[Python-checkins] cpython: Issue #19641: Added the audioop.byteswap() function to convert big-endian
serhiy.storchaka
python-checkins at python.org
Sat Nov 23 21:27:41 CET 2013
http://hg.python.org/cpython/rev/fbebc90abcd1
changeset: 87454:fbebc90abcd1
user: Serhiy Storchaka <storchaka at gmail.com>
date: Sat Nov 23 22:26:01 2013 +0200
summary:
Issue #19641: Added the audioop.byteswap() function to convert big-endian
samples to little-endian and vice versa.
files:
Doc/library/audioop.rst | 8 ++++
Doc/whatsnew/3.4.rst | 3 +
Lib/test/audiotests.py | 18 ---------
Lib/test/test_aifc.py | 5 +-
Lib/test/test_audioop.py | 17 +++++++++
Lib/test/test_sunau.py | 3 +-
Lib/test/test_wave.py | 18 ++-------
Lib/wave.py | 51 ++++-----------------------
Misc/NEWS | 3 +
Modules/audioop.c | 32 +++++++++++++++++
10 files changed, 80 insertions(+), 78 deletions(-)
diff --git a/Doc/library/audioop.rst b/Doc/library/audioop.rst
--- a/Doc/library/audioop.rst
+++ b/Doc/library/audioop.rst
@@ -77,6 +77,14 @@
sample. Samples wrap around in case of overflow.
+.. function:: byteswap(fragment, width)
+
+ "Byteswap" all samples in a fragment and returns the modified fragment.
+ Converts big-endian samples to little-endian and vice versa.
+
+ .. versionadded: 3.4
+
+
.. function:: cross(fragment, width)
Return the number of zero crossings in the fragment passed as an argument.
diff --git a/Doc/whatsnew/3.4.rst b/Doc/whatsnew/3.4.rst
--- a/Doc/whatsnew/3.4.rst
+++ b/Doc/whatsnew/3.4.rst
@@ -415,6 +415,9 @@
Added support for 24-bit samples (:issue:`12866`).
+Added the :func:`~audioop.byteswap` function to convert big-endian samples
+to little-endian and vice versa (:issue:`19641`).
+
base64
------
diff --git a/Lib/test/audiotests.py b/Lib/test/audiotests.py
--- a/Lib/test/audiotests.py
+++ b/Lib/test/audiotests.py
@@ -5,24 +5,6 @@
import pickle
import sys
-def byteswap2(data):
- a = array.array('h')
- a.frombytes(data)
- a.byteswap()
- return a.tobytes()
-
-def byteswap3(data):
- ba = bytearray(data)
- ba[::3] = data[2::3]
- ba[2::3] = data[::3]
- return bytes(ba)
-
-def byteswap4(data):
- a = array.array('i')
- a.frombytes(data)
- a.byteswap()
- return a.tobytes()
-
class UnseekableIO(io.FileIO):
def tell(self):
raise io.UnsupportedOperation
diff --git a/Lib/test/test_aifc.py b/Lib/test/test_aifc.py
--- a/Lib/test/test_aifc.py
+++ b/Lib/test/test_aifc.py
@@ -1,6 +1,7 @@
from test.support import findfile, TESTFN, unlink
import unittest
from test import audiotests
+from audioop import byteswap
import os
import io
import sys
@@ -122,7 +123,7 @@
E5040CBC 617C0A3C 08BC0A3C 2C7C0B3C 517C0E3C 8A8410FC B6840EBC 457C0A3C \
""")
if sys.byteorder != 'big':
- frames = audiotests.byteswap2(frames)
+ frames = byteswap(frames, 2)
class AifcALAWTest(AifcTest, unittest.TestCase):
@@ -143,7 +144,7 @@
E4800CC0 62000A40 08C00A40 2B000B40 52000E40 8A001180 B6000EC0 46000A40 \
""")
if sys.byteorder != 'big':
- frames = audiotests.byteswap2(frames)
+ frames = byteswap(frames, 2)
class AifcMiscTest(audiotests.AudioTests, unittest.TestCase):
diff --git a/Lib/test/test_audioop.py b/Lib/test/test_audioop.py
--- a/Lib/test/test_audioop.py
+++ b/Lib/test/test_audioop.py
@@ -448,6 +448,23 @@
self.assertEqual(audioop.getsample(data, w, 3), maxvalues[w])
self.assertEqual(audioop.getsample(data, w, 4), minvalues[w])
+ def test_byteswap(self):
