A simplistic fileinput module

fileinput.py

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+"""
+This is a simplistic implementation of fileinput module
+"""
+import sys
+
+class FileInput(object):
+    def __init__(self, files=None):
+        if not files:
+            self._files = sys.argv[1:]
+            if not self._files:
+                self._files = ("_", )
+        elif isinstance(files, list):
+            self._files = tuple(files)
+        elif isinstance(files, basestring):
+            self._files = (files, )
+        else:
+            raise ValueError("Invalid input")
+
+        self._file = None
+        self._fileindex = 0
+        self._lineindex = 0
+        self._buffer = None
+        self._filename = None
+        self._is_stdin = False
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        line = self.get_next_line()
+        if line:
+            return line
+        else:
+            raise StopIteration
+
+    def get_next_line(self):
+        if not self._buffer:
+            if not self.load_next_file():
+                return None
+        try:
+            line = self._buffer[self._lineindex]
+        except IndexError:
+            if self.load_next_file():
+                return self.get_next_line()
+            else:
+                return None
+        else:
+            self._lineindex += 1
+            return line
+
+    def load_next_file(self):
+        if not self._files:
+            return False
+        _filename = self._files[0]
+        self._files = self._files[1:]
+        self._fileindex += 1
+
+        if _filename == "_":
+            self._filename = "<std input>"
+            self._file = sys.stdin
+            self._is_stdin = True
+        else:
+            self._filename = _filename
+            if self._file and not self._is_stdin:
+                self._file.close()
+            try:
+                self._file = open(_filename, "r")
+            except:
+                return self.load_next_file()
+        self._lineindex = 0
+        self._buffer = self._file.readlines()
+        if not self._buffer:
+            return load_next_file()
+        return True
+
+    def lineno(self):
+        return self._lineindex
+
+    def fileno(self):
+        return self._fileindex
+
+    def filename(self):
+        return self._filename
+
+if __name__ == "__main__":
+    f = FileInput()
+    f = FileInput("../test.js")
+    f = FileInput(["../test.js", "../weixin.txt", "foobar.txt"])
+    for line in f:
+        print "%s(%d):%d\t%s"%(f.filename(), f.fileno(), f.lineno(), line)
+
+