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worblehat-old/python/PyZ3950/grs1.py

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Python

#!/usr/bin/env python
"""Utility functions for GRS-1 data"""
from __future__ import nested_scopes
# XXX still need to tag non-leaf nodes w/ (tagType, tagValue)
# XXX tagType can be omitted. If so, default either supplied
# dynamically by tagSet-M or statically spec'd by schema
# from TAG (Z39.50-1995 App 12): tagType 1 is tagSet-M, 2 tagSet-G,
# 3 locally defined.
class Node:
"""Defined members are:
tag - tag (always present, except for top node)
metadata - metadata (opt, seriesOrder only for nonleaf - v. RET.3.2.3 )
children - list of Node
leaf - leaf data (children and leaf are mutually exclusive)
"""
def __init__ (self, **kw):
self.__dict__.update (kw)
self.tab_size = 3 # controls str() indentation width
def str_depth (self, depth):
l = []
children = getattr (self, 'children', [])
leaf = getattr (self, 'leaf', None)
tag = getattr (self, 'tag', None)
indent = " " * (self.tab_size * depth)
if leaf <> None:
l.append ("%s%s %s" % (
indent, str (tag), leaf.content))
else:
if tag <> None:
l.append (indent + str (tag))
meta = getattr (self, 'metadata', None)
if meta <> None:
l.append (indent + 'metadata: ' + str (meta))
l.append ("".join (map (
lambda n: n.str_depth (depth + 1), children)))
return "\n".join (l)
def __str__ (self):
return "\n" + self.str_depth (-1)
def preproc (raw):
"""Transform the raw output of the asn.1 decoder into something
a bit more programmer-friendly. (This is automatically called
by the ZOOM API, so you don't need to worry about it unless you're
using the raw z3950 API.)
"""
if isinstance (raw, type ([])):
return Node (children = map (preproc, raw))
else: # TaggedElement
kw = {}
tag = (raw.tagType, raw.tagValue [1])
# Value [0] is str vs. num indicator
kw ['tag'] = tag
meta = getattr (raw, 'metaData', None)
if meta <> None:
kw ['metadata'] = meta
if raw.content[0] == 'subtree':
return Node (children = map (preproc, raw.content [1]), **kw)
else:
# tag and metadata are here redundantly encoded as
# both attributes of leaf and of Node. Use the Node
# attribs, I'll try to clean this up sometime.
return Node (leaf = raw, **kw)