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# pyuca - Unicode Collation Algorithm 

# Version: 2006-02-13 

# 

# James Tauber 

# http://jtauber.com/ 

 

# Copyright (c) 2006 James Tauber 

# 

# Permission is hereby granted, free of charge, to any person obtaining a copy 

# of this software and associated documentation files (the "Software"), to deal 

# in the Software without restriction, including without limitation the rights 

# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 

# copies of the Software, and to permit persons to whom the Software is 

# furnished to do so, subject to the following conditions: 

# 

# The above copyright notice and this permission notice shall be included in 

# all copies or substantial portions of the Software. 

# 

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 

# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 

# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 

# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 

# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 

# THE SOFTWARE. 

 

 

""" 

Preliminary implementation of the Unicode Collation Algorithm. 

 

 

This only implements the simple parts of the algorithm but I have successfully 

tested it using the Default Unicode Collation Element Table (DUCET) to collate 

Ancient Greek correctly. 

 

Usage example: 

 

    from pyuca import Collator 

    c = Collator("allkeys.txt") 

 

    sorted_words = sorted(words, key=c.sort_key) 

 

allkeys.txt (1 MB) is available at 

 

    http://www.unicode.org/Public/UCA/latest/allkeys.txt 

 

but you can always subset this for just the characters you are dealing with. 

""" 

from builtins import map 

from builtins import range 

from builtins import object 

 

 

class Trie(object): 

 

    def __init__(self): 

        self.root = [None, {}] 

 

    def add(self, key, value): 

        curr_node = self.root 

        for part in key: 

            curr_node = curr_node[1].setdefault(part, [None, {}]) 

        curr_node[0] = value 

 

    def find_prefix(self, key): 

        curr_node = self.root 

        remainder = key 

        for part in key: 

            if part not in curr_node[1]: 

                break 

            curr_node = curr_node[1][part] 

            remainder = remainder[1:] 

        return (curr_node[0], remainder) 

 

 

class Collator(object): 

 

    def __init__(self, filename): 

 

        self.table = Trie() 

        self.load(filename) 

 

    def load(self, filename): 

        for line in open(filename): 

            if line.startswith("#") or line.startswith("%"): 

                continue 

            if line.strip() == "": 

                continue 

            line = line[:line.find("#")] + "\n" 

            line = line[:line.find("%")] + "\n" 

            line = line.strip() 

 

            if line.startswith("@"): 

                pass 

            else: 

                semicolon = line.find(";") 

                charList = line[:semicolon].strip().split() 

                x = line[semicolon:] 

                collElements = [] 

                while True: 

                    begin = x.find("[") 

                    if begin == -1: 

                        break 

                    end = x[begin:].find("]") 

                    collElement = x[begin:begin + end + 1] 

                    x = x[begin + 1:] 

 

                    alt = collElement[1] 

                    chars = collElement[2:-1].split(".") 

 

                    collElements.append((alt, chars)) 

                integer_points = [int(ch, 16) for ch in charList] 

                self.table.add(integer_points, collElements) 

 

    def sort_key(self, string): 

 

        collation_elements = [] 

 

        lookup_key = [ord(ch) for ch in string] 

        while lookup_key: 

            value, lookup_key = self.table.find_prefix(lookup_key) 

            if not value: 

                # @@@ 

                raise ValueError(list(map(hex, lookup_key))) 

            collation_elements.extend(value) 

 

        sort_key = [] 

 

        for level in range(4): 

            if level: 

                sort_key.append(0)  # level separator 

            for element in collation_elements: 

                ce_l = int(element[1][level], 16) 

                if ce_l: 

                    sort_key.append(ce_l) 

 

        return tuple(sort_key)