#ifndef BUFFER_H
#define BUFFER_H

#include <cstring>
#include <iostream>
#include <unistd.h>
#include <sys/uio.h>
#include <vector>
#include <atomic>
#include <cassert>

using namespace std;

class Buffer
{
public:
 Buffer(int initBuffSize = 1024);
 ~Buffer() = default;

 size_t writableBytes() const;
 size_t readableBytes() const;
 size_t prependableBytes() const;

 const char* peek() const;
 void ensureWritable(size_t len);
 void hasWritten(size_t len);

 void retrieve(size_t len);
 void retrieveUntil(const char* end);

 void retrieveAll();
 string retrieveAllToStr();

 const char* beginWriteConst() const;
 char* beginWrite();

 void append(const string& str);
 void append(const char* str, size_t len);
 void append(const void* data, size_t len);
 void append(const Buffer& buffer);

 ssize_t readfd(int fd, int* Errno);
 ssize_t writefd(int fd, int* Errno);

private:
 char* beginPtr();
 const char* beginPtr() const;
 void makeSpace(size_t len);

 vector<char> buffer;
 atomic<size_t> readPos;
 atomic<size_t> writePos;
};

#endif