/* Minimalist POSIX I/O (unbuffered, dies on error)
 * J. Welsh, May 2019
 */

#include <errno.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include "io.h"

void write_all(int fd, char const *buf, size_t len) {
	while (len) {
		ssize_t n = write(fd,buf,len);
		if (n < 0) {
			if (errno == EINTR) continue;
			if (fd != 2) /* prevent loop */
				perr("write_all");
			_exit(errno);
		}
		buf += n;
		len -= n;
	}
}

size_t read_all(int fd, unsigned char *buf, size_t len) {
	size_t olen = len;
	while (len) {
		ssize_t n = read(fd,buf,len);
		if (n <= 0) {
			if (n) {
				if (errno == EINTR) continue;
				perr("read_all");
				_exit(errno);
			}
			break;
		}
		buf += n;
		len -= n;
	}
	return olen - len;
}

void write_str(int fd, char const *s) {
	write_all(fd,s,strlen(s));
}

void newline(int fd) {
	write_all(fd,"\n",1);
}

void write_line(int fd, char const *s) {
	write_str(fd,s);
	newline(fd);
}

void assert_fail(char const *expr) {
	write_str(2,"Assertion failed: ");
	write_line(2,expr);
	raise(SIGABRT);
	_exit(1);
}

void perr(char const *context) {
	write_str(2,context);
	write_str(2,": ");
	write_line(2,strerror(errno));
}

int chkp(char const *context, int ret) {
	if (ret == -1) {
		perr(context);
		_exit(errno);
	}
	return ret;
}