Chunking combinations and simple lists

chunker.py

#!/usr/bin/env python


class SimpleChunker:
    """For chunking simple lists"""
    def __init__(self, size, chunksize):
        self.size = size
        self.chunksize = chunksize
        self.chunk = 0
        self.total = size
    
    def gen_chunks(self):
        self.chunk += 1
        begin = (self.chunk - 1) * self.chunksize
        end = begin + self.chunksize
        if end > self.size:
            end = self.size
        if begin > self.size:
            begin = self.size
        return range(begin,end)
    
    def get_chunk(self):
        return list(self.gen_chunks())
    
    def chunk_available(self):
        return self.chunk * self.chunksize <= self.total


class CombinationChunker:
    """For chunking combinations"""
    def __init__(self, size, chunksize):
        self.size = size
        self.chunksize = chunksize
        self.chunk = 0
        self.total = int(self.size * (self.size - 1) / 2)
    
    def gen_chunks(self):
        self.chunk += 1
        t = self.chunk*self.chunksize
        stop = 1
        
        for i in range(self.size - 1):
            ii = self.size - 1 -i
            if t > ii:
                t -= ii
                stop += 1
            else:
                break
        
        z0 = (self.chunk-1)*self.chunksize
        z = self.chunk*self.chunksize
        for x in range(stop):
            h = self.size - 1 -x
            p = 1 + x
            if z0+1 > h:
                begin = self.size
            else:
                if z0 < 0:
                    z0 = 0
                begin = z0 + p
            if z+1 > h:
                end = self.size
            else:
                end = z + p
            z0 -= h
            z -= h
            for y in range(begin,end):
                yield((x,y))
    
    def get_chunk(self):
        return list(self.gen_chunks())
    
    def chunk_available(self):
        return self.chunk*self.chunksize <= self.total


def main():
    print("\nCHUNKED ITEM GENERATION")
    c = SimpleChunker(10,3)
    print("Chunk Available" if c.chunk_available() else "Finished", c.get_chunk()) #=> (0,3)
    print("Chunk Available" if c.chunk_available() else "Finished", c.get_chunk()) #=> (3,6)
    print("Chunk Available" if c.chunk_available() else "Finished", c.get_chunk()) #=> (6,9)
    print("Chunk Available" if c.chunk_available() else "Finished", c.get_chunk()) #=> (9,10)
    print("Chunk Available" if c.chunk_available() else "Finished", c.get_chunk()) #=> (10,10)
    print("Chunk Available" if c.chunk_available() else "Finished", c.get_chunk()) #=> (10,10)

    print("\nCHUNKED COMBINATION GENERATION")
    b = CombinationChunker(10, 3)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (1,4)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (4,7)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (7,10)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (10,10) (2,5)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (10,10) (5,8)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (10,10) (8,10) (3,4)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (10,10) (10,10) (4,7)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (10,10) (10,10) (7,10)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (10,10) (10,10) (10,10) (4,7)
    print("Chunk Available" if b.chunk_available() else "Finished", b.get_chunk()) #=> (10,10) (10,10) (10,10) (7,10) ...

if __name__ == "__main__":
    main()