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diff --git a/lib/python2.7/StringIO.py b/lib/python2.7/StringIO.py
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+r"""File-like objects that read from or write to a string buffer.
+
+This implements (nearly) all stdio methods.
+
+f = StringIO()      # ready for writing
+f = StringIO(buf)   # ready for reading
+f.close()           # explicitly release resources held
+flag = f.isatty()   # always false
+pos = f.tell()      # get current position
+f.seek(pos)         # set current position
+f.seek(pos, mode)   # mode 0: absolute; 1: relative; 2: relative to EOF
+buf = f.read()      # read until EOF
+buf = f.read(n)     # read up to n bytes
+buf = f.readline()  # read until end of line ('\n') or EOF
+list = f.readlines()# list of f.readline() results until EOF
+f.truncate([size])  # truncate file at to at most size (default: current pos)
+f.write(buf)        # write at current position
+f.writelines(list)  # for line in list: f.write(line)
+f.getvalue()        # return whole file's contents as a string
+
+Notes:
+- Using a real file is often faster (but less convenient).
+- There's also a much faster implementation in C, called cStringIO, but
+  it's not subclassable.
+- fileno() is left unimplemented so that code which uses it triggers
+  an exception early.
+- Seeking far beyond EOF and then writing will insert real null
+  bytes that occupy space in the buffer.
+- There's a simple test set (see end of this file).
+"""
+try:
+    from errno import EINVAL
+except ImportError:
+    EINVAL = 22
+
+__all__ = ["StringIO"]
+
+def _complain_ifclosed(closed):
+    if closed:
+        raise ValueError, "I/O operation on closed file"
+
+class StringIO:
+    """class StringIO([buffer])
+
+    When a StringIO object is created, it can be initialized to an existing
+    string by passing the string to the constructor. If no string is given,
+    the StringIO will start empty.
+
+    The StringIO object can accept either Unicode or 8-bit strings, but
+    mixing the two may take some care. If both are used, 8-bit strings that
+    cannot be interpreted as 7-bit ASCII (that use the 8th bit) will cause
+    a UnicodeError to be raised when getvalue() is called.
+    """
+    def __init__(self, buf = ''):
+        # Force self.buf to be a string or unicode
+        if not isinstance(buf, basestring):
+            buf = str(buf)
+        self.buf = buf
+        self.len = len(buf)
+        self.buflist = []
+        self.pos = 0
+        self.closed = False
+        self.softspace = 0
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        """A file object is its own iterator, for example iter(f) returns f
+        (unless f is closed). When a file is used as an iterator, typically
+        in a for loop (for example, for line in f: print line), the next()
+        method is called repeatedly. This method returns the next input line,
+        or raises StopIteration when EOF is hit.
+        """
+        _complain_ifclosed(self.closed)
+        r = self.readline()
+        if not r:
+            raise StopIteration
+        return r
+
+    def close(self):
+        """Free the memory buffer.
+        """
+        if not self.closed:
+            self.closed = True
+            del self.buf, self.pos
+
+    def isatty(self):
+        """Returns False because StringIO objects are not connected to a
+        tty-like device.
+        """
+        _complain_ifclosed(self.closed)
+        return False
+
+    def seek(self, pos, mode = 0):
+        """Set the file's current position.
+
+        The mode argument is optional and defaults to 0 (absolute file
+        positioning); other values are 1 (seek relative to the current
+        position) and 2 (seek relative to the file's end).
+
+        There is no return value.
+        """
+        _complain_ifclosed(self.closed)
+        if self.buflist:
+            self.buf += ''.join(self.buflist)
+            self.buflist = []
+        if mode == 1:
+            pos += self.pos
+        elif mode == 2:
+            pos += self.len
+        self.pos = max(0, pos)
+
+    def tell(self):
+        """Return the file's current position."""
+        _complain_ifclosed(self.closed)
+        return self.pos
+
+    def read(self, n = -1):
+        """Read at most size bytes from the file
+        (less if the read hits EOF before obtaining size bytes).
+
+        If the size argument is negative or omitted, read all data until EOF
+        is reached. The bytes are returned as a string object. An empty
+        string is returned when EOF is encountered immediately.
+        """
+        _complain_ifclosed(self.closed)
+        if self.buflist:
+            self.buf += ''.join(self.buflist)
+            self.buflist = []
+        if n is None or n < 0:
+            newpos = self.len
+        else:
+            newpos = min(self.pos+n, self.len)
+        r = self.buf[self.pos:newpos]
+        self.pos = newpos
+        return r
+
+    def readline(self, length=None):
+        r"""Read one entire line from the file.
+
+        A trailing newline character is kept in the string (but may be absent
+        when a file ends with an incomplete line). If the size argument is
+        present and non-negative, it is a maximum byte count (including the
+        trailing newline) and an incomplete line may be returned.
+
+        An empty string is returned only when EOF is encountered immediately.
+
+        Note: Unlike stdio's fgets(), the returned string contains null
+        characters ('\0') if they occurred in the input.
