/* Copyright 2013 The Perkeep Authors 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 testkeys import ( "strconv" "github.com/cockroachdb/errors" ) // parseUintBytes is like strconv.ParseUint, but using a []byte. Use of this // function avoids an allocation when parsing an integer out of a []byte. // // This function is copied from go4.org/strconv. func parseUintBytes(s []byte, base int, bitSize int) (n uint64, err error) { var cutoff, maxVal uint64 if bitSize == 0 { bitSize = int(strconv.IntSize) } s0 := s switch { case len(s) < 1: err = strconv.ErrSyntax goto Error case 2 <= base && base <= 36: // valid base; nothing to do case base == 0: // Look for octal, hex prefix. switch { case s[0] == '0' && len(s) > 1 && (s[1] == 'x' || s[1] == 'X'): base = 16 s = s[2:] if len(s) < 1 { err = strconv.ErrSyntax goto Error } case s[0] == '0': base = 8 default: base = 10 } default: err = errors.New("invalid base " + strconv.Itoa(base)) goto Error } n = 0 cutoff = cutoff64(base) maxVal = 1<= base { n = 0 err = strconv.ErrSyntax goto Error } if n >= cutoff { // n*base overflows n = 1<<64 - 1 err = strconv.ErrRange goto Error } n *= uint64(base) n1 := n + uint64(v) if n1 < n || n1 > maxVal { // n+v overflows n = 1<<64 - 1 err = strconv.ErrRange goto Error } n = n1 } return n, nil Error: return n, &strconv.NumError{Func: "ParseUint", Num: string(s0), Err: err} } // Return the first number n such that n*base >= 1<<64. func cutoff64(base int) uint64 { if base < 2 { return 0 } return (1<<64-1)/uint64(base) + 1 }