47 lines
936 B
Go
47 lines
936 B
Go
package db
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import (
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"bytes"
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"strings"
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)
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func IteratePrefix(db DB, prefix []byte) Iterator {
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var start, end []byte
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if len(prefix) == 0 {
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start = BeginningKey()
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end = EndingKey()
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} else {
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start = cp(prefix)
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end = cpIncr(prefix)
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}
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return db.Iterator(start, end)
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}
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//----------------------------------------
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func cp(bz []byte) (ret []byte) {
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ret = make([]byte, len(bz))
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copy(ret, bz)
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return ret
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}
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// CONTRACT: len(bz) > 0
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func cpIncr(bz []byte) (ret []byte) {
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ret = cp(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] += 1
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return
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} else {
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ret[i] = byte(0x00)
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}
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}
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return EndingKey()
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}
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func checkKeyCondition(key string, start, end []byte) bool {
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leftCondition := bytes.Equal(start, BeginningKey()) || strings.Compare(key, string(start)) >= 0
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rightCondition := bytes.Equal(end, EndingKey()) || strings.Compare(key, string(end)) < 0
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return leftCondition && rightCondition
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}
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