examples/synthetic/StdVectorSynthProvider.py

class StdVectorSynthProvider:

    def __init__(self, valobj, dict):
        self.valobj = valobj;
        self.update()

    def num_children(self):
        start_val = self.start.GetValueAsUnsigned(0)
        finish_val = self.finish.GetValueAsUnsigned(0)
        end_val  = self.end.GetValueAsUnsigned(0)
        # Before a vector has been constructed, it will contain bad values
        # so we really need to be careful about the length we return since
        # unitialized data can cause us to return a huge number. We need
        # to also check for any of the start, finish or end of storage values
        # being zero (NULL). If any are, then this vector has not been 
        # initialized yet and we should return zero
        
        # Make sure nothing is NULL
        if start_val == 0 or finish_val == 0 or end_val == 0:
            return 0
        # Make sure start is less than finish
        if start_val >= finish_val:
            return 0
        # Make sure finish is less than or equal to end of storage
        if finish_val > end_val:
            return 0

        # We might still get things wrong, so cap things at 256 items for now
        # TODO: read a target "settings set" variable for this to allow it to
        # be customized
        num_children = (finish_val-start_val)/self.data_size
        if num_children > 256:
            return 256
        return num_children

    def get_child_index(self,name):
        if name == "len":
            return self.num_children();
        else:
            return int(name.lstrip('[').rstrip(']'))

    def get_child_at_index(self,index):
        if index == self.num_children():
            return self.valobj.CreateValueFromExpression("len",str(self.num_children()))
        else:
            offset = index * self.data_size
            return self.start.CreateChildAtOffset('['+str(index)+']',offset,self.data_type)

    def update(self):
        impl = self.valobj.GetChildMemberWithName('_M_impl')
        self.start = impl.GetChildMemberWithName('_M_start')
        self.finish = impl.GetChildMemberWithName('_M_finish')
        self.end = impl.GetChildMemberWithName('_M_end_of_storage')
        self.data_type = self.start.GetType().GetPointeeType()
        self.data_size = self.data_type.GetByteSize()