// Returns the symbol offset within the TextContainer of this Position.
internal static int GetSymbolOffset(TextContainer tree, TextTreeNode node, ElementEdge edge)
{
int offset;
switch (edge)
{
case ElementEdge.BeforeStart:
offset = node.GetSymbolOffset(tree.Generation);
break;
case ElementEdge.AfterStart:
offset = node.GetSymbolOffset(tree.Generation) + 1;
break;
case ElementEdge.BeforeEnd:
offset = node.GetSymbolOffset(tree.Generation) + node.SymbolCount - 1;
break;
case ElementEdge.AfterEnd:
offset = node.GetSymbolOffset(tree.Generation) + node.SymbolCount;
break;
default:
Invariant.Assert(false, "Unknown value for position edge");
offset = 0;
break;
}
return offset;
}