
# pylint: disable-msg=C0302
# C0302: I'm afraid we need a huge module, at least for now

'''
Module provides a timsort.  This will probably be a bit slower than the hand coded C extension module, but it's nice for comparing to
other sorts in Cython
'''

import exceptions
from array import array

def timsort_2lists(list_1, list_2, comparefn=cmp):
	'''Sort function for timsort'''
	timsort_object = Timsort(list_1, list_2, comparefn=comparefn)
	timsort_object.sort(low = 0, high = len(list_))
	
def array_copy(list1_1, list1_2, base1, list2_1, list2_2, base2, length):
	'''
	Copy from list1 to list2 at offsets base1 and base2, for length elements.
	Like Java's System.arraycopy.
	'''

	#print 'in array_copy length is', length
	#length += 1
	#print 'in array_copy length is', length

	#print 'in array_copy copying from', list1, list1[base1:base1+length]
	#print 'in array_copy copying to  ', list2, list2[base2:base2+length]
	if id(list1_1) == id(list2_1):
		#print 'in array_copy lists are the same'
		if base1 < base2:
			# we're copying from a low position to a higher position in the same array, so copy backwards
			copy_forward = False
		else:
			# we're copying from a high position to a lower position in the same array, so copy forwards
			copy_forward = True
	else:
		# two different lists - direction doesn't matter
		copy_forward = True

	if copy_forward:
		#print 'in array_copy copying forward'
		for offset in xrange(length):
			list2_1[base2 + offset] = list1_1[base1 + offset]
			list2_2[base2 + offset] = list1_2[base1 + offset]
	else:
		#print 'in array_copy copying backward'
		for offset in xrange(length-1, -1, -1):
			list2_1[base2 + offset] = list1_1[base1 + offset]
			list2_2[base2 + offset] = list1_2[base1 + offset]

	#print 'in array_copy result is   ', list2, list2[base2:base2+length]

	#raise exceptions.AssertionError

def gallop_right(key, list_, base, length, hint, comparefn):
	# pylint: disable-msg=R0913
	# R0913: We need a lot of arguments, at least for now
	'''
	Like gallop_left, except that if the range contains an element equal to
	key, gallop_right returns the index after the rightmost equal element.
	
	@param key the key whose insertion point to search for
	@param list_ the array in which to search
	@param base the index of the first element in the range
	@param length the length of the range; must be > 0
	@param hint the index at which to begin the search, 0 <= hint < number.
	 The closer hint is to the result, the faster this method will run.
	@param comparefn the comparator used to order the range, and to search
	@return the int k,  0 <= k <= number such that list_[b + k - 1] <= key < list_[b + k]
	'''
	assert length > 0 and hint >= 0 and hint < length

	offset = 1
	last_offset = 0
	if comparefn(key, list_[base + hint]) < 0:
		# Gallop left until list_[b+hint - offset] <= key < list_[b+hint - last_offset]
		max_offset = hint + 1
		while offset < max_offset and comparefn(key, list_[base + hint - offset]) < 0:
			last_offset = offset
			offset = (offset << 1) + 1
			if offset <= 0:
				# int overflow
				offset = max_offset
		if offset > max_offset:
			offset = max_offset

		# Make offsets relative to b
		tmp = last_offset
		last_offset = hint - offset
		offset = hint - tmp
	else:
		# list_[b + hint] <= key
		# Gallop right until list_[b+hint + last_offset] <= key < list_[b+hint + offset]
		max_offset = length - hint
		while offset < max_offset and comparefn(key, list_[base + hint + offset]) >= 0:
			last_offset = offset
			offset = (offset << 1) + 1
			if offset <= 0:
				# int overflow
				offset = max_offset
		if offset > max_offset:
			offset = max_offset

		# Make offsets relative to b
		last_offset += hint
		offset += hint
	assert -1 <= last_offset and last_offset < offset and offset <= length

	#
	# Now list_[b + last_offset] <= key < list_[b + offset], so key belongs somewhere to
	# the right of last_offset but no farther right than offset.  Do a binary
	# search, with invariant list_[b + last_offset - 1] <= key < list_[b + offset].
	#
	last_offset += 1
	while last_offset < offset:
		midpoint = last_offset + ((offset - last_offset) / 2)

		if comparefn(key, list_[base + midpoint]) < 0:
			# key < list_[b + midpoint]
			offset = midpoint
		else:
			# list_[b + midpoint] <= key
			last_offset = midpoint + 1
	# so list_[b + offset - 1] <= key < list_[b + offset]
	assert last_offset == offset
	return offset

def gallop_left(key, list_, base, length, hint, comparefn):
	# pylint: disable-msg=R0913
	# R0913: We need a lot of arguments, at least for now
	'''
	Locates the position at which to insert the specified key into the
	specified sorted range; if the range contains an element equal to key,
	returns the index of the leftmost equal element.
	
