Line data    Source code

       1             : // Copyright 2018 The LevelDB-Go and Pebble Authors. All rights reserved. Use
       2             : // of this source code is governed by a BSD-style license that can be found in
       3             : // the LICENSE file.
       4             : 
       5             : package sstable
       6             : 
       7             : import (
       8             :         "unsafe"
       9             : 
      10             :         "github.com/cockroachdb/pebble/internal/manual"
      11             : )
      12             : 
      13           1 : func getBytes(ptr unsafe.Pointer, length int) []byte {
      14           1 :         return (*[manual.MaxArrayLen]byte)(ptr)[:length:length]
      15           1 : }
      16             : 
      17           1 : func decodeVarint(ptr unsafe.Pointer) (uint32, unsafe.Pointer) {
      18           1 :         if a := *((*uint8)(ptr)); a < 128 {
      19           1 :                 return uint32(a),
      20           1 :                         unsafe.Pointer(uintptr(ptr) + 1)
      21           1 :         } else if a, b := a&0x7f, *((*uint8)(unsafe.Pointer(uintptr(ptr) + 1))); b < 128 {
      22           1 :                 return uint32(b)<<7 | uint32(a),
      23           1 :                         unsafe.Pointer(uintptr(ptr) + 2)
      24           1 :         } else if b, c := b&0x7f, *((*uint8)(unsafe.Pointer(uintptr(ptr) + 2))); c < 128 {
      25           1 :                 return uint32(c)<<14 | uint32(b)<<7 | uint32(a),
      26           1 :                         unsafe.Pointer(uintptr(ptr) + 3)
      27           1 :         } else if c, d := c&0x7f, *((*uint8)(unsafe.Pointer(uintptr(ptr) + 3))); d < 128 {
      28           1 :                 return uint32(d)<<21 | uint32(c)<<14 | uint32(b)<<7 | uint32(a),
      29           1 :                         unsafe.Pointer(uintptr(ptr) + 4)
      30           1 :         } else {
      31           1 :                 d, e := d&0x7f, *((*uint8)(unsafe.Pointer(uintptr(ptr) + 4)))
      32           1 :                 return uint32(e)<<28 | uint32(d)<<21 | uint32(c)<<14 | uint32(b)<<7 | uint32(a),
      33           1 :                         unsafe.Pointer(uintptr(ptr) + 5)
      34           1 :         }
      35             : }