03bca7b791
Co-authored-by: cool-developer <51834436+cool-develope@users.noreply.github.com> Co-authored-by: yihuang <huang@crypto.com>
54 lines
863 B
Go
54 lines
863 B
Go
package util
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// IterateWithPrefix returns the begin and end keys for an iterator over a domain
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// and prefix.
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func IterateWithPrefix(prefix, begin, end []byte) ([]byte, []byte) {
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if len(prefix) == 0 {
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return begin, end
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}
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begin = cloneAppend(prefix, begin)
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if end == nil {
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end = CopyIncr(prefix)
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} else {
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end = cloneAppend(prefix, end)
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}
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return begin, end
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}
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func cloneAppend(front, tail []byte) (res []byte) {
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res = make([]byte, len(front)+len(tail))
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n := copy(res, front)
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copy(res[n:], tail)
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return res
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}
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func CopyIncr(bz []byte) []byte {
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if len(bz) == 0 {
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panic("copyIncr expects non-zero bz length")
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}
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ret := make([]byte, len(bz))
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copy(ret, bz)
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for i := len(bz) - 1; i >= 0; i-- {
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if ret[i] < byte(0xFF) {
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ret[i]++
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return ret
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}
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ret[i] = byte(0x00)
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if i == 0 {
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// overflow
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return nil
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}
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}
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return nil
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}
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