880 * 2)
         r2 = np.rec.array(fd, formats='f8,i4,a5', shape=3, byteorder='big')
+        fd.seek(2880 * 2)
+        bytes_array = BytesIO()
+        bytes_array.write(fd.read())
+        bytes_array.seek(0)
+        r3 = np.rec.fromfile(bytes_array, formats='f8,i4,a5', shape=3, byteorder='big')
         fd.close()
         assert_equal(r1, r2)
+        assert_equal(r2, r3)
 
     def test_recarray_from_obj(self):
         count = 10

From 107c02951d400e69df92d2d5c5d96ef2964aa315 Mon Sep 17 00:00:00 2001
From: sidhant007 <sidhbansal@gmail.com>
Date: Mon, 29 Jun 2020 10:24:07 +0800
Subject: [PATCH 2/5] Refactor: Remove isfilelikeobj function

---
 numpy/compat/py3k.py              |  5 +----
 numpy/compat/tests/test_compat.py | 18 +-----------------
 numpy/core/records.py             | 17 +++++++++--------
 3 files changed, 11 insertions(+), 29 deletions(-)

diff --git a/numpy/compat/py3k.py b/numpy/compat/py3k.py
index 0ea40107575f..fd9f8bd4217e 100644
--- a/numpy/compat/py3k.py
+++ b/numpy/compat/py3k.py
@@ -10,7 +10,7 @@
 compatibility with numpy while they transition their code to newer versions of
 Python.
 """
-__all__ = ['bytes', 'asbytes', 'isfileobj', 'isfilelikeobj', 'getexception', 'strchar',
+__all__ = ['bytes', 'asbytes', 'isfileobj', 'getexception', 'strchar',
            'unicode', 'asunicode', 'asbytes_nested', 'asunicode_nested',
            'asstr', 'open_latin1', 'long', 'basestring', 'sixu',
            'integer_types', 'is_pathlib_path', 'npy_load_module', 'Path',
@@ -53,9 +53,6 @@ def asstr(s):
 def isfileobj(f):
     return isinstance(f, (io.FileIO, io.BufferedReader, io.BufferedWriter))
 
-def isfilelikeobj(f):
-    return hasattr(f, 'readinto')
-
 def open_latin1(filename, mode='r'):
     return open(filename, mode=mode, encoding='iso-8859-1')
 
diff --git a/numpy/compat/tests/test_compat.py b/numpy/compat/tests/test_compat.py
index a6f7a8f49db0..2b8acbaa0662 100644
--- a/numpy/compat/tests/test_compat.py
+++ b/numpy/compat/tests/test_compat.py
@@ -1,11 +1,9 @@
 from os.path import join
 
-from numpy.compat import isfileobj, isfilelikeobj
+from numpy.compat import isfileobj
 from numpy.testing import assert_
 from numpy.testing import tempdir
 
-import io
-import gzip
 
 def test_isfileobj():
     with tempdir(prefix="numpy_test_compat_") as folder:
@@ -19,17 +17,3 @@ def test_isfileobj():
 
         with open(filename, 'rb') as f:
             assert_(isfileobj(f))
-
-def test_isfilelikeobj():
-    with tempdir(prefix="numpy_test_compat_") as folder:
-        filename = join(folder, 'a.bin')
-
-        with open(filename, 'wb') as f:
-            assert_(isfilelikeobj(f))
-
-        with gzip.open(filename, 'rb') as f:
-            assert_(isfilelikeobj(f))
-
-        assert_(isfilelikeobj(io.BytesIO()))
-
-        assert_(not isfilelikeobj(io.StringIO()))
diff --git a/numpy/core/records.py b/numpy/core/records.py
index df91091b74ff..c512be8921a8 100644
--- a/numpy/core/records.py
+++ b/numpy/core/records.py
@@ -40,7 +40,7 @@
 from . import numeric as sb
 from . import numerictypes as nt
 from numpy.compat import (
-    isfilelikeobj, os_fspath, contextlib_nullcontext
+    os_fspath, contextlib_nullcontext
 )
 from numpy.core.overrides import set_module
 from .arrayprint import get_printoptions
@@ -848,10 +848,11 @@ def fromstring(datastring, dtype=None, shape=None, offset=0, formats=None,
 
 def get_remaining_size(fd):
     pos = fd.tell()
-    fd.seek(0, 2)
-    size = fd.tell() - pos
-    fd.seek(pos, 0)
-    return size
+    try:
+        fd.seek(0, 2)
+        return fd.tell() - pos
+    finally:
+        fd.seek(pos, 0)
 
 def fromfile(fd, dtype=None, shape=None, offset=0, formats=None,
              names=None, titles=None, aligned=False, byteorder=None):
@@ -909,7 +910,7 @@ def fromfile(fd, dtype=None, shape=None, offset=0, formats=None,
     elif isinstance(shape, int):
         shape = (shape,)
 
