rss-tools/vendor/github.com/PuerkitoBio/goquery/array.go (view raw)
| 1 | package goquery |
| 2 | |
| 3 | import ( |
| 4 | "golang.org/x/net/html" |
| 5 | ) |
| 6 | |
| 7 | const ( |
| 8 | maxUint = ^uint(0) |
| 9 | maxInt = int(maxUint >> 1) |
| 10 | |
| 11 | // ToEnd is a special index value that can be used as end index in a call |
| 12 | // to Slice so that all elements are selected until the end of the Selection. |
| 13 | // It is equivalent to passing (*Selection).Length(). |
| 14 | ToEnd = maxInt |
| 15 | ) |
| 16 | |
| 17 | // First reduces the set of matched elements to the first in the set. |
| 18 | // It returns a new Selection object, and an empty Selection object if the |
| 19 | // the selection is empty. |
| 20 | func (s *Selection) First() *Selection { |
| 21 | return s.Eq(0) |
| 22 | } |
| 23 | |
| 24 | // Last reduces the set of matched elements to the last in the set. |
| 25 | // It returns a new Selection object, and an empty Selection object if |
| 26 | // the selection is empty. |
| 27 | func (s *Selection) Last() *Selection { |
| 28 | return s.Eq(-1) |
| 29 | } |
| 30 | |
| 31 | // Eq reduces the set of matched elements to the one at the specified index. |
| 32 | // If a negative index is given, it counts backwards starting at the end of the |
| 33 | // set. It returns a new Selection object, and an empty Selection object if the |
| 34 | // index is invalid. |
| 35 | func (s *Selection) Eq(index int) *Selection { |
| 36 | if index < 0 { |
| 37 | index += len(s.Nodes) |
| 38 | } |
| 39 | |
| 40 | if index >= len(s.Nodes) || index < 0 { |
| 41 | return newEmptySelection(s.document) |
| 42 | } |
| 43 | |
| 44 | return s.Slice(index, index+1) |
| 45 | } |
| 46 | |
| 47 | // Slice reduces the set of matched elements to a subset specified by a range |
| 48 | // of indices. The start index is 0-based and indicates the index of the first |
| 49 | // element to select. The end index is 0-based and indicates the index at which |
| 50 | // the elements stop being selected (the end index is not selected). |
| 51 | // |
| 52 | // The indices may be negative, in which case they represent an offset from the |
| 53 | // end of the selection. |
| 54 | // |
| 55 | // The special value ToEnd may be specified as end index, in which case all elements |
| 56 | // until the end are selected. This works both for a positive and negative start |
| 57 | // index. |
| 58 | func (s *Selection) Slice(start, end int) *Selection { |
| 59 | if start < 0 { |
| 60 | start += len(s.Nodes) |
| 61 | } |
| 62 | if end == ToEnd { |
| 63 | end = len(s.Nodes) |
| 64 | } else if end < 0 { |
| 65 | end += len(s.Nodes) |
| 66 | } |
| 67 | return pushStack(s, s.Nodes[start:end]) |
| 68 | } |
| 69 | |
| 70 | // Get retrieves the underlying node at the specified index. |
| 71 | // Get without parameter is not implemented, since the node array is available |
| 72 | // on the Selection object. |
| 73 | func (s *Selection) Get(index int) *html.Node { |
| 74 | if index < 0 { |
| 75 | index += len(s.Nodes) // Negative index gets from the end |
| 76 | } |
| 77 | return s.Nodes[index] |
| 78 | } |
| 79 | |
| 80 | // Index returns the position of the first element within the Selection object |
| 81 | // relative to its sibling elements. |
| 82 | func (s *Selection) Index() int { |
| 83 | if len(s.Nodes) > 0 { |
| 84 | return newSingleSelection(s.Nodes[0], s.document).PrevAll().Length() |
| 85 | } |
| 86 | return -1 |
| 87 | } |
| 88 | |
| 89 | // IndexSelector returns the position of the first element within the |
| 90 | // Selection object relative to the elements matched by the selector, or -1 if |
| 91 | // not found. |
| 92 | func (s *Selection) IndexSelector(selector string) int { |
| 93 | if len(s.Nodes) > 0 { |
| 94 | sel := s.document.Find(selector) |
| 95 | return indexInSlice(sel.Nodes, s.Nodes[0]) |
| 96 | } |
| 97 | return -1 |
| 98 | } |
| 99 | |
| 100 | // IndexMatcher returns the position of the first element within the |
| 101 | // Selection object relative to the elements matched by the matcher, or -1 if |
| 102 | // not found. |
| 103 | func (s *Selection) IndexMatcher(m Matcher) int { |
| 104 | if len(s.Nodes) > 0 { |
| 105 | sel := s.document.FindMatcher(m) |
| 106 | return indexInSlice(sel.Nodes, s.Nodes[0]) |
| 107 | } |
| 108 | return -1 |
| 109 | } |
| 110 | |
| 111 | // IndexOfNode returns the position of the specified node within the Selection |
| 112 | // object, or -1 if not found. |
| 113 | func (s *Selection) IndexOfNode(node *html.Node) int { |
| 114 | return indexInSlice(s.Nodes, node) |
| 115 | } |
| 116 | |
| 117 | // IndexOfSelection returns the position of the first node in the specified |
| 118 | // Selection object within this Selection object, or -1 if not found. |
| 119 | func (s *Selection) IndexOfSelection(sel *Selection) int { |
| 120 | if sel != nil && len(sel.Nodes) > 0 { |
| 121 | return indexInSlice(s.Nodes, sel.Nodes[0]) |
| 122 | } |
| 123 | return -1 |
| 124 | } |