#pragma implementation
#include <stdio.h>
#include <textfile.h>
#include <string.h>
#include <fcntl.h>
#include <bufio.h>

BufFile::BufFile() {
  io = 0;
  rewind();
}

BufFile::BufFile(const char *name) {
  io = new bufio(::open(name,O_RDONLY));
  rewind();
}

void BufFile::open(int fd) {
  delete io;
  io = new bufio(fd);
  rewind();
}

BufFile::~BufFile() {
  delete io;
}

void BufFile::rewind() {
  filesize = 0;
  eof = 0;
  pos.clear();
  pos.add(0);
  if (io)
    io->seek(0);
}

long BufFile::offsetOf(int i) {
  if (i < 0 || !io) return 0;
  while (i >= pos.size()) {
    if (eof) return filesize;
    const char *p = (char *)io->read(filesize,0);
    int n = io->getcnt();
    if (n <= 0) {
      // fprintf(stderr,"textfile::EOF\n");
      eof = 1;
      return filesize;
    }
    const char *q = p;
    for (;;) {
      int len = n - (q - p);
      if (!len) break;
      if (*q != '\f' || q - p + filesize != pos[pos.size() - 1]) {
	q = (const char *)memchr(q,'\n',len);
	if (!q) break;
      }
      long bufoff = ++q - p + filesize;
      pos.add(bufoff);
      /* fprintf(stderr,"pos %ld\n",bufoff); */
    }
    filesize += n;
    // fprintf(stderr,"textfile::filesize = %ld, idx = %d\n",filesize,i);
  }
  return pos[i];
}

const char *BufFile::operator[](int i) {
  int offset = offsetOf(i);
  int size = offsetOf(i + 1) - offset;
  if (size == 0) return 0;
  char *p = (char *)io->read(offset,size);
  if (p) {
    if (*p == '\f')
      return "\f";
    if (size > 1 && p[size - 2] == '\r')
      p[size - 2] = 0;	// null terminate
    else
      p[size - 1] = 0;	// null terminate
  }
  return p;
}

int BufFile::size() {
  if (eof) return pos.size();
  (*this)[pos.size()];
  int i = pos.size();
  while (i > 0 && !(*this)[i-1]) --i;
  return i;
}

int BufFile::getfd() const { return io->getfd(); }