-    if isfilelikeobj(fd):
+    if hasattr(fd, 'readinto'):
         # file already opened
         ctx = contextlib_nullcontext(fd)
     else:
@@ -1034,7 +1035,7 @@ def array(obj, dtype=None, shape=None, offset=0, strides=None, formats=None,
     array('def', dtype='<U3')
     """
 
-    if ((isinstance(obj, (type(None), str)) or isfilelikeobj(obj)) and
+    if ((isinstance(obj, (type(None), str)) or hasattr(obj, 'readinto')) and
            formats is None and dtype is None):
         raise ValueError("Must define formats (or dtype) if object is "
                          "None, string, or an open file")
@@ -1076,7 +1077,7 @@ def array(obj, dtype=None, shape=None, offset=0, strides=None, formats=None,
             new = new.copy()
         return new
 
-    elif isfilelikeobj(obj):
+    elif hasattr(obj, 'readinto'):
         return fromfile(obj, dtype=dtype, shape=shape, offset=offset)
 
     elif isinstance(obj, ndarray):

From 09fdf11cd90e4dafd9d5ce5f012d99a858ba7d06 Mon Sep 17 00:00:00 2001
From: sidhant007 <sidhbansal@gmail.com>
Date: Fri, 3 Jul 2020 14:44:10 +0800
Subject: [PATCH 3/5] Add comment for better explanation

---
 numpy/core/records.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/numpy/core/records.py b/numpy/core/records.py
index c512be8921a8..e95be0e3f9e0 100644
--- a/numpy/core/records.py
+++ b/numpy/core/records.py
@@ -911,6 +911,8 @@ def fromfile(fd, dtype=None, shape=None, offset=0, formats=None,
         shape = (shape,)
 
     if hasattr(fd, 'readinto'):
+        # GH issue 2504. fd supports io.RawIOBase or io.BufferedIOBase interface. 
+        # Example of fd: gzip, BytesIO, BufferedReader
         # file already opened
         ctx = contextlib_nullcontext(fd)
     else:

From c2727d074c4503a9c77698c04ea9e1725a4e17a0 Mon Sep 17 00:00:00 2001
From: mattip <matti.picus@gmail.com>
Date: Mon, 10 Aug 2020 10:42:42 +0300
Subject: [PATCH 4/5] DOC: add release note

---
 doc/release/upcoming_changes/16675.improvement.rst | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 doc/release/upcoming_changes/16675.improvement.rst

diff --git a/doc/release/upcoming_changes/16675.improvement.rst b/doc/release/upcoming_changes/16675.improvement.rst
new file mode 100644
index 000000000000..310e44cfb57a
--- /dev/null
+++ b/doc/release/upcoming_changes/16675.improvement.rst
@@ -0,0 +1,3 @@
+`numpy.core.records.fromfile` now supports file-like objects
+------------------------------------------------------------
+`numpy.rec.fromfile` can now use file-like objects, for instance `BytesIO`

From 58d3bc9cf8bec2cac213724652dc374ee2ea72b2 Mon Sep 17 00:00:00 2001
From: Ross Barnowski <rossbar@berkeley.edu>
Date: Mon, 10 Aug 2020 12:00:39 -0700
Subject: [PATCH 5/5] DOC: intersphinx release note

---
 doc/release/upcoming_changes/16675.improvement.rst | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/doc/release/upcoming_changes/16675.improvement.rst b/doc/release/upcoming_changes/16675.improvement.rst
index 310e44cfb57a..bc70d7e0f0b6 100644
--- a/doc/release/upcoming_changes/16675.improvement.rst
+++ b/doc/release/upcoming_changes/16675.improvement.rst
@@ -1,3 +1,4 @@
 `numpy.core.records.fromfile` now supports file-like objects
 ------------------------------------------------------------
-`numpy.rec.fromfile` can now use file-like objects, for instance `BytesIO`
+`numpy.rec.fromfile` can now use file-like objects, for instance 
+:py:class:`io.BytesIO`