github.com/jeffallen/go-ethereum@v1.1.4-0.20150910155051-571d3236c49c/core/vm/memory.go (about)

     1  // Copyright 2015 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package vm
    18  
    19  import "fmt"
    20  
    21  type Memory struct {
    22  	store []byte
    23  }
    24  
    25  func NewMemory() *Memory {
    26  	return &Memory{nil}
    27  }
    28  
    29  func (m *Memory) Set(offset, size uint64, value []byte) {
    30  	// length of store may never be less than offset + size.
    31  	// The store should be resized PRIOR to setting the memory
    32  	if size > uint64(len(m.store)) {
    33  		panic("INVALID memory: store empty")
    34  	}
    35  
    36  	// It's possible the offset is greater than 0 and size equals 0. This is because
    37  	// the calcMemSize (common.go) could potentially return 0 when size is zero (NO-OP)
    38  	if size > 0 {
    39  		copy(m.store[offset:offset+size], value)
    40  	}
    41  }
    42  
    43  func (m *Memory) Resize(size uint64) {
    44  	if uint64(m.Len()) < size {
    45  		m.store = append(m.store, make([]byte, size-uint64(m.Len()))...)
    46  	}
    47  }
    48  
    49  func (self *Memory) Get(offset, size int64) (cpy []byte) {
    50  	if size == 0 {
    51  		return nil
    52  	}
    53  
    54  	if len(self.store) > int(offset) {
    55  		cpy = make([]byte, size)
    56  		copy(cpy, self.store[offset:offset+size])
    57  
    58  		return
    59  	}
    60  
    61  	return
    62  }
    63  
    64  func (self *Memory) GetPtr(offset, size int64) []byte {
    65  	if size == 0 {
    66  		return nil
    67  	}
    68  
    69  	if len(self.store) > int(offset) {
    70  		return self.store[offset : offset+size]
    71  	}
    72  
    73  	return nil
    74  }
    75  
    76  func (m *Memory) Len() int {
    77  	return len(m.store)
    78  }
    79  
    80  func (m *Memory) Data() []byte {
    81  	return m.store
    82  }
    83  
    84  func (m *Memory) Print() {
    85  	fmt.Printf("### mem %d bytes ###\n", len(m.store))
    86  	if len(m.store) > 0 {
    87  		addr := 0
    88  		for i := 0; i+32 <= len(m.store); i += 32 {
    89  			fmt.Printf("%03d: % x\n", addr, m.store[i:i+32])
    90  			addr++
    91  		}
    92  	} else {
    93  		fmt.Println("-- empty --")
    94  	}
    95  	fmt.Println("####################")
    96  }