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/*
Copyright (c) 2009 Yahoo! Inc. All rights reserved. The copyrights
embodied in the content of this file are licensed under the BSD
(revised) open source license
*/
#ifndef IO_H__
#define IO_H__
#include <fcntl.h>
#include "v_array.h"
#include<iostream>
#ifndef O_LARGEFILE //for OSX
#define O_LARGEFILE 0
#endif
using namespace std;
class io_buf {
public:
v_array<char> space; //space.begin = beginning of loaded values. space.end = end of read or written values.
v_array<int> files;
size_t count; // maximum number of file descriptors.
size_t current; //file descriptor currently being used.
char* endloaded; //end of loaded values
v_array<char> currentname;
v_array<char> finalname;
static const int READ = 1;
static const int WRITE = 2;
void init(){
size_t s = 1 << 16;
reserve(space, s);
current = 0;
count = 0;
endloaded = space.begin;
}
virtual int open_file(const char* name, int flag=READ){
int ret;
switch(flag){
case READ:
ret = open(name, O_RDONLY|O_LARGEFILE);
if(ret!=-1)
push(files,ret);
break;
case WRITE:
ret = open(name, O_CREAT|O_WRONLY|O_LARGEFILE|O_TRUNC,0666);
if(ret!=-1)
push(files,ret);
break;
default:
cerr << "Unknown file operation. Something other than READ/WRITE specified" << endl;
ret = -1;
}
return ret;
}
virtual void reset_file(int f){
lseek(f, 0, SEEK_SET);
endloaded = space.begin;
space.end = space.begin;
}
io_buf() {
init();
}
virtual ~io_buf(){
free(files.begin);
free(space.begin);
}
void set(char *p){space.end = p;}
virtual ssize_t read_file(int f, void* buf, size_t nbytes){
return read(f, buf, nbytes);
}
size_t fill(int f) {
if (space.end_array - endloaded == 0)
{
size_t offset = endloaded - space.begin;
reserve(space, 2 * (space.end_array - space.begin));
endloaded = space.begin+offset;
}
ssize_t num_read = read_file(f, endloaded, space.end_array - endloaded);
if (num_read >= 0)
{
endloaded = endloaded+num_read;
return num_read;
}
else
return 0;
}
virtual ssize_t write_file(int f, const void* buf, size_t nbytes){
return write(f, buf, nbytes);
}
virtual void flush() {
if (write_file(files[0], space.begin, space.index()) != (int) space.index())
cerr << "error, failed to write example\n";
space.end = space.begin; fsync(files[0]); }
virtual bool close_file(){
if(files.index()>0){
close(files.pop());
return true;
}
return false;
}
void close_files(){
while(close_file());
}
};
void buf_write(io_buf &o, char* &pointer, int n);
unsigned int buf_read(io_buf &i, char* &pointer, int n);
size_t readto(io_buf &i, char* &pointer, char terminal);
#endif
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