	@param key the key whose insertion point to search for
	@param list_ the array in which to search
	@param base the index of the first element in the range
	@param length the length of the range; must be > 0
	@param hint the index at which to begin the search, 0 <= hint < number.
	 The closer hint is to the result, the faster this method will run.
	@param c the comparator used to order the range, and to search
	@return the int k,  0 <= k <= number such that list_[b + k - 1] < key <= list_[b + k],
	pretending that list_[b - 1] is minus infinity and list_[b + number] is infinity.
	In other words, key belongs at index b + k; or in other words,
	the first k elements of list_ should precede key, and the last number - k
	should follow it.
	'''
	assert length > 0 and hint >= 0 and hint < length
	last_offset = 0
	offset = 1
	if comparefn(key, list_[base + hint]) > 0:
		# Gallop right until list_[base+hint+last_offset] < key <= list_[base+hint+offset]
		max_offset = length - hint
		while offset < max_offset and comparefn(key, list_[base + hint + offset]) > 0:
			last_offset = offset
			offset = (offset << 1) + 1
			if offset <= 0:
				# int overflow
				offset = max_offset
		if offset > max_offset:
			offset = max_offset

		# Make offsets relative to base
		last_offset += hint
		offset += hint
	else:
		# key <= list_[base + hint]
		# Gallop left until list_[base+hint-offset] < key <= list_[base+hint-last_offset]
		max_offset = hint + 1
		while offset < max_offset and comparefn(key, list_[base + hint - offset]) <= 0:
			last_offset = offset
			offset = (offset << 1) + 1
			if offset <= 0:
				# int overflow
				offset = max_offset
		if offset > max_offset:
			offset = max_offset

		# Make offsets relative to base
		tmp = last_offset
		last_offset = hint - offset
		offset = hint - tmp
	assert -1 <= last_offset and last_offset < offset and offset <= length

	#
	# Now list_[base+last_offset] < key <= list_[base+offset], so key belongs somewhere
	# to the right of last_offset but no farther right than offset.  Do list_ binary
	# search, with invariant list_[base + last_offset - 1] < key <= list_[base + offset].
	#
	last_offset += 1
	while last_offset < offset:
		midpoint = last_offset + ((offset - last_offset) / 2)

		if comparefn(key, list_[base + midpoint]) > 0:
			# list_[base + midpoint] < key
			last_offset = midpoint + 1
		else:
			# key <= list_[base + midpoint]
			offset = midpoint
	# so list_[base + offset - 1] < key <= list_[base + offset]
	assert last_offset == offset
	return offset

def binary_sort(list_1, list_2, low,  high,  start, comparefn):
	'''
	Sorts the specified portion of the specified array using a binary
	insertion sort.  This is the best method for sorting small numbers
	of elements.  It requires O(n log n) compares, but O(n^2) data
	movement (worst case).
	
	If the initial part of the specified range is already sorted,
	this method can take advantage of it: the method assumes that the
	elements from index {@code low}, inclusive, to {@code start},
	exclusive are already sorted.
	
	@param list_ the array in which a range is to be sorted
	@param low the index of the first element in the range to be sorted
	@param high the index after the last element in the range to be sorted
	@param start the index of the first element in the range that is
		not already known to be sorted (@code low <= start <= high}
	@param comparefn comparator to used for the sort
	'''
	#print 'at start of binary_sort list_ is', list_
	#print 'at start of binary_sort low is', low, 'start is', start, 'high is', high
	assert low <= start and start <= high
	if start == low:
		start += 1
	for start in xrange(start, high):
		#print 'in binary_search at top of main loop, sorted so far is', list_[low:start]
		pivot = list_1[start]
		pivot_2 = list_2[start]
		#print 'in binary_sort placing %s (index %d)' % (pivot, start)

