#5391 make mmap work exclusively with bytes
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Benjamin Peterson
parent
f3abcc9d3c
commit
e099b37428
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@ -6,13 +6,13 @@
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:synopsis: Interface to memory-mapped files for Unix and Windows.
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Memory-mapped file objects behave like both strings and like file objects.
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Unlike normal string objects, however, these are mutable. You can use mmap
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objects in most places where strings are expected; for example, you can use
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the :mod:`re` module to search through a memory-mapped file. Since they're
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mutable, you can change a single character by doing ``obj[index] = 'a'``, or
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change a substring by assigning to a slice: ``obj[i1:i2] = '...'``. You can
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also read and write data starting at the current file position, and
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Memory-mapped file objects behave like both :class:`bytes` and like file
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objects. Unlike normal :class:`bytes` objects, however, these are mutable.
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You can use mmap objects in most places where :class:`bytes` are expected; for
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example, you can use the :mod:`re` module to search through a memory-mapped file.
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Since they're mutable, you can change a single byte by doing ``obj[index] = 97``,
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or change a subsequence by assigning to a slice: ``obj[i1:i2] = b'...'``.
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You can also read and write data starting at the current file position, and
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:meth:`seek` through the file to different positions.
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A memory-mapped file is created by the :class:`mmap` constructor, which is
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@ -94,21 +94,21 @@ To map anonymous memory, -1 should be passed as the fileno along with the length
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# write a simple example file
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with open("hello.txt", "wb") as f:
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f.write("Hello Python!\n")
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f.write(b"Hello Python!\n")
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with open("hello.txt", "r+b") as f:
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# memory-map the file, size 0 means whole file
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map = mmap.mmap(f.fileno(), 0)
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# read content via standard file methods
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print(map.readline()) # prints "Hello Python!"
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print(map.readline()) # prints b"Hello Python!\n"
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# read content via slice notation
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print(map[:5]) # prints "Hello"
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print(map[:5]) # prints b"Hello"
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# update content using slice notation;
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# note that new content must have same size
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map[6:] = " world!\n"
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map[6:] = b" world!\n"
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# ... and read again using standard file methods
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map.seek(0)
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print(map.readline()) # prints "Hello world!"
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print(map.readline()) # prints b"Hello world!\n"
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# close the map
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map.close()
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@ -120,7 +120,7 @@ To map anonymous memory, -1 should be passed as the fileno along with the length
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import os
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map = mmap.mmap(-1, 13)
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map.write("Hello world!")
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map.write(b"Hello world!")
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pid = os.fork()
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@ -140,10 +140,10 @@ To map anonymous memory, -1 should be passed as the fileno along with the length
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result in an exception being raised.
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.. method:: find(string[, start[, end]])
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.. method:: find(sub[, start[, end]])
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Returns the lowest index in the object where the substring *string* is
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found, such that *string* is contained in the range [*start*, *end*].
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Returns the lowest index in the object where the subsequence *sub* is
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found, such that *sub* is contained in the range [*start*, *end*].
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Optional arguments *start* and *end* are interpreted as in slice notation.
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Returns ``-1`` on failure.
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@ -172,15 +172,15 @@ To map anonymous memory, -1 should be passed as the fileno along with the length
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.. method:: read(num)
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Return a string containing up to *num* bytes starting from the current
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file position; the file position is updated to point after the bytes that
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were returned.
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Return a :class:`bytes` containing up to *num* bytes starting from the
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current file position; the file position is updated to point after the
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bytes that were returned.
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.. method:: read_byte()
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Returns a string of length 1 containing the character at the current file
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position, and advances the file position by 1.
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Returns a byte at the current file position as an integer, and advances
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the file position by 1.
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.. method:: readline()
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@ -196,10 +196,10 @@ To map anonymous memory, -1 should be passed as the fileno along with the length
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throw a :exc:`TypeError` exception.
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.. method:: rfind(string[, start[, end]])
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.. method:: rfind(sub[, start[, end]])
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Returns the highest index in the object where the substring *string* is
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found, such that *string* is contained in the range [*start*, *end*].
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Returns the highest index in the object where the subsequence *sub* is
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found, such that *sub* is contained in the range [*start*, *end*].
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Optional arguments *start* and *end* are interpreted as in slice notation.
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Returns ``-1`` on failure.
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@ -223,9 +223,9 @@ To map anonymous memory, -1 should be passed as the fileno along with the length
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Returns the current position of the file pointer.
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.. method:: write(string)
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.. method:: write(bytes)
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Write the bytes in *string* into memory at the current position of the
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Write the bytes in *bytes* into memory at the current position of the
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file pointer; the file position is updated to point after the bytes that
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were written. If the mmap was created with :const:`ACCESS_READ`, then
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writing to it will throw a :exc:`TypeError` exception.
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@ -233,7 +233,7 @@ To map anonymous memory, -1 should be passed as the fileno along with the length
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.. method:: write_byte(byte)
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Write the single-character string *byte* into memory at the current
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Write the the integer *byte* into memory at the current
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position of the file pointer; the file position is advanced by ``1``. If
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the mmap was created with :const:`ACCESS_READ`, then writing to it will
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throw a :exc:`TypeError` exception.
