libowfat/buffer/buffer_putflush.c

#ifndef __MINGW32__
#include <sys/types.h>
#include <sys/uio.h>
#include <errno.h>
#include <unistd.h>
#endif
#include "buffer.h"

#ifndef __unlikely
#ifdef __GNUC__
#define __unlikely(x) __builtin_expect((x),0)
#else
#define __unlikely(x) (x)
#endif
#endif

extern ssize_t buffer_stubborn(ssize_t (*op)(),int fd,const char* buf, size_t len,void* cookie);

int buffer_putflush(buffer* b,const char* x,size_t len) {
  /* Since we know we are going to flush anyway, let's see if we can
   * optimize a bit */
  if (!b->p)	/* if the buffer is empty, just call buffer_stubborn directly */
    return buffer_stubborn(b->op,b->fd,x,len,b);
#ifndef __MINGW32__
  if (b->op==write && len>sizeof(struct iovec)*2) {
    struct iovec v[2];
    ssize_t w;
    size_t cl=b->p+len;
    v[0].iov_base=b->x;
    v[0].iov_len=b->p;
    v[1].iov_base=(char*)x;
    v[1].iov_len=len;
    while ((w=writev(b->fd,v,2))<0) {
      if (errno == EINTR) continue;
      return -1;
    }
    if (__unlikely((size_t)w!=cl)) {
      /* partial write. ugh. */
      if ((size_t)w<v[0].iov_len) {
	if (buffer_stubborn(b->op,b->fd,v[0].iov_base+w,v[0].iov_len-w,b) ||
	    buffer_stubborn(b->op,b->fd,v[1].iov_base,v[0].iov_len,b)) return -1;
      } else {
	w-=v[0].iov_len;
	return buffer_stubborn(b->op,b->fd,v[1].iov_base+w,v[1].iov_len-w,b);
      }
    }
    b->p=0;
    return 0;
  }
#endif
  if (buffer_put(b,x,len)<0) return -1;
  if (buffer_flush(b)<0) return -1;
  return 0;
}