[eigen] gdb pretty quaternion and vector printing

[Daniel Lowengrub <lowdanie@xxxxxxxxx>]

Hi,
I've been using the gdb-python pretty printing support as described here:
http://listengine.tuxfamily.org/lists.tuxfamily.org/eigen/2009/12/msg00066.html
I added two things to the printers.py file:
1) When the type is has a single column or row then the variable is
displayed as a vector like this:
[0] = x
[1] = y
....
instead of the current:
[0,0] = x
[1,0] = y
....

2) Support for quaternions has been added.  They output looks like this:
Eigen::Quaternion<double> (data ptr: 0xbffff440) = {
[x] = 0.0079
[y] = 0.0345
[z] = 0.0364
[w] = 0.9942}

Cheers,
Daniel Lowengrub
------------------------------------

import gdb
import re
import itertools


class EigenMatrixPrinter:
	"Print Eigen Matrix of some kind"

	def __init__(self, val):
		"Extract all the necessary information"
		# The gdb extension does not support value template arguments - need
to extract them by hand
		type = val.type
		if type.code == gdb.TYPE_CODE_REF:
			type = type.target()
		self.type = type.unqualified().strip_typedefs()
		tag = self.type.tag
		regex = re.compile('\<.*\>')
		m = regex.findall(tag)[0][1:-1]
		template_params = m.split(',')
		template_params = map(lambda x:x.replace(" ", ""), template_params)

		self.rows = int(template_params[1])
		self.cols = int(template_params[2])
		self.options = 0 # default value
		if len(template_params) > 3:
			self.options = template_params[3];
		
		self.rowMajor = (int(self.options) & 0x1)

		if self.rows == 10000:
			self.rows = val['m_storage']['m_rows']

		if self.cols == 10000:
			self.cols = val['m_storage']['m_cols']

		self.innerType = self.type.template_argument(0)

		self.val = val
		
		# Fixed size matrices have a struct as their storage, so we need to
walk through this
		self.data = self.val['m_storage']['m_data']
		if self.data.type.code == gdb.TYPE_CODE_STRUCT:
			self.data = self.data['array']
			self.data = self.data.cast(self.innerType.pointer())
			
	class _iterator:
		def __init__ (self, rows, cols, dataPtr, rowMajor):
			self.rows = rows
			self.cols = cols
			self.dataPtr = dataPtr
			self.currentRow = 0
			self.currentCol = 0
			self.rowMajor = rowMajor

		def __iter__ (self):
			return self

		def next(self):
		
			row = self.currentRow
			col = self.currentCol
			if self.rowMajor == 0:
				if self.currentCol >= self.cols:
					raise StopIteration
					
				self.currentRow = self.currentRow + 1
				if self.currentRow >= self.rows:
					self.currentRow = 0
					self.currentCol = self.currentCol + 1
			else:
				if self.currentRow >= self.rows:
					raise StopIteration
					
				self.currentCol = self.currentCol + 1
				if self.currentCol >= self.cols:
					self.currentCol = 0
					self.currentRow = self.currentRow + 1
				

			item = self.dataPtr.dereference()
			self.dataPtr = self.dataPtr + 1
			if (self.cols == 1): #if it's a column vector
				return ('[%d]' % (row,), item)
			elif (self.rows == 1): #if it's a row vector
				return ('[%d]' % (col,), item)
			return ('[%d,%d]' % (row, col), item)

	def children(self):
		
		return self._iterator(self.rows, self.cols, self.data, self.rowMajor)

	def to_string(self):
		return "Eigen::Matrix<%s,%d,%d,%s> (data ptr: %s)" %
(self.innerType, self.rows, self.cols, "RowMajor" if self.rowMajor
else  "ColMajor", self.data)

class EigenQuaternionPrinter:
	"Print an Eigen Quaternion"

	def __init__(self, val):
		"Extract all the necessary information"
		# The gdb extension does not support value template arguments - need
to extract them by hand
		type = val.type
		if type.code == gdb.TYPE_CODE_REF:
			type = type.target()
		self.type = type.unqualified().strip_typedefs()
		self.innerType = self.type.template_argument(0)
		self.val = val
		
		# Quaternions have a struct as their storage, so we need to walk through this
		self.data = self.val['m_coeffs']['m_storage']['m_data']['array']
		self.data = self.data.cast(self.innerType.pointer())
			
	class _iterator:
		def __init__ (self, dataPtr):
			self.dataPtr = dataPtr
			self.currentElement = 0
			self.elementNames = ['x', 'y', 'z', 'w']

		def __iter__ (self):
			return self

		def next(self):
			element = self.currentElement

			if self.currentElement >= 4: #there are 4 elements in a quanternion
				raise StopIteration
			
			self.currentElement = self.currentElement + 1

			item = self.dataPtr.dereference()
			self.dataPtr = self.dataPtr + 1
			return ('[%s]' % (self.elementNames[element],), item)
			
	def children(self):
		
		return self._iterator(self.data)

	def to_string(self):
		return "Eigen::Quaternion<%s> (data ptr: %s)" % (self.innerType, self.data)

def build_eigen_dictionary ():
	pretty_printers_dict[re.compile('^Eigen::Quaternion<.*>$')] = lambda
val: EigenQuaternionPrinter(val)
	pretty_printers_dict[re.compile('^Eigen::Matrix<.*>$')] = lambda val:
EigenMatrixPrinter(val)

def register_eigen_printers(obj):
	"Register eigen pretty-printers with objfile Obj"

	if obj == None:
		obj = gdb
	obj.pretty_printers.append(lookup_function)

def lookup_function(val):
	"Look-up and return a pretty-printer that can print va."

	type = val.type

	if type.code == gdb.TYPE_CODE_REF:
		type = type.target()
	
	type = type.unqualified().strip_typedefs()

	typename = type.tag
	if typename == None:
		return None

	for function in pretty_printers_dict:
		if function.search(typename):
			return pretty_printers_dict[function](val)

	return None

pretty_printers_dict = {}

build_eigen_dictionary ()