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122 lines
3 KiB
Python
Executable file
122 lines
3 KiB
Python
Executable file
# port of StringIO.py using arrays
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# ArrayIO.py
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# jjk 02/28/96 001 direct mod of StringIO, test suite checks out
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# jjk 02/28/96 002 inherit from StringIO, test suite checks out
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# jjk 02/28/96 003 add __xx__() functions
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#
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# class ArrayIO implements file-like objects that read/write a
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# string buffer (a.k.a. "memory files").
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#
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# all methods that interface with ArrayIO pass strings. Internally, however,
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# ArrayIO uses an array object.
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#
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# the interface is the same as StringIO.py
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# also handles len(a), a[i], a[i]='x', a[i:j], a[i:j] = aString
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#
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import string
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import array
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import StringIO
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class ArrayIO(StringIO.StringIO):
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# jjk 02/28/96
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def __init__(self, buf = ''):
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#jjk 02/28/96
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self.buf = array.array('c', buf)
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self.pos = 0
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self.closed = 0
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def __len__(self):
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#jjk 02/28/96
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return len(self.buf)
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def __getitem__(self, key):
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#jjk 02/28/96
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return self.buf[key]
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def __setitem__(self, key, item):
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#jjk 02/28/96
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self.buf[key] = item
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def __getslice__(self, i, j):
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#jjk 02/28/96
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return self.buf[i:j].tostring()
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def __setslice__(self, i, j, aString):
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#jjk 02/28/96
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self.buf[i:j] = array.array('c', aString)
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def read(self, n = 0):
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#jjk 02/28/96
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r = StringIO.StringIO.read(self, n)
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return (r.tostring())
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def _findCharacter(self, char, start):
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#probably very slow
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#jjk 02/28/96
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for i in range(max(start, 0), len(self.buf)):
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if (self.buf[i] == char):
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return(i)
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return(-1)
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def readline(self):
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#jjk 02/28/96
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i = self._findCharacter('\n', self.pos)
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if i < 0:
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newpos = len(self.buf)
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else:
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newpos = i+1
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r = self.buf[self.pos:newpos].tostring()
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self.pos = newpos
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return r
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def write(self, s):
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#jjk 02/28/96
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if not s: return
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if self.pos > len(self.buf):
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self.buf.fromstring('\0'*(self.pos - len(self.buf)))
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newpos = self.pos + len(s)
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self.buf[self.pos:newpos] = array.array('c', s)
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self.pos = newpos
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def getvalue(self):
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#jjk 02/28/96
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return self.buf.tostring()
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# A little test suite
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# identical to test suite in StringIO.py , except for "f = ArrayIO()"
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# too bad I couldn't inherit this :-)
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def test():
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import sys
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if sys.argv[1:]:
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file = sys.argv[1]
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else:
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file = '/etc/passwd'
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lines = open(file, 'r').readlines()
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text = open(file, 'r').read()
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f = ArrayIO()
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for line in lines[:-2]:
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f.write(line)
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f.writelines(lines[-2:])
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if f.getvalue() != text:
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raise RuntimeError, 'write failed'
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length = f.tell()
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print 'File length =', length
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f.seek(len(lines[0]))
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f.write(lines[1])
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f.seek(0)
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print 'First line =', `f.readline()`
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here = f.tell()
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line = f.readline()
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print 'Second line =', `line`
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f.seek(-len(line), 1)
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line2 = f.read(len(line))
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if line != line2:
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raise RuntimeError, 'bad result after seek back'
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f.seek(len(line2), 1)
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list = f.readlines()
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line = list[-1]
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f.seek(f.tell() - len(line))
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line2 = f.read()
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if line != line2:
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raise RuntimeError, 'bad result after seek back from EOF'
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print 'Read', len(list), 'more lines'
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print 'File length =', f.tell()
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if f.tell() != length:
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raise RuntimeError, 'bad length'
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f.close()
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if __name__ == '__main__':
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test()
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