/**
* Returns the original source, line, and column information for the generated
* source's line and column positions provided. The only argument is an object
* with the following properties:
*
* - line: The line number in the generated source.
* - column: The column number in the generated source.
*
* and an object is returned with the following properties:
*
* - source: The original source file, or null.
* - line: The line number in the original source, or null.
* - column: The column number in the original source, or null.
* - name: The original identifier, or null.
*/
public override OriginalPosition OriginalPositionFor(int line, int column, EBias?bias = null)
{
var needle = new MappingItemIndexed
{
GeneratedLine = line,
GeneratedColumn = column
};
// Find the section containing the generated position we're trying to map
// to an original position.
var sectionIndex = BinarySearch.Search(
needle,
_sections,
(n, s) =>
{
var cmp = n.GeneratedLine - s.GeneratedOffset.GeneratedLine;
if (cmp == 0)
{
return(cmp);
}
return(n.GeneratedColumn - s.GeneratedOffset.GeneratedColumn);
},
EBias.GREATEST_LOWER_BOUND);
var section = _sections[sectionIndex];
if (section == null)
{
return(new OriginalPosition
{
Source = null,
Line = null,
Column = null,
Name = null
});
}
return(section.Consumer.OriginalPositionFor(
needle.GeneratedLine - (section.GeneratedOffset.GeneratedLine - 1),
needle.GeneratedColumn - (section.GeneratedOffset.GeneratedLine == needle.GeneratedLine
? section.GeneratedOffset.GeneratedColumn - 1
: 0),
bias));
}
/**
* Find the mapping that best matches the hypothetical "needle" mapping that
* we are searching for in the given "haystack" of mappings.
*/
protected int FindMapping(
MappingItemIndexed needle,
List <MappingItemIndexed> aMappings,
Func <MappingItemIndexed, int?> line,
Func <MappingItemIndexed, int?> column,
Func <MappingItemIndexed, MappingItemIndexed, int> aComparator,
EBias aBias)
{
// To return the position we are searching for, we must first find the
// mapping for the given position and then return the opposite position it
// points to. Because the mappings are sorted, we can use binary search to
// find the best mapping.
if (line(needle) <= 0)
{
throw new ArgumentException($"Line must be greater than or equal to 1, got {line(needle)}");
}
if (column(needle) < 0)
{
throw new ArgumentException($"Column must be greater than or equal to 0, got {column(needle)}");
}
return(BinarySearch.Search <MappingItemIndexed>(needle, aMappings, aComparator, aBias));
}