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@ -37,7 +37,7 @@ class MmapTests(unittest.TestCase):
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# Simple sanity checks
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tp = str(type(m)) # SF bug 128713: segfaulted on Linux
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self.assertEqual(m.find('foo'), PAGESIZE)
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self.assertEqual(m.find(b'foo'), PAGESIZE)
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self.assertEqual(len(m), 2*PAGESIZE)
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@ -262,38 +262,38 @@ class MmapTests(unittest.TestCase):
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def test_find_end(self):
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# test the new 'end' parameter works as expected
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f = open(TESTFN, 'w+')
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data = 'one two ones'
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f = open(TESTFN, 'wb+')
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data = b'one two ones'
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n = len(data)
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f.write(data)
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f.flush()
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m = mmap.mmap(f.fileno(), n)
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f.close()
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self.assertEqual(m.find('one'), 0)
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self.assertEqual(m.find('ones'), 8)
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self.assertEqual(m.find('one', 0, -1), 0)
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self.assertEqual(m.find('one', 1), 8)
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self.assertEqual(m.find('one', 1, -1), 8)
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self.assertEqual(m.find('one', 1, -2), -1)
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self.assertEqual(m.find(b'one'), 0)
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self.assertEqual(m.find(b'ones'), 8)
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self.assertEqual(m.find(b'one', 0, -1), 0)
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self.assertEqual(m.find(b'one', 1), 8)
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self.assertEqual(m.find(b'one', 1, -1), 8)
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self.assertEqual(m.find(b'one', 1, -2), -1)
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def test_rfind(self):
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# test the new 'end' parameter works as expected
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f = open(TESTFN, 'w+')
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data = 'one two ones'
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f = open(TESTFN, 'wb+')
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data = b'one two ones'
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n = len(data)
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f.write(data)
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f.flush()
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m = mmap.mmap(f.fileno(), n)
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f.close()
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self.assertEqual(m.rfind('one'), 8)
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self.assertEqual(m.rfind('one '), 0)
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self.assertEqual(m.rfind('one', 0, -1), 8)
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self.assertEqual(m.rfind('one', 0, -2), 0)
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self.assertEqual(m.rfind('one', 1, -1), 8)
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self.assertEqual(m.rfind('one', 1, -2), -1)
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self.assertEqual(m.rfind(b'one'), 8)
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self.assertEqual(m.rfind(b'one '), 0)
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self.assertEqual(m.rfind(b'one', 0, -1), 8)
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self.assertEqual(m.rfind(b'one', 0, -2), 0)
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self.assertEqual(m.rfind(b'one', 1, -1), 8)
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self.assertEqual(m.rfind(b'one', 1, -2), -1)
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def test_double_close(self):
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@ -506,21 +506,15 @@ class MmapTests(unittest.TestCase):
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# Test write_byte()
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for i in range(len(data)):
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self.assertEquals(m.tell(), i)
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m.write_byte(data[i:i+1])
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m.write_byte(data[i])
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self.assertEquals(m.tell(), i+1)
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self.assertRaises(ValueError, m.write_byte, b"x")
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self.assertRaises(ValueError, m.write_byte, b"x"[0])
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self.assertEquals(m[:], data)
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# Test read_byte()
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m.seek(0)
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for i in range(len(data)):
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self.assertEquals(m.tell(), i)
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# XXX: Disable this test for now because it's not clear
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# which type of object m.read_byte returns. Currently, it
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# returns 1-length str (unicode).
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if 0:
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self.assertEquals(m.read_byte(), data[i:i+1])
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else:
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m.read_byte()
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self.assertEquals(m.read_byte(), data[i])
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self.assertEquals(m.tell(), i+1)
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self.assertRaises(ValueError, m.read_byte)
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# Test read()
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@ -11,6 +11,7 @@ What's New in Python 3.1 alpha 2?
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Core and Builtins
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-----------------
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- Implement PEP 378, Format Specifier for Thousands Separator, for
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integers.
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@ -128,6 +129,8 @@ Library
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Extension Modules
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-----------------
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- Issue #5391: mmap now deals exclusively with bytes.
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- Issue #5463: In struct module, remove deprecated overflow wrapping
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when packing an integer: struct.pack('=L', -1) now raises
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struct.error instead of returning b'\xff\xff\xff\xff'. The
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@ -204,7 +204,7 @@ mmap_read_byte_method(mmap_object *self,
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if (self->pos < self->size) {
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char value = self->data[self->pos];
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self->pos += 1;
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return Py_BuildValue("c", value);
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return Py_BuildValue("b", value);
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} else {
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PyErr_SetString(PyExc_ValueError, "read byte out of range");
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return NULL;
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@ -264,7 +264,7 @@ mmap_gfind(mmap_object *self,
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Py_ssize_t len;
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CHECK_VALID(NULL);
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if (!PyArg_ParseTuple(args, reverse ? "s#|nn:rfind" : "s#|nn:find",
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if (!PyArg_ParseTuple(args, reverse ? "y#|nn:rfind" : "y#|nn:find",
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&needle, &len, &start, &end)) {
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return NULL;
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} else {
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@ -348,7 +348,7 @@ mmap_write_method(mmap_object *self,
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char *data;
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CHECK_VALID(NULL);
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if (!PyArg_ParseTuple(args, "s#:write", &data, &length))
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if (!PyArg_ParseTuple(args, "y#:write", &data, &length))
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return(NULL);
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if (!is_writable(self))
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@ -371,7 +371,7 @@ mmap_write_byte_method(mmap_object *self,
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char value;
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CHECK_VALID(NULL);
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if (!PyArg_ParseTuple(args, "c:write_byte", &value))
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if (!PyArg_ParseTuple(args, "b:write_byte", &value))
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return(NULL);
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if (!is_writable(self))
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