+ swapped_datas = {
+ 1: datas[1],
+ 2: packs[2](0, 0x3412, 0x6745, -0x6646, -0x81, 0x80, -1),
+ 3: packs[3](0, 0x563412, -0x7698bb, 0x7798ba, -0x81, 0x80, -1),
+ 4: packs[4](0, 0x78563412, -0x547698bb, 0x557698ba,
+ -0x81, 0x80, -1),
+ }
+ for w in 1, 2, 3, 4:
+ self.assertEqual(audioop.byteswap(b'', w), b'')
+ self.assertEqual(audioop.byteswap(datas[w], w), swapped_datas[w])
+ self.assertEqual(audioop.byteswap(swapped_datas[w], w), datas[w])
+ self.assertEqual(audioop.byteswap(bytearray(datas[w]), w),
+ swapped_datas[w])
+ self.assertEqual(audioop.byteswap(memoryview(datas[w]), w),
+ swapped_datas[w])
+
def test_negativelen(self):
# from issue 3306, previously it segfaulted
self.assertRaises(audioop.error,
diff --git a/Lib/test/test_sunau.py b/Lib/test/test_sunau.py
--- a/Lib/test/test_sunau.py
+++ b/Lib/test/test_sunau.py
@@ -1,6 +1,7 @@
from test.support import TESTFN
import unittest
from test import audiotests
+from audioop import byteswap
import sys
import sunau
@@ -124,7 +125,7 @@
E5040CBC 617C0A3C 08BC0A3C 2C7C0B3C 517C0E3C 8A8410FC B6840EBC 457C0A3C \
""")
if sys.byteorder != 'big':
- frames = audiotests.byteswap2(frames)
+ frames = byteswap(frames, 2)
if __name__ == "__main__":
diff --git a/Lib/test/test_wave.py b/Lib/test/test_wave.py
--- a/Lib/test/test_wave.py
+++ b/Lib/test/test_wave.py
@@ -1,6 +1,7 @@
from test.support import TESTFN
import unittest
from test import audiotests
+from audioop import byteswap
import sys
import wave
@@ -46,13 +47,7 @@
E4B50CEB 63440A5A 08CA0A1F 2BBA0B0B 51460E47 8BCB113C B6F50EEA 44150A59 \
""")
if sys.byteorder != 'big':
- frames = audiotests.byteswap2(frames)
-
- if sys.byteorder == 'big':
- @unittest.expectedFailure
- def test_unseekable_incompleted_write(self):
- super().test_unseekable_incompleted_write()
-
+ frames = byteswap(frames, 2)
class WavePCM24Test(audiotests.AudioWriteTests,
@@ -82,7 +77,7 @@
51486F0E44E1 8BCC64113B05 B6F4EC0EEB36 4413170A5B48 \
""")
if sys.byteorder != 'big':
- frames = audiotests.byteswap3(frames)
+ frames = byteswap(frames, 3)
class WavePCM32Test(audiotests.AudioWriteTests,
@@ -112,12 +107,7 @@
51486F800E44E190 8BCC6480113B0580 B6F4EC000EEB3630 441317800A5B48A0 \
""")
if sys.byteorder != 'big':
- frames = audiotests.byteswap4(frames)
-
- if sys.byteorder == 'big':
- @unittest.expectedFailure
- def test_unseekable_incompleted_write(self):
- super().test_unseekable_incompleted_write()
+ frames = byteswap(frames, 4)
if __name__ == '__main__':
diff --git a/Lib/wave.py b/Lib/wave.py
--- a/Lib/wave.py
+++ b/Lib/wave.py
@@ -82,17 +82,12 @@
_array_fmts = None, 'b', 'h', None, 'i'
+import audioop
import struct
import sys
from chunk import Chunk
from collections import namedtuple
-def _byteswap3(data):
- ba = bytearray(data)
- ba[::3] = data[2::3]
- ba[2::3] = data[::3]
- return bytes(ba)
-
_wave_params = namedtuple('_wave_params',
'nchannels sampwidth framerate nframes comptype compname')
@@ -243,29 +238,9 @@
self._data_seek_needed = 0
if nframes == 0:
return b''
- if self._sampwidth in (2, 4) and sys.byteorder == 'big':
- # unfortunately the fromfile() method does not take
- # something that only looks like a file object, so
- # we have to reach into the innards of the chunk object
- import array
- chunk = self._data_chunk
- data = array.array(_array_fmts[self._sampwidth])
