find string in file using just read(1)

read(1).py

import cProfile
import pstats

def meth():
	check = 'abst'
	c=1
	r=1
	location = (-1, -1)
	with open("temp.txt", 'rb') as p:
		ch = p.read(1)
		while(ch != ""):
			if ch == check[0]:
				st = p.read(len(check)-1)
				if ch+st == check:
					location = (r, c)
					break
				else:
					p.seek(-len(check)+1, 1)
			ch = p.read(1)
			#print("-- {:<2} {:<4}".format(ch, ord(ch)))
			c+=1
			if ch == '\n':
				c=0
				r+=1
	print("loc: {}, {}".format(*location))

#import mmap
#with open('temp.txt', 'rb') as f:
#	m = mmap.mmap(f.fileno(), 0, mmap.MAP_PRIVATE, mmap.PROT_READ)
#	position = m.index('abst')

def meth2():
	string = "abst"
	f = open("temp.txt", "rb")
	f.seek(0)
	location = (-1, -1)
	row = 1
	col = 0 
	cont = 1
	idx = 0
	while True:
		c = f.read(1)
		col += 1

		if c == '':
			break
		if c == string[idx]:
			idx += 1
		else:
			idx = 0

		if c == '\n':
			col = 0
			row += 1
		if idx == len(string):
			location = (row, col-len(string)+1)
			break
	print location
	
def meth3():
	string = "abst"
	f = open("temp.txt", "rb")
	f.seek(0)

	cont = 1
	idx = 0
	while True:
		c = f.read(1)
		if c == '':
			break
		if c == string[idx]:
			idx += 1
		else:
			idx = 0
		if idx == len(string):
			print "Found"
			break

def find(file, name):
    length = len(name)
    part = file.read(length)
    i = 0
    while True:
        if part == name:
            break
        char = file.read(1)
        if not char:
            return
        part = part[1:] + char
        i += 1
    return i, i + length, part

def meth4():
    with open("temp.txt", 'rb') as f:
        print find(f, "abst")
	
def main():
	cProfile.run("meth()", "f1")
	cProfile.run("meth2()", "f2")
	cProfile.run("meth3()", "f3")	
	cProfile.run("meth3()", "f4")	
	
	p1 = pstats.Stats("f1")
	p2 = pstats.Stats("f2")
	p3 = pstats.Stats("f3")
	p4 = pstats.Stats("f4")
	
	p1.sort_stats('cumulative').print_stats(15)
	p2.sort_stats('cumulative').print_stats(15)
	p3.sort_stats('cumulative').print_stats(15)
	p4.sort_stats('cumulative').print_stats(15)

if __name__ == "__main__":
	main()

http://stackoverflow.com/questions/7052883/how-to-find-substring-in-file/