rss-tools @ a5ac527

package goquery

import (

	"golang.org/x/net/html"

)

const (

	maxUint = ^uint(0)

	maxInt  = int(maxUint >> 1)

	// ToEnd is a special index value that can be used as end index in a call

	// to Slice so that all elements are selected until the end of the Selection.

	// It is equivalent to passing (*Selection).Length().

	ToEnd = maxInt

)

// First reduces the set of matched elements to the first in the set.

// It returns a new Selection object, and an empty Selection object if the

// the selection is empty.

func (s *Selection) First() *Selection {

	return s.Eq(0)

}

// Last reduces the set of matched elements to the last in the set.

// It returns a new Selection object, and an empty Selection object if

// the selection is empty.

func (s *Selection) Last() *Selection {

	return s.Eq(-1)

}

// Eq reduces the set of matched elements to the one at the specified index.

// If a negative index is given, it counts backwards starting at the end of the

// set. It returns a new Selection object, and an empty Selection object if the

// index is invalid.

func (s *Selection) Eq(index int) *Selection {

	if index < 0 {

		index += len(s.Nodes)

	}

	if index >= len(s.Nodes) || index < 0 {

		return newEmptySelection(s.document)

	}

	return s.Slice(index, index+1)

}

// Slice reduces the set of matched elements to a subset specified by a range

// of indices. The start index is 0-based and indicates the index of the first

// element to select. The end index is 0-based and indicates the index at which

// the elements stop being selected (the end index is not selected).

//

// The indices may be negative, in which case they represent an offset from the

// end of the selection.

//

// The special value ToEnd may be specified as end index, in which case all elements

// until the end are selected. This works both for a positive and negative start

// index.

func (s *Selection) Slice(start, end int) *Selection {

	if start < 0 {

		start += len(s.Nodes)

	}

	if end == ToEnd {

		end = len(s.Nodes)

	} else if end < 0 {

		end += len(s.Nodes)

	}

	return pushStack(s, s.Nodes[start:end])

}

// Get retrieves the underlying node at the specified index.

// Get without parameter is not implemented, since the node array is available

// on the Selection object.

func (s *Selection) Get(index int) *html.Node {

	if index < 0 {

		index += len(s.Nodes) // Negative index gets from the end

	}

	return s.Nodes[index]

}

// Index returns the position of the first element within the Selection object

// relative to its sibling elements.

func (s *Selection) Index() int {

	if len(s.Nodes) > 0 {

		return newSingleSelection(s.Nodes[0], s.document).PrevAll().Length()

	}

	return -1

}

// IndexSelector returns the position of the first element within the

// Selection object relative to the elements matched by the selector, or -1 if

// not found.

func (s *Selection) IndexSelector(selector string) int {

	if len(s.Nodes) > 0 {

		sel := s.document.Find(selector)

		return indexInSlice(sel.Nodes, s.Nodes[0])

	}

	return -1

}

// IndexMatcher returns the position of the first element within the

// Selection object relative to the elements matched by the matcher, or -1 if

// not found.

func (s *Selection) IndexMatcher(m Matcher) int {

	if len(s.Nodes) > 0 {

		sel := s.document.FindMatcher(m)

		return indexInSlice(sel.Nodes, s.Nodes[0])

	}

	return -1

}

// IndexOfNode returns the position of the specified node within the Selection

// object, or -1 if not found.

func (s *Selection) IndexOfNode(node *html.Node) int {

	return indexInSlice(s.Nodes, node)

}

// IndexOfSelection returns the position of the first node in the specified

// Selection object within this Selection object, or -1 if not found.

func (s *Selection) IndexOfSelection(sel *Selection) int {

	if sel != nil && len(sel.Nodes) > 0 {

		return indexInSlice(s.Nodes, sel.Nodes[0])

	}

	return -1

}