/*************************************************************************
 *
 * HTCd - Copyright (C) 1998-2006 Henrik Rydberg
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <mt/mread.h>
#include <mt/split.h>
#include <poll.h>
#include <signal.h>
#include <errno.h>

const int MSEC=4000;
const int RETRY=3;
const int TIMEOUT=2;

//////////////////////////////////////////////////////////////////////////

mread::mread() : fd(-1),buf()
{
}

mread::mread(int f) : fd(f),buf()
{
}

//////////////////////////////////////////////////////////////////////////

void mread::clear()
{
  buf.clear();
}

int mread::poll()
{
  pollfd pfd={fd,POLLIN,0};
  return ::poll(&pfd,1,MSEC);
}

int mread::read(char* s,int n)
{
  if(buf.empty()) {
    int m=::read(fd,s,n);
    for(int i=0;i<RETRY&&m<0&&errno==EAGAIN&&poll()>=0;i++) m=::read(fd,s,n);
    if(m<0&&n) *s=0;
    return m;
  }
  else {
    if(n>buf.size()) n=buf.size();
    memcpy(s,buf.data(),n);
    buf.erase(0,n);
    return n;
  }
}

void mread::putback(const sref& s)
{
  if(s.nempty()) buf.insert(0,s);
}

//////////////////////////////////////////////////////////////////////////

int mread::readx(char* s,int n)
{
  int tries=0,acc=0;
  while(acc<n) {
    int m=read(s+acc,n-acc);
    if(m<0) return -1;
    else if(m==0) {
      if(poll()<0) return -1;
      if(tries++>=TIMEOUT) return acc;
    }
    else {
      acc+=m;
      tries=0;
    }
  }
  return acc;
}

//////////////////////////////////////////////////////////////////////////

int mread::readln(char* s,int n)
{
  int tries=0,acc=0;
  while(acc<n) {
    int m=read(s+acc,n-acc);
    if(m<0) return -1;
    else if(m==0) {
      if(poll()<0) return -1;
      if(tries++>=TIMEOUT) return acc?-1:0;
    }
    else {
      int p=sref(s+acc,m).find('\n')+1;
      if(p>0) { acc+=p; putback(sref(s+acc,m-p)); return acc; }
      else { acc+=m; tries=0; }
    }
  }
  return acc;
}

int mread::readpara(char* s,int n)
{
  int tries=0,acc=0;
  while(acc<n) {
    int m=read(s+acc,n-acc);
    if(m<0) return -1;
    else if(m==0) {
      if(poll()<0) return -1;
      if(tries++>=TIMEOUT) return acc?-1:0;
    }
    else {
      int found=0;
      sref first,rest(s+acc,m);
      while(Splitln(first,rest)) if(first.empty()) { found=1; break; }
      if(found) { acc=rest.begin()-s; putback(rest); return acc; }
      else { acc+=m; tries=0; }
    }
  }
  return acc;
}