#!/usr/bin/python

from printf import printf
import time
import re
import numpy as np
import itertools
import struct
import array
import os
import mmap

class Timer():
    def __init__(self, arg):
        self.arg = arg
    def __enter__(self): self.start = time.time()
    def __exit__(self, *args): printf("%s: %f klines/sec\n", self.arg, 1e3 / (time.time() - self.start))

def test_struct1():
    """read with struct.unpack"""
    f = open('1m.bin', 'rb')
    f.seek(0,os.SEEK_END)
    filesize = f.tell()
    f.seek(0,os.SEEK_SET)
    packer = struct.Struct('!dHHHHHH')
    items = filesize / packer.size
    for n in xrange(items):
        s = f.read(packer.size)
        out = packer.unpack(s)
        if (n % 100000 == 0):
            printf("line %d = %s\n", n, str(out))

def test_struct2():
    """read with struct.unpack, convert to string"""
    f = open('1m.bin', 'rb')
    f.seek(0,os.SEEK_END)
    filesize = f.tell()
    f.seek(0,os.SEEK_SET)
    packer = struct.Struct('!dHHHHHH')
    items = filesize / packer.size
    for n in xrange(items):
        s = f.read(packer.size)
        out = packer.unpack(s)
        x = str(out)
        if (n % 100000 == 0):
            printf("line %d = %s\n", n, str(out))

def test_mmap():
    """struct.unpack with mmap"""
    with open('1m.bin', 'rb') as f:
        f.seek(0,os.SEEK_END)
        filesize = f.tell()
        f.seek(0,os.SEEK_SET)
        m = mmap.mmap(f.fileno(), filesize, access=mmap.ACCESS_READ)
        packer = struct.Struct('!dHHHHHH')
        items = filesize / packer.size
        for n in xrange(items):
            out = packer.unpack(m[packer.size*n : packer.size*(n+1)])
            if (n % 100000 == 0):
                printf("line %d = %s\n", n, str(out))

with Timer("mmap"):
    test_mmap()  # 1600k

with Timer("struct1"):
    test_struct1()  # 1460k

with Timer("struct2"):
    test_struct2()  # 210k

# Reading from the file is again much quicker than converting to string
# Use mmap, it's good