		# Set left (and right) to the index where list_[start] (pivot) belongs
		left = low
		right = start
		assert left <= right
		#
		# Invariants:
		#   pivot >= all in [low, left).
		#   pivot <  all in [right, start).
		#
		while left < right:
			mid = (left + right) / 2
			if comparefn(pivot, list_1[mid]) < 0:
				right = mid
			else:
				left = mid + 1
		assert left == right

		#
		# The invariants still hold: pivot >= all in [low, left) and
		# pivot < all in [left, start), so pivot belongs at left.  Note
		# that if there are elements equal to pivot, left points to the
		# first slot after them -- that's why this sort is stable.
		# Slide elements over to make room to make room for pivot.
		#
		# The number of elements to move
		#print 'pivot value %s belongs at index %d' % (pivot, left)
		number = start - left
		#print 'in binary_sort main loop number of elements to copy is', number
		# Switch is just an optimization for arraycopy in default case
#			switch(number)
#				case 2:  list_[left + 2] = list_[left + 1]
#				case 1:  list_[left + 1] = list_[left]
#						 break
#				default: System.arraycopy(list_, left, list_, left + 1, number)
		array_copy(list_1, list_2, left, list_1, list_2, left + 1, number)
		list_1[left] = pivot
		list_2[left] = pivot2
		#print 'at end of binary_sort main loop list_ is', list_
	#print 'at end of binary_sort list_ is', list_

def reverse_range(list_1, list_2, low, high):
	'''
	Reverse the specified range of the specified array.
	
	@param list_ the array in which a range is to be reversed
	@param low the index of the first element in the range to be reversed
	@param high the index after the last element in the range to be reversed
	'''
	#print 'at start of reverse_range list_ is', list_, 'low is', low, 'high is', high
	high -= 1
	while low < high:
		#temp = list_[low]
		#list_[low] = list_[high]
		#low += 1
		#list_[high] = temp
		#high -= 1
		list_1[low], list_1[high] = list_1[high], list_1[low]
		list_2[low], list_2[high] = list_2[high], list_2[low]
		low += 1
		high -= 1
	#print 'at end of reverse_range list_ is  ', list_, 'low is', low, 'high is', high
	#raise exceptions.AssertionError

def count_run_and_make_ascending(list_1, list_2, low, high, comparefn):
	'''
	Returns the length of the run beginning at the specified position in
	the specified array and reverses the run if it is descending (ensuring
	that the run will always be ascending when the method returns).
	
	A run is the longest ascending sequence with:
	
		list_[low] <= list_[low + 1] <= list_[low + 2] <= ...
	
	or the longest descending sequence with:
	
		list_[low] >  list_[low + 1] >  list_[low + 2] >  ...
	
	For its intended use in a stable mergesort, the strictness of the
	definition of "descending" is needed so that the call can safely
	reverse a descending sequence without violating stability.
	
	@param list_ the array in which a run is to be counted and possibly reversed
	@param low index of the first element in the run
	@param high index after the last element that may be contained in the run.
	 It is required that @code{low < high}.
	@param comparefn the comparator to used for the sort
	@return  the length of the run beginning at the specified position in
			  the specified array
	'''
	#print 'in count_run_and_make_ascending low is', low, 'high is', high
	assert low < high
	run_high = low + 1
	if run_high == high:
		return 1

	# Find end of run, and reverse range if descending
	if comparefn(list_1[run_high], list_1[low]) < 0:
		# Descending
		run_high += 1
		while run_high < high and comparefn(list_1[run_high], list_1[run_high - 1]) < 0:
			run_high += 1
		reverse_range(list_1, low, run_high)
	else:
		# Ascending
		run_high += 1
		while run_high < high and comparefn(list_1[run_high], list_1[run_high - 1]) >= 0:
			run_high += 1

	return run_high - low

class Timsort:
	# pylint: disable-msg=R0902
	# R0902: We need lots of instance attributes, at least for now
	'''Class for timsort'ing'''

