#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

int setvbuf(FILE * restrict fp, char * restrict buf, int mode, size_t size)
{
	if(fp->bufmode != _IONBF) {
		fflush(fp);
		if(fp->bufowned)
			free(fp->buf);
	}

	fp->buf = NULL;
	fp->bufowned = false;
	fp->bufmode = _IONBF;
	fp->bufsize = 0;

	if(mode == _IONBF)
		return 0;

	if(buf) {
		fp->buf = buf;
		fp->bufsize = size;
		fp->bufmode = mode;
	}
	else {
		fp->buf = malloc(size);
		if(!fp->buf)
			return -1;
		fp->bufsize = size;
		fp->bufowned = true;
		fp->bufmode = mode;
	}

	return 0;
}