ceremonyclient/pebble/sstable/unsafe.go

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2024-01-03 07:31:42 +00:00
// Copyright 2018 The LevelDB-Go and Pebble Authors. All rights reserved. Use
// of this source code is governed by a BSD-style license that can be found in
// the LICENSE file.
package sstable
import (
"unsafe"
"github.com/cockroachdb/pebble/internal/manual"
)
func getBytes(ptr unsafe.Pointer, length int) []byte {
return (*[manual.MaxArrayLen]byte)(ptr)[:length:length]
}
func decodeVarint(ptr unsafe.Pointer) (uint32, unsafe.Pointer) {
if a := *((*uint8)(ptr)); a < 128 {
return uint32(a),
unsafe.Pointer(uintptr(ptr) + 1)
} else if a, b := a&0x7f, *((*uint8)(unsafe.Pointer(uintptr(ptr) + 1))); b < 128 {
return uint32(b)<<7 | uint32(a),
unsafe.Pointer(uintptr(ptr) + 2)
} else if b, c := b&0x7f, *((*uint8)(unsafe.Pointer(uintptr(ptr) + 2))); c < 128 {
return uint32(c)<<14 | uint32(b)<<7 | uint32(a),
unsafe.Pointer(uintptr(ptr) + 3)
} else if c, d := c&0x7f, *((*uint8)(unsafe.Pointer(uintptr(ptr) + 3))); d < 128 {
return uint32(d)<<21 | uint32(c)<<14 | uint32(b)<<7 | uint32(a),
unsafe.Pointer(uintptr(ptr) + 4)
} else {
d, e := d&0x7f, *((*uint8)(unsafe.Pointer(uintptr(ptr) + 4)))
return uint32(e)<<28 | uint32(d)<<21 | uint32(c)<<14 | uint32(b)<<7 | uint32(a),
unsafe.Pointer(uintptr(ptr) + 5)
}
}