	# This is the minimum sized sequence that will be merged.  Shorter
	# sequences will be lengthened by calling binary_sort.  If the entire
	# array is less than this length, no merges will be performed.
	#
	# This constant should be a power of two.  It was 64 in Tim Peter's C
	# implementation, but 32 was empirically determined to work better in
	# this implementation.  In the unlikely event that you set this constant
	# to be a number that's not a power of two, you'll need to change the
	# {@link #min_run_length} computation.
	#
	# If you decrease this constant, you must change the stackLen
	# computation in the Timsort constructor, or you risk an
	# ArrayOutOfBounds exception.  See listsort.txt for a discussion
	# of the minimum stack length required as a function of the length
	# of the array being sorted and the minimum merge sequence length.
	#
	

	#
	# The array being sorted.
	#
	

	#
	# The comparator for this sort.
	#
	#private final Comparator<? super T> comparefn
	

	#
	# When we get into galloping mode, we stay there until both runs win less
	# often than MIN_GALLOP consecutive times.
	#
	#private static final int  MIN_GALLOP = 7
	

	#
	# This controls when we get *into* galloping mode.  It is initialized
	# to self.min_gallop.  The merge_low and merge_high methods nudge it higher for
	# random data, and lower for highly structured data.
	#
	

	#
	# Maximum initial size of tmp array, which is used for merging.  The array
	# can grow to accommodate demand.
	#
	# Unlike Tim's original C version, we do not allocate this much storage
	# when sorting smaller arrays.  This change was required for performance.
	#
	

	#
	# Temp storage for merges.
	#
	# Actual runtime type will be Object[], regardless of T
	

	#
	# A stack of pending runs yet to be merged.  Run i starts at
	# address base[i] and extends for length[i] elements.  It's always
	# true (so long as the indices are in bounds) that:
	#
	#	 run_base[i] + run_len[i] == runBase[i + 1]
	#
	# so we could cut the storage for this, but it's a minor amount,
	# and keeping all the info explicit simplifies the code.
	#
	# Number of pending runs on stack
	
	
	
	

	#
	# Creates a Timsort instance to maintain the state of an ongoing sort.
	#
	# @param list_ the array to be sorted
	# @param comparefn the comparator to determine the order of the sort
	#
	def __init__(self, list_1, list_2, comparefn=cmp):
		self.min_merge = 32
		self.initial_min_gallop = 7
		self.stack_size = 0

		self.initial_tmp_storage_length = 256

		self.run_base = []
		self.run_len = []

		self.min_gallop = self.initial_min_gallop

		self.list_1 = list_1
		self.list_2 = list_2
		self.comparefn = comparefn

		# Allocate temp storage (which may be increased later if necessary)
		length = len(list_1)
		#T[] newArray = (T[]) new Object[length < 2 * self.initial_tmp_storage_length ? length / 2 : self.initial_tmp_storage_length]
		if length < self.initial_tmp_storage_length * 2:
			ternary = length / 2
		else:
			ternary = self.initial_tmp_storage_length
		self.tmp = range(ternary)

		#
		# Allocate runs-to-be-merged stack (which cannot be expanded).  The
		# stack length requirements are described in listsort.txt.  The C
		# version always uses the same stack length (85), but this was
		# measured to be too expensive when sorting "mid-sized" arrays (e.g.,
		# 100 elements) in Java.  Therefore, we use smaller (but sufficiently
		# large) stack lengths for smaller arrays.  The "magic numbers" in the
		# computation below must be changed if min_merge is decreased.  See
		# the min_merge declaration above for more information.
		#
		#self.stack_len = (length <	120  ?  5 : length <   1542  ? 10 : length < 119151  ? 19 : 40)
		if length < 120:
			self.stack_len = 5
		elif length < 1542:
			self.stack_len = 10
		elif length < 119151:
			self.stack_len = 19
		else:
			self.stack_len = 40
		self.run_base = range(self.stack_len)
		self.run_len = range(self.stack_len)

	def sort(self, low, high, comparefn = cmp):
		'''sort method - perform a sort :)'''
		list_1 = self.list_1
		list_2 = self.list_2
		range_check(len(list_), low, high)
		num_remaining = high - low
		if num_remaining < 2:
			# Arrays of size 0 and 1 are always sorted
			return

		# If array is small, do a "mini-Timsort" with no merges
		if num_remaining < self.min_merge:
			initial_run_len = count_run_and_make_ascending(list_1, list_2, low, high, comparefn)
			#print 'in sort initial_run_len is', initial_run_len
			binary_sort(self.list_1, self.list_2, low, high, low + initial_run_len, comparefn)
			return