+        """
+        _complain_ifclosed(self.closed)
+        if self.buflist:
+            self.buf += ''.join(self.buflist)
+            self.buflist = []
+        i = self.buf.find('\n', self.pos)
+        if i < 0:
+            newpos = self.len
+        else:
+            newpos = i+1
+        if length is not None and length >= 0:
+            if self.pos + length < newpos:
+                newpos = self.pos + length
+        r = self.buf[self.pos:newpos]
+        self.pos = newpos
+        return r
+
+    def readlines(self, sizehint = 0):
+        """Read until EOF using readline() and return a list containing the
+        lines thus read.
+
+        If the optional sizehint argument is present, instead of reading up
+        to EOF, whole lines totalling approximately sizehint bytes (or more
+        to accommodate a final whole line).
+        """
+        total = 0
+        lines = []
+        line = self.readline()
+        while line:
+            lines.append(line)
+            total += len(line)
+            if 0 < sizehint <= total:
+                break
+            line = self.readline()
+        return lines
+
+    def truncate(self, size=None):
+        """Truncate the file's size.
+
+        If the optional size argument is present, the file is truncated to
+        (at most) that size. The size defaults to the current position.
+        The current file position is not changed unless the position
+        is beyond the new file size.
+
+        If the specified size exceeds the file's current size, the
+        file remains unchanged.
+        """
+        _complain_ifclosed(self.closed)
+        if size is None:
+            size = self.pos
+        elif size < 0:
+            raise IOError(EINVAL, "Negative size not allowed")
+        elif size < self.pos:
+            self.pos = size
+        self.buf = self.getvalue()[:size]
+        self.len = size
+
+    def write(self, s):
+        """Write a string to the file.
+
+        There is no return value.
+        """
+        _complain_ifclosed(self.closed)
+        if not s: return
+        # Force s to be a string or unicode
+        if not isinstance(s, basestring):
+            s = str(s)
+        spos = self.pos
+        slen = self.len
+        if spos == slen:
+            self.buflist.append(s)
+            self.len = self.pos = spos + len(s)
+            return
+        if spos > slen:
+            self.buflist.append('\0'*(spos - slen))
+            slen = spos
+        newpos = spos + len(s)
+        if spos < slen:
+            if self.buflist:
+                self.buf += ''.join(self.buflist)
+            self.buflist = [self.buf[:spos], s, self.buf[newpos:]]
+            self.buf = ''
+            if newpos > slen:
+                slen = newpos
+        else:
+            self.buflist.append(s)
+            slen = newpos
+        self.len = slen
+        self.pos = newpos
+
+    def writelines(self, iterable):
+        """Write a sequence of strings to the file. The sequence can be any
+        iterable object producing strings, typically a list of strings. There
+        is no return value.
+
+        (The name is intended to match readlines(); writelines() does not add
+        line separators.)
+        """
+        write = self.write
+        for line in iterable:
+            write(line)
+
+    def flush(self):
+        """Flush the internal buffer
+        """
+        _complain_ifclosed(self.closed)
+
+    def getvalue(self):
+        """
+        Retrieve the entire contents of the "file" at any time before
+        the StringIO object's close() method is called.
+
+        The StringIO object can accept either Unicode or 8-bit strings,
+        but mixing the two may take some care. If both are used, 8-bit
+        strings that cannot be interpreted as 7-bit ASCII (that use the
+        8th bit) will cause a UnicodeError to be raised when getvalue()
+        is called.
+        """
+        _complain_ifclosed(self.closed)
+        if self.buflist:
+            self.buf += ''.join(self.buflist)
+            self.buflist = []
+        return self.buf
+
+
+# A little test suite
+
+def test():
+    import sys
+    if sys.argv[1:]:
+        file = sys.argv[1]
+    else:
+        file = '/etc/passwd'
+    lines = open(file, 'r').readlines()
+    text = open(file, 'r').read()
+    f = StringIO()
+    for line in lines[:-2]:
+        f.write(line)
+    f.writelines(lines[-2:])
+    if f.getvalue() != text:
+        raise RuntimeError, 'write failed'
+    length = f.tell()
+    print 'File length =', length
+    f.seek(len(lines[0]))
+    f.write(lines[1])
+    f.seek(0)
+    print 'First line =', repr(f.readline())
+    print 'Position =', f.tell()
+    line = f.readline()
+    print 'Second line =', repr(line)
+    f.seek(-len(line), 1)
+    line2 = f.read(len(line))
+    if line != line2:
+        raise RuntimeError, 'bad result after seek back'
+    f.seek(len(line2), 1)
+    list = f.readlines()
+    line = list[-1]
+    f.seek(f.tell() - len(line))
+    line2 = f.read()
+    if line != line2:
+        raise RuntimeError, 'bad result after seek back from EOF'
+    print 'Read', len(list), 'more lines'
+    print 'File length =', f.tell()
+    if f.tell() != length:
+        raise RuntimeError, 'bad length'
+    f.truncate(length/2)
+    f.seek(0, 2)
+    print 'Truncated length =', f.tell()
+    if f.tell() != length/2:
+        raise RuntimeError, 'truncate did not adjust length'
+    f.close()
+
+if __name__ == '__main__':
+    test()