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forgejo/vendor/github.com/blevesearch/zapx/v12/intDecoder.go

110 lines
2.6 KiB
Go

// Copyright (c) 2019 Couchbase, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package zap
import (
"encoding/binary"
"fmt"
)
type chunkedIntDecoder struct {
startOffset uint64
dataStartOffset uint64
chunkOffsets []uint64
curChunkBytes []byte
data []byte
r *memUvarintReader
}
func newChunkedIntDecoder(buf []byte, offset uint64) *chunkedIntDecoder {
rv := &chunkedIntDecoder{startOffset: offset, data: buf}
var n, numChunks uint64
var read int
if offset == termNotEncoded {
numChunks = 0
} else {
numChunks, read = binary.Uvarint(buf[offset+n : offset+n+binary.MaxVarintLen64])
}
n += uint64(read)
if cap(rv.chunkOffsets) >= int(numChunks) {
rv.chunkOffsets = rv.chunkOffsets[:int(numChunks)]
} else {
rv.chunkOffsets = make([]uint64, int(numChunks))
}
for i := 0; i < int(numChunks); i++ {
rv.chunkOffsets[i], read = binary.Uvarint(buf[offset+n : offset+n+binary.MaxVarintLen64])
n += uint64(read)
}
rv.dataStartOffset = offset + n
return rv
}
func (d *chunkedIntDecoder) loadChunk(chunk int) error {
if d.startOffset == termNotEncoded {
d.r = newMemUvarintReader([]byte(nil))
return nil
}
if chunk >= len(d.chunkOffsets) {
return fmt.Errorf("tried to load freq chunk that doesn't exist %d/(%d)",
chunk, len(d.chunkOffsets))
}
end, start := d.dataStartOffset, d.dataStartOffset
s, e := readChunkBoundary(chunk, d.chunkOffsets)
start += s
end += e
d.curChunkBytes = d.data[start:end]
if d.r == nil {
d.r = newMemUvarintReader(d.curChunkBytes)
} else {
d.r.Reset(d.curChunkBytes)
}
return nil
}
func (d *chunkedIntDecoder) reset() {
d.startOffset = 0
d.dataStartOffset = 0
d.chunkOffsets = d.chunkOffsets[:0]
d.curChunkBytes = d.curChunkBytes[:0]
d.data = d.data[:0]
if d.r != nil {
d.r.Reset([]byte(nil))
}
}
func (d *chunkedIntDecoder) isNil() bool {
return d.curChunkBytes == nil
}
func (d *chunkedIntDecoder) readUvarint() (uint64, error) {
return d.r.ReadUvarint()
}
func (d *chunkedIntDecoder) SkipUvarint() {
d.r.SkipUvarint()
}
func (d *chunkedIntDecoder) SkipBytes(count int) {
d.r.SkipBytes(count)
}
func (d *chunkedIntDecoder) Len() int {
return d.r.Len()
}