		#
		# March over the array once, left to right, finding natural runs,
		# extending short natural runs to min_run elements, and merging runs
		# to maintain stack invariant.
		#
		#timothy_sort = Timsort(list_, comparefn)
		min_run = self.min_run_length(num_remaining)
		while True:
			# Identify next run
			#print 'list_ is', list_, 'low is', low, 'high is', high, 'comparefn is', comparefn
			run_len = count_run_and_make_ascending(list_1, list_2, low, high, comparefn)
			#print 'after'

			# If run is short, extend to min(min_run, num_remaining)
			if run_len < min_run:
				#force = num_remaining <= min_run ? num_remaining : min_run
				if num_remaining <= min_run:
					ternary = num_remaining
				else:
					ternary = min_run
				force = ternary
				binary_sort(self.list_1, self.list_2, low, low + force, low + run_len, comparefn)
				run_len = force

			# Push run onto pending-run stack, and maybe merge
			self.push_run(low, run_len)
			self.merge_collapse()

			# Advance to find next run
			low += run_len
			num_remaining -= run_len
			if num_remaining == 0:
				break

		# Merge all remaining runs to complete sort
		assert low == high
		self.merge_force_collapse()
		assert self.stack_size == 1

	def min_run_length(self, number):
		'''
		Returns the minimum acceptable run length for an array of the specified
		length. Natural runs shorter than this will be extended with
		{@link #binary_sort}.
		
		Roughly speaking, the computation is:
		
		 If number < self.min_merge, return number (it's too small to bother with fancy stuff).
		 Else if number is an exact power of 2, return self.min_merge/2.
		 Else return an int k, self.min_merge/2 <= k <= self.min_merge, such that number/k
		  is close to, but strictly less than, an exact power of 2.
		
		For the rationale, see listsort.txt.
		
		@param number the length of the array to be sorted
		@return the length of the minimum run to be merged
		'''

		assert number >= 0
		low_bit = 0
		# Becomes 1 if any 1 bits are shifted off
		while number >= self.min_merge:
			low_bit |= (number & 1)
			number >>= 1
		return number + low_bit

	def push_run(self, run_base, run_len):
		'''
		Pushes the specified run onto the pending-run stack.
		
		@param self.run_base index of the first element in the run
		@param self.run_len  the number of elements in the run
		'''
		self.run_base[self.stack_size] = run_base
		self.run_len[self.stack_size] = run_len
		self.stack_size += 1

	def merge_collapse(self):
		'''
		Examines the stack of runs waiting to be merged and merges adjacent runs
		until the stack invariants are reestablished:
		
		 1. self.run_len[i - 3] > self.run_len[i - 2] + self.run_len[i - 1]
		 2. self.run_len[i - 2] > self.run_len[i - 1]
		
		This method is called each time a new run is pushed onto the stack,
		so the invariants are guaranteed to hold for i < self.stack_size upon
		entry to the method.
		'''
		while self.stack_size > 1:
			number = self.stack_size - 2
			if number > 0 and self.run_len[number-1] <= self.run_len[number] + self.run_len[number+1]:
				if self.run_len[number - 1] < self.run_len[number + 1]:
					number -= 1
				self.merge_at(number)
			elif self.run_len[number] <= self.run_len[number + 1]:
				self.merge_at(number)
			else:
				# Invariant is established
				break

	def merge_force_collapse(self):
		'''
		Merges all runs on the stack until only one remains.  This method is
		called once, to complete the sort.
		'''
		while self.stack_size > 1:
			number = self.stack_size - 2
			if number > 0 and self.run_len[number - 1] < self.run_len[number + 1]:
				number -= 1
			self.merge_at(number)

	def merge_at(self,  i):
		'''
		Merges the two runs at stack indices i and i+1.  Run i must be
		the penultimate or antepenultimate run on the stack.  In other words,
		i must be equal to self.stack_size-2 or self.stack_size-3.
		
