mirror of
https://github.com/go-gitea/gitea.git
synced 2024-10-31 08:37:35 -04:00
58 lines
2.1 KiB
Go
58 lines
2.1 KiB
Go
// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
|
|
// All rights reserved.
|
|
//
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
// Package comparer provides interface and implementation for ordering
|
|
// sets of data.
|
|
package comparer
|
|
|
|
// BasicComparer is the interface that wraps the basic Compare method.
|
|
type BasicComparer interface {
|
|
// Compare returns -1, 0, or +1 depending on whether a is 'less than',
|
|
// 'equal to' or 'greater than' b. The two arguments can only be 'equal'
|
|
// if their contents are exactly equal. Furthermore, the empty slice
|
|
// must be 'less than' any non-empty slice.
|
|
Compare(a, b []byte) int
|
|
}
|
|
|
|
// Comparer defines a total ordering over the space of []byte keys: a 'less
|
|
// than' relationship.
|
|
type Comparer interface {
|
|
BasicComparer
|
|
|
|
// Name returns name of the comparer.
|
|
//
|
|
// The Level-DB on-disk format stores the comparer name, and opening a
|
|
// database with a different comparer from the one it was created with
|
|
// will result in an error.
|
|
//
|
|
// An implementation to a new name whenever the comparer implementation
|
|
// changes in a way that will cause the relative ordering of any two keys
|
|
// to change.
|
|
//
|
|
// Names starting with "leveldb." are reserved and should not be used
|
|
// by any users of this package.
|
|
Name() string
|
|
|
|
// Bellow are advanced functions used to reduce the space requirements
|
|
// for internal data structures such as index blocks.
|
|
|
|
// Separator appends a sequence of bytes x to dst such that a <= x && x < b,
|
|
// where 'less than' is consistent with Compare. An implementation should
|
|
// return nil if x equal to a.
|
|
//
|
|
// Either contents of a or b should not by any means modified. Doing so
|
|
// may cause corruption on the internal state.
|
|
Separator(dst, a, b []byte) []byte
|
|
|
|
// Successor appends a sequence of bytes x to dst such that x >= b, where
|
|
// 'less than' is consistent with Compare. An implementation should return
|
|
// nil if x equal to b.
|
|
//
|
|
// Contents of b should not by any means modified. Doing so may cause
|
|
// corruption on the internal state.
|
|
Successor(dst, b []byte) []byte
|
|
}
|