64 lines
1.0 KiB
Go
64 lines
1.0 KiB
Go
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package internal
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import "github.com/boltdb/bolt"
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// Cursor that can be reversed
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type Cursor struct {
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C *bolt.Cursor
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Reverse bool
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}
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// First element
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func (c *Cursor) First() ([]byte, []byte) {
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if c.Reverse {
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return c.C.Last()
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}
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return c.C.First()
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}
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// Next element
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func (c *Cursor) Next() ([]byte, []byte) {
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if c.Reverse {
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return c.C.Prev()
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}
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return c.C.Next()
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}
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// RangeCursor that can be reversed
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type RangeCursor struct {
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C *bolt.Cursor
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Reverse bool
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Min []byte
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Max []byte
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CompareFn func([]byte, []byte) int
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}
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// First element
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func (c *RangeCursor) First() ([]byte, []byte) {
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if c.Reverse {
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return c.C.Seek(c.Max)
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}
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return c.C.Seek(c.Min)
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}
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// Next element
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func (c *RangeCursor) Next() ([]byte, []byte) {
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if c.Reverse {
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return c.C.Prev()
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}
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return c.C.Next()
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}
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// Continue tells if the loop needs to continue
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func (c *RangeCursor) Continue(val []byte) bool {
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if c.Reverse {
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return val != nil && c.CompareFn(val, c.Min) >= 0
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}
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return val != nil && c.CompareFn(val, c.Max) <= 0
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}
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