		@param i stack index of the first of the two runs to merge
		'''
		assert self.stack_size >= 2
		assert i >= 0
		assert i == self.stack_size - 2 or i == self.stack_size - 3

		base1 = self.run_base[i]
		len1 = self.run_len[i]
		base2 = self.run_base[i + 1]
		len2 = self.run_len[i + 1]
		assert len1 > 0 and len2 > 0
		assert base1 + len1 == base2

		#
		# Record the length of the combined runs; if i is the 3rd-last
		# run now, also slide over the last run (which isn't involved
		# in this merge).  The current run (i+1) goes away in any case.
		#
		self.run_len[i] = len1 + len2
		if i == self.stack_size - 3:
			self.run_base[i + 1] = self.run_base[i + 2]
			self.run_len[i + 1] = self.run_len[i + 2]
		self.stack_size -= 1

		#
		# Find where the first element of run2 goes in run1. Prior elements
		# in run1 can be ignored (because they're already in place).
		#
		k = gallop_right(self.list_1[base2], self.list_2[base2], self.list_1, self.list_2, base1, len1, 0, self.comparefn)
		assert k >= 0
		base1 += k
		len1 -= k
		if len1 == 0:
			return

		#
		# Find where the last element of run1 goes in run2. Subsequent elements
		# in run2 can be ignored (because they're already in place).
		#
		len2 = gallop_left(self.list_1[base1 + len1 - 1], self.list_2[base1 + len1 - 1], self.list_1, self.list_2, base2, len2, len2 - 1, self.comparefn)
		assert len2 >= 0
		if len2 == 0:
			return

		# Merge remaining runs, using tmp array with min(len1, len2) elements
		if len1 <= len2:
			self.merge_low(base1, len1, base2, len2)
		else:
			self.merge_high(base1, len1, base2, len2)

	def merge_low(self, base1, len1, base2, len2):
		# pylint: disable-msg=R0914,R0912,R0915
		# R0914: We need lots of local variables, at least for now
		# R0912: We need lots of branches, at least for now
		# R0915: We need lots of statements, at least for now
		'''
		Merges two adjacent runs in place, in a stable fashion.  The first
		element of the first run must be greater than the first element of the
		second run (list_[base1] > list_[base2]), and the last element of the first run
		(list_[base1 + len1-1]) must be greater than all elements of the second run.
		
		For performance, this method should be called only when len1 <= len2
		its twin, merge_high should be called if len1 >= len2.  (Either method
		may be called if len1 == len2.)
		
		@param base1 index of first element in first run to be merged
		@param len1  length of first run to be merged (must be > 0)
		@param base2 index of first element in second run to be merged
			(must be aBase + aLen)
		@param len2  length of second run to be merged (must be > 0)
		'''
		assert len1 > 0 and len2 > 0 and base1 + len1 == base2

		# Copy first run into temp array
		# For performance
		list_1 = self.list_1
		list_2 = self.list_2
		tmp = self.ensure_capacity(len1)
		array_copy(list_1, list_2, base1, tmp, 0, len1)

		# Indexes into tmp array
		cursor1 = 0
		# Indexes int list_
		cursor2 = base2
		# Indexes int list_
		dest = base1

		# Move first element of second run and deal with degenerate cases
		list_1[dest] = list_1[cursor2]
		dest += 1
		cursor2 += 1
		len2 -= 1
		if len2 == 0:
			array_copy(tmp, cursor1, list_1, list_2, dest, len1)
			return
		if len1 == 1:
			array_copy(list_, cursor2, list_, dest, len2)
			# Last elt of run 1 to end of merge
			list_[dest + len2] = tmp[cursor1]
			return

		# Use local variable for performance
		comparefn = self.comparefn
		#  "	"	   "	 "	  "
		min_gallop = self.min_gallop

		loops_done = False
		while True:
			# Number of times in a row that first run won
			count1 = 0
			# Number of times in a row that second run won
			count2 = 0

			#
			# Do the straightforward thing until (if ever) one run starts
			# winning consistently.
			#
			while True:
				assert len1 > 1 and len2 > 0
				if comparefn(list_[cursor2], tmp[cursor1]) < 0:
					list_[dest] = list_[cursor2]
					dest += 1
					cursor2 += 1
					count2 += 1
					count1 = 0
					len2 -= 1
					if len2 == 0:
						loops_done = True
						break
				else:
					list_[dest] = tmp[cursor1]
					dest += 1
					cursor1 += 1
					count1 += 1
					count2 = 0
					len1 -= 1
					if len1 == 1:
						loops_done = True
						break
				if (count1 | count2) >= min_gallop:
					break
			if loops_done:
				break