- assert data.itemsize == self._sampwidth
- nitems = nframes * self._nchannels
- if nitems * self._sampwidth > chunk.chunksize - chunk.size_read:
- nitems = (chunk.chunksize - chunk.size_read) // self._sampwidth
- data.fromfile(chunk.file.file, nitems)
- # "tell" data chunk how much was read
- chunk.size_read = chunk.size_read + nitems * self._sampwidth
- # do the same for the outermost chunk
- chunk = chunk.file
- chunk.size_read = chunk.size_read + nitems * self._sampwidth
- data.byteswap()
- data = data.tobytes()
- else:
- data = self._data_chunk.read(nframes * self._framesize)
- if self._sampwidth == 3 and sys.byteorder == 'big':
- data = _byteswap3(data)
+ data = self._data_chunk.read(nframes * self._framesize)
+ if self._sampwidth != 1 and sys.byteorder == 'big':
+ data = audioop.byteswap(data, self._sampwidth)
if self._convert and data:
data = self._convert(data)
self._soundpos = self._soundpos + len(data) // (self._nchannels * self._sampwidth)
@@ -441,20 +416,10 @@
nframes = len(data) // (self._sampwidth * self._nchannels)
if self._convert:
data = self._convert(data)
- if self._sampwidth in (2, 4) and sys.byteorder == 'big':
- import array
- a = array.array(_array_fmts[self._sampwidth])
- a.frombytes(data)
- data = a
- assert data.itemsize == self._sampwidth
- data.byteswap()
- data.tofile(self._file)
- self._datawritten = self._datawritten + len(data) * self._sampwidth
- else:
- if self._sampwidth == 3 and sys.byteorder == 'big':
- data = _byteswap3(data)
- self._file.write(data)
- self._datawritten = self._datawritten + len(data)
+ if self._sampwidth != 1 and sys.byteorder == 'big':
+ data = audioop.byteswap(data, self._sampwidth)
+ self._file.write(data)
+ self._datawritten += len(data)
self._nframeswritten = self._nframeswritten + nframes
def writeframes(self, data):
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -68,6 +68,9 @@
Library
-------
+- Issue #19641: Added the audioop.byteswap() function to convert big-endian
+ samples to little-endian and vice versa.
+
- Issue #15204: Deprecated the 'U' mode in file-like objects.
- Issue #17810: Implement PEP 3154, pickle protocol 4.
diff --git a/Modules/audioop.c b/Modules/audioop.c
--- a/Modules/audioop.c
+++ b/Modules/audioop.c
@@ -1108,6 +1108,37 @@
}
static PyObject *
+audioop_byteswap(PyObject *self, PyObject *args)
+{
+ Py_buffer view;
+ unsigned char *ncp;
+ Py_ssize_t i;
+ int size;
+ PyObject *rv = NULL;
+
+ if (!PyArg_ParseTuple(args, "y*i:swapbytes",
+ &view, &size))
+ return NULL;
+
+ if (!audioop_check_parameters(view.len, size))
+ goto exit;
+
+ rv = PyBytes_FromStringAndSize(NULL, view.len);
+ if (rv == NULL)
+ goto exit;
+ ncp = (unsigned char *)PyBytes_AsString(rv);
+
+ for (i = 0; i < view.len; i += size) {
+ int j;
+ for (j = 0; j < size; j++)
+ ncp[i + size - 1 - j] = ((unsigned char *)view.buf)[i + j];
+ }
+ exit:
+ PyBuffer_Release(&view);
+ return rv;
+}
+
+static PyObject *
audioop_lin2lin(PyObject *self, PyObject *args)
{
Py_buffer view;
@@ -1698,6 +1729,7 @@
{ "tostereo", audioop_tostereo, METH_VARARGS },
{ "getsample", audioop_getsample, METH_VARARGS },
{ "reverse", audioop_reverse, METH_VARARGS },
+ { "byteswap", audioop_byteswap, METH_VARARGS },
{ "ratecv", audioop_ratecv, METH_VARARGS },
{ 0, 0 }
};
--
Repository URL: http://hg.python.org/cpython
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