printers.py

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# -*- coding: utf-8 -*-
# This file is part of Eigen, a lightweight C++ template library
# for linear algebra.
#
# Copyright (C) 2009 Benjamin Schindler <bschindler@inf.ethz.ch>
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# Pretty printers for Eigen::Matrix
# This is still pretty basic as the python extension to gdb is still pretty basic. 
# It cannot handle complex eigen types and it doesn't support any of the other eigen types
# Such as quaternion or some other type. 
# This code supports fixed size as well as dynamic size matrices

# To use it:
#
# * Create a directory and put the file as well as an empty __init__.py in 
#   that directory.
# * Create a ~/.gdbinit file, that contains the following:
#      python
#      import sys
#      sys.path.insert(0, '/path/to/eigen/printer/directory')
#      from printers import register_eigen_printers
#      register_eigen_printers (None)
#      end

import gdb
import re
import itertools


class EigenMatrixPrinter:
        "Print Eigen Matrix or Array of some kind"

        def __init__(self, variety, val):
                "Extract all the necessary information"
                
                # Save the variety (presumably "Matrix" or "Array") for later usage
                self.variety = variety
                
                # 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 = [x.replace(" ", "") for x in template_params]
                
                if template_params[1] == '-0x00000000000000001' or template_params[1] == '-0x000000001' or template_params[1] == '-1':
                        self.rows = val['m_storage']['m_rows']
                else:
                        self.rows = int(template_params[1])
                
                if template_params[2] == '-0x00000000000000001' or template_params[2] == '-0x000000001' or template_params[2] == '-1':
                        self.cols = val['m_storage']['m_cols']
                else:
                        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)
                
                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):
                        return self.__next__()  # Python 2.x compatibility

                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::%s<%s,%d,%d,%s> (data ptr: %s)" % (self.variety, 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):
                        return self.__next__()  # Python 2.x compatibility

                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("Matrix", val)
        pretty_printers_dict[re.compile('^Eigen::Array<.*>$')]  = lambda val: EigenMatrixPrinter("Array",  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 ()