			#
			# One run is winning so consistently that galloping may be a
			# huge win. So try that, and continue galloping until (if ever)
			# neither run appears to be winning consistently anymore.
			#
			while True:
				assert len1 > 1 and len2 > 0
				count1 = gallop_right(list_[cursor2], tmp, cursor1, len1, 0, comparefn)
				if count1 != 0:
					array_copy(tmp, cursor1, list_, dest, count1)
					dest += count1
					cursor1 += count1
					len1 -= count1
					if len1 <= 1:
						# len1 == 1 or len1 == 0
						loops_done = True
						break
				list_[dest] = list_[cursor2]
				dest += 1
				cursor2 += 1
				len2 -= 1
				if len2 == 0:
					loops_done = True
					break

				count2 = gallop_left(tmp[cursor1], list_, cursor2, len2, 0, comparefn)
				if count2 != 0:
					array_copy(list_, cursor2, list_, dest, count2)
					dest += count2
					cursor2 += count2
					len2 -= count2
					if len2 == 0:
						loops_done = True
						break
				list_[dest] = tmp[cursor1]
				dest += 1
				cursor1 += 1
				len1 -= 1
				if len1 == 1:
					loops_done = True
					break
				min_gallop -= 1

				if not (count1 >= self.initial_min_gallop | count2 >= self.initial_min_gallop):
					break

			if loops_done:
				break

			if min_gallop < 0:
				min_gallop = 0
			# Penalize for leaving gallop mode
			min_gallop += 2
		# End of "outer" loop

		# Write back to field
		#self.min_gallop = min_gallop < 1 ? 1 : min_gallop
		if min_gallop < 1:
			ternary = 1
		else:
			ternary = min_gallop
		self.min_gallop = ternary

		if len1 == 1:
			assert len2 > 0
			array_copy(list_, cursor2, list_, dest, len2)
			#  Last elt of run 1 to end of merge
			list_[dest + len2] = tmp[cursor1]
		elif len1 == 0:
			raise exceptions.ValueError, "Comparison function violates its general contract!"
		else:
			assert len2 == 0
			assert len1 > 1
			array_copy(tmp, cursor1, list_, dest, len1)

	def merge_high(self, base1, len1, base2, len2):
		# pylint: disable-msg=R0914,R0912,R0915
		# R0914: We need lots of local variables, at least for now
		# R0912: We need lots of branches, at least for now
		# R0915: We need lots of statements, at least for now
		'''
		Like merge_low, except that this method should be called only if
		len1 >= len2; merge_low should be called if len1 <= len2.  (Either method
		may be called if len1 == len2.)
		
		@param base1 index of first element in first run to be merged
		@param len1  length of first run to be merged (must be > 0)
		@param base2 index of first element in second run to be merged
			(must be aBase + aLen)
		@param len2  length of second run to be merged (must be > 0)
		'''

		assert len1 > 0 and len2 > 0 and base1 + len1 == base2

		# Copy second run into temp array
		# For performance
		list_ = self.list_
		tmp = self.ensure_capacity(len2)
		array_copy(list_, base2, tmp, 0, len2)

		# Indexes into list_
		cursor1 = base1 + len1 - 1
		# Indexes into tmp array
		cursor2 = len2 - 1
		# Indexes into list_
		dest = base2 + len2 - 1

		# Move last element of first run and deal with degenerate cases
		list_[dest] = list_[cursor1]
		dest -= 1
		cursor1 -= 1
		len1 -= 1
		if len1 == 0:
			array_copy(tmp, 0, list_, dest - (len2 - 1), len2)
			return
		if len2 == 1:
			dest -= len1
			cursor1 -= len1
			array_copy(list_, cursor1 + 1, list_, dest + 1, len1)
			list_[dest] = tmp[cursor2]
			return

		# Use local variable for performance
		comparefn = self.comparefn
		#  "	"	   "	 "	  "
		min_gallop = self.min_gallop

		loops_done = False
		while True:
			# Number of times in a row that first run won
			count1 = 0
			# Number of times in a row that second run won
			count2 = 0

