#include "buffer.h"

#include "byte.h"

#include "error.h"

static int oneread(int (*op)(),int fd,char *buf,unsigned int len)

{

  int r;

  for (;;) {

    r = op(fd,buf,len);

    if (r == -1) if (errno == error_intr) continue;

    return r;

  }

}

static int getthis(buffer *s,char *buf,unsigned int len)

{

  if (len > s->p) len = s->p;

  s->p -= len;

  byte_copy(buf,len,s->x + s->n);

  s->n += len;

  return len;

}

int buffer_feed(buffer *s)

{

  int r;

  if (s->p) return s->p;

  r = oneread(s->op,s->fd,s->x,s->n);

  if (r <= 0) return r;

  s->p = r;

  s->n -= r;

  if (s->n > 0) byte_copyr(s->x + s->n,r,s->x);

  return r;

}

int buffer_bget(buffer *s,char *buf,unsigned int len)

{

  int r;

  if (s->p > 0) return getthis(s,buf,len);

  if (s->n <= len) return oneread(s->op,s->fd,buf,s->n);

  r = buffer_feed(s); if (r <= 0) return r;

  return getthis(s,buf,len);

}

int buffer_get(buffer *s,char *buf,unsigned int len)

{

  int r;

  if (s->p > 0) return getthis(s,buf,len);

  if (s->n <= len) return oneread(s->op,s->fd,buf,len);

  r = buffer_feed(s); if (r <= 0) return r;

  return getthis(s,buf,len);

}

char *buffer_peek(buffer *s)

{

  return s->x + s->n;

}

void buffer_seek(buffer *s,unsigned int len)

{

  s->n += len;

  s->p -= len;

}