Two new generally useful modules: types defines names for all built-in types,

StringIO implements pseudo files writing into and reading from strings.

diff --git a/Lib/StringIO.py b/Lib/StringIO.py
new file mode 100644 (file)
index 0000000..715e71e
--- /dev/null
+++ b/Lib/StringIO.py
@@ -0,0 +1,130 @@
+# class StringIO implements  file-like objects that read/write a
+# string buffer (a.k.a. "memory files").
+#
+# 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.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).
+# - 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).
+
+import string
+
+class StringIO:
+       def __init__(self, buf = ''):
+               self.buf = buf
+               self.pos = 0
+               self.closed = 0
+       def close(self):
+               if not self.closed:
+                       self.closed = 1
+                       del self.buf, self.pos
+       def isatty(self):
+               return 0
+       def seek(self, pos, mode = 0):
+               if mode == 1:
+                       pos = pos + self.pos
+               elif mode == 2:
+                       pos = pos + len(self.buf)
+               self.pos = max(0, pos)
+       def tell(self):
+               return self.pos
+       def read(self, n = 0):
+               if n <= 0:
+                       newpos = len(self.buf)
+               else:
+                       newpos = min(self.pos+n, len(self.buf))
+               r = self.buf[self.pos:newpos]
+               self.pos = newpos
+               return r
+       def readline(self):
+               i = string.find(self.buf, '\n', self.pos)
+               if i < 0:
+                       newpos = len(self.buf)
+               else:
+                       newpos = i+1
+               r = self.buf[self.pos:newpos]
+               self.pos = newpos
+               return r
+       def readlines(self):
+               lines = []
+               line = self.readline()
+               while line:
+                       lines.append(line)
+                       line = self.readline()
+               return lines
+       def write(self, s):
+               if not s: return
+               if self.pos > len(self.buf):
+                       self.buf = self.buf + '\0'*(self.pos - len(self.buf))
+               newpos = self.pos + len(s)
+               self.buf = self.buf[:self.pos] + s + self.buf[newpos:]
+               self.pos = newpos
+       def writelines(self, list):
+               self.write(string.joinfields(list, ''))
+       def getvalue(self):
+               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 =', `f.readline()`
+       here = f.tell()
+       line = f.readline()
+       print 'Second line =', `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.close()
+
+if __name__ == '__main__':
+       test()

diff --git a/Lib/types.py b/Lib/types.py
new file mode 100644 (file)
index 0000000..531d405
--- /dev/null
+++ b/Lib/types.py
@@ -0,0 +1,43 @@
+# Define names for all type symbols known in the standard interpreter.
+# Types that are part of optional modules (e.g. array) are not listed.
+
+import sys
+
+NoneType = type(None)
+TypeType = type(NoneType)
+
+IntType = type(0)
+LongType = type(0L)
+FloatType = type(0.0)
+
+StringType = type('')
+
+TupleType = type(())
+ListType = type([])
+DictionaryType = type({})
+
+def func(): pass
+FunctionType = type(func)
+
+class C:
+       def meth(self): pass
+ClassType = type(C)
+UnboundMethodType = type(C.meth)       # Same as MethodType
+x = C()
+InstanceType = type(x)
+MethodType = type(x.meth)
+
+BuiltinFunctionType = type(len)                # Also used for built-in methods
+
+ModuleType = type(sys)
+
+FileType = type(sys.stdin)
+XRangeType = type(xrange(0))
+
+try:
+       raise TypeError
+except TypeError:
+       TracebackType = type(sys.exc_traceback)
+       FrameType = type(sys.exc_traceback.tb_frame)
+
+del sys, func, C, x                    # These are not for export