			#
			# Do the straightforward thing until (if ever) one run
			# appears to win consistently.
			#
			while True:
				assert len1 > 0 and len2 > 1
				if comparefn(tmp[cursor2], list_[cursor1]) < 0:
					list_[dest] = list_[cursor1]
					dest -= 1
					cursor1 -= 1
					count1 += 1
					count2 = 0
					len1 -= 1
					if len1 == 0:
						loops_done = True
						break
				else:
					list_[dest] = tmp[cursor2]
					dest -= 1
					cursor2 -= 1
					count2 += 1
					count1 = 0
					len2 -= 1
					if len2 == 1:
						loops_done = True
						break
				if not ((count1 | count2) < min_gallop):
					break

			if loops_done:
				break

			#
			# One run is winning so consistently that galloping may be a
			# huge win. So try that, and continue galloping until (if ever)
			# neither run appears to be winning consistently anymore.
			#
			while True:
				assert len1 > 0 and len2 > 1
				count1 = len1 - gallop_right(tmp[cursor2], list_, base1, len1, len1 - 1, comparefn)
				if count1 != 0:
					dest -= count1
					cursor1 -= count1
					len1 -= count1
					array_copy(list_, cursor1 + 1, list_, dest + 1, count1)
					if len1 == 0:
						loops_done = True
						break
				list_[dest] = tmp[cursor2]
				dest -= 1
				cursor2 -= 1
				len2 -= 1
				if len2 == 1:
					loops_done = True
					break

				count2 = len2 - gallop_left(list_[cursor1], tmp, 0, len2, len2 - 1, comparefn)
				if count2 != 0:
					dest -= count2
					cursor2 -= count2
					len2 -= count2
					array_copy(tmp, cursor2 + 1, list_, dest + 1, count2)
					if len2 <= 1:
						# len2 == 1 or len2 == 0
						loops_done = True
						break
				list_[dest] = list_[cursor1]
				dest -= 1
				cursor1 -= 1
				len1 -= 1
				if len1 == 0:
					loops_done = True
					break
				min_gallop -= 1
				if not (count1 >= self.initial_min_gallop | count2 >= self.initial_min_gallop):
					break

			if loops_done:
				break

			if min_gallop < 0:
				min_gallop = 0
			# Penalize for leaving gallop mode
			min_gallop += 2
		# End of "outer" loop

		# Write back to field
		#self.min_gallop = min_gallop < 1 ? 1 : min_gallop
		if min_gallop < 1:
			ternary = 1
		else:
			ternary = min_gallop
		self.min_gallop = ternary

		if len2 == 1:
			assert len1 > 0
			dest -= len1
			cursor1 -= len1
			array_copy(list_, cursor1 + 1, list_, dest + 1, len1)
			# Move first elt of run2 to front of merge
			list_[dest] = tmp[cursor2]
		elif len2 == 0:
			raise exceptions.ValueError, "Comparison function violates its general contract!"
		else:
			assert len1 == 0
			assert len2 > 0
			array_copy(tmp, 0, list_, dest - (len2 - 1), len2)

	def ensure_capacity(self, min_capacity):
		'''
		Ensures that the external array tmp has at least the specified
		number of elements, increasing its size if necessary.  The size
		increases exponentially to ensure amortized linear time complexity.
		
		@param min_capacity the minimum required capacity of the tmp array
		@return tmp, whether or not it grew
		'''
		if len(self.tmp) < min_capacity:
			# Compute smallest power of 2 > min_capacity
			new_size = min_capacity
			new_size |= new_size >> 1
			new_size |= new_size >> 2
			new_size |= new_size >> 4
			new_size |= new_size >> 8
			new_size |= new_size >> 16
			new_size += 1

			if new_size < 0:
				# Not likely!
				new_size = min_capacity
			else:
				new_size = min(new_size, len(self.list_) / 2)

			self.tmp = range(new_size)
		return self.tmp

def range_check(array_len, from_index, to_index):
	'''
	Checks that from_index and to_index are in range, and throws an
	appropriate exception if they aren't.
	
	@param array_len the length of the array
	@param from_index the index of the first element of the range
	@param to_index the index after the last element of the range
	@throws IllegalArgumentException if from_index > to_index
	@throws ArrayIndexOutOfBoundsException if from_index < 0
		 or to_index > array_len
	'''
	if from_index > to_index:
		raise exceptions.ValueError, "from_index(" + from_index + ") > to_index(" + to_index+")"
	if from_index < 0:
		raise exceptions.IndexError, str(from_index)
	if to_index > array_len:
		raise exceptions.IndexError, str(to_index)


