LinuxC/C++±à³Ì»ù´¡(35) std::istreamʹÓÃʵÀý

#include <istream>
#include <iostream>
#include <fstream>
#define PACKETRECV_SIZE 20
typedef char Int8;
typedef unsigned char UInt8;
typedef signed int Int32;
typedef unsigned int UInt32;
using namespace std;
UInt8 _buff[PACKETRECV_SIZE]={0xad,0x83,0xce,0xb4,0x5d,0xf3,0x40,0x97,0xf0,0x70,
0x8e,0x23,0xa4,0x56,0xb0,0x72,0x9b,0x77,0x90,0xcb};
UInt8 buffer[2]={0x40,0x5d};
class MemoryStreamBuf: public std::streambuf {
public:
MemoryStreamBuf(char* pBuffer,UInt32 bufferSize);

public:

UInt32 _written;

char* _pBuffer;

UInt32 _bufferSize;

};
MemoryStreamBuf::MemoryStreamBuf(char* pBuffer, UInt32 bufferSize): _pBuffer(pBuffer),_bufferSize(bufferSize),_written(0) {
setg(_pBuffer, _pBuffer,_pBuffer + _bufferSize);
setp(_pBuffer, _pBuffer + _bufferSize);
}
class MemoryIOS: public virtual std::ios
{
public:
MemoryIOS(char* pBuffer,UInt32 bufferSize);
~MemoryIOS(){}
MemoryStreamBuf* rdsbuf(){
return &_buf;
}
public:
MemoryStreamBuf _buf;
};
MemoryIOS::MemoryIOS(char* pBuffer, UInt32 bufferSize):_buf(pBuffer, bufferSize) {
}
class MemoryInputStream: public MemoryIOS,public std::istream
{
public:
MemoryInputStream(const char* pBuffer, UInt32 bufferSize);
};
MemoryInputStream::MemoryInputStream(const char* pBuffer, UInt32 bufferSize):

MemoryIOS(const_cast<char*>(pBuffer), bufferSize),istream(rdsbuf())

{}

class BinaryReader{
public:
BinaryReader(std::istream& istr);
void read(UInt8& value);
void read(Int8& value);
public:
std::istream& _istr;
};
BinaryReader::BinaryReader(std::istream& istr):

_istr(istr){}

void BinaryReader::read(UInt8& value){
_istr.read((char*)&value,sizeof(value));
}
void BinaryReader::read(Int8& value){
_istr.read(&value,sizeof(value));
}
int main () {
MemoryInputStream _memory((const char*) buffer,2);
BinaryReader reader(_memory);
unsigned char a = 0;
unsigned char b = 0;
unsigned char d = 0;
if(reader._istr.read((char*)&a,1).good()){
printf("0x%.2x\n",a);
}
if(reader._istr.read((char*)&b,1).good()){
printf("0x%.2x\n",b);
}
if(reader._istr.read((char*)&d,1).good()){
printf("0x%.2x\n",d);
}
return 0;

}

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