findindex.py

#!/usr/bin/env python

import sys
import numpy as np
import struct

f = open(sys.argv[1])
byte_offset = int(sys.argv[2], 0)

ulong_size = struct.unpack("<i", f.read(4))[0]
ulong_fmt = '<u%d' % ulong_size
FMT = "%%0%dx" % (ulong_size*2)
dtype = np.dtype( [ ('caller', ulong_fmt), ('pc', ulong_fmt), ('cr3', ulong_fmt), ('count', '<u8') ] )
data = np.fromfile(f, dtype=dtype)

# Get cumulative sum of the sizes, starting at 0
offsets = np.zeros(data.shape[0]+1,dtype=int)
offsets[1:] = np.cumsum(data['count'])

# Use binary search to find out which tap point that byte
# offest maps to
index = np.searchsorted(offsets, byte_offset, side='right') - 1

row = data[index]
print (FMT + " " + FMT + " " + FMT) % (row['caller'], row['pc'], row['cr3'])