ponysay/src/metadata.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

'''
ponysay - Ponysay, cowsay reimplementation for ponies

Copyright (C) 2012, 2013  Erkin Batu Altunbaş et al.


This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.


If you intend to redistribute ponysay or a fork of it commercially,
it contains aggregated images, some of which may not be commercially
redistribute, you would be required to remove those. To determine
whether or not you may commercially redistribute an image make use
that line ‘FREE: yes’, is included inside the image between two ‘$$$’
lines and the ‘FREE’ is and upper case and directly followed by
the colon.
'''
from common import *



class Metadata():
    '''
    Metadata functions
    '''
    
    @staticmethod
    def makeRestrictionLogic(restriction):
        '''
        Make restriction test logic function
        
        @param   restriction:list<string>  Metadata based restrictions
        @return  :dict<str, str>→bool      Test function
        '''
        def get_test(cell):
            strict = cell[0][-1] != '?'
            key = cell[0]
            if not strict:
                key = key[:-1]
            invert = cell[1][0] == '!'
            value = cell[1][1 if invert else 0:]
            
            class SITest():
                def __init__(self, cellkey, cellvalue):
                    (self.cellkey, self.cellvalue) = (cellkey, cellvalue)
                def __call__(self, has):
                    return False if self.cellkey not in has else (self.cellvalue not in has[self.cellkey])
                def __str__(self):
                    return 'si(%s : %s)' % (self.cellkey, self.callvalue)
            class STest():
                def __init__(self, cellkey, cellvalue):
                    (self.cellkey, self.cellvalue) = (cellkey, cellvalue)
                def __call__(self, has):
                    return False if self.cellkey not in has else (self.cellvalue in has[self.cellkey])
                def __str__(self):
                    return 's(%s : %s)' % (self.cellkey, self.callvalue)
            class ITest():
                def __init__(self, cellkey, cellvalue):
                    (self.cellkey, self.cellvalue) = (cellkey, cellvalue)
                def __call__(self, has):
                    return True if self.cellkey not in has else (self.cellvalue not in has[self.cellkey])
                def __str__(self):
                    return 'i(%s : %s)' % (self.cellkey, self.callvalue)
            class NTest():
                def __init__(self, cellkey, cellvalue):
                    (self.cellkey, self.cellvalue) = (cellkey, cellvalue)
                def __call__(self, has):
                    return True if self.cellkey not in has else (self.cellvalue in has[self.cellkey])
                def __str__(self):
                    return 'n(%s : %s)' % (self.cellkey, self.callvalue)
            
            if strict and invert:  return SITest(key, value)
            if strict:             return STest(key, value)
            if invert:             return ITest(key, value)
            return NTest(key, value)
        
        class Logic():
            def __init__(self, table):
                self.table = table
            def __call__(self, cells):
                for alternative in self.table:
                    ok = True
                    for cell in alternative:
                        if not cell(cells):
                            ok = False
                            break
                    if ok:
                        return True
                return False
        
        table = [[get_test((cell[:cell.index('=')].upper(), cell[cell.index('=') + 1:]))
                  for cell in clause.replace('_', '').replace(' ', '').split('+')]
                  for clause in restriction
                ]
        
        return Logic(table)
    
    
    @staticmethod
    def restrictedPonies(ponydir, logic):
        '''
        Get ponies that pass restriction
        
        @param   ponydir:str       Pony directory, must end with `os.sep`
        @param   logic:(str)→bool  Restriction test functor
        @return  :list<str>        Passed ponies
        '''
        import pickle
        passed = []
        if os.path.exists(ponydir + 'metadata'):
            data = None
            with open(ponydir + 'metadata', 'rb') as file:
                data = pickle.load(file)
            for ponydata in data:
                (pony, meta) = ponydata
                if logic(meta):
                    passed.append(pony)
        return passed
    
    
    @staticmethod
    def getFitting(fitting, requirement, file):
        '''
        Get ponies that fit the terminal
        
        @param  fitting:add(str)→void  The set to fill
        @param  requirement:int        The maximum allowed value
        @param  file:istream           The file with all data
        '''
        data = file.read() # not too much data, can load everything at once
        ptr = 0
        while data[ptr] != 47: # 47 == ord('/')
            ptr += 1
        ptr += 1
        size = 0
        while data[ptr] != 47: # 47 == ord('/')
            size = (size * 10) - (data[ptr] & 15)
            ptr += 1
        ptr += 1
        jump = ptr - size
        stop = 0
        backjump = 0
        while ptr < jump:
            size = 0
            while data[ptr] != 47: # 47 == ord('/')
                size = (size * 10) - (data[ptr] & 15)
                ptr += 1
            ptr += 1
            if -size > requirement:
                if backjump > 0:
                    ptr = backjump
                    while data[ptr] != 47: # 47 == ord('/')
                        stop = (stop * 10) - (data[ptr] & 15)
                        ptr += 1
                    stop = -stop
                break
            backjump = ptr
            while data[ptr] != 47: # 47 == ord('/')
                ptr += 1
            ptr += 1
        if ptr == jump:
            stop = len(data)
        else:
            ptr = jump
            stop += ptr
        passed = data[jump : stop].decode('utf8', 'replace').split('/')
        for pony in passed:
            fitting.add(pony)