/*
Copyright © 2019 Keith Packard

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials provided
with the distribution.

3. Neither the name of the copyright holder nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <stdint.h>
#include <errno.h>
#include <sys/stat.h>

#ifdef TINY_STDIO
/* Buffered output routines for newlib-nano stdio */

static char write_buf[512];
static int write_len;

static int
ao_flush(FILE *ignore)
{
	if (write_len) {
		int off = 0;
		while (write_len) {
			int this = write(1, write_buf + off, write_len);
			if (this < 0) {
				write_len = 0;
				return -1;
			}
			off += this;
			write_len -= this;
		}
	}
	return 0;
}

static int
ao_putc(char c, FILE *ignore)
{
	write_buf[write_len++] = c;
	if (write_len < sizeof (write_buf))
		return 0;
	return ao_flush(ignore);
}

static char read_buf[512];
static int read_len;
static int read_off;

static int
ao_getc(FILE *ignore)
{
	if (read_off >= read_len) {
		(void) ao_flush(ignore);
		read_off = 0;
		read_len = read(0, read_buf, sizeof (read_buf));
		if (read_len <= 0) {
			read_len = 0;
			return -1;
		}
	}
	return (unsigned char) read_buf[read_off++];
}

__attribute__((destructor))
static void ao_exit(void)
{
	ao_flush(stdout);
}

static FILE __stdio = {
	.flags = __SRD|__SWR,
	.put = ao_putc,
	.get = ao_getc,
	.flush = ao_flush,
};

#ifdef __strong_reference
#define STDIO_ALIAS(x) __strong_reference(stdin, x);
#else
#define STDIO_ALIAS(x) FILE *const x = &__stdio;
#endif

FILE *const stdin = &__stdio;
STDIO_ALIAS(stdout);
STDIO_ALIAS(stderr);

#else
int fstat(int fd, struct stat *statb) { errno = ENOTTY; return -1; }
#endif