range.go

// Copyright (c) 2014, 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 util

// Range is a key range.
type Range struct {
	// Start of the key range, include in the range.
	Start []byte

	// Limit of the key range, not include in the range.
	Limit []byte
}

// BytesPrefix returns key range that satisfy the given prefix.
// This only applicable for the standard 'bytes comparer'.
func BytesPrefix(prefix []byte) *Range {
	var limit []byte
	for i := len(prefix) - 1; i >= 0; i-- {
		c := prefix[i]
		if c < 0xff {
			limit = make([]byte, i+1)
			copy(limit, prefix)
			limit[i] = c + 1
			break
		}
	}
	return &Range{prefix, limit}
}