e-rsatz

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Here below a function decoding IIOP's CDR streams:

def ACE_read(typeLength):    if typeLength:  # scalar (char:1, int:4, ...)      def sclRead(buf, index, big=1):        alignedIndex=(index + (typeLength-1)) & ~(typeLength-1)        if alignedIndex + typeLength > len(buf):          return None, None, False        endIndex=alignedIndex + typeLength        return ordn(big)(buf[alignedIndex:endIndex]), endIndex, True      return sclRead    else:   # string      def strRead(buf,index,length,big=1):        endIndex =index + length        if endIndex > len(buf): return None, None, False          return buf[index:endIndex], endIndex, True      return strRead

I like nested functions...
And I like functions returning tuples !

Usage examples:

    # reads a 13 bytes string and actualize index
    __aString, index, ok = ACE_read(0)(buffer, index, 13)
    if not ok: doSomething()

    # reads an aligned-4-byte-long integer located somewhere by index
    __anInteger, index, ok = ACE_read(4)(buffer, index)   

This entry

The following function converts a sequence of bytes into an integer. It is endianness-sensitive:

def ordn(big=1):    if big % 2:      def bordn(seq):        if len(seq) > 1: return ord(seq[-1]) + (bordn(seq[:-1]) << 8)        else: return ord(seq[0])      return bordn    else:      def lordn(seq):        if len(seq) >1: return ord(seq[0]) + (lordn(seq[1:]) << 8)        else: return ord(seq[0])      return lordn

>>> ordn(1)('\x01\x00')
256
>>> ordn(0)('\x01\x00')
1

Ok, that's probably not the prettiest nor the fastest way to do...

This entry

To insert a white space before each uppercase letter within a string:

    "".join([(i.isupper() and " "+i) or i for i in "PythonIsCool"])

or for the ones who like functional programming:

    "".join(map(lambda x:(x.isupper() and " "+x) or x,"PythonIsCool"))

But I do personnally do like list comprehensions...