github.com/annchain/OG@v0.0.9/vm/common/bitvec.go (about)

     1  // Copyright © 2019 Annchain Authors <EMAIL ADDRESS>
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  package common
    15  
    16  // Bitvec is a bit vector which maps bytes in a program.
    17  // An unset bit means the byte is an opcode, a set bit means
    18  // it's data (i.e. argument of PUSHxx).
    19  type Bitvec []byte
    20  
    21  func (bits *Bitvec) Set(pos uint64) {
    22  	(*bits)[pos/8] |= 0x80 >> (pos % 8)
    23  }
    24  func (bits *Bitvec) Set8(pos uint64) {
    25  	(*bits)[pos/8] |= 0xFF >> (pos % 8)
    26  	(*bits)[pos/8+1] |= ^(0xFF >> (pos % 8))
    27  }
    28  
    29  // codeSegment checks if the position is in a code segment.
    30  func (bits *Bitvec) CodeSegment(pos uint64) bool {
    31  	return ((*bits)[pos/8] & (0x80 >> (pos % 8